Rockshox Reba Race 08 strange problems

bails87

Basically....are my forks borked?!

I've had them for 2 years, done the basic service and fluid replacement every 50 hours as advised. I recently found out about this tuning tip from SRAM, and when I checked there was no fluid in the positive chamber, so I topped it up with 5ml but it hasn't helped.

The FAQs on fork setup say to set the sag by putting air in the +ve, then once it's set, put air in the -ve.

If I do that I start off with 125mm of exposed stanchion (115mm of travel supposedly, but I get about 123mm of travel :? ) then set 20% sag, so I end up with 100mm of stanchion showing when I'm in the 'attack' position.

Then I put air in the -ve chamber to match the air in the +ve. And the fork sucks right down, when I'm then in the attack position I end up with about 50mm of stanchion showing. Meaning 70mm has already been used.

The first bit of travel is very 'soft' but then it ramps up pretty harshly.

In order to get anywhere near 20% sag I have to put in over 150psi (Me + gear weighs 70kg tops, so according to rockshox's guide, which is normally too high, I should need around 105psi at most) When I first got the bike I remember using around 80psi. 150psi gives about 30% sag, which is better than the 60% I get when I set up the forks as per the FAQ, but then they're incredibly harsh.

Any ideas?

thel33ter

Try running much less in the -ve. I know some people who don't run any negative air at all.

bails87

But surely that's just a bodge to mask an underlying problem? It seems like as soon as the -ve gets any air in it, it sucks the forks right down, loads more than it used to

ride_whenever

Ignore the RS pressures, they're random.

Set +ve to give sag, then -ve to the same plus or minus about 2 psi

bails87

That's what I've done, but then half the travel disappears as soon as I put air in -ve. They haven't been doing this for the two years that I've had them, only the last few weeks.

ride_whenever

Sounds like you've nicked (sp? as it a small cut rather than stole ) a seal. Probably time for a send away service to replace all the seals.

ddraver

TFTuned did mine beautifully - expensive but they will be as new!

I think the above is right - that sounds like a real problem, not something that can be fixed with a bodge!

The Northern Monkey

bails87 wrote:

That's what I've done, but then half the travel disappears as soon as I put air in -ve. They haven't been doing this for the two years that I've had them, only the last few weeks.

My revs have also started doing something similar...

150psi in +ve.
anything over 100psi in the -ve and the travel is sucked down

diy

I think you need to set +ve and -ve based on your correct weight (start with them equal) and then adjust to get the sag you need.

I think it is sucking down, because you are setting the -ve after the sag with +ve only.

I set mine to be about the correct weight on the guide. I initially found them to be too hard and was running as much as 30-35 psi below the table, but after a full service, I have increased the pressure to pretty close to the table.

Its very odd, because you can run them at 90/90 or 130/130 and get very similar sag and reaction, its only the progressiveness that changes. The more pressure the higher the curve.

Also give the oil a chance to work through before writing the seals off.

bails87

Again, I''ve tried that, but the travel disappears. It used to be that the fork would be fairly supple and I'd have around 20% of the stanchion hidden in the lower leg. Now, regardless of pressure, as soon as I get near equal in positive and negative, I lose a load of travel and they just feel "wrong". There's definitely a problem. I've been using them for two years and they've never felt like this. At llandegla the other week I ended up with about 40mm of upper leg showing, and even pulling the bars up while holding the wheel down would only get about 80mm to show. That was with equal pressures, ranging from 70 to 140 psi.

I'll probably send them to tftuned. Might treat myself to a PUSH too

diy

Do you still have oil in your top chamber or has it been sucked in to the -ve?

It sounds like you have the same problem. I fixed mine by relubing all the seals and putting 5cl of oil in the top tube. I needed to do this a few times as it initially sucks through.

Seems to be holding now.

I must admit - i am really unimpressed with the Rebas - but I think my forks were just abused by the previous owner.

bails87

I haven't ridden them properly since topping the oil, so I don't know what will happen when I do. But after a couple of days of them sitting in the garage and then a bit of testing on the drive the oil was still there, but obviously that doesn't compare to a proper ride.[/quote]