My Wren is supposed to arrive soon, and I have seen lots of minor notes on other threads both in Fat Bikes and Foes about the fork. I wanted to make this single thread so riders could post what their setup is in terms if pressure, dampening, etc.
Wren 150mm Tuning/Setup Guide
JCHKeys
21 - 40 of 505 Posts
Joined
·
4,057 Posts
and yes Dorothy, the Wren is oodles better than the Bluto. In fact, it's so good that I'd buy one
Im glad to see your opinion changed in one week.
Joined
·
358 Posts
As I read all these observations, adjustments, and what not, I couldn't help but think... "Why can't they just make a plug and play fork that would serve its purpose and my objectives in the first mile and the thousandt mile without me having to take a degree in engineering?"
I guess I will pass on this one and stick with the steel ICT fork.
I guess I will pass on this one and stick with the steel ICT fork.
Don't shoot, but I think those that are the pickiest about fork performance are those that tend to have the skill set to make modifications.
For those of us laymen that aren't as comfortable tearing a fork apart, I suspect we notice less and aren't as sensitive to the forks function.
But that's just my guess.
For those of us laymen that aren't as comfortable tearing a fork apart, I suspect we notice less and aren't as sensitive to the forks function.
But that's just my guess.
Joined
·
15,339 Posts
Has it been a week already?
Nope, two weeks, but who's counting
I still think the rebound is slow, but I have seen some improvement and varying the pressure in a "weird way" has been an interesting experiment.
The Bluto is just so bad, I mean who in their right mind would put a Reba level fork on a big hit bike? Anyway, the point is that the Bluto was such a poor choice for this aplicatiopn that it would n't take much to improve the situation.
The Wren checks off most of the boxes:
Stiff/Robust
Not too heavy
Long travel
Not too expensive
150mm TA
Responsive mfg
No stiction
The only question remaining is the slow rebound and quirky damper. I think the rebound is improving with use, I think playing with pressures has made a difference, and I'm confident that Wren will make this fork happen.
Buying a fork like the Wren is still a crap shoot no matter how you cut it. Wren is a small company and this is their only fork; they are not a suspension mfg. per se.
More to come as I get ride time on non snowy surface
Nope, two weeks, but who's counting
I still think the rebound is slow, but I have seen some improvement and varying the pressure in a "weird way" has been an interesting experiment.
The Bluto is just so bad, I mean who in their right mind would put a Reba level fork on a big hit bike? Anyway, the point is that the Bluto was such a poor choice for this aplicatiopn that it would n't take much to improve the situation.
The Wren checks off most of the boxes:
Stiff/Robust
Not too heavy
Long travel
Not too expensive
150mm TA
Responsive mfg
No stiction
The only question remaining is the slow rebound and quirky damper. I think the rebound is improving with use, I think playing with pressures has made a difference, and I'm confident that Wren will make this fork happen.
Buying a fork like the Wren is still a crap shoot no matter how you cut it. Wren is a small company and this is their only fork; they are not a suspension mfg. per se.
More to come as I get ride time on non snowy surface
Joined
·
15,339 Posts
Nah, I suck
I'd call myself an "every person" rider, I'm not great, I ride hard, I've been riding wheel contraption for a long time, I work on my own stuff, and I know a few things about how things work.
I don't want anyone making a choice because I misled them, so I tell what I think, sometimes I change my mind, but for the most part I say what I believe is true.
It would be wonderful if we had a "ready to go burly fork", but this is just a fringe area of biking that hasn't seen a lot of play, so we just gotta go with it.
It could be worse, we could be talking about telemark bindings...
Nah, don't go there
Joined
·
718 Posts
For me the Wren fork is the only option, since I am riding fat bike all year round With wide tires (4.8" is too wide for boost forks), there is no other. The Bluto was just making me angry :madman:
I think Wren have the ambitions to make these fork work regarding rebound and compression.
I mean it is a positive thing that it is exactly a small manufacturer behind these fork, it would have been a totally different story With one of the big manufacturers. They would give a damn about feedback from the customers.....
I think Wren have the ambitions to make these fork work regarding rebound and compression.
I mean it is a positive thing that it is exactly a small manufacturer behind these fork, it would have been a totally different story With one of the big manufacturers. They would give a damn about feedback from the customers.....
Joined
·
718 Posts
I have just got the user manual for the fork, and there is ONLY travel adjustment limiting options, not a travel length adjustment. The Clip is pushing the bumper that stops the travel lower, to limit the travel. That confirms what I meant before from the drawing of the fork and where the Clips sits. Here is from the user manual:
"Before your first ride you should check if you have enough tire to crown clearance. This
fork comes standard with either 110 mm or 150 mm of travel from the factory. If you are
using narrow rims and big tires, you must check if you have enough clearance between
your crown and tire before you ride with this fork. If you do not have enough clearance,
the air spring needs to be modified with a stopper(s) that will give you the proper
clearance. Stoppers are sold separately and can modify the travel in 10 mm increments.
!
150 mm of travel - pre-set at factory
For 140 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 130 mm of travel - leave the 20 mm clip in place and add the 10 mm UNDERNEATH. The
20 mm must be on top."
"Before your first ride you should check if you have enough tire to crown clearance. This
fork comes standard with either 110 mm or 150 mm of travel from the factory. If you are
using narrow rims and big tires, you must check if you have enough clearance between
your crown and tire before you ride with this fork. If you do not have enough clearance,
the air spring needs to be modified with a stopper(s) that will give you the proper
clearance. Stoppers are sold separately and can modify the travel in 10 mm increments.
!
150 mm of travel - pre-set at factory
For 140 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 130 mm of travel - leave the 20 mm clip in place and add the 10 mm UNDERNEATH. The
20 mm must be on top."
