You are hereForums / By Discipline / Mountain (off road) / MTB Gear / Suntour XCR fork service - need some help
Suntour XCR fork service - need some help
So my forks have not been working well for a while and I should have looked at this a long time ago but I never found the time and just kept riding. Considering these are not expensive forks I figured I might as well learn now before I purchase a new bike and the stakes are higher with more expensive suspension.
I was convinced I needed fork oil for my forks but after doing some research and opening them up I'm not so sure. When I opened them up I found a huge mess I found liquid that looked more like dirty water than oil and a lot of sludge that looked like it may have been white grease. There was too much of this sludge to ignore which made me wonder if I even need the fork oil?
I found a article last night that seemed to indicate that all the forks need is grease but now I am confused. One side of my fork has a spring with dampening adjustment and the other had a hydraulic?? lockout. You will have to excuse my terminology here as I have no experience with suspension at all.
I have posted some pics of what I am left with after cleaning out all the crap and would be really appreciative if someone could offer some guidance. The suntour website and the bike shop where I purchased the bike have not been much help.
- Login to post comments
- Bookmark & share
Not sure I can be a lot of help but I have serviced my RockShox forks so here is what I know.
One side of the fork contains the spring, usually the left when you are sitting on the bike. It may be an air spring of a coil as in your case. Mine was air and it needed a small amount of oil for lubrication.
The other side of you for is the damper, it damps the vibrations of the spring by forcing oil through small holes of shim stacks. So it should have oil in it. The compression control or hydraulic lockout slow or stop the flow of oil when the fork gets shorter. The rebound control changes the rate at which the oil flows when the fork gets longer.
There are also different weight suspension oils the heavier (thicker) ones flow more slowly. You really need to find a service manual to get the right type of oil and the right amount. Too little oil in my forks stops the lockout from working, too much limits the travel and can damage the internals.
Good Luck!
The RL and LO look like they have a hydraulic cartridge system but the standard XRC don't.
Going off the photos yours look like the LO http://www.srsuntour-cycling.com/customGates/scr...
Without having a set here to double check, being a cartridge system, the damperunit may be sealed and that's where the oil will, or should, be. With maybe a little splashed around the outside for lubrication.
With this type of fork what happens is dirt slowly makes it's way through the seals and turns the lube oil and grease into gunk. Give them a good clean down and use a light grease such as slick honey to lube up the bushings and then a slightly heavier grease to grease the spring.
Might be worth changing the seals too but if not grease them with the slick honey too. Whack them back together and see how they feel.
The slick honey?
I have some general grease 'with Teflon'
and then I have some fork oil on the way as well. Anyone know where I can get some more certain information? I really want to go riding on the weekend.
The general grease is probably going to be a bit heavy and sticky. You want either a realy light grease or heavy (20W or more)oil to lube the bushes up
So it sounds like I don't need any fork oil?
The side with the spring gets lubed up with my normal grease and the side with the hydraulic shock just gets lubed up with some 20w oil? After taking another look at the hydraulic part it has a warning on it saying not to pierce as it is filled with nitrogen. If thats the case it would not be sucking oil in as described above right?
I had ordered 10w fork oil which may not be the right oil for lubing up. So for the 20w oil are we just talking normal motor oil or should I got to the LBS and get something specific?
Thanks for taking the time to help the clueless bike mechanic
If it is a sealed nitrogen cartridge that is your hydraulic system. so all you should need to do is lube up the bushings. Depending on how well the suntour seals work a 20mm of fork oil would work for that. Motor oil would work but you are better off with a proper fork oil, which you'll get a lot cheaper at a motorbike shop.
If the seals aren't designed to hold oil it will just leak out though, so you might be better off with the light grease.
Went down to the local bike shop and they confirmed it's a sealed cartridge so they reccomended greasing up the springs and lubing the other side with a bit of 20w oil as reccoemended here.
Hopefully I will be back in action tomorrow with fresh forks and new brakes. Shame Manly dam will be closed