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Discussion Starter · #1 ·
How can I increase small bump compliance on my Reba without changing the sag?

I was riding some churned-up ice today and it almost took my fillings out. I just purchased a Commencal Meta 5 with a Fox Float R @ 130mm and the small bump compliance is waaay better, even when the fork is pumped quite firm.

Data points:
Me: 175lbs, 195 or so loaded up.
Bike: SIR9
Reba set-up: 80mm travel, 90 neg, 100 positive (or so)
Sag: currently 25%
 

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Discussion Starter · #3 ·
um, dunno. Don't recall adjusting it. Bike is out in shed, -10C, me in pajamas... will post tomorrow!

Where should I start?
 

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Coward..go look..lol..:D

I have mine set on full fast...the "Hare".

Can you run lower pressure in the shock? Try 90psi positive and 80psi negative.

You should be seeing full travel on the big hits every ride.


R.
 

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Discussion Starter · #5 ·
Ya, I think I will lower the overall pressure. On reflection I think the rebound is set to full hare or very close. I never get close to bottoming the fork. Can you maintain the same sag by lowering both positive and negative pressure?
 

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If you keep 10psi difference between the positive and negative air chambers it will keep the fork 'up' as the positive pressure is your main 'spring'.

So set the positive at whatever pressure suits your riding weight when you are ready to ride, and make sure you are getting full travel on the sliders when you hit the big bumps. The negative setting should always be below the positive one ... otherwise you are just weakening your main 'spring' pressure in the positive chamber and getting too much sag in the fork.

Start at 90 pos / 80 neg and see how she feels. Use a ziptie on one of the sliders to check travel. Take a shock pump with you on the trail. Adjust as needed. ALWAYS set the positive chamber..[pump it to the required psi] FIRST, then do the negative.

ok?

R.
 

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Pos 1st?

Rainman said:
If you keep 10psi difference between the positive and negative air chambers it will keep the fork 'up' as the positive pressure is your main 'spring'.

So set the positive at whatever pressure suits your riding weight when you are ready to ride, and make sure you are getting full travel on the sliders when you hit the big bumps. The negative setting should always be below the positive one ... otherwise you are just weakening your main 'spring' pressure in the positive chamber and getting too much sag in the fork.

Start at 90 pos / 80 neg and see how she feels. Use a ziptie on one of the sliders to check travel. Take a shock pump with you on the trail. Adjust as needed. ALWAYS set the positive chamber..[pump it to the required psi] FIRST, then do the negative.

ok?

R.
I have a new reba setting at my LBS waiting for my new frame so I am interested in all thing reba right now, so....... why do you say to do pos chamber 1st????
 

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Discussion Starter · #8 ·
Thanks, Rainman. I have the ziptie on the fork already. Is 90/80 what you would recommend for a rider my weight or is that based on my current settings, or both?
 

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I just guessed that setting because of the current conditions you are riding in, your posted weight, and the fact that you aren't seeing full travel on the sliders...etc..etc.. it all points to too high a psi setting.

R.
 

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trail717 said:
I have a new reba setting at my LBS waiting for my new frame so I am interested in all thing reba right now, so....... why do you say to do pos chamber 1st????
Always pump the positive chamber first. This is recommended by the fork maker, too.

Remember...Reba air psi amounts aren't set in concrete. I change mine according to the trail. But...I always maintain the 10psi difference between the positive and negative air chambers.

If you are riding trails with quite big drops or lots of very rocky sections you may need to up the pressures slightly, an extra 5 psi can make a big difference to how the fork handles the bumps.

You should ALWAYS be seeing good full travel on the sliders from the big hits. Otherwise you are just wasting the travel available.

HTH,

R.
 

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OK, Rainman- I have a bit of a challenge for you. I run the short fork internal in my Reba. This gives me about 67mm of travel to bottom out, which I do every ride a couple of times.


My current settings are 110psi positive, 100psi negative, and the rebound full fast. I may slow the rebound down a bit soon, as the fork is now nicely broken in, but for now it's wide open. I honestly don't know what the sag is at these settings- I approached it from the other direction. I just kept decreasing air in the positive chamber until I started getting proper travel and feel. I'm very pleased with the way it works now, and happy as a clam to have the fiddling with the internals work the way I thought it would...

Anyhow, here's the question:
Obviously with the shorter travel I start out, in effect, with 13mm of sag before I get on the bike, right? After all, extension would be 80mm if I had the short sliders on there, but the long sliders limit the max extension. If 20% sag is ideal, that would be 16mm... so should I set the fork up with 3mm of sag when I am astride the bike, or calculate 20% of 67mm, or 13mm of sag (and ignore the fact that some is buried and therefore does not come into play)?


miles
 

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miles said:
OK, Rainman- I have a bit of a challenge for you. I run the short fork internal in my Reba. This gives me about 67mm of travel to bottom out, which I do every ride a couple of times.

My current settings are 110psi positive, 100psi negative, and the rebound full fast. I may slow the rebound down a bit soon, as the fork is now nicely broken in, but for now it's wide open. I honestly don't know what the sag is at these settings- I approached it from the other direction. I just kept decreasing air in the positive chamber until I started getting proper travel and feel. I'm very pleased with the way it works now, and happy as a clam to have the fiddling with the internals work the way I thought it would...

Anyhow, here's the question:
Obviously with the shorter travel I start out, in effect, with 13mm of sag before I get on the bike, right? After all, extension would be 80mm if I had the short sliders on there, but the long sliders limit the max extension. If 20% sag is ideal, that would be 16mm... so should I set the fork up with 3mm of sag when I am astride the bike, or calculate 20% of 67mm, or 13mm of sag (and ignore the fact that some is buried and therefore does not come into play)?

miles
Miles...first, why are you running the fork at 67mm?