Joined
·
15,339 Posts
Yes, it doesn't make sense, I read the same info in an email I got from Wren.
I'll ask my buddy what he thinks; he's an ex Manitou fork team engineer.
How does the Dorado adjust by using air pressure? Could that be part of the equation?
I'll ask my buddy what he thinks; he's an ex Manitou fork team engineer.
How does the Dorado adjust by using air pressure? Could that be part of the equation?
Joined
·
1,177 Posts
I'm very interested in whether a travel adjustment alters the a-c height. 570mm is a non starter for me, it's just too much of a jump from the relatively low a-c of the bluto
Sent from my SAMSUNG-SM-N910A using Tapatalk
Sent from my SAMSUNG-SM-N910A using Tapatalk
Joined
·
15,339 Posts
Joined
·
15,339 Posts
Joined
·
15,339 Posts
Yes. On the Stanchion, I measured the travel and it stops with enough stanchion remaining to mount the guards.
Joined
·
15,339 Posts
Russ wrote back, he said he was mistaken, travel changes but length does not change fork length:
"Hi Ben!
Sorry it took so long to get back to you I've been traveling today. First, I must apologize that I gave you bad info last time. Out travel clips limit travel only, do not affect AC. Our clips clip onto the air spring rod outside of the air chamber. Not sure what I was thinking at the time. We offer the Wren fork in 505, 530 and 570 AC lengths to work with most frame geometries. Hope this helps. Sorry for the brain fade earlier!"
I wrote Russ back and asked him if there would be air shafts available for changing fork length, no response yet.
So I mounted up my Wren and did the first test right last night. There is definitely a loose feel, but side by side with my other fat bike with a Bluto, doing the simple test of holding the front wheel with my knees and turning the handlebars, there was a difference. The wren had a very loose feeling for about 3/4 inch turn of the handlebars, but then became solid and wouldn't move any more. The bluto felt like a wet noodle where I could put more force and keep twisting the handlebars.
So are the Wren doesn't have as much breaking twist as the Bluto, but this has only been street riding as my trails still have a foot of snow on them.
Has anyone gotten their fork back from any servicing by Wren or Hippie Tech? Were they able to fix this looseness?
Oh and when I dumped out the Wren box, two awesome clamps for the carbon guards dropped out, so much nicer than my hokie zip ties.
So are the Wren doesn't have as much breaking twist as the Bluto, but this has only been street riding as my trails still have a foot of snow on them.
Has anyone gotten their fork back from any servicing by Wren or Hippie Tech? Were they able to fix this looseness?
Oh and when I dumped out the Wren box, two awesome clamps for the carbon guards dropped out, so much nicer than my hokie zip ties.
Joined
·
1,177 Posts
This is a major bummer for me. I was hoping to run a 150mm @ 130mm with an a-c of 550 (+19mm from my 120mm bluto). I can only wait and hope they make a shorter air shaft to allow a more reasonable a-c height.
Sent from my SAMSUNG-SM-N910A using Tapatalk
Joined
·
15,339 Posts
Yes, you can have your cake and eat it too!
Russell got back to me "again" and he said that there is a way to change A-C when travel is reduced. He had re-writen the manual to include text that describes the process. I'll post the revised manual when I get to work on Tuesday, in the meantime I will post yhe added text:
Air Spring Travel and AC Length Modification and Assembly:
You can reduce travel and the AC Length of the fork by placing the travel clips INSIDE the air spring.
1. Follow steps 1 through 4 above to remove the stanchion with the air spring from the fork. Be sure ALL air is
released from the air spring.
2. Looking at the top of the air spring, you will see a silver cap with 2 holes. This is the stanchion assembly cap.
Using a pair of bent nose pliers in the holes, unscrew the cap completely.
3. Grip the top of the air spring firmly and pull it out of the stanchion. This may take some effort.
4. Locate the Small Steel Spring at the bottom of the air spring. The clips will be installed on TOP of that spring
and below the white plastic bumper above that spring. The clips snap onto the rod same as above.
5. If only one clip is used, it must be the 20 mm clip because it is designed to rest on the spring. Remember that
the wide-mouth side of the 20 mm clip must face up. The 10 mm clip should only be used with the 20 mm clip
and must be installed on TOP of the 20 mm clip.
6. Be sure the Large Steel Spring is well greased. All coils should be "filled" with grease. If riding in cold
weather, be sure to use a grease specified for use in the temperature you will be riding in.
7. Lightly grease the air piston seals and insert the air spring back into the stanchion. CAREFULLY thread the
stanchion assembly cap back into the stanchion making sure not to cross thread the cap. Tighten securely
with the bent nose pliers.
8. Now reverse steps 1 to 4 from the travel modification section and install the stanchion into the fork. Be sure to
check your air pressure.
Russell got back to me "again" and he said that there is a way to change A-C when travel is reduced. He had re-writen the manual to include text that describes the process. I'll post the revised manual when I get to work on Tuesday, in the meantime I will post yhe added text:
Air Spring Travel and AC Length Modification and Assembly:
You can reduce travel and the AC Length of the fork by placing the travel clips INSIDE the air spring.
1. Follow steps 1 through 4 above to remove the stanchion with the air spring from the fork. Be sure ALL air is
released from the air spring.
2. Looking at the top of the air spring, you will see a silver cap with 2 holes. This is the stanchion assembly cap.
Using a pair of bent nose pliers in the holes, unscrew the cap completely.
3. Grip the top of the air spring firmly and pull it out of the stanchion. This may take some effort.
4. Locate the Small Steel Spring at the bottom of the air spring. The clips will be installed on TOP of that spring
and below the white plastic bumper above that spring. The clips snap onto the rod same as above.
