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Discussion Starter · #1 ·
I just got my first Reba SL '06 from Ebay this week. It was never used other than being mounted on a new bike. It arrived very clean, unscratched, etc. I had it mounted at my LBS and took my first ride on a mostly rooty hilly trail this morning.. a good maiden test run trail.

All was well until I started hearing this air escape from the right fork leg upon each compression after the first mile. It seemed to hold compression fine, I checked it out but wasn't able to really see anything wrong. So I rode for 2-3 miles and it stopped making the air escaping noise. I had not clue what made it stop.. so I continued and about 5 miles later the noise returned.

Once I got home after the ride (about a 12 mi. ride) I went over the manual and rechecked all the settings: floodgate, neg/pos air, rebound. All set to my weight specs.. but the escaping air noise still occurs upon compressing the fork.. even while standing still in the garage.

I scoured the web (SRAM/Rockshox site useless) about this and found some posts that reported the same findings but no root cause or solution was described. Some owners claimed "Yeah, mine does that too".

Obvious questions I have.. Is this normal ? Should I be concerned ? Where may the air be coming from ? The neg/pos chambers had 100+ lbs each when I checked them after the ride.. so I don't believe I am losing air.. perplexed to say the least !!

Any troubleshooting tips etc would be appreciated... as you know.. I am not the orig. owner, so Warranty is void without original invoice.. so I'm on my own !!
 

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Most forks that I have ever owned....

make some sort of gurggling, sucking, squishy, or hissing sound either on compression or rebound or both. What you are most likely hearing is air escaping from between the stanchions and the lowers passed the seals. If this did not occur then the fork would either be too stiff as the air space between the stanchions and the lowers would act as an additional air spring, or the fork would end up locked down becuase air could not get back in. All forks MUST have a way for the air between the uppers and lowers to escape and return. The air chambers are housed inside the stanchion tubes, the oil bath is housed between them and the lower legs, but the oil bath does not fill up all the space between them. There is considerable air space in there. Every time you compress the fork you decrease the volume that the air is contained in. If that air is not to act as a secondary spring then it must escape, and if it is not to cause suction it must have a way to return. So the wiper and oil seals let that air pass. The volume of air that passes the seals is actually quite small, but it is enough to make noise in many instances. I have a Manitou Black on my Stumpjumper that is absolutely silent either on road or fork the first few minutes of a ride. But as the oil from the semi-bath starts to splash around inside it makes more noise as the air slurps past the oily seals. The fork doesn't leak oil at all. But it does make noise. This is in addition to the noise that the oil in the damper makes as it passes through the valves.

Anyway, what you are experiencing is pretty normal for most forks. As long as you are not loosing air pressure from the positive or negative chambers, and the fork is peforming as it should you have nothing to worry about. If this really annoys you, you can try changing the wipers/seals. You can either go with stock seals or try a set of Enduro seals. In some cases new seals can stop or reduce the noise. I had an old Zocch Z3 that quieted down considerably after installing a set of Enduros. Another thing you might try is to empty the oil from between the lowers and stanchions. This can be done without even disassembling the fork. And then carefully replacing it with EXACTLY the amount recommended in the owners manual. You may have more oil than recommended in the right leg, thus reducing the amount of air space. This could cause excessive blow by due to reduced air volume. Either way these are the only two possibilities that I can think of. As I said, most forks make some noise when compressed. So it is pretty much normal. But it is remotely possible to lessen the effect.

Good Dirt
 

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Discussion Starter · #3 ·
Great detail

Squash.. it's all coming together now.. I gotta admit this is a major fork upgrade for me. Great description on what's going on inside the unit. Thanks for filling in all the details, now I just have to find decent manual for the fork and not the crappy manual provided with it.

After coming off my silent ancient Marchozzi Bomber '02 this is heaven on a fork for me..
 
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