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Discussion Starter · #1 ·
I just got a new bike (Radon Slide Trail 8.0), it came with a Pike Select + fork. The bike is sweet, but the fork feels a bit strange. When I ride slightly rougher stuff, it's great. But when it comes to small bumps, it doesn't really want to move.
For example if i'm riding on a double track dirt road that's not that rough, but uneven with tractor tracks, a few small rocks, few small holes, I can feel the rear of the bike working, but the fork just sits there and does nothing, and I can feel my hand getting more and more beat up.
When I move the fork up and down by just pushing on the bars, I can hear a sort of "sshh" (not air hissing) sound as it goes down, and I can feel friction. Is all of this supposed to be normal? The last time I rode a bike with suspension, it had 26" wheels and v-brakes. Obviously this fork is light years ahead of that kind of stuff, but i'm still not satisfied.
I'm around 65kg, tried to play around with air pressure and tokens, but I didn't notice a huge difference in small bump sensitivity. Even with 30% sag, the fork is not as sensitive as i would like.
I did a lower leg service in case the fork was dry from the factory, but it looked fine inside and the service didn't really make a difference.
The fork has about 8-9 hours of (not very hard) riding on it. Do forks really need to break in, or is that a myth?

Oh and the compression dial (Charger 2.1) doesn't seem to make any difference at all. Is that normal? :D
 

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Discussion Starter · #3 · (Edited)

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I have a 2021 Pike Ultimate at 130mm. I have the same issue with mine. In JRA situations like you describe I find it to feel quite harsh and severely lacking in small bump compliance however when the trail turns down and it starts to get chunkier and chunkier it starts to feel better and better. Maybe I'm cutting it too much slack but I tell myself the Pike isn't really designed for JRA it is a trail bike fork. I sometimes wonder if a SID would have been a better choice for me. My Fox 34 had much better small bump compliance in the JRA situations but wasn't nearly as good when things got rough so I find it to be a trade off.

I will say it doesn't sound normal to me that your compression dial doesn't make any noticeable difference.
 

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I just got bought a 140 pike for my hardtail and feel the same thing. Same bump compliance is lacking , but it takes the big hits better than a fox 34 IMO. I think it may just be a stiffer overall fork.

I might try slowing down the rebound and see if that helps any.

I added one extra volume spacer and dropped the pressure about 15 psi below the recommended setting for my might (155 lbs). Sag still isn't even 20%.

My compression dial feels like it doesn't do anything as well, but I keep it wide open so not a big deal.
 

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Discussion Starter · #6 ·
I have a 2021 Pike Ultimate at 130mm. I have the same issue with mine. In JRA situations like you describe I find it to feel quite harsh and severely lacking in small bump compliance however when the trail turns down and it starts to get chunkier and chunkier it starts to feel better and better. Maybe I'm cutting it too much slack but I tell myself the Pike isn't really designed for JRA it is a trail bike fork. I sometimes wonder if a SID would have been a better choice for me. My Fox 34 had much better small bump compliance in the JRA situations but wasn't nearly as good when things got rough so I find it to be a trade off.

I will say it doesn't sound normal to me that your compression dial doesn't make any noticeable difference.
Thanks for the response. So far this is my most expensive fork (and bike) so I kinda expected it to handle a bit of everything, and I didn't think just riding along would be a big deal... :D
I'll ride my bike as is for now, but over the winter i'm gonna try the bushing thing that JB450 suggested above.

I just got bought a 140 pike for my hardtail and feel the same thing. Same bump compliance is lacking , but it takes the big hits better than a fox 34 IMO. I think it may just be a stiffer overall fork.

I might try slowing down the rebound and see if that helps any.

I added one extra volume spacer and dropped the pressure about 15 psi below the recommended setting for my might (155 lbs). Sag still isn't even 20%.