5. If only one clip is used, it must be the 20 mm clip because it is designed to rest on the spring. Remember that
the wide-mouth side of the 20 mm clip must face up. The 10 mm clip should only be used with the 20 mm clip
and must be installed on TOP of the 20 mm clip.
6. Be sure the Large Steel Spring is well greased. All coils should be "filled" with grease. If riding in cold
weather, be sure to use a grease specified for use in the temperature you will be riding in.
7. Lightly grease the air piston seals and insert the air spring back into the stanchion. CAREFULLY thread the
stanchion assembly cap back into the stanchion making sure not to cross thread the cap. Tighten securely
with the bent nose pliers.
8. Now reverse steps 1 to 4 from the travel modification section and install the stanchion into the fork. Be sure to
check your air pressure.
Joined
·
15,339 Posts
Here's the revised Wren manual, sorry for the low quality and lack of formatting
Page 1
Wren
Inverted
Suspension
Fork
with Keyed Stanchions

and TwinAir System
Owners Manual
________________________________________
Page 2
Congratulations!
You have just purchased a Wren Inverted Suspension Fork. The culmination of years of design, testing and riding.
Please read this entire owner's manual carefully before riding to learn about all the possibilities this fork
offers to you. Please make sure that you follow the safety and maintenance instructions strictly.
Quick explanation of the fork
Modular Fork:
This fork is assembled and designed from a modular point of view. This means all parts can be exchanged for
new parts when needed. These parts can be ordered from your local dealer or service center. However, we prefer
that the exchange of parts and any service to internal parts be done by one of the certified service centers that we
have appointed. If your country has no service center available, the fork may be returned to our factory for
service. If a fork is serviced by anyone other than a certified service center, the consumer warranty will void.
Please refer to page 5 for complete fork description.
Fork Features
Hydraulic Damping with Adjustable Compression and Rebound (right leg):
The hydraulic oil damper is a sealed unit and designed to be replaced by a certified service center. You can
modify the fork's ride feel by changing the presets as described later in this manual.
Air Spring (left leg):
The air damper is fully serviceable and all parts are replaceable. We strongly recommend that this be done by a
certified service center. However, if you have good wrenching skills, you can do this yourself (check the
performance tuning section before doing this).
Dropouts and Quick Release:
This fork is made for QR15 hubs only and has a specific QR which is supplied with the fork and works with all
QR15 front hubs that fit your fork. Wheel installation on an inverted fork can be a bit tricky compared to regular
forks and requires attention. Before you insert the wheel, make sure both legs are at the same level and the
dropouts are facing forward, this makes QR assembly easier.
Warranty
The original manufacturer warrants this fork for a period of two years from the date of purchase to be free from
defects in materials or workmanship for the first owner only. During this warranty period we will replace or repair
any defective component of the fork. Paint, anodizing or seal damage caused by normal use ("wear and tear") are
not covered by this warranty. We shall not be held liable for any damage caused by a crash, insufficient
maintenance or ignorance of the safety and maintenance instructions. We shall not be held liable for normal
maintenance, damage or failure due to abuse or misuse.
Important Safety and Maintenance Instructions
Warning:
It is extremely important that your Wren Inverted Fork be installed correctly by a dealer. Incorrectly installed forks
are dangerous and can result in loss of control of the bicycle and severe and/or fatal injuries. Follow the
instructions below to avoid this. If you do not follow these instructions, your warranty will be void.
Maintenance:
To maintain safety, long life and high performance of your Wren Inverted Fork, periodic maintenance is required. If
you frequently join competitions, ride in wet, muddy or other extreme conditions, a 50% reduction in
recommended maintenance intervals listed below is necessary.
1. After every ride clean and dry the exterior of your fork.
Page 2
________________________________________
Page 3
2. Minimum every 25 hours of riding you should check the smoothness of your fork. The stanchions need to run
smoothly up and down the seals. If they do not run smoothly, put 2-3 drops of a Teflon-based oil on the
stanchions and move them up and down through the compression stroke (this is easier when you release
some air pressure through the air valve).
3. Check if all dials and nuts are still tightened properly.
4. Check the stanchion tubes for scratches and also inspect the lower seals for any wear or tear. If one of the
above mentioned parts appears damaged, do not ride and send your fork to a certified service center.
5. After 100 hours of riding, your fork should be fully serviced by a certified service center. You may contact your
dealer or Wren directly in order to find a certified service center.
General instructions:
1. This Wren fork is designed for off-road use. It is not designed for excessive riding like extreme jumps, etc. To
use it on-road, you will have to follow your country's specific traffic regulations and laws and equip your bike
and your fork accordingly.
2. Do not ride your bike if you notice technical problems or material failures like bending, cracking or broken
parts. Immediately take your bike to a qualified dealer to prevent further damage. Failure to do this may result
in damage and severe and/or fatal injury.
3. Make sure the quick release lever is tightened and the hub axle is correctly fixed in the bore of the dropouts.
When the quick release is locked, the lever should point backwards in the horizontal position on the post
mount disc brake side of the fork.
4. Adjust the headset until there is no play or drag.
5. Install the brakes according to the manufacturers instructions and adjust brake pads properly. Use the fork
only with brakes that fit to the existing brake mounts and use up to a 160 mm rotor. For larger rotors up to a
maximum of 180 mm, use a proper post mount adapter for installation. Before riding the bicycle, ensure the
brakes are properly installed and working properly.
