Bicycle Mechanics - Auto-shifting across the cassette in last two cogs.

My chain is "auto-shifting" across the last two cogs on my cassette. In fact in the last cog it wants to jump off and go into the spokes. In have no problems on the other cogs. It is enough of a problem to limit myself to using only 7 out of the 9 cogs. I'll admit my chain is a little dirty (because of the weather)....I'm going to take it off the bike and clean it to see if that helps. I haven't measure chain wear yet....I'll go do that right now.

why are you on them anyway? you're mister 53-11! seriously, it sounds like the exact thing I had happening on my 14 and 15T cogs, the ones I use the most. It turned out that they were just flat out worn out. I had 5280 miles on that cassette, though. how many miles are on your cassette?

try shifting while not on the bike and look to see where the derailleur is going. it might be a limit screw

aren't those the "N00b cogs" why are YOU using them anyway?

but seriously, they're probably worn (unlikely, since god forbid 53-11 would use the noob gears) or your derailleur is out of adjustment. Chain into spokes sounds like a limit adjustment problem.

Isn't automatic what everone wants? Patent it, quick.

We'll the chain has got 1/16" of wear on it. It is also the first chain on this cassette ( I didn't see any shark finning on the cogs).

I'll change out the chain anyway (I don't let it get past 1/16" as rule) and I'll try adjusting the limit screw like you guys said.

well that would probably be your best bet, just when you have the chain off put your shifter at gear 1 and just see how far the derailleur travels, if its not right below the cog, like it is traveling closer to the spokes, its a limit screw problem

Also check that the der is hanging straight.

Also check that the der is hanging straight.

I agree with Andrew. Whenever you have a shifting problem that seems strange, the first thing to do is to check to be sure everything is in the default mode. In this case that means derailleur hanger alignment.

Also check that the der is hanging straight.

After that, check the cable tension. I once cured 'auto-shifting' on the last two cogs by changing rear derailler tension a bit. Can be done with that thingie that 'guides' the cable on the right-hand side of your down tube.

Yup, echo those above with the following:

1. Check hanger & derailleur are straight

2. Check limit screws

3. Adjust cable tension for correct indexing

4. Ride and check, repeat if necessary

Cheers and good luck,

Ed

Good luck,

Ed

Sounds to me like your doohickey has been fandangled. Try adjusting it with the monkey wrench.

:)

55/Rad