Rockshox Reba RLT 29er static sag and marking?

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sanchez89
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Rockshox Reba RLT 29er static sag and marking?

Postby sanchez89 » Tue Jan 01, 2013 12:05 pm

Hi everyone, i know this may seem a bit trivial but i just want some reassurance that this is what is supposed to be happening!

Did a standard lower leg service on my second hand set of 2011 Reba RLT's yesterday, i had a right game actually getting the lowers off, i think this was the first time they had been done, b
ut when i did finally get them off i cleaned the crap out and did the usual check bushes and stanchions for damage.

on the back side of the right hand fork stanchion, approx 30mm from the bottom of the stanchion was a black mark, the best way to describe it would be like nail varnish, you could feel it with your nail but i couldn't scratch it off, i only tried gently though. would this have any detrimental effect on the fork that far down? i assume it was caused by something around the lower bush but i couldnt see any damage to it. i havent ridden the fork yet so cant say if it feels bad/broken just wondering if anyone has experienced this before. i dont have photos but the mark was only about 4-5mm wide by about 2-3mm high.

when i finished the service and put the air back into the fork i noticed the fork would compress slightly.

with just the positive chamber inflated it looked like this on the sag gauge:

Image

as soon as i put any sort of meaningful pressure, i.e more than 50psi, into the negative side it sinks down like this:

Image

no matter how much pressure i put into the positive (i went to about 160psi) it always stay like this. running approx 5% sag constantly.

i have measured from the wiper seal lip to the red o-ring at the top of the stanchion and its virtually bang on 100mm. anyone with a Reba, is this normal?

if anyone has any comments regarding the mark they would be greatly appreciated, i know its difficult without images but it was definitely raised, i thought about carefully flattening it off with some 1500grit wet and dry? or should i just leave it as its so far down?

sorry for the essay.
2011 KHS Full Susser Carbon 29er Race Build
Clank wrote:M'eh, I might just go back to zapping it with frikken lay-zur beeeems. And sharks.


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The Northern Monkey
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby The Northern Monkey » Tue Jan 01, 2013 12:37 pm

Dual air or solo?

Same sort of think happened to my dual air revs after a service, got sucked down when adding air afterwards.

Never found the reason!

sharky1029
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby sharky1029 » Tue Jan 01, 2013 14:28 pm

I know it can happen if you inflate the forks (from empty) in the wrong order (i.e. negative first then positive) however from your description it would appear that you inflated +ve then -ve in which case I don't know.
You could try re-inflating if you have not done so already.
I would try adding air to each chamber in chunks so 50psi to +ve, then 40 to -ve, then 50 to +ve then 50 to -ve, or similar to reach your desired pressures however I wouldn't be too hopeful that this will resolve the issue it just seems the best way to inflate from zero without having too uneven pressures in each and maintaining the +ve having higher pressures than -ve until you set your final settings.

Also, if you run higher -ve pressure than +ve the travel is shortened a little.

Hope it helps but don't hold your breath.

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supersonic
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby supersonic » Tue Jan 01, 2013 15:02 pm

The black ring is fairly common, happened to my forks, but didn't effect use at all. I think it is caused by contaminants getting through the seals. Keep an eye on it though, and if it flakes use a scourer to smooth off.

The sag thing is pretty normal, a few mm is within the travel tolerances anyway. Inflate the positive first, then negative to the same amount, and check sag using the gradients. Increase/decrease until you get the desired sag. the add/subtract up to 15psi from the negative chamber to tune feel.

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sanchez89
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby sanchez89 » Tue Jan 01, 2013 18:40 pm

supersonic wrote:The black ring is fairly common, happened to my forks, but didn't effect use at all. I think it is caused by contaminants getting through the seals. Keep an eye on it though, and if it flakes use a scourer to smooth off.

The sag thing is pretty normal, a few mm is within the travel tolerances anyway. Inflate the positive first, then negative to the same amount, and check sag using the gradients. Increase/decrease until you get the desired sag. the add/subtract up to 15psi from the negative chamber to tune feel.


thanks for all replies.

Supersonic, its more just a mark on the 1 side than a ring. as i said earlier the best way i could describe it is like a smear of black nail varnish.

from where it is it looks to be caused by the lower bush in the fork leg, when i drop the lowers off again in a few months i will see if its any worse.

just another question, the foam rings were pretty manky, i tried to give them a clean out with some IPA but they were still fairly brown when i soaked them in oil and but them back in. do you recon it might be best just to order a new set of wipers and foams to make sure there isnt any issues with them letting stuff through?
2011 KHS Full Susser Carbon 29er Race Build
Clank wrote:M'eh, I might just go back to zapping it with frikken lay-zur beeeems. And sharks.


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supersonic
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby supersonic » Tue Jan 01, 2013 18:54 pm

Always get new seals if in doubt.

This is what mine were like:

Image

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sanchez89
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby sanchez89 » Tue Jan 01, 2013 20:40 pm

supersonic wrote:Always get new seals if in doubt.

This is what mine were like:

Image


yes mate spot on. thats exactly what it is. just no where near that size. was that down the bottom end of your forks?

actually a better question is did it get any worse? i might order a new set of wiper seals and foams, just had to order a new set for my revs so might aswell spend another 15 quid on a set for the Reba too.

thanks for your help Supersonic.
2011 KHS Full Susser Carbon 29er Race Build
Clank wrote:M'eh, I might just go back to zapping it with frikken lay-zur beeeems. And sharks.


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supersonic
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Re: Rockshox Reba RLT 29er static sag and marking?

Postby supersonic » Tue Jan 01, 2013 20:51 pm

Yeah, down the bottom. That pic was after a bit of soft buffing, but has been ok since, hardly changed.


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