My compression dial feels like it doesn't do anything as well, but I keep it wide open so not a big deal.
Thanks! I wonder what's the deal with the compression adjuster. It's supposed to be low speed compression, so that's stuff like brake dive, pedal bob, right? What about stuff like landing a jump, does low speed compression deal with that as well?
 

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The compression dial on the charger damper found on the select + only changes the feel very slightly, so that part is working as it should.

The small bump compliance could be the bushings. I would also do an airspring service to make sure it was not over or under lubricated out of the factory.
 

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Could you please explain why?
The spring rate in an air fork (and shock) is not linear and as you get further into the travel it increases. For example, if you have a coil, that takes say 100 pounds to compress it the first inch, it takes 200 to compress it two inches (it is a linear 100 pound/inch spring). An air fork by contrast may take 100 pounds to compress the first inch and 250 pounds the second inch (so the spring rate would be 100 pounds an inch for the first inch, 150 an inch for the second). As you decrease sag in an air fork, you are getting further and further into the increased spring rate where any given force will result in less fork movement. As a result, while lowering the pressure and increasing the sag lower the overall spring rate, it increases the rate at sag, leading to a hasher feel.

The other side of this is rebound dampening. Too much will cause the fork to get stuck down on repeated hits feeling harsh as it is held in the steep part of the spring curve. I recommend trying less rebound dampening to see if improves the feel. Personally, I back out rebound on a fork until I start to lose traction and then add a click or two back in.

Finally, depending on how small the bumps are, there is a limit to how low the breakaway force can be. Even my plushest air forks still feed back on washboard fire roads. A coil is better in this regard, as you don't have the seals for the air spring, so lower breakaway force, but there is a tradeoff, weight and you don't get the ramp up at the end of travel that an air spring has (which can be dealt with by damper tuning as well as in some forks a hydraulic bottom out control or low pressure air spring). Like everything, there are tradeoffs, the design and tuning that gets you a fork that works well under a Cat 1 racer, feels very harsh and will not use travel for a casual rider.
 

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Discussion Starter · #12 · (Edited)
The spring rate in an air fork (and shock) is not linear and as you get further into the travel it increases. For example, if you have a coil, that takes say 100 pounds to compress it the first inch, it takes 200 to compress it two inches (it is a linear 100 pound/inch spring). An air fork by contrast may take 100 pounds to compress the first inch and 250 pounds the second inch (so the spring rate would be 100 pounds an inch for the first inch, 150 an inch for the second). As you decrease sag in an air fork, you are getting further and further into the increased spring rate where any given force will result in less fork movement. As a result, while lowering the pressure and increasing the sag lower the overall spring rate, it increases the rate at sag, leading to a hasher feel.

The other side of this is rebound dampening. Too much will cause the fork to get stuck down on repeated hits feeling harsh as it is held in the steep part of the spring curve. I recommend trying less rebound dampening to see if improves the feel. Personally, I back out rebound on a fork until I start to lose traction and then add a click or two back in.

Finally, depending on how small the bumps are, there is a limit to how low the breakaway force can be. Even my plushest air forks still feed back on washboard fire roads. A coil is better in this regard, as you don't have the seals for the air spring, so lower breakaway force, but there is a tradeoff, weight and you don't get the ramp up at the end of travel that an air spring has (which can be dealt with by damper tuning as well as in some forks a hydraulic bottom out control or low pressure air spring). Like everything, there are tradeoffs, the design and tuning that gets you a fork that works well under a Cat 1 racer, feels very harsh and will not use travel for a casual rider.
Thank you for the explanation. I'll try a bit less sag and i'll also play with the rebound.

What about tokens, do they have anything to do with small bump sensitivity, or just the ramp up at the end of the travel?
 

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Volume spacers affect the end stroke ramp up mainly. As for what you are feeling with the small bump compliance, I had similar experience on a 130mm Pike Ultimate. Opening up the bushings helped sort the issue. My new 150mm Pike has no such issues, but I ran my bushing tool through it anyway and gained a bit more compliance
 

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i've been riding a 21 ultimate since april and was blown away on the way it smooths everything out. the not air sound squish you hear is oil passing through different parts of the damper and is completely normal. i'm assuming you used rockshox guidelines to set up? for the people with stiction, what is your weight? i'm a solid 200# geared and ride front heavy a lot. this is a huge factor imo, along with it's a trail fork

although it's more money, there is the coil conversion.
 

