Suntour Raidon converted to oil now damper reduces travel
I have converted my raidon forks to oil but the damper has ingested the oil and now has reduced the travel from 120mm to around 100mm.
I am not sure what to do next, the fork performed much better with oil but the damper is a sealed unservicable unit.
this is the damper that is in it https://www.srsuntour.us/collections/raidon-service-parts/products/raidon-lo-r-cartridge?variant=27528904003
Is the damper incompatible with oil and will I need a replacement and go back to grease?Posted 9 months ago
converted to oil? what is this witchcraft?Posted 9 months ago
I did this and converted mine from 120 to 140. How much oil have you put in the lowers? If the damper is sealed it’s unlikely to have sucked oil in from the fork lowers. I put some mildly modified rockshox foam wiper rings in too. Worked miles better but the seals weren’t too weather-proof.
I can’t think of anything that would restrict the travel unless you’ve assembled it in the wrong order or you’ve filled the lowers up enough to stop the forks compressing.Posted 9 months ago
I can’t think of anything that would restrict the travel unless you’ve assembled it in the wrong order or you’ve filled the lowers up enough to stop the forks compressing.
This. You only need a smidge of oil in the lowers to lubricate them, the oil doesn’t actually do any damping.Posted 9 months ago
Pump them up and see if they fully extend.
Mine seemed to not return fully after I added oil/ removed grease. After putting too much air in, and then letting some back out, they were fine.Posted 9 months ago
When I say it reduces travel there is always 20mil of stanchion visible no matter how hard you press down on the fork (the picture in the first post is after a ride around cannock and you can sort of see that it never touches the top parts).
I used 20ml of Fox 20wt in each leg. I took the lowers off when I noticed the reduced travel, there was almost no oil left in the damper side.
It’s definitely the damper that is restricting travel I took it out and it even makes a wierd sloshy noise when you move it quickly, theres no resitance on the airspring side.
I’m pretty sure I need a new damper but I’d like to keep it on oil as it’s much improved over small bumps. I can’t really find any info on putting a better damper in there or if I buy the same one again will the same thing happen.Posted 9 months ago
If its like the old Suntour cartridge in some Marzocchi forks it can ingest oil and eventually lock completely.
Old “fix” used to be to drill the cartridge to convert it to open bath.
I think the damper may be orientated the wrong way to run open bath. The hole would be near the very top of the fork?
I will have a go at drilling the existing damper in the hopes of staying on oil but I’ve bought a replacement and will go back to grease if I I end up breaking it.Posted 9 months ago
does sound like hydraulic lockingPosted 9 months ago
Having the same issue. . .did you have any luck drilling? my backup is to release the ingested oil from the damper and lubricate with grease on the damper side and oil on the air spring side.Posted 1 week ago
Has oil migrated into the damper or into the air spring?Posted 1 week ago
Can you access the spring volume to confirm?
I bought a replacement damper and went back to grease. The damper is a sealed unit and unservicable. If you drill a hole the damper stops working and I didnt know of a way to repressureise it.Posted 1 week ago
I thought the point was only to add oil soaked felt rings at the seal to overcome stiction.
If there’s enough oil sloshing about in the RH leg to get sucked past the seal on the damper (basically sealed gas strut), is there just too much (and too low a viscosity?) oil being poured in?
Surely you can still use the oil soaked felt rings and maybe add a smidge of oil to the LH (air spring) leg just to minimise stiction? and smear grease on the RH bushes/damper shaft to avoid the damper ingesting extra oil…
I suppose the other obvious question is, can the fixed damper be replaced with something else?
Other than that gas strut the fork is of pretty similar construction to lots of others like Rebas etc (air spring in LH leg, Damper in RH leg), so could an old Marzocchi style “open bath” hollow pumping rod with a hole at the base be installed in the LH leg? or could a fully serviceable aftermarket “Damping Cartridge” be assembled?
Or is that a bit much effort for what is essentially a bargain bin fork?Posted 1 week ago
Gotcha, thanks for the response! I think I will do oil in the air spring lower and grease in the damper lower so that it is at least a little better.Posted 3 days ago
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