6. Do not add threads to the thread-less steerer tube.
7. Do not replace the steerer tube by yourself as it needs to be pressed in under very high pressure.
8. Do not disassemble the oil cartridge (right side leg) yourself. High pressure inside the cartridge may cause
injuries and disassembly may lead to damage. Only an authorized service center should disassemble the oil
cartridge. The air side of the fork may be disassembled in order to modify the fork's travel in 10 mm
increments. This is done by installing stoppers, sold separately. This may be needed to make sure that your
tire does not hit the crown while the fork is fully compressed when using bigger volume tires. This must be
checked properly before each first ride with a different tire width or height. Generally, the 135 mm hub fork can
fit up to a 4" tire and the 150 mm hub fork can fit up to a 5" tire. Every rim tire combination can fit differently so
you must check your travel and clearance. See page 7 for how to modify travel.
9. Disassembly, maintenance and replacement of the oil damper must be made by an authorized service center.
10. Avoid directing water pressure at the stanchions and/or seals.
11. Be cautious when mounting the bicycle to a carrier. Carriers that hold the bike in trays with the wheels on are
preferred. Follow the instructions of the carrier manufacturer. Avoid mounting the bike by fixing it at the
dropouts (front wheel removed). The dropouts could be damaged.
12. If your bike is transported by air, release the air pressure from the air spring side of the fork before packing.
Deflating the air spring before transport avoids pressure damage and will guarantee proper function after
transport.
13. After a crash, have your bike and your fork inspected by a qualified dealer as internal damage may occur.
14. Always use genuine Wren parts. Use of different parts voids the warranty and could cause structural failure of
the fork resulting in loss of control of the bike with possible damage and/or injuries.
Page 3
________________________________________
Page 4


Page 4
Air Spring Insert
Complete Fork Description
Axle Nut
Axle
QR Lever
Wren Inverted Suspension Fork
QR15 Quick Release Axle
Steerer Tube
Red Air Spring Cap
Blue Air Cap
Crown
Red Oil
Damper Cap
Oil Seals
Stanchion Tubes
Upper Legs
Red Rebound Dial
Right Dropout -
Rebound Side
Left Dropout -
Brake Side
Post Mount
Brake Mount
Blue
Compression/
Lockout Lever
Serial Number
Red Valve Cap - only
on TwinAir forks
Upper Assembly
Cap Nut
Air Valve
Travel Clip
(if installed)
Bumper
(various sizes)
Air Spring Rod
Stanchion
Assembly Cap
Air Piston
Travel Limiter with
Large Steel Spring
Small Steel Spring
________________________________________
Page 5
AIR Spring Travel and AC Length Modifications
Before your first ride you should check if you have enough tire to crown clearance. Depending on the
model, this fork comes standard with either 100 mm (505 mm AC), 110 mm (530 mm AC) or 150 mm (570
mm AC) of travel from the factory. If you are using narrow rims and big tires, you must check if you have
enough clearance between your crown and tire before you ride with this fork. If you do not have enough
clearance, the air spring needs to be modified with a clip(s) that will give you the proper clearance. Clips
are now supplied with every fork. If you have an older fork, you may contact us to purchase clips. The
clips reduce travel or travel and AC Length in 10 mm increments. As an example:
150 mm of travel - pre-set at factory
For 140 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 130 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE the 20 mm clip. The 10 mm
clip must always be on top.
110 mm of travel - pre-set at the factory
For 100 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 90 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE. The 10 mm clip must be on
top.
100 mm of travel - pre-set at the factory
For 90 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 80 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE. The 10 mm clip must be on
top.
Checking for Crown to Tire Clearance:
1. Install the front wheel on the fork being sure tire is properly inflated.
2. Release air from the air spring to make fork easier to compress.
3. Push down on the handlebars until the fork bottoms out and check for the amount of clearance between crown
and tire. A minimum of 5 mm is recommended.
Air Spring Travel Modification and Assembly:
1. Place your bike in a work stand and remove the front wheel.
2. Remove the blue air cap from the left leg and release all the air from the system. If your fork is a TwinAir, be
sure to empty both top and bottom air chambers.
3. Loosen and carefully remove the air spring assembly cap (large silver nut below the blue air cap) with a 26
mm socket. DO NOT remove the red air spring assembly cap.
4. Unscrew the seals from the stanchions by hand. Now the air spring can be pulled out including the air side
stanchion from the bottom of the fork.
Warning: At this stage please absolutely make sure again that all the air has been released from the air
spring unit to avoid severe and/or fatal injuries.
5. Select the correct stopper(s) as discussed above.
6. Insert the proper stopper size into the air spring at the top directly below the upper assembly cap and onto the
flattened sides of the rod. For a 10 mm stopper, snap onto the rod and slide up over the flattened surfaces of
the upper assembly cap. For the 20 mm stopper, be sure the wide-mouth end is at the top, facing up. This end
is chamfered to fit over the flattened surfaces. Lineup with the flattened surfaces and snap onto the rod. If
using both stoppers, be sure the 10 mm is on top.
7. Reverse steps 1 to 4 for reassembly. Be sure to torque the air spring assembly cap to 10Nm. Be sure the fork
seals are hand tight. Be sure to check your air pressure and sag.
Page 5
________________________________________
Page 6
Air Spring Travel and AC Length Modification and Assembly:
You can reduce travel and the AC Length of the fork by placing the travel clips INSIDE the air spring.
1. Follow steps 1 through 4 above to remove the stanchion with the air spring from the fork. Be sure ALL air is
released from the air spring.
2. Looking at the top of the air spring, you will see a silver cap with 2 holes. This is the stanchion assembly cap.
Using a pair of bent nose pliers in the holes, unscrew the cap completely.
