Is my RS Revelation broken or are they rubbish?

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Is my RS Revelation broken or are they rubbish?

14 posts & 9 voices | Started 1 year ago by boriselbrus | Latest reply from boriselbrus

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boriselbrus - Member

I have a second hand Revelation 426 dual air, about 2 years old but in perfect cosmetic condition. I have spent ages playing about with + and - air and can get it so that the sag is right (about25%) and the action feels fine riding up and down the curbs outside my house.

However when I take it on a proper ride, it sinks down in it's travel (to about 40-50%) and doesn't come up all the way even when I get off the bike. There is also virtually no small bump sensitivity.

So is it just a rubbish fork (not what I've heard and read), or does it need to go and see Mr Flooks? And if it goes to the god of suspension is it worth getting it PUSHed at the same time.

Cheers

Posted 1 year ago #
Northwind - Member

Definately something wrong with it, I had a set of that model and nothing like that- it wasn't the most sophisticated fork but still very nice. Or, could be setup I suppose, but I'm not sure how you'd create that effect.

Posted 1 year ago #
simons_nicolai-uk - Member

Sounds like the seal between the positive and negative air chambers has gone.

Dual Air Rev's are (were) damn good - nothing to choose between them and Fox 99% of the time. The PUSH conversion adds speed sensitive damping which felt like am improvement to me - it meant there was more LS compression damping for climbing without needed to reach down and adjust. It's not cheap though.

Posted 1 year ago #
PeterPoddy - Member

I have spent ages playing about with + and - air and can get it so that the sag is right (about25%)

There could be something wrong, but it could be the way you're setting them up too.

When you spend ages setting them up it's possible you can end up with too much air in the -ve, which drags the fork down. Always set air pressures in this order:

1)Let out -ve air (most of it)
2)Set +ve pressure
3)Reset -ve to the same psi as +ve
4)Check sag
5)If sag is wrong, go back to 1)

Try this first. If the fork is still dropping down you most likely have an air leak between the +ve and -ve chambers. A service will cure that. It might not even need new O rings, sometimes it happens if the seals are dry (There's lubrication oil in the air chamber)

One more thought - You're not trying to set the sag by pumping in more -ve air are you?

Posted 1 year ago #
Mike_T - Member

i had a +ve/-ve leak with rev's this is how it went with them:

1) Let all the air from your -ve,, bike upside down
2) pump your spring rate psi into the +ve
3) turn the bike upside down again and pump the -ve until the fork start suck down, no more than a mm or 2.

if the +ve/-ve seal has gone you wont be able to equalise the fork, you'll also see the psi in pump very, i could actually see the psi in the -ve decrease with the pump left on the valve.

If it's sucking down on a ride i would suggest that you have more -ve than +ve and possibly not a seal leak, this is something else i suffered with.

Step 3 was advice that came via mtbr and a guy who was given some tips by PUSH'd., I actually end up with just over 5psi more in the –ve and the forks feeling plush.

btw i have 150mm rev's , i hated them until i actual took the time to read how to set them up properly, there now way better an capable than a set of Van36's I had, awesome hard hitting forks.

Posted 1 year ago #
glenh - Member

Sounds like the seal between the positive and negative air chambers has gone.

+1

15 min job to fix if you have the tools

Posted 1 year ago #
LoCo - Member

http://www.sram.com/_media/pdf/rockshox/dealers/2011-Revelation-Technical-Manual.pdf

service guide, I've got all relevant seal kits if you need them too .

Posted 1 year ago #
PeterPoddy - Member

if the +ve/-ve seal has gone you wont be able to equalise the fork

Err, yes you will. In fact it won't do anyhting else if there's a leak between the 2!

If it's sucking down on a ride i would suggest that you have more -ve than +ve and possibly not a seal leak, this is something else i suffered with.

Err no. If there's a leak when the fork is compressed during use the pressure in the main chamber rises, and the pressure in the -ve chamber drops. As this happens, some air leaks form high to low pressure. As this happens a faster then the other way round, it drags the fork down.

Posted 1 year ago #
boriselbrus - Member

I've just had another go setting up the forks as per PP's instruction - I'm pretty sure I was doing this anyway, but best to check.

After another ride, it's still doing the same. I then tried running the -ve air 20psi lower and after a few cycles the pressures had equalised. I know there is some air loss when you connect the pump (using a Magura zero loss pump, so probably not much).

So I think it's the seal between =ve and -ve air. I'll have a look at the service guides and see what I think, I'm not an idiot when it comes to mechanics, but I haven't had a fork apart since the days of elastomers!

Thanks all for your help.

Boris

Posted 1 year ago #
Mike_T - Member

Thanks for the correction PP, I must have been pi55d over the last 4 wks while sorting my particular issue out

Posted 1 year ago #
james - Member

"I have spent ages playing about with + and - air and can get it so that the sag is right (about25%) and the action feels fine riding up and down the curbs outside my house"
That reads as if you're trying to use the +ve and -ve pressures to sag the fork 25% before getting on the bike?

Posted 1 year ago #
PeterPoddy - Member

James, it did to me yes, but ut seems he's set them up properly and it's still happening now. My first set of Rebas did exactly this. A service will sort it, with new seals, but if you can take the fork apart it's worth just changing the lubrication. If the seals are dry they can leak. I've had that before as well. It might work, might not....

Posted 1 year ago #
tk46hal - Member

Get them serviced!

The forks are great and work very well with the + and - air controls.

Posted 1 year ago #
boriselbrus - Member

LOL! No I was actually sitting on them when the sag was at 25%

I'm not quite that silly...

Posted 1 year ago #

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