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Had an off on the ice in Jan (back wheel slid out from under me & bike slid along the ground on drive side) & bent the mech hanger. This has been replaced, but still not indexing properly. There was a suggestion that I might have done the mech too, but replacing this hasn't helped.
Given that there isn't any obvious frame damage (ie. cracked paint etc) how likely is it that I've knocked the (alloy) frame out of true?
Andy
it's a 10 minute job for someone with the right tools to check frame alignment so probably best just to pop to a local shop with the tools and get it tested?
Pics?
Sure everything has been set up and adjusted properly?
Sure everything has been set up and adjusted properly?
No; it's going to the shop next week but I'm worrying myself there's something very wrong. Also broke chain x2 today which can't be right either.
Andy
if whoever fitted your new mech hanger aligned it to the wheel with the right tool it shouldn't matter if your frame is slightly bent.
Most alu frame are suprisingly out of alignment at the rear from new anyway.
what oblique said - as long as the mech is parallel to the wheel then there's something else causing it.
agree with above, it actually needs to be really bent for a derailler not to be able to be adjusted round it.
Last month my mate took his bike to two different bike shops as it kept skipping the chain, 1st replaced rear mech, cassette, chain and cable, still wasn't fixed, 2nd charged for 2 hrs of investigating and it still wasn't fixed, they cited a bent frame. I rode it up the road once and instantly spotted it was jumpin down from middle ring to granny and back up again every rotation. 4 bent teeth on middle ring.
Some bike shops are not as comprehensive in what they do as I am ....
As Al and Oblique said, if the hanger is straight it should still shift. Nevertheless, if you want a quick check for frame alignment, as always [url= http://www.sheldonbrown.com/frame-spacing.html ]Sheldon has the answer[/url]!
From
The String Method:
1. Tie a piece of string to one rear fork end so that the string runs along the outside of the fork end.
2. Run the string around the front of the head tube and back to the other rear fork end.
3. Pull the string taut, making sure that it's contacting the same part of each fork end.
4. Use a ruler to measure the distance from the string to the side of the seat tube where they cross. Take this measurement on both sides, it should be the same on each side.
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I'll measure it up later and report back. As I've said above, there's no paint cracking or anything to suggest it's more bent that it was when new.
To ask a stupid question, would very worn chainrings and a misaligned front mech stop the back indexing properly? I know the chainrings need doing but have been holding off until chain done then was going to do cassette as well...
Andy
toys19 - Member
Last month my mate took his bike to two different bike shops as it kept skipping the chain, 1st replaced rear mech, cassette, chain and cable, still wasn't fixed, 2nd charged for 2 hrs of investigating and it still wasn't fixed, they cited a bent frame
Outrageous!
Gte back to your carbon calculations! 😡
By the string method, it looks like it's about 30mm bilaterally from string to seat tube (& therefore symmetrical).
So, that takes us back to mech (rear ?bent, front possibly misaligned as I fitted after wrecking its predecessor) or knackered chainrings/cassette. Anyone any other suggestions?
Andy