3. Grip the top of the air spring firmly and pull it out of the stanchion. This may take some effort.
4. Locate the Small Steel Spring at the bottom of the air spring. The clips will be installed on TOP of that spring
and below the white plastic bumper above that spring. The clips snap onto the rod same as above.
5. If only one clip is used, it must be the 20 mm clip because it is designed to rest on the spring. Remember that
the wide-mouth side of the 20 mm clip must face up. The 10 mm clip should only be used with the 20 mm clip
and must be installed on TOP of the 20 mm clip.
6. Be sure the Large Steel Spring is well greased. All coils should be "filled" with grease. If riding in cold
weather, be sure to use a grease specified for use in the temperature you will be riding in.
7. Lightly grease the air piston seals and insert the air spring back into the stanchion. CAREFULLY thread the
stanchion assembly cap back into the stanchion making sure not to cross thread the cap. Tighten securely
with the bent nose pliers.
8. Now reverse steps 1 to 4 from the travel modification section and install the stanchion into the fork. Be sure to
check your air pressure and sag.
Fork Setup/Performance Tuning
Please follow these instructions if you want to modify the ride or feel of this fork. For additional information, please
ask your dealer or contact Wren directly.
After installing the fork on your bike correctly, you must determine the correct fork setup for your weight and riding
style. First step is to inflate the fork because the fork is shipped with less air than you need to ride (air freight
requires forks at very low or no air pressure). Remember, the following is a guide. The final settings are
determined by paying attention to the feel of the fork and adjusting over your first few rides.
Air Spring - TwinAir
If your fork is equipped with an air valve on the bottom of the Air side (left) leg, you have a TwinAir fork. This fork
has air valves top and bottom under protective caps. Begin by filling both chambers with 30psi as a STARTING
point to set your sag (see below). Adjusting the pressure up or down in the top or bottom chamber affects slow
speed compression. This can help smooth out the small stuff. Once sag is set, increasing air in the top chamber
will give the fork a plusher feel, increasing air in the bottom chamber gives the fork a stiffer feel. The only way you
will know for sure how it affects your ride is to play with it on your first few rides. Maximum air pressure is
120psi.
Air Spring - Single Air
If you have a single air valve on top of the left leg, you have a single air fork. Remove the blue air valve cap and
use a suspension pump to pump up the fork to 30 psi as a starting point. Push down on the fork a few times to
determine if it feels about right for you. Adjust pressure if necessary. Maximum air pressure is 120psi. Now
check for the proper sag.
Fork Sag Setup:
Sag is the amount of travel that is used when a rider sits on the bike and the suspension compresses under the
rider's weight. Sag, also known as negative travel, is needed to achieve a well-functioning fork. Sag on this fork
should be around 20% of the fork's travel. This can be easily measured by first locating the rubber o-rings on the
stanchion tubes. Be sure no one is on the bike and the fork is uncompressed. Slide the o-rings up against the
seals. Now carefully sit on the bike in your riding position with all your gear and let your weight slowly compress
the fork. Do not bounce the fork. Carefully dismount being sure not to compress the fork. Now measure the
distance between the o-rings and the seals. If the distance for the 110mm travel fork is around 22mm, your
starting sag setup is good. If the distance is less than 22 mm, reduce the air pressure in the air spring. If the
distance is more than 22 mm, increase the air pressure in the air spring. Remember, for a TwinAir fork add or
decrease pressure equally when setting your sag. This is now your starting point. Adjustments from here need to
be done as you ride and feel out your new fork.
Page 6
________________________________________
Page 7
Rebound Knob:
The rebound speed of the hydraulic damper can be fine-tuned by turning the external red knob at the bottom of
the right leg. Turn the knob clockwise for slower rebound. Slower rebound means that the outward movement of
the fork after compression is slower (the damping is higher). Turn the knob counter-clockwise for faster rebound.
Faster rebound brings the fork back to its original position faster. For bumpy rides, we recommend a fast setting to
avoid over-damping. To start, try setting the Rebound knob to the middle setting.
Do not turn the rebound knob past its limits. Squishy sounds in the sealed rebound stages are normal, it's just the
oil flowing back into the compression stage of the cartridge. This means your fork works! If you choose a faster
rebound setting, the squishy noise will lessen and the fork will bounce back to its extended position faster, but the
damping will become less.
Lockout / Compression Adjustment Lever:
In addition to the rebound adjustment, the fork can be completely locked out from compression by the lockout
system. Just turn the blue lockout lever clockwise until its limit to lock out the fork (do not move past this limit). We
recommend this when climbing uphill or when no front suspension is needed. A very slight inward movement of
the fork may appear even when the lockout is activated. This is required to avoid damage to the cartridge and the
fork. To unlock the lockout function, turn the lockout lever counter-clockwise (do not move past the fully open
limit).
In between the two limits (fully open / locked) is the compression adjustment range.
The compression becomes firmer when the lever is turned clockwise toward the lockout and softer when turned
counter-clockwise toward the fully open position.
First Ride
It is advised to ride the fork on a flat surface at first in order to make any adjustments necessary to achieve the
ride you want. A new fork will have slight seal friction. Seals and stanchions need to break in and after a few hours
of riding the fork will move up and down smoother. If this changes the feeling you want, simply readjust your
settings. On your first off-road ride, it is advised to bring a suspension pump in order to be able to make additional
adjustments if needed.
Thank you for purchasing the Wren Inverted Suspension Fork. To see other fine Wren products, please visit
www.wrensports.com. Should you ever have any questions, comments or just need more information, please
contact us at:
WREN SPORTS, LLC
106 Camino Del Sol, Vallejo, CA 94591
707-652-2737
www.wrensports.com

Page 7
________________________________________
![]()
=> If anyone wants the PDF, send me a PM with your email and I'll reply with the attachment.
