BMarino

Hello everyone!


Last week I got heavily bogged in mud while riding, front tire completely blocked by hard mud against fork arch.


Later that day, after thoroughly cleaning my bike, I found this:





Some rocks in the mud must have scoured those spots in the RIGHT HAND SIDE stanchion.

The fork is a Rock Shox XC32 Solo Air (air chamber is on the left hand side fork leg).

Stanchions are steel.


I would appreciate any advice on what procedure works best to file out those burrs to avoid damaging the seals on the fork leg.


Thanks for reading and for any feedback!

BarryVee

No bike mech pro but think I’d try:
fine needle file
point file
fine sharpening stone or ceramic
Use a light even motion that follows the rounded surface to avoid creating flat spots.

And looks like job could be easier pulling the lower off for access. Once any burr or high spots are gone I think you’ll be OK. Believe the oil dampening occurs inside the chrome plated tube. And the outside just slides through the wiper & a foam dust ring at the top of the black lower tube, plus through some bushings further on down. See pages 36-37.
https://www.servicearchive.sram.com/...pc_-_rev_g.pdf

jimc101

Does it really matter? they are steel, and a little bit of damage isn't going to impact their performance, maybe you will get some corrosion after time, but no repair will stop that.

Realistically, they are a low-end fork (not that's that is bad) and if you were ever to consider servicing them, buying replacements would probably be just as cost-effective an option.

Would enjoy using them as-is, till they wear out.

BMarino

Thanks for the link, BarryVee. It'll be helpful for identifying replacement parts.

I'm a bit wary about using an iron file... do you have any first-hand experience with emery paper on this kind of fix?





I wonder there must be at least an advantage of steel stanchions over other fancier metals or alloys used for stanchions in high-end forks, as I have read here and there that those higher-end stanchions are, once scratched (real scratch or burr), done for (non-fixable by filing) and must be replaced. I would suppose this is not the case for steel stanchions. Is this what you mean when saying "a little bit of damage won't impact their performance" ?

I know this is a low-end fork, but actually it is (was) the best fork available for 26-inch mountain bikes AND with v-brake mounts, so I need it to last, cause once this is gone, there will be no new same quality replacement for my classic 26 inch mountain bike (a '99 Voodoo Hoodoo).

By the way, earlier last year I sent the fork to a LBS to service the fork, replace seals, bushings, and oil, and the cost was below 20 dollars (Rock Shox parts were used).

.

jimc101

No advantage for with steel, the only other material you will see on stanchions is aluminium, and this will weigh significantly less (combined with other parts) and may have a different coating to improve performance.

for scratching Alu stanchions, it's annoying and will kill the resale value, but won't kill them if the damage is similar to yours, puncture/crease it, then game over, but you will have probably damaged other stuff as well if you did that.

For the service cost, you had a lower leg service, this is the cheap one, a full service is where you need to consider the price of the service vs replacement

For the forks being 26" & V, and replacements, I was looking for a v-brake fork last year, depending on your market, they are around, but very limited choice, if you can find a good used Marzocchi Bomber, these can go on for years with minimal service which you can do at home.

BMarino

Thanks for clearing up that.

Yeah, probably a complete service will outweigh the cost of a new fork, but for me, the problem is there are NO new 26-inch forks at this level of quality. SRAM has discontinued the XC in 26-inch size.

I wouldn't trust a used fork with unknown use history.


I did read sometime ago that there is a RockShox PIKE in 26-inch size, but then again, its travel is beyond what would be ok for my bike's frame geometry and has a tapered steerer which again is not compatible with by frame's head tube (or can it be adapted with a specific headset?).

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phughes

Yes, it does matter. If the scratches are large enough, they will erode the fork seals as they travel over the scratches, or gouges.

I wouldn't go crazy over them, but I would smooth the surface using the least aggressive method first, possibly a very fine emery cloth. You want to knock off the high spots so the seal can slide smoothly over the area without getting nicked. You can polish out the area with a metal polish after you smooth it out.

cpach

On that fork it's probably worth it to try to knock off any burrs, but it's not the biggest deal in the world. I'd use a fine file or diamond stone to try to knock off the burr and some very fine sandpaper, and maybe metal polish, to try to smooth it out. It won't be perfect but removing sharp burrs will help your seals last longer.

