Help: chain shifting into back wheel

garetjax

I ride a Ribble Audxx winter training bike (compact). I bought it about six years go and it's been great.

I recently changed the rear cassette ( put on 11-28), the chain ( sram 10 speed) and the wheels. I've had a nightmare since...

Whilst out on a ride I rode up a hill, changed down a gear and heard a loud crunching sound. The chain had shifted into the back wheel and got completely jammed. I couldn't get it out and had to be rescued.

1. Took it into my local bike shop and they re-indexed the gears, but it happened again.
2. Took it back to the shop and he re-indexed, it happened again.
3. Tried another bike shop. They thought too it was just an indexing issue, fixed it, but out on a ride I again got chain jam..
4. Took the bike back to the second bike shop and asked him to put a brand new derailleur on ( i had a spare, like for like, and the bike club said it could be the culprit). He also replaced the chain and front chain ring as I had spares there too. I really thought this would finally sort it. Today, 10 minutes into my ride as I shifted down for a climb, it happened AGAIN.

Any ideas what is persistently causing this? I'm not great with repairing bikes, but I have been riding for twenty years at a good level, and never had this before.

Thanks

keezx

Do the rear wheel RH spokes cross after eachother?
BTW, i'm in roadracing for >40 years and NEVER a derailleur ended up in the spokes . allthough I rarely check the adjustment after changing wheels.....

bbrap

Surely its the limit screw that needs adjusting not the indexing (or do you count indexing as covering both?).

dj58

Is the low limit screw on the RD set correctly, is the B-Tension screw set correctly for the larger 28T sprocket, is your RD hanger bent? Can you replicate the over shifting with the bike in a bike stand?

garetjax

Hi again,

yes when the bike shops worked I assume they looked at the gear indexing and also the limit screws. They did say that they had done this.

I'm thinking of ordering a rear derailleur hanger, and going back to my old gears which were 12-26; however, I'd be surprised if this sorted it. So strange that two good bike shops have had the bike twice each, and not fixed it.

bbrap

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19743029#p19743029]garetjax[/url] wrote:

So strange that two good bike shops have had the bike twice each, and not fixed it.

I'd suggest that they might not be that good if they cannot diagnose the problem.

jgsi

How maintained is this bike?
What you describe can be a single fault or multiple...
chain wear.... cable wear inner and outer.. just plain p1sspoor screwdrivering error..
If you dont like getting your hands dirty just find a spannermonkey who knows their stuff about bikes.... I mean re indexing ( everyone makes it sound like rocket fuffin science ? .. its undoing a bloody cable and tightening it up again.

dj58

Take the chain off and manually push the RD cage towards the low/sprocket/wheel spokes and observe if it moves past the low sprocket and by how much. If the top guide pulley stops directly under the low sprocket and the tension pulley is heading towards the spokes, the RD hanger is bent. Or maybe there is something wrong with the new wheel, dishing/centring?

chaos75

Have you got the right spacers behind the cassette. depending on wheels you might need two, a 1.75mm and a thinner 1mm one. I had this exact issue with new wheels which were 11 speed compatible when using a 10 speed cassette.

6wheels

Could the chain be too short?

desweller

If the hanger is bent inwards or loose, no amount of fiddling with the indexing/limit screws will get the derailleur to shift correctly AND avoid the wheel. Check your hanger.