Page 1
Wren
Inverted
Suspension
Fork
with Keyed Stanchions

and TwinAir System
Owners Manual
________________________________________
Page 2
Congratulations!
You have just purchased a Wren Inverted Suspension Fork. The culmination of years of design, testing and riding.
Please read this entire owner's manual carefully before riding to learn about all the possibilities this fork
offers to you. Please make sure that you follow the safety and maintenance instructions strictly.
Quick explanation of the fork
Modular Fork:
This fork is assembled and designed from a modular point of view. This means all parts can be exchanged for
new parts when needed. These parts can be ordered from your local dealer or service center. However, we prefer
that the exchange of parts and any service to internal parts be done by one of the certified service centers that we
have appointed. If your country has no service center available, the fork may be returned to our factory for
service. If a fork is serviced by anyone other than a certified service center, the consumer warranty will void.
Please refer to page 5 for complete fork description.
Fork Features
Hydraulic Damping with Adjustable Compression and Rebound (right leg):
The hydraulic oil damper is a sealed unit and designed to be replaced by a certified service center. You can
modify the fork's ride feel by changing the presets as described later in this manual.
Air Spring (left leg):
The air damper is fully serviceable and all parts are replaceable. We strongly recommend that this be done by a
certified service center. However, if you have good wrenching skills, you can do this yourself (check the
performance tuning section before doing this).
Dropouts and Quick Release:
This fork is made for QR15 hubs only and has a specific QR which is supplied with the fork and works with all
QR15 front hubs that fit your fork. Wheel installation on an inverted fork can be a bit tricky compared to regular
forks and requires attention. Before you insert the wheel, make sure both legs are at the same level and the
dropouts are facing forward, this makes QR assembly easier.
Warranty
The original manufacturer warrants this fork for a period of two years from the date of purchase to be free from
defects in materials or workmanship for the first owner only. During this warranty period we will replace or repair
any defective component of the fork. Paint, anodizing or seal damage caused by normal use ("wear and tear") are
not covered by this warranty. We shall not be held liable for any damage caused by a crash, insufficient
maintenance or ignorance of the safety and maintenance instructions. We shall not be held liable for normal
maintenance, damage or failure due to abuse or misuse.
Important Safety and Maintenance Instructions
Warning:
It is extremely important that your Wren Inverted Fork be installed correctly by a dealer. Incorrectly installed forks
are dangerous and can result in loss of control of the bicycle and severe and/or fatal injuries. Follow the
instructions below to avoid this. If you do not follow these instructions, your warranty will be void.
Maintenance:
To maintain safety, long life and high performance of your Wren Inverted Fork, periodic maintenance is required. If
you frequently join competitions, ride in wet, muddy or other extreme conditions, a 50% reduction in
recommended maintenance intervals listed below is necessary.
1. After every ride clean and dry the exterior of your fork.
Page 2
________________________________________
Page 3
2. Minimum every 25 hours of riding you should check the smoothness of your fork. The stanchions need to run
smoothly up and down the seals. If they do not run smoothly, put 2-3 drops of a Teflon-based oil on the
stanchions and move them up and down through the compression stroke (this is easier when you release
some air pressure through the air valve).
3. Check if all dials and nuts are still tightened properly.
4. Check the stanchion tubes for scratches and also inspect the lower seals for any wear or tear. If one of the
above mentioned parts appears damaged, do not ride and send your fork to a certified service center.
5. After 100 hours of riding, your fork should be fully serviced by a certified service center. You may contact your
dealer or Wren directly in order to find a certified service center.
General instructions:
1. This Wren fork is designed for off-road use. It is not designed for excessive riding like extreme jumps, etc. To
use it on-road, you will have to follow your country's specific traffic regulations and laws and equip your bike
and your fork accordingly.
2. Do not ride your bike if you notice technical problems or material failures like bending, cracking or broken
parts. Immediately take your bike to a qualified dealer to prevent further damage. Failure to do this may result
in damage and severe and/or fatal injury.
3. Make sure the quick release lever is tightened and the hub axle is correctly fixed in the bore of the dropouts.
When the quick release is locked, the lever should point backwards in the horizontal position on the post
mount disc brake side of the fork.
4. Adjust the headset until there is no play or drag.
5. Install the brakes according to the manufacturers instructions and adjust brake pads properly. Use the fork
only with brakes that fit to the existing brake mounts and use up to a 160 mm rotor. For larger rotors up to a
maximum of 180 mm, use a proper post mount adapter for installation. Before riding the bicycle, ensure the
brakes are properly installed and working properly.
6. Do not add threads to the thread-less steerer tube.
7. Do not replace the steerer tube by yourself as it needs to be pressed in under very high pressure.
8. Do not disassemble the oil cartridge (right side leg) yourself. High pressure inside the cartridge may cause
injuries and disassembly may lead to damage. Only an authorized service center should disassemble the oil
cartridge. The air side of the fork may be disassembled in order to modify the fork's travel in 10 mm
increments. This is done by installing stoppers, sold separately. This may be needed to make sure that your
tire does not hit the crown while the fork is fully compressed when using bigger volume tires. This must be
checked properly before each first ride with a different tire width or height. Generally, the 135 mm hub fork can
fit up to a 4" tire and the 150 mm hub fork can fit up to a 5" tire. Every rim tire combination can fit differently so
you must check your travel and clearance. See page 7 for how to modify travel.
9. Disassembly, maintenance and replacement of the oil damper must be made by an authorized service center.
10. Avoid directing water pressure at the stanchions and/or seals.
11. Be cautious when mounting the bicycle to a carrier. Carriers that hold the bike in trays with the wheels on are
preferred. Follow the instructions of the carrier manufacturer. Avoid mounting the bike by fixing it at the
dropouts (front wheel removed). The dropouts could be damaged.
