Rear mech making contact with cassette - WTF?

[αdαmsκι]

I've got a 10 speed Campag compact setup, 34T / 50T up front.

When I use 34T and the second largest sprocket the rear cassette touches the rear mech. It's only in this combination I have this issue. I've no idea what's going off; anyone got any hints?

 








I knew there was a reason to ride fixed.

[Samuel D]

You just need to loosen the ‘A-tension’ adjustment (or whatever Campagnolo calls the screw that does the opposite of a Shimano B-tension screw). The problem only arises in the smaller chainring because then chain tension on the ‘slack’ run is lower.

Mavic makes chains? I never knew.

[Brucey]

before you do that, you should take a look at the way the rear mech is bolted together; I think you have the inner cage plate on upside down, and that this will be the thing making contact rather than the pulley itself perhaps.

Have you just cleaned/serviced the pulleys by any chance...?

BTW this isn't your mech but it does nicely show the inner cage plate as it should be (which yours clearly isn't....)


cheers

[Hot Flatus]

Alternatively, remove from bike (and all other drivetrain) and replace with something that works (Shimano). You'll need a new back wheel too

[Biggsy]

The chain being too long can leave the upper pulley wheel too close to the cassette, but that's not the problem here.  I think Bruce is right.

[αdαmsκι]

I'll check out first thing tomorrow morning.

The jockey wheels may have been off at some point but it's difficult to remember. This bike hasn't been used for ages as I have been riding the fixed gear bike this year and in 2016 was using the touring bike.

Flatus: Thanks for your useful input.

[Biggsy]

I can see some black cheese on the jockey wheel so it looks like it's been ridden like that.  Perhaps some unimportant thing made the mech position change slightly to make the real problem apparent at last.

[αdαmsκι]

Perhaps some unimportant thing made the mech position change slightly to make the real problem apparent at last.

Hmm. Like being dumped into the boot of a car and then placed in storage and then extracted from storage again

[Ian H]

I think Brucey is right in this instance.  However, I have had old, rather worn and floppy mechs ting gently against the spokes on the lowest gear.  A low-tech solution is to firmly yank the tension arm away from the wheel (worked for me, anyway).

[Brucey]

Mavic makes chains? I never knew.

IIRC they had Wipperman make chains with Mavic branding on them at one time.

cheers

[αdαmsκι]

I think you have the inner cage plate on upside down, and that this will be the thing making contact rather than the pulley itself

Well spotted. Now sorted. Thanks.

[Samuel D]

That’s all you have to say for yourself, αdαmsκι?

[nobby]

That’s all you have to say for yourself, αdαmsκι?

 

[vorsprung]

Flatus: Thanks for your useful input.

snigger 

[Hot Flatus]

Flatus: Thanks for your useful input.

snigger 

I know this bike and its parts well