Chain-slap when using a Wolftooth link

[Malcmeister]

To get the widest possible range of gear ratios I've fitted my Ti tourer with a Wolftooth link, using a Shimano GRX 48/31 crankset and 11/42 cassette running with an Ultegra RD-6800GS rear mech. A bit outside the recommended range for the Wolftooth, I know, but It all works fine except that I get a bit of chain-slap in the highest gears. I've already fitted the cage return-spring in the hole that gives the most tension. Was wondering if increasing the return-spring strength would help. Is there a stronger version available? Is the SS type cage return spring stronger or weaker than the GS, and can they be swapped, or is it the same part? Might a GRX rear mech with a clutch solve the problem?

[roubaixtuesday]

To get the widest possible range of gear ratios I've fitted my Ti tourer with a Wolftooth link, using a Shimano GRX 48/31 crankset and 11/42 cassette running with an Ultegra RD-6800GS rear mech. A bit outside the recommended range for the Wolftooth, I know, but It all works fine except that I get a bit of chain-slap in the highest gears. I've already fitted the cage return-spring in the hole that gives the most tension. Was wondering if increasing the return-spring strength would help. Is there a stronger version available? Is the SS type cage return spring stronger or weaker than the GS, and can they be swapped, or is it the same part? Might a GRX rear mech with a clutch solve the problem?

Do you get chain slap in the 48 or the 31 chainring, or both?

Can the chain be shortened and still run 48/42?

[Nearholmer]

Whatever else, the GRX clutch does work a treat, so I’d put it high on your list of things to consider.

As an aside, is there any disadvantage of the clutch? I run with mine engaged all the time, and would be interested to know if I’m suffering some (theoretical?) penalty as a result.

[rareposter]

You're way outside the specs of what the RoadLink and the Ultegra mech will do.
Fitting a GRX 810 rear mech might help but the whole system is still outside spec and you'll still be dealing with a chain that needs to be that long in order to cope with that gear range.

An SS mech won't cover that range and the spring is the same as the GS anyway.

[Pendodave]

Whatever else, the GRX clutch does work a treat, so I’d put it high on your list of things to consider.

As an aside, is there any disadvantage of the clutch? I run with mine engaged all the time, and would be interested to know if I’m suffering some (theoretical?) penalty as a result.

I have a grx rear mech and I'd also like to hear opinions on this. Fwiw, I run mine off, but not for any reason.

Also, how does "chain slap" manifest itself? Is it a noise, or can you only tell afterwards by (for example) marks on the chainstays etc?

[Malcmeister]

Hi 'chain slap' only happens in the two or three smallest cassette cogs. It does it for both chainrings, but I would always avoid using the small chainring with those cogs. The chain can't be any shorter, I've tried.

[Malcmeister]

The chain-slap manifests itself as a 'jolt' felt through the pedals when stopping pedalling (or worse back pedalling) as the chain overruns and there's a pause before the cage takes up the slack. The jolt is the cage snapping back into tension. This can also be heard.

[roubaixtuesday]

6800GS capacity is quoted as 37

Your setup requires a capacity of 48, so you can expect chain slap.

However, on the big ring alone, you're within capacity, so there may be something else causing your issue - chain slap should only happen in the little ring?

Grx 812 quoted capacity is 40. Again, you can probably expect issues on the small chainring, I think?

[geocycle]

I have a grx 810 mech with the wolf tooth and an 11-40 cassette, all works well. All gears are usable with the inner ring, and all but the three largest cogs while on the big ring. When initially set up by Spa I used the clutch on all the time, however after a bash I replaced the hanger and it works but I always feel the shift isn’t quite as smooth as it was before. With the clutch off it feels smoother.

[pq]

I ran my tourer for a while with a 10 speed campag triple rear mech with a knock-off wolf tooth extender and had the same problem (+ the inevitable vague shifting). I've now abandoned that and fitted a grx mech which is near enough Campag compatible and the problem has gone away - and the shifting is nice and crisp. My solution won't work for you, my point is that using the right tool for the job worked better than bodging up what I already had, and I imagine you can find a rear mech which will do what you want out of the box.

[Pendodave]

I have a grx 810 mech with the wolf tooth and an 11-40 cassette, all works well. All gears are usable with the inner ring, and all but the three largest cogs while on the big ring. When initially set up by Spa I used the clutch on all the time, however after a bash I replaced the hanger and it works but I always feel the shift isn’t quite as smooth as it was before. With the clutch off it feels smoother.

Sorry to be a bit dim...
Is the hanger still the wolf tooth one?

Fwiw, I've just put an 11-40 on my grx 810. Didn't put the wolf tooth on, just put a bit more twist on the B screw. It seems to be fine. I'm going to try clutch on and off to check whether I can tell a difference. All gears seem to work fine, but I couldn't imagine putting it above the 34 tooth on the big ring - if it's that steep, I'd have been in the small ring some time earlier!

Re. Slap, I might have experienced the delayed pickup described above, but need to do a bit more experimentation.

I've kept the 11-34 handy just in case!

[geocycle]

I have a grx 810 mech with the wolf tooth and an 11-40 cassette, all works well. All gears are usable with the inner ring, and all but the three largest cogs while on the big ring. When initially set up by Spa I used the clutch on all the time, however after a bash I replaced the hanger and it works but I always feel the shift isn’t quite as smooth as it was before. With the clutch off it feels smoother.

Sorry to be a bit dim...
Is the hanger still the wolf tooth one?

Fwiw, I've just put an 11-40 on my grx 810. Didn't put the wolf tooth on, just put a bit more twist on the B screw. It seems to be fine. I'm going to try clutch on and off to check whether I can tell a difference. All gears seem to work fine, but I couldn't imagine putting it above the 34 tooth on the big ring - if it's that steep, I'd have been in the small ring some time earlier!

Re. Slap, I might have experienced the delayed pickup described above, but need to do a bit more experimentation.

I've kept the 11-34 handy just in case!

Yes, it was set up with a hanger and a wolf tooth. The hanger had bent beyond what I could easily straighten without a derailleur alignment tool so I put a new hanger on. I’m slightly concerned the wolf tooth bent as well but everything changes just fine so it can’t be much. I can get the chain big onto big so the chain 8s long enough but the chatter in the three biggest sprockets tells me I shouldn’t, as you say I would have changed down at the front by then anyway. Without the clutch everything is really sweet, but with the clutch on it feels a bit laggy which I didn’t notice from new. The clutch does stop chain slap and I’ve never had a chain come off.