Chain rubbing on outer chainring

[DWM]

Hi

Over the weekend I fitted new wheels (together with a new chain and cassette), and replaced the BB on my Croix de Fer 20 2015. All components were a direct replacement. I'm running 10 speed, 34/46 chainrings.

Now, when in the inner ring, the chain rubs on the outer chainring when using the smallest 3/4 sprockets (I know you shouldn't cross-chain too much, but this seems a bit excessive!). The new wheels are 11s compatible, so I fitted the spacer that came with them before my 10s cassette.

I've read a lot online that suggest using a small spacer between the chainrings, but I don't think I should have to do that as it all worked perfectly well before (in fact I think I could run small-small without the chain rubbing).

I think the cranks (Tiagra) are fitted correctly (no spacer between the BB and the drive-side crank) as they spin freely and there is no play, so this suggests that the cassette is not fitted properly, however I can't see how this can be the case. The cassette was a bit difficult to get on the free hub, but there is no movement anywhere, and the lockring is correctly torqued.

Any ideas on what I can try next?

Many thanks

Dave

 

[lpretro1]

new wheels may mean cassette not sitting in exact same position so you may need to adj derailleur cages slightly to accommodate. No reasons to start doing anything else at all

 

[DWM]

new wheels may mean cassette not sitting in exact same position so you may need to adj derailleur cages slightly to accommodate. No reasons to start doing anything else at all

Thanks for your reply.

I should have mentioned that I re-indexed the gears after fitting the new wheels.

Cheers

Dave

 

[lpretro1]

Bit more tension of fd cable then...

 

[DWM]

Bit more tension of fd cable then...

Thanks again.

The chain is definitely rubbing on the inside of the outer chainring, not the FD cage.

Cheers

Dave

 

[fossyant]

New wheels can mean slight rubbing I'm afraid as the sprockets can be slightly differently aligned.

Double check you have a 10 speed chain. Did you use a spacer on the crank before ? If 'yes' then re-fit it as it can change the alignment slightly.

If all is OK, then there isn't much you can do. PS check the trim on the front mech - is the chain rubbing on the front mech as I'd expect to trim the front if using those sprockets

 

[Ajax Bay]

I'd put the spacer inside the right Tiagra crank anyway, whether or not it 'ought' to need to be there. This will get the front of the chain line more than 1mm right and should alleviate your problem, except maybe small-small which if you ever go there you won't stay long.

The cassette was a bit difficult to get on the free hub

In what way 'difficult'?

 

[DWM]

Thanks all

There was no spacer originally, and the new BB did not come with one (the Shimano docs suggest it is not required). I may however try one anyway to see if it helps.

In what way 'difficult'?

Difficult was perhaps the wrong word. The cassette needed a bit of force to get it in place. I will double check that it is has been fitted properly.

Cheers

Dave

 

[lpretro1]

You maybe need a slightly narrower spacer behind the rear cassette if it was a very tight fit?

 

[Ajax Bay]

The cassette needed a bit of force to get it in place.

In no way should slotting a cassette onto a freehub require any force at all, until you tighten the lockring to 40Nm.

Double check you have a 10 speed chain.

 

[DWM]

Thanks for all your replies.

I've had another play and the problem persists.

The cassette seems to be fitted correctly. I removed the 10s spacer on the hub and tried it but as expected the lock ring would not engage properly. With a light smear of grease on the free hub the cassette goes on smoothly.

The chain is definitely 10 speed.

The only thing I can think to try next is to re-fit the old drive side BB cup to see if that alters the position of the crank - I can't imagine it will make any difference but it's worth a try.

Cheers

Dave

 

[Tigerbiten]

Whats the gap between the chainring ??
If the new spider is thinner than the old one, then the distance between the rings will be narrower and the chain may rub.
Hold the old chainrings in line with the new ones (big to little will help) and see if the gap is the same.

I've had to a washer on each bolt to increase the distance between my chainrings by 1 mm otherwise the chain rubs on the outer ring when on the inner ring.

 

[Ajax Bay]

This is not a new chainset @Tigerbiten (see OP's first post), it's the BB and wheels he's changed. He had discounted (or was reluctant to adopt) the spacer between chainrings option:

I've read a lot online that suggest using a small spacer between the chainrings, but I don't think I should have to do that as it all worked perfectly well before

Nevertheless your washer suggestion may work as the FD is not really indexed and the trim stops will still allow effective changing.

 

[raleighnut]

It sounds to me like fitting the new rear wheel has simply changed the chainline and fitting the spacer/shim to the crank may be the only option to fix it.
The other choice may be to change the back wheel to a 10 speed freehub (from an 11) that doesn't need the spacer, that'd put the cassette back where it was previously.

EDIT this is the type of spacer I'm referring to, not one that sits between the bearing cup and the Bottom Bracket


Although fitting one there would probably do the job too.