I bought a Cannondale Killer V500 mountain bike 10+ years ago. It has a Rock Shox 21-R front suspension on it. Once I got into tris I stopped riding it and it sat in my parents basement. Recently, my Dad has been riding it a lot.
He noticed the shocks seemed really bouncy and almost worthless. He got to tinkering, pulled the whole thing apart (from what he explain to me on the phone it’s in 2 pieces, the upper piece with the steerer tube attached and the lower piece with the bridge and the two fork legs). Any, I don’t know much about mountain bike suspension, but I guess it was some kind of oil/fluid suspension or something? Either way, he said a lot of the internal pieces had corroded and fallen apart.
Now, are those internals replaceable? Keep in mind we are talking about a 10+ front fork. Or would he be better off just buying an entry level front shock for the bike. The frame is in great shape and he rides it a lot. His riding is mostly road/hard-packed trails, some cross country stuff, nothing really technical so I am not worried about a super light or super andvanced shock.
If he goes the new shock route, what does he need to know when looking in terms of steerer tube diameter? How about height or anything, does that matter or is it a pretty standard number? Will the new forks steerer tube just slide up through the headtube and then there is a compression plus and attach the stem? Anything I am overlooking? Thanks!
go to ebay and buy a used air sprung fork for $50, like the rock shox Reba or Duke or Sid. You cant replace the innards on that old thing. the fork on a mountain bike attaches to the bike exactly the same as a fork on a road bike (with an aluminum steerer.) It’s an 1-1/8 steerer tube (just make sure you have enough lenggth to match the current fit, and make sure it has posts for v-brakes - i’mn assuming your killer v doesnt have disc brakes. The fork will go up through the headset, you pop on the stem, top-cap & tighten it down. mount the brakes and your done.
The easiest way to tell is to measure the external diameter of the steerer tube with either cailpers or a ruler across the top end. If the top of the fork has threads, it is a standard headset, and not an “ahead set” type that uses a compression cap on the top. Either way, the old fork will have a ‘race’ on the bottom of it that matches with the headset. You will have to take that off and use it on the new fork so that it seats/matches properly. Best for a bike shop to do this since the correct tools make it much easier.
Since it is a 10+ year old fork, I would try to find via a local bike shop, ebay, or craigslist a fork that is the same steer tube diameter that would work as a replacement. Probably an 80mm travel fork would work well. OR if he is not doing much off road riding or the off road riding that he does is very non-technical, you could get a rigid for for the bike as a replacement. That would be easier to find and probably less expensive.
Make sure the suspension travel is at least close to what the old fork was. You cant go and put a 100mm fork on a bike that had 63mm of travel before and expect it to handle the same. More than likely an 80mm fork will do the trick.
It might not be as easy and sliding one fork out and the other in. The fork crown race might be hard to remove from the steerer tube. Might be worth it to have a shop just put on a new $20 headset as well. That would require special tools.
You wont be able to find any parts for the fork, Rock Shox has gone onto new ownership and no parts available. As others have said find out the steerer tube diameter. and look for a used fork. Given the mountain bikes have progressed a lot since you bought the bike I would advise against putting a lot of money into it, at a certain point it makes more sense to buy a new bike as a $500 bike would probably be better than the old Cannondale.
You wont be able to find any parts for the fork, Rock Shox has gone onto new ownership and no parts available. As others have said find out the steerer tube diameter. and look for a used fork. Given the mountain bikes have progressed a lot since you bought the bike I would advise against putting a lot of money into it, at a certain point it makes more sense to buy a new bike as a $500 bike would probably be better than the old Cannondale.
Kevin
Yep, I have an older (~7yrs old) Rock Shox SID SL on my current MTB. It was the top of the line fork back then. Turns out they stopped making parts for them within three years. I had my LBS do a tune up, but it didn’t last. Seems they develop revotltionary new technologies every year for shocks, and so they are quickly obsolete.
I’ve got around $5000 invested in my MTB, so I’ll be getting a new fork. Depending on how much you paid for your bike, may be time to buy a new one, and use the old bike for parts.