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I'll try and keep this as short as possible. (there's a TL;DR at the end...)
Bike is a 2018 Whyte T130S, fork is a RockShox Revelation RC, 130mm travel with the Debonair spring. Bought from Leisure Lakes in Cheltenham.
Last October had a new damper fitted by Sram (Zyro Fisher) as letting all the air out of the spring still gave me 4" of suspension...
This year, had a lower leg service done, new foam rings and seals etc by the mechs at Leisure Lakes at Flyup417 (10 minutes from home). The forks had been feeling a bit harsh and I thought this might help. It did, a bit but they still felt a bit harsh. I am not a maniac rider, much more a wheels on the ground sort. I have tinkered with pressure, anything from 75 to 120 psi (the Trailhead Rockshox webpage recommends 120psi for my riding weight) and added or subtracted bottomless tokens as well. I'm getting sag of around 30% and at the end of some rides it looks like I've had maybe 85-90% of travel, which seems fine.
However over small bumps the fork is super harsh, it's very difficult to hold a line without being bounced off course. It feels like riding my Marin Pine Mountain (which was fully rigid!) I'm not talking big rock steps or insanely rutted terrain, I'm just riding on local trails (Cranham) which can be loamy and rooty one minute and then a bit Cotswold stoney the next.
I took the bike back in to LL in Cheltenham with a similar issue as before, I could let the air out of the spring and the fork still sat at about 4" of travel. They couldn't quite grasp the issue, pumped the fork up and said it was fine. I explained again that it was very harsh over small bumps, and they then said that it would be possible to let the air out of the negative spring as that would help with small bump sensitivity. So they did. Riding back to my van the fork bounced up and down nicely so I thought maybe this had done it...
The ride is still very harsh. Today on a quick loop through the woods my hands were buzzing. If I let the air out of the spring it sucks right down now, but I have to put closer to 130psi in to get near 30% sag, and the fork sits at 10-15% sag unweighted.
Can anyone suggest a solution? Please don't say buy new forks, I don't have the money for that and I don't think it's unreasonable to expect the forks on an 18 month old £2750 bike to perform better than this. I know that the Revs aren't the best forks in the world, but they should be better than they are! If this is a warranty job, what do I say to the shop to describe the problem? Or do I simply need to put air back in the negative chamber? (How do I do that?)
I'm getting super frustrated, and getting to the point where I don't want to go for a ride as it's actually not that enjoyable. Any helpful suggestions are appreciated.
(TL;DR Rockshox Revelations are harsh over small bumps. Tried different psi, etc but still bad. Warranty job or have you got any suggestions?)
What tyre pressure are you running?
If it's sucking down in travel with no pressure in the air shaft, sounds like the port may be blocked with grease. Release all pressure, remove top cap on air side and pull up on your bars while holding the fork lower (to extend the fork). Might take a few goes and a bit of effort but eventually it should release and you'll hear the air return to the negative chamber. Compress and depress a few times to ensure air is travelling between positive and negative chambers. Then replace top cap and repressurise.
I'm struggling to find the sweet spot with my rev. At 70kg without gear I find one token and 75psi as good as I can get with 120mm travel.
The revelations with the motion control damper are known to be quite harsh over small bumps, even more so when going fast.
Mine have improved slightly by setting the rebound (which doesn't seem to change a lot) to fully open, but you're fighting against the damper limitations.
Save up and fit a charger damper.
Have they got worse since new or have they always been harsh?
The internals if the RCs aren't much to write home about, super old technology used is rockshox forks for years and are hit or miss. Save all the messing about and head scratching taking it to people with basic knowledge. Get a debonair air shaft fitted. Will make a work of difference.
According to the OP it's already got a Debonair shaft...
Thanks for the replies everyone.
Tyre pressure is around 22psi in 2.4 High Roller on the front.
I have just tried removing the air valve and cycling the fork to clear any blockage. Sad to report that despite nearly giving my old hernias a relapse nothing has changed. I would hope that after a lower leg service there wouldn't be any grease where it shouldn't be anyway.
I'm not sure that LL letting the air out of the negative spring has helped so how do I put it back in..?
I’m not sure that LL letting the air out of the negative spring has helped so how do I put it back in..?
If the port is blocked with grease, it won't equalize the 2 chambers. If it's not blocked it will equalize itself, you don't need to do anything.
OK, in that case I assume it's blocked. Unweighted sag is about 10-15%. So to sort that I need to take the lower legs off I'm guessing?
You can do this:
but need to be careful not to roll the seal of move the wipers. That won't clear the port, but might give you an idea if that's an issue if you hear air escape.
I've discovered that 10% sag marker on a 170 Lyrik is actually zero...
I don't think there's any air in the lowers. If I let the air pressure out the fork sucks down completely, no gap between lowers and crown.
Apologies if this is teaching you to suck eggs, but SRAM recommend equalising the positive and negative pressures during sag set up by 5 boings of 50% and then a final pressure check, see between 25 seconds - 1min30secs and see if it helps:
If they are sucking down fully after you have let the air out then the only thing this can be is trapped air in the negative side of the air spring. Try pumping up to maximum pressure and then cycling the fork. Make sure you put your foot on the tyre and pull up hard on the bars to ensure that the piston actually passes the transfer port.
Get a charger 2 damper. Totally transformed my revelation. WAY smoother over chattery and chunky stuff now.
I've just got the same forks, I've come to the conclusion that they're not great.
I've had recons sektors and Raidons before these and these are the harshest on small bumps. I'm thinking now as I write this that it could be because the chassis is so much stiffer that it shows up the weaknesses in the actual fork performance.
I'm tempted to get a charger damper, my hands were tingling for a good couple of hours post ride yesterday, and that was only a fairly gentle cross country pootle over Cannock chase. But I ain't got the funds at the moment
The motion control damper is very simple, it's basically a hole that the oil flows through, increasing damping makes the hole smaller. There's not a lot more to it.
OK, latest update!
Had tried the zip tie trick, and also cycling the fork at 50% etc to no avail.
So inflated to 163(ish) psi and cycled and pulled, and then pulled some more, with no joy.
Let all air out of spring, fork compresses all the way again. Right then, I clamp on both brakes, lean back on the work bench, jam a foot on the tyre and haul on the bars with all I've got. At this point I'm hoping nothing slips or I'm taking a handlebar to the tenders with some force. Instead on agonising underpiece pain this time I'm rewarded with a bit of a "pfft" sound, coming from the fork not me. I heave again to be on the safe side, ease the bars back down et voila, the fork now sits at about three inches, with very squishy travel.
I inflate to 50 psi, cycle half a dozen times, then get up to 120 psi, cycle again (both times removing the shock pump) and check sag. It's hovering around 30% which is cool.
So thanks for all the advice and suggestions, the proof of the pudding will be in the riding, which will hopefully be tomorrow pm. I'm taking the shock pump with me to make on the fly adjustments as necessary.