Secondly, I never ever even consider "sag" in my setup of my Reba's. I just go by what is happening to the fork on the trails that I ride.

I realise this flies in the face of what a lot of others might say, but the acid test for a fork ....... is riding it. So I set up as I have written, and i'm normally running my fork at 100mm, but have also run it at 80mm.

However, I want to know why you aren't starting off with 80mm of travel on your fork?

Also, what is the bike? How heavy are you R to R?

R.
 

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Well, I liked the bike rigid but it really sucked at higher speeds, so this is a compromise. Around here most trails are relentlessly bumpy and I simply couldn't keep up a good pace on the rigid fork.
Even though it flies in the face of current thinking, a while back I realized my trail speed has decreased as my forks have gotten longer travel. On my 26er, I rode great with a 63mm SID, then70mm Marzocchi, then with an 80mm Manitou. I got myself a 100mm fork and man, did it ever suck. I lost all downhill cornering ability, and gave up in turns any gain I might have made in the straights from the longer travel. The fork (Fox RLC) was changeable, so I set it back at 80mm and life got immeasurably better.
I have a long travel bike also, and enjoy it for some things- riding like an idiot over rough ground is its strength. It doesn't corner well at all, and I certainly can't hustle it through a twisty singletrack with anything like the speed achievable with the shorter travel bikes I own.

The bike in question is an Inbred. A very large Inbred (21"). I weigh in at 175 pounds currently, but ride pretty light. I am more of a finesse rider than a "smash into stuff" rider.

I agree that the ride is the key- and right now, my Reba is treating me EXTREMELY well. I expected it would, as I've had very good results with a dual-air SID and a couple of Dukes. If you can't tune a dual air fork to exactly what you want out of the ride, you simply aren't doing it right. As you frequently point out, the key to happiness is to get the positive perfect first, then tune the feel with the negative. Quality travel is far more important than quantity as far as I am concerned.

miles
 

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miles said:
Quality travel is far more important than quantity as far as I am concerned.

miles
I agree with the 'quality of travel' statement. I achieve that on my 29'er with the Reba simply by 'feel' and tuning as I ride it.

However, your setup still puzzles me. I don't see why you cannot get the feel you want and like with the fork set at the standard 80mm travel.

Anyways, asking me about "sag" is pretty much a waste of time, ... as I said, I don't set my forks by sag.

Maybe the Inbred and the Reba aren't getting along too well with each other with the Reba set at 80mm. Brant would be the guy to talk to about that... but it certainly would seem strange to me if they didn't.

I'm afraid I can't help you much Miles...all my previous posts apply to tuning the Reba's at either 80mm or 100mm settings.

I don't want to give you the wrong information on this, but if you are 'Extremely' happy with your current setup, then just leave it alone.. :D

R.
 

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pinkheadedbug said:
How can I increase small bump compliance on my Reba without changing the sag?

I was riding some churned-up ice today and it almost took my fillings out. I just purchased a Commencal Meta 5 with a Fox Float R @ 130mm and the small bump compliance is waaay better, even when the fork is pumped quite firm.

Data points:
Me: 175lbs, 195 or so loaded up.
Bike: SIR9
Reba set-up: 80mm travel, 90 neg, 100 positive (or so)
Sag: currently 25%
I had this same problem on a long ride last weekend and slowing the rebound a little (maybe a 1/2 turn toward hare) seemed to fix it.
 

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Rainman said:
<snip>
I don't want to give you the wrong information on this, but if you are 'Extremely' happy with your current setup, then just leave it alone.. :D

R.
Well, I wasn't really asking for help- I am extremely happy with it the way it is, and I've had plenty of good times with Dual Air forks so I have a really solid handle on how to tune it. Mainly I wanted to throw out my unusual setup and get some theoretical discussion on the matter going.

I'd thought my explanation for the short travel was pretty explanatory, but maybe I didn't explain it plainly.
Short travel moves up and down less. This is good for cornering. Also, as a byproduct, I get a lower ride height and slightly quicker head angle (but HA is a completely different thread).
I guess it boils down to suiting my style and riding techniques better than it would at 80mm, and far better than 100mm.

miles
 

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AuntieAPE said:
I had this same problem on a long ride last weekend and slowing the rebound a little (maybe a 1/2 turn toward hare) seemed to fix it.
Turning the rebound adjuster towards the "Hare" or fast setting makes the rebound ---> Faster. :D

R.
 

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miles said:
Well, I wasn't really asking for help- I am extremely happy with it the way it is, and I've had plenty of good times with Dual Air forks so I have a really solid handle on how to tune it. Mainly I wanted to throw out my unusual setup and get some theoretical discussion on the matter going.

I'd thought my explanation for the short travel was pretty explanatory, but maybe I didn't explain it plainly.
Short travel moves up and down less. This is good for cornering. Also, as a byproduct, I get a lower ride height and slightly quicker head angle (but HA is a completely different thread).
I guess it boils down to suiting my style and riding techniques better than it would at 80mm, and far better than 100mm.

miles
I can understand your reasoning and see where you are coming from. Obviously, your Reba setup and style of 29'er riding suits you on that bike.

However, most people that I speak to are just looking for a nice plush feeling fork with the ability to soak up the hits, so my tuning tips are mainly aimed at them.

Your setup just goes to show how "tune-able" the Reba is ... which is a 'good thing' imo.. :thumbsup:

Your original query put me off a bit because you posed it as a question needing a solution. However, you then said that you were very happy with the fork as it was... :D

Anyways, i'm happy that you are happy... :D

If we can help other Reba owners get the feel and performance they like from their fork, then that is really all that matters.

R.
 
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