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orthonormal
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I just bought a used 2010 Epic marathon 29er and i'm looking for some suspension setup tips. The RockShox site has tips for setting up the fork's motion control damper but nothing on air pressure settings. Didn't find anything at all about the Fox/Specialized Brain rear shock. I'm ~175-180 lbs. w/o gear and typically ride with ~10 lbs. of water/food/tools on my back.
 

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andy f said:
I just bought a used 2010 Epic marathon 29er and i'm looking for some suspension setup tips. The RockShox site has tips for setting up the fork's motion control damper but nothing on air pressure settings. Didn't find anything at all about the Fox/Specialized Brain rear shock. I'm ~175-180 lbs. w/o gear and typically ride with ~10 lbs. of water/food/tools on my back.
Not too familiar with setting up a Reba shock but I know that those have a negative and a positive air chamber. My LBS does recommend adding air to the lower chamber first always...

For rear brain shock, add about the same PSI as your weight plus gear. You'll need to experiment with the brain settings. I like it at 6 clicks back from full. It allows the suspension to react to smallish bumps, yet it does not bob when I am grinding the cranks.

I would start at 4 clicks back from full and see how that is.

Here's a link to the Specialized suspension set-up videos...

http://www.specialized.com/bc/microsite/suspensionsetup/main.html?x=y
 

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I have a 2011 Epic Comp 29er. I weigh about 180-185 with grear and run 180 psi in my rear shock with brain 5 clicks from full firm. This gives me good small bump absorption and I can climb out of the saddle with no bob.

I have my reba with 120 psi in the pos and 105 in the neg. Any less than 120 in the positive for me and the shock seems to ride too low in it's travel. I set compression to about 6 clicks toward full firm and floodgate 3 full turns towards pos to control some of the brake dive and pedal bob.
 

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Always add positive air pressure first. This is how I start to set sag. Let the air out of both chambers. Pump your positive up to set your sag. Once you have you sag set air up your negative chamber just until the sag starts to decrease. This is just a starting point but if you go
to the Fork and Suspension Tuning thread and click on the reba fine tuning thread. Lots of info there.
 

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DECKMAN said:
Always add positive air pressure first. This is how I start to set sag. Let the air out of both chambers. Pump your positive up to set your sag. Once you have you sag set air up your negative chamber just until the sag starts to decrease. This is just a starting point but if you go
to the Fork and Suspension Tuning thread and click on the reba fine tuning thread. Lots of info there.
I read somewhere that their should never be more than a 15psi difference in the chambers, maybe that just meant when actually riding.
 

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http://goo.gl/D8HB8

Rear Brain Shock:
Riding Weight + 10 is a good starting place for the rear shock. When checking sag, Spec recommends that the Brain Fade (blue) knob be set one full revolution back from full firm (full firm= full clockwise) and the Rebound (red, on actual shock) at three revolutions back from full slow (full slow rebound= full clockwise). Push the o-ring up to the seal on the shock. Sit on the bike for a minute in your riding gear. Get off and check sag. Should be 8-12mm to the O-ring. Once you dial in the pressure, then re-set your Brain Fade and Rebound to your liking. I typically ride the BFade about 2-3 clicks back from full firm for lots of climbing and getting to/ from trails, and open it up between 3-6 for descending, but I come from a HT world. You can go further for a more plush ride. I ride my rebound about 1/3-1/2 back from full fast, and make adjustments on the trail. If I feel like the bike is bucking me forward out of little rollers and boosts, then it's too fast.

Rock Shox Reba:
The air chart for your positive and negative chambers should be on the side of your fork lowers. For the weight range of 180-200 they suggest a starting point of 120-135 in both chambers (so, for 190 riding weight, maybe 125-130? 127.5? :)). There seems to be some growing consensus that the fork performs really well with 10-15psi LESS in the negative chamber than in the positive. What I've seen suggested often is to let all of the air out of the negative chamber, then fill up your positive to the recommended setting and check sag [make sure your compression damping is open (open= counter-clockwise). Sag should be 10-15% of travel, which is 100mm, so you want between 10-15mm of sag. Then, begin to fill the negative chamber and watch the stanchion at the seal. As soon as the fork starts to get sucked down into the lowers, stop adding air (or even let a tiny bit out). Seems most people are finding that spot to be about 10-15psi less than the positive chamber.

Rebound is similar to the rear- I ride mine about 2/3 of the way towards full fast, but there's a lot of personal preference in this. Too slow, and the fork will pack down (it won't rebound back to full extension between bumps, therefore, "packing down") over multiple, fast bumps. Too fast, and it'll kick you up off of bumps and might be twitchy/ chattery-feeling in tight, fast turns.

Compression and Floodgate: Still a little bit of a mystery to some and lots of differing opinions- search the forums. Basically, I ride mine with compression locked out (clockwise) and floodgate 1/2-2/3 closed/ firm (closed=fully clockwise) for most climbing/ flat, rolling conditions, and open up the compression (without touching the floodgate) for descending. Sometimes, I'll leave the compression closed and open the floodgate back a little if I feel like I'm getting too much brake dive/ compression in tight switchbacks on the way down. Still experimenting with this and, again, lots of personal preference for riding style.

Just my two cents- I'm sure there are others who will disagree with some of these suggestions- and I'm always open to learning more about this fork.
 

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Caution using RockShox suspension pump

Just a tip to those with Rockshox forks and shock on setting pressure, may apply to others. Couldnt figure out why I lost so much pressure in forks and shock each ride. I use a Rockshox suspension pump to set these and found that when I unscrewed the fitting from the fork or shock valve a slight hiss occurs. Thought this was just the air in the pump tube at first. But then just out of curiosity reconnected immediately and found the pressure was down 25psi on what I'd just set it at. Tried this on all the valves a couple of times and found the pressures dropped between 20 and 30 psi on both + and - fork valves and 15 to 25 on the shock.

In other words it was losing pressure on disconnect. Got a tip on how to avoid this (which you all may know :( ). When connecting the pump to the valve screw it down till the gauge needle just moves then stop. Pump up to pressure required then disconnect. No loss of pressure. :)
FWIW.
 
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