12. If your bike is transported by air, release the air pressure from the air spring side of the fork before packing.
Deflating the air spring before transport avoids pressure damage and will guarantee proper function after
transport.
13. After a crash, have your bike and your fork inspected by a qualified dealer as internal damage may occur.
14. Always use genuine Wren parts. Use of different parts voids the warranty and could cause structural failure of
the fork resulting in loss of control of the bike with possible damage and/or injuries.
Page 3
________________________________________
Page 4


Page 4
Air Spring Insert
Complete Fork Description
Axle Nut
Axle
QR Lever
Wren Inverted Suspension Fork
QR15 Quick Release Axle
Steerer Tube
Red Air Spring Cap
Blue Air Cap
Crown
Red Oil
Damper Cap
Oil Seals
Stanchion Tubes
Upper Legs
Red Rebound Dial
Right Dropout -
Rebound Side
Left Dropout -
Brake Side
Post Mount
Brake Mount
Blue
Compression/
Lockout Lever
Serial Number
Red Valve Cap - only
on TwinAir forks
Upper Assembly
Cap Nut
Air Valve
Travel Clip
(if installed)
Bumper
(various sizes)
Air Spring Rod
Stanchion
Assembly Cap
Air Piston
Travel Limiter with
Large Steel Spring
Small Steel Spring
________________________________________
Page 5
AIR Spring Travel and AC Length Modifications
Before your first ride you should check if you have enough tire to crown clearance. Depending on the
model, this fork comes standard with either 100 mm (505 mm AC), 110 mm (530 mm AC) or 150 mm (570
mm AC) of travel from the factory. If you are using narrow rims and big tires, you must check if you have
enough clearance between your crown and tire before you ride with this fork. If you do not have enough
clearance, the air spring needs to be modified with a clip(s) that will give you the proper clearance. Clips
are now supplied with every fork. If you have an older fork, you may contact us to purchase clips. The
clips reduce travel or travel and AC Length in 10 mm increments. As an example:
150 mm of travel - pre-set at factory
For 140 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 130 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE the 20 mm clip. The 10 mm
clip must always be on top.
110 mm of travel - pre-set at the factory
For 100 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 90 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE. The 10 mm clip must be on
top.
100 mm of travel - pre-set at the factory
For 90 mm of travel - remove the pre-installed 10 mm clip and insert 1 - 20 mm clip.
For 80 mm of travel - leave the 20 mm clip in place and add the 10 mm clip ABOVE. The 10 mm clip must be on
top.
Checking for Crown to Tire Clearance:
1. Install the front wheel on the fork being sure tire is properly inflated.
2. Release air from the air spring to make fork easier to compress.
3. Push down on the handlebars until the fork bottoms out and check for the amount of clearance between crown
and tire. A minimum of 5 mm is recommended.
Air Spring Travel Modification and Assembly:
1. Place your bike in a work stand and remove the front wheel.
2. Remove the blue air cap from the left leg and release all the air from the system. If your fork is a TwinAir, be
sure to empty both top and bottom air chambers.
3. Loosen and carefully remove the air spring assembly cap (large silver nut below the blue air cap) with a 26
mm socket. DO NOT remove the red air spring assembly cap.
4. Unscrew the seals from the stanchions by hand. Now the air spring can be pulled out including the air side
stanchion from the bottom of the fork.
Warning: At this stage please absolutely make sure again that all the air has been released from the air
spring unit to avoid severe and/or fatal injuries.
5. Select the correct stopper(s) as discussed above.
6. Insert the proper stopper size into the air spring at the top directly below the upper assembly cap and onto the
flattened sides of the rod. For a 10 mm stopper, snap onto the rod and slide up over the flattened surfaces of
the upper assembly cap. For the 20 mm stopper, be sure the wide-mouth end is at the top, facing up. This end
is chamfered to fit over the flattened surfaces. Lineup with the flattened surfaces and snap onto the rod. If
using both stoppers, be sure the 10 mm is on top.
7. Reverse steps 1 to 4 for reassembly. Be sure to torque the air spring assembly cap to 10Nm. Be sure the fork
seals are hand tight. Be sure to check your air pressure and sag.
Page 5
________________________________________
Page 6
Air Spring Travel and AC Length Modification and Assembly:
You can reduce travel and the AC Length of the fork by placing the travel clips INSIDE the air spring.
1. Follow steps 1 through 4 above to remove the stanchion with the air spring from the fork. Be sure ALL air is
released from the air spring.
2. Looking at the top of the air spring, you will see a silver cap with 2 holes. This is the stanchion assembly cap.
Using a pair of bent nose pliers in the holes, unscrew the cap completely.
3. Grip the top of the air spring firmly and pull it out of the stanchion. This may take some effort.
4. Locate the Small Steel Spring at the bottom of the air spring. The clips will be installed on TOP of that spring
and below the white plastic bumper above that spring. The clips snap onto the rod same as above.
5. If only one clip is used, it must be the 20 mm clip because it is designed to rest on the spring. Remember that
the wide-mouth side of the 20 mm clip must face up. The 10 mm clip should only be used with the 20 mm clip
and must be installed on TOP of the 20 mm clip.
6. Be sure the Large Steel Spring is well greased. All coils should be "filled" with grease. If riding in cold
weather, be sure to use a grease specified for use in the temperature you will be riding in.
7. Lightly grease the air piston seals and insert the air spring back into the stanchion. CAREFULLY thread the
stanchion assembly cap back into the stanchion making sure not to cross thread the cap. Tighten securely
with the bent nose pliers.
