UKH

After spending too much time on google, and finding only SRAM/Shimano comaprisons, I'll try the all knowing hive mind.

Is there any difference in spacing between the MTB and road SRAM 11x cassettes?

I tried a used 11 cassette from a mtb wheelset on my cyclocross bike, and cannot get the derailleur aligned so that the chain is not jumping somewhere in the range.

I know that the road and mtb shifters work only with the corresponding derailleurs, as they take in different lengths per step, but AFAIK the end result should be the same.

Any ideas?

Thanks, CB

In typically UKC style, I'm going to say that I've previously mixed SRAM and Shimano cassettes on road and mtb without any issues, but only with 9-speed - I put the SRAM cassette off my MTB (XT shifters) on my road bike (Ultegra shifters) for a very hilly event.

I was under the impression that at 11 speed, the spacing between Campag and Shimano cassettes is exactly the same (or as near as makes no odds) and they are interchangable (I've yet to try it personally), so I don't see why SRAM would be any different.

Some cheap digital callipers can be your friend here, you should measure the ‘cog’ spacing and compare the 2 cassettes. Also measure the back of the cassette with a straight edge and feeler gauges to see if you need a spacer or not. see this video from 11 minutes:

youtube.com/watch?v=V-MjUp7EVjQ&

It may be the rear mech, is it a long cage? 

That would be cheating!

The real problem is that the two bikes are parked 500km apart. I will measure mine here and teh other one next time I visit my family, but had hoped to get an answer so I could order the proper cassette if required, and have it delivered by next week!

CB

The cage does not seem to be the problem, the biggest two (36 and 42 teeth) sprockets shift easily and precisely, the chain starts jumping around the fourth to second smallest ones. The smallest is fine again. The only hypothesis I have for the smallest one working again is that the derailleur actually tries to move the chain lower as well (based on cable tension) but is stopped by the stopper screw, which would be consistent with the spacing being slightly off.

CB

Shimano 11x  with SRAM shifters is no issue, that is what I put on my son's bike and it works a treat. In the process I swapped around some parts between several bikes. My son's cyclocross bike and my wife's MTB are running well, but I FUBARed my cyclocross bike.......

CB

I have used mob/road without issue but I checked in with a friend who is a bike mechanic and they said its fine, spacing is the same on 11x road & MTB.

Are the sprockets worn or the chain stretched?

Sounds a bit like your derailleur could be bent slightly, or at least the cage.  If you follow the Shimano setup procedure fully to align the 1st and last gear with the stops, and the shift point with the cable adjