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Timberjack chainstay gouging

4K views 14 replies 9 participants last post by  MTBeing 
#1 ·
Is this happening to anybody else's Timberjack? I noticed it after the first ride or two and It's getting worse the more I ride. I've never laid the bike down or bashed it or otherwise damaged it. Other frames I've owned have a protector in that spot (see photo of an Evil The Following), but the TJ does not. Seems to be a manufacturing or design defect.
 

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#3 ·
Its on the outside of the chainstay. (Stupid MTBR uploading tool always rotates pictures.) I've never had chainsuck on this bike. I clean and lube the chain before every ride. The clutch XT rear derailleur is properly adjusted and the bike was purchased in April of this year, so the chain and chainring are almost new. Not maintenance related.

Hmm. Is anyone is using a 50t largest rear ring on their cassette? I'm wondering if that's the problem.
 
#4 ·
yes, it's obviously the outside. I asked top or bottom. which direction in the photo points towards the top of the bike? It's relevant.

It is the chain. there's not really anything else it can be. It's not the chainring because it's too far away. The top or bottom makes it relevant and can help diagnose the cause. chainsuck isn't always caused by drivetrain maintenance. but it usually is. Maybe it's chain SLAP instead. or, maybe there's excess drag in your freehub, resulting in slack on the chain when you coast or ratchet the pedals, and that slack gets jammed between the chainring and the frame (some will call this chainsuck, too).
 
#5 ·
Yeah, well, blame MTBR for their stupid photo hosting feature. Kinda top of the chainstay, but really more on the side of the chainstay than the top.

I've had two sets of wheels with different hubs and this gouging was happening with both hubs. No hub drag I can feel on either. I've never felt the chain get jammed or stuck either pedaling or coasting. With the clutch derailleur, the chain is pretty tight through all gears and I can't hear or feel slap.

It's a mystery, wrapped in an enigma, in a big ol' puzzle box.
 
#6 ·
Not so much of an enigma, TBH. The clutch on the RD mostly just helps with chain slap on the underside. It does a little for slap issues on the top run of chain, but it doesn't do so much there. When you're pedaling, the top run is under tension, anyway, and not so likely to flop around. When coasting or backpedaling, it absolutely can and will get loose and floppy enough to slap the chainstays. Though frame designs have often been tweaked a bit to give a little more clearance between the frame and the chain. This floppy upper run of chain can happen especially if you've got some drag in the freehub or if you've got a stiff link in the chain that hangs up somewhere in the derailleur. The hub drag doesn't have to be REALLY bad for this to happen, FWIW. It can be subtle. Pedal the bike up to a pretty high speed in a workstand and just let the whole thing coast. Do the cranks "auto pedal" when you let go of the pedal? You've got some drag. Ride over some bumps when this is relaxing the upper run of chain, and it'll hit the frame. If the chain fits REALLY snug (especially if there's some mud/dirt buildup), pedaling a little backwards can cause a bit of backwards chain suck.

If you know someone with a GoPro, you can clamp the camera back there and record video of this happening.
 
#8 ·
I'd guess that you backpedaled once or twice and the chain -- for whatever reason -- was semi-stuck to the chainring. @Harold is correct that nothing else but the chain could reach that spot. A 50T cog, especially if it overhangs the frreehub, could potentially contribute to a severe chainline that would increase chances that the chain sticks on the chainring when backpedalling.
I wouldn't worry about it. Its a small cosmetic flaw on the solid aluminum yoke (ie, no hollow center to rub thru to). Virtually no aluminum frames use the protectors that you are referencing . . . they are almost exclusively on carbon bikes, because carbon has far less abrasion resistance than most metals.
If you upgraded to the 50T cog versus stock, did you install a new chain? Because going from 46T to 50T, for example, would require two links of additional length to maintain the same chain length/tension.
 
#9 ·
Whatever it is causing it, it's just cosmetic. Had the same thing happen to my '18 TJ. I just cleaned the area up, and the put some gorilla tape over the area to protect it. Problem solved. Would be nice if Salsa would've put a decent chainstay protector on the bike for issues such as this, but since they didn't, black gorilla tape on the top of pretty much the entire chainstay works just fine for me.
 
#12 ·
Just noticed this same problem on my TJ XT as well. Very annoying having missing paint and big nick in a brand new bike that I've never laid down. I am also noticing significant issues while in the smallest cog gear, once I get in that highest gear it cha-chunks like it can't stay in it it very well, typically when I'm wanting to go max speed. Very uninspiring and a little nerve-racking actually. Any known fixes for either or both issues?
 
#13 ·
Yes. Gorilla tape over the entire chainstay will keep it from getting scratched. Also, it sounds like your derailleur needs adjusting if it's wanting to try to jump out of gear. Have the lbs get it adjusted. The shifter cable has likely stretched from when it was new. Most bike shops will make this adjustment for free if you bought the bike from them. If you didn't it don't usually cost much as no new parts are needed and it doesn't take very long to fix.
 
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