I wouldn't be looking for a replacement if I were you. If you really like the bike it may be worth doing a full damper/spring service the next time you replace the seals.

For what it's worth you can still get a Recon Silver TK for 26" wheels with rim brake posts and an air spring, which is pretty dang similar to the fork you already have. Probably the nicest thing available new would be a Manitou Markhour, which comes in 100mm straight taper for 26" wheels. A lot lighter, a more sophisticated damper, etc. Disc only though, but I'd have no reservations about running a mullet with a mechanical disc in front.

WizardOfBoz

A file would be tool steel (not iron*). But you are correct: a file would be too aggressive for this scratch. A machinist would use a stone. Like a whetstone. Look up polishing stones on Amazon or at one of the supply houses. One person suggested fixing a nick in a hydraulic rod using "a medium India stone and finishing with 600 wet and dry silicon carbide paper used like a shoeshine rag to blend it all in." This same person suggested getting 0.001" brass shim stock and taping in place around the nick to protect the rest of the rod. That my be overboard, though.

But you are best off using a stone, carefully, on this scratch.

*Pure iron (ferrite) is soft, takes no edge, and has only limited uses (like inductor cores in electronics). Cast iron is ferrite with about 4% carbon dissolved into the ferrite in the molten state. When it cools it has great ability to bear weight under compression, and is one of the few metals that slides on itself without galling at all and it slides on itself with low friction. But it doesn't take an edge. Ferrite with 0.2 to about 1.5% carbon is called steel. Files are generally high carbon (1-1.25% carbon) steels.

BarryVee

Think the stanchion is chrome plated so the burr is harder than a file. I considered Emory and only rejected due to probable additional marring of the surface. But really the surface only needs to be smooth enough to not damage what it slides through. So IMO some additional superficial marring isn’t going to hurt a thing. And disassembly can be avoided!

I’ tear off about 10-12” from a roll of Emory and slide it back & forth over as little of the radius as possible. And remove all the resultant dust so none of it has an opportunity to get past the wiper/foam ring and into the bushing surfaces below.

Marylander

I have repaired similar damage to motorcycle forks (albeit my damage was from falling in a rock garden). I first cleaned up with 600 grit sandpaper (specifically bought this pack https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). I used a technique something like this (sheets of sandpaper are long):


When it was smooth I then filled the holes with JB Weld (this is to keep the forks from leaking) before going at them with increasingly fine sandpaper.

They have been working great after this with no leaks and without tearing up the seals. I can't feel any remnants of the damage with my fingers.

I meant to take pictures while I did it but only managed to take a couple. After the removal of the burrs and such:


After application of the JB Weld but before I went at it with sandpaper:

BMarino

Thanks! I wasn't aware of that Rock Shox model. That Recon Silver TK seems to have exactly the same specs as my 2015 XC32. Definitely that Manitou one would be a nice upgrade, but I'd like to keep the v-brake system on this bike. At least as long as my Mavic wheels hold up.



Thanks for clearing that out!









Thanks everyone for your advice and feedback!



I used 600 sandpaper as suggested, rolled some of it around a bic pen and gently smoothed out the burrs' edges using a circular motion, stopping every once in a while to clean dust and inspect progress. Ended up with some light marring around the burrs, but I guess that will be cleaned off once I apply some metal polish to it.













From the photos it would seem those burrs are still a problem, but actually their edges are pretty much gone and ended up really smooth! I'll give it a go and we'll see if any leaks show up eventually! If they do, I'll probably apply JB Weld as Marylander suggests, if not, I'll leave it this way.


Thanks again everyone!



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Amt0571

Good job. I think it will work ok like it is now and I wouldn't do anything else to it.

Only issues that come to my mind are that it's possible that the seal on that side of the fork wears faster, and that water gets in and oil gets out easier than before.

No big deal if you have a good maintenance schedule. Seals are cheap, and replacing the oil bath is almost free and can be done in 30 minutes.