X-Fusion Velvet Volume reducers (too linear)?
I am bottoming out the 140mm RL too easily. With proper sag (25%) I can blow through 90% travel doing a bunny hop. It also bottoms out on the trail a lot. The problem seems to be landing to flat, even a tiny height bottoms out (less than a foot)
Currently riding with 5-10% sag to stiffen it up and avoid bottoming out. I am getting almost full travel every ride, even if there is nothing on the trail that requires that. I can still almost bottom it just standing on the bike and loading the fork or bunny hopping, but its better on the trail.
I was thinking about a volume reducer to make the fork more progressive and ramp up stronger at the end of the stroke. The easy way is to add oil to the air spring, but this is not sustainable as oil will eventually leak to the bottom, and that air spring was not designed as an oil chamber with dedicated oil seals.
Do others have similar problem? I didn't see any mention of it or any parts that you can buy (like for Float shocks). If you do have that problem, what is the solution?
Personally I would just try adding oil above the air piston. I have run 15wt. on several air forks w/o a drop of migration or seal failure.
The first thing I would do as add a little more air. 25% sag is just a starting point for correct air pressure, its not a strict guideline. some people run as little as 15%.
Try running something closer to 20% and see if it helps out. If it helps bottoming, but doesn't give you satisfactory small bump sensitivity, then try what keen said and add a little oil on top the air piston. Just a few cc's at a time. (this will only work if you have a coil negative spring which I am pretty sure that you do, but its worth a look to make sure)
Thanks guys. I also think it has negative coil.
I am running 10mm sag now and still get almost bottom out. On a 140mm fork it is less than 10%. I think that's pretty low sag.
What's a reasonable amount of oil? The surface of the piston is little bit less than 8 square CM, so in theory 8CC of oil will push the bottom out 1CM down. I think I probably need to push it something like 2 CM down.
Did anyone try to remove the top cap on the air spring side on this fork? They don't show it in the manuals, but I assume if you drain the air you can just unscrew it like on other forks.
By the way, how far do you push the travel when you stand on the bike and bounce on the suspension? Bunny hop? Just as a point of reference.
Add a few cc's at a time. Start with 5cc and add 2-3 more at a time until you get to the result you are looking for. Always test after you add some to make sure you still can get full travel with no air.
I use about 80-100mm of travel on my 170mm fork when dunny hoping. all depends on how I land.
It would be worth giving x fusion a call or a sending them an email asking their opinion. At 10mm( thats about 7%) of sag, the fork should barely move. Definitely not bottom out on small hits, or even medium for that matter. There may be something else wrong that is causing your problem.
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