8. Now reverse steps 1 to 4 from the travel modification section and install the stanchion into the fork. Be sure to
check your air pressure and sag.
Fork Setup/Performance Tuning
Please follow these instructions if you want to modify the ride or feel of this fork. For additional information, please
ask your dealer or contact Wren directly.
After installing the fork on your bike correctly, you must determine the correct fork setup for your weight and riding
style. First step is to inflate the fork because the fork is shipped with less air than you need to ride (air freight
requires forks at very low or no air pressure). Remember, the following is a guide. The final settings are
determined by paying attention to the feel of the fork and adjusting over your first few rides.
Air Spring - TwinAir
If your fork is equipped with an air valve on the bottom of the Air side (left) leg, you have a TwinAir fork. This fork
has air valves top and bottom under protective caps. Begin by filling both chambers with 30psi as a STARTING
point to set your sag (see below). Adjusting the pressure up or down in the top or bottom chamber affects slow
speed compression. This can help smooth out the small stuff. Once sag is set, increasing air in the top chamber
will give the fork a plusher feel, increasing air in the bottom chamber gives the fork a stiffer feel. The only way you
will know for sure how it affects your ride is to play with it on your first few rides. Maximum air pressure is
120psi.
Air Spring - Single Air
If you have a single air valve on top of the left leg, you have a single air fork. Remove the blue air valve cap and
use a suspension pump to pump up the fork to 30 psi as a starting point. Push down on the fork a few times to
determine if it feels about right for you. Adjust pressure if necessary. Maximum air pressure is 120psi. Now
check for the proper sag.
Fork Sag Setup:
Sag is the amount of travel that is used when a rider sits on the bike and the suspension compresses under the
rider's weight. Sag, also known as negative travel, is needed to achieve a well-functioning fork. Sag on this fork
should be around 20% of the fork's travel. This can be easily measured by first locating the rubber o-rings on the
stanchion tubes. Be sure no one is on the bike and the fork is uncompressed. Slide the o-rings up against the
seals. Now carefully sit on the bike in your riding position with all your gear and let your weight slowly compress
the fork. Do not bounce the fork. Carefully dismount being sure not to compress the fork. Now measure the
distance between the o-rings and the seals. If the distance for the 110mm travel fork is around 22mm, your
starting sag setup is good. If the distance is less than 22 mm, reduce the air pressure in the air spring. If the
distance is more than 22 mm, increase the air pressure in the air spring. Remember, for a TwinAir fork add or
decrease pressure equally when setting your sag. This is now your starting point. Adjustments from here need to
be done as you ride and feel out your new fork.
Page 6
________________________________________
Page 7
Rebound Knob:
The rebound speed of the hydraulic damper can be fine-tuned by turning the external red knob at the bottom of
the right leg. Turn the knob clockwise for slower rebound. Slower rebound means that the outward movement of
the fork after compression is slower (the damping is higher). Turn the knob counter-clockwise for faster rebound.
Faster rebound brings the fork back to its original position faster. For bumpy rides, we recommend a fast setting to
avoid over-damping. To start, try setting the Rebound knob to the middle setting.
Do not turn the rebound knob past its limits. Squishy sounds in the sealed rebound stages are normal, it's just the
oil flowing back into the compression stage of the cartridge. This means your fork works! If you choose a faster
rebound setting, the squishy noise will lessen and the fork will bounce back to its extended position faster, but the
damping will become less.
Lockout / Compression Adjustment Lever:
In addition to the rebound adjustment, the fork can be completely locked out from compression by the lockout
system. Just turn the blue lockout lever clockwise until its limit to lock out the fork (do not move past this limit). We
recommend this when climbing uphill or when no front suspension is needed. A very slight inward movement of
the fork may appear even when the lockout is activated. This is required to avoid damage to the cartridge and the
fork. To unlock the lockout function, turn the lockout lever counter-clockwise (do not move past the fully open
limit).
In between the two limits (fully open / locked) is the compression adjustment range.
The compression becomes firmer when the lever is turned clockwise toward the lockout and softer when turned
counter-clockwise toward the fully open position.
First Ride
It is advised to ride the fork on a flat surface at first in order to make any adjustments necessary to achieve the
ride you want. A new fork will have slight seal friction. Seals and stanchions need to break in and after a few hours
of riding the fork will move up and down smoother. If this changes the feeling you want, simply readjust your
settings. On your first off-road ride, it is advised to bring a suspension pump in order to be able to make additional
adjustments if needed.
Thank you for purchasing the Wren Inverted Suspension Fork. To see other fine Wren products, please visit
www.wrensports.com. Should you ever have any questions, comments or just need more information, please
contact us at:
WREN SPORTS, LLC
106 Camino Del Sol, Vallejo, CA 94591
707-652-2737
www.wrensports.com

Page 7
________________________________________
=> If anyone wants the PDF, send me a PM with your email and I'll reply with the attachment.
Joined
·
718 Posts
That is awesome! Then this fork is a Clear Winner of Fat Bike forks. Will try to lower Down to 140mm AC, to see if that fits the Foes Mutz better. Now it is a bit hig in the front, when climbing. There is so easy to open and take out air damper that you will only use 15 minutes to put in the Clips. I will also get a New compression damper, though the original Works, but it is a bit tricky to adjust sinci it is really progressive the last 4mm of the adjustment knob. Starting to love the feel of these fork now, and I am getting hold of the air pressure adjustment also. Running 55psi in both Chambers. Before I used a 150mm travel Pike on my skinny FS, I would say the Wren fork is more rigid and stiff then the pike.
21 - 40 of 505 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