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Discussion Starter · #15 · (Edited)
i've been riding a 21 ultimate since april and was blown away on the way it smooths everything out. the not air sound squish you hear is oil passing through different parts of the damper and is completely normal. i'm assuming you used rockshox guidelines to set up? for the people with stiction, what is your weight? i'm a solid 200# geared and ride front heavy a lot. this is a huge factor imo, along with it's a trail fork

although it's more money, there is the coil conversion.
It's not the "oil sound" that I hear, I only hear that on rebound. It sounds like friction. I know that probably sounds dumb, but that's the best way I can explain it.
I checked out the trailhead app when I first set up the fork, but I played around with the pressure and rebound since then.

I'm only 65kg (without kit), that's about 143lbs.
 

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Try 25-30% sag, it will increase small bump compliance. Enduro or SFK low friction wipers will help too

• More sag (20% - 30%) increases bump sensitivity and suspension movement. More bump sensitivity results in a smoother ride and is typically preferred on longer travel bicycles. • Less sag (10% - 20%) decreases bump sensitivity and suspension movement. Less bump sensitivity results in a more firm, efficient ride and is typically preferred on shorter travel bicycles.


What tire pressure are you running?
 

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Spring rate is important to consider when continuing to reduce sag--BUT--most people are okay with lower spring rate versus much higher. Wind open the adjusters on your fork (and maybe the back too; you don't need to adjust the pressure in back, since it 'feels' right), and try to match the spring rate to your shock; bounce on the bike, and both should move/bounce back evenly.

Once you can match the front, return your settings on the shock to where they were. What model of Charger do you have? 3 position? Hi/Lo compression? Set the rebound on the fork to return you at the same speed as the rear. Compression should be adjusted to: support your braking/pedalling, ideally as evenly as the rear of the bike.

If, with the damper adjustments wound out all the way, you can get the springs to behave 'evenly' front to rear, then your beef would seem to lie with the damper, not the fork. If the fork behaves unpredictably with the damper open, that kind of points towards tight bushings (or maybe the air spring needs to be greased, who knows?). You can sort out whether it's the damper, spring, or chassis by doing a lowers service, and removing the seals from the fork (have extras, they will probably be damaged from removal). If the stanchions do not drop into the fork under their own weight, or bind, you need to take corrective action there. The spring misbehaving should be easy to sort at that point; purge the air from the spring, if it hasn't already been done, remove the top cap/valve, and remove the circlip from the bottom of the stanchion. Hold a rag over the bottom, and give it a firm pull to remove it. Clean the insides with IPA, put slickoleum/Judy/Sram butter on a rag, then push it through the insides. Grease the seal on the spring, likewise, and around the sealhead. Reassemble. Make sure you are not trapping air in the lowers when you reassemble; slightly pressurize the air spring, and fully extend the damper when reattaching everything, and only insert as far as you have to to catch the threads in the spring.

The damper would require some serious disassembly to get to the shim stacks, if you cannot get the fork where you want it with the above stuff.

You are only going to wind up fighting your full-suspension if both front+rear are not working together. For what it's worth: both of my Charger 2.1 forks with debonair springs are fairly active, but I wouldn't describe them as "eating" anything but minor rills in the surface of the trail. They are quite clearly active from use, and the difference from that to rigid is immediately obvious.
 

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You should let the Sram engineers know they don't know what they're talking about

25% works great for me. 15 feels terrible.
Did you read the original post? Your advice is basically the setup this rider is already using and has determined isn't working. It's not about your setup; if you're happy, that's great. Most folks that know any about suspension, don't set it up that way. Read Cary's post above; it's spot on.
 
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