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I've had the same Trek bike for 3 and a half years with ongoing shifting problems, but for the last 6 months I've had a litany of problems. My LBS is at their wits end.

Spokes are shearing regularly, the chain is jumping gears while not shifting and derailing when shifting, etc. This was going on before replacing anything, and is continuing after the following replacements:

  • Several spokes replaced
  • All spokes replaced
  • All front and back gears replaced
  • All spokes replaced again with the strongest ones the shop could get
  • Chain replaced
  • derailleurs cogs replaced
  • derailleur replaced
  • all cables replaced

I've had years of issues with gears not shifting correctly and chains jumping on both this and other bikes, so on that level it could be partially related to the way I'm riding (please advise), BUT this is a whole other level. I put a lot of power into my ride and push hard uphill in hilly terrain, though I'm not sure if or to what extent that would impact this.

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    Are you a heavy rider? Also i assume the wheels were trued professionally with spoke replacement? And what brand/model shifters and derailluer are they? Could be that they use different pull ratios and are there for impossible to adjust perfectly. Is the "best bike shop in town" the only bike shop in town? :P – Nate W Jun 30 '16 at 17:25
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    Find a different shop. You also may need to split this into multiple questions, since it basically sounds like nothing is in adjustment, everythign is replaced and everything is wrong. – Batman Jun 30 '16 at 18:00
  • Is the axle in good condition? I was once riding on a broken axle, and the quiick release was really the only thing holding it together. – Kibbee Jun 30 '16 at 20:32
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    I've significantly edited the question to trim it down and clarify it. If I've stuffed up what you're asking please revert my edit or re-edit it to make your question stand out. – Móż Jun 30 '16 at 21:54
  • I wonder if you've cracked or bend the frame about 6 months ago, and everything is a follow-on from that? – Criggie Jun 30 '16 at 22:57
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Have you and the shop both checked the frame very carefully for damage?

It sounds as though you're probably too heavy or too strong for the frame you ride. Bikes are built light, and have a designed weight limit. But that limit is generally based on an average rider, so the stronger you are and the more you slog rather than spin, the more you have to allow as a margin over your actual weight.

It's quite possible that your long-term shifting problems stem from this - when you put the power in your frame flexes, the cable routing changes a little, and the gears shift. You can try crossing your gear cables under the down tube to reduce the size of the problem, but that only helps mask the problem, it doesn't fix it.

Over time you're also likely to crack the frame. Once cracks appear your frame will be weaker, and flex more than it used to. That will make the shifting problems worse. But the cracks will start out very small, and you'll need to clean the frame and basically polish it, then very carefully check for cracks in the paint in good light. One trick is to get contrasting touch-up paint and put that over any suspect areas, then once it's good and dry flex the frame. The touch-up paint will crack much more obviously than the underlying frame paint if there's a problem with the frame underneath it.

The solution to this is to buy a stronger bike. Especially if you're a heavier rider who tends to push big gears, you put a lot more stress on the frame than an average rider. You may find you need to add 10kg or 20kg to your actual weight and buy a bike rated to that weight.

(anecdote: I'm quite a powerful rider and have broken a stupid number of frames, and also handlebars. I've learned that carrying an extra kilo by buying stronger parts is well worth the effort, and my current lightweight road bike is between 9 and 10kg in "race trim", including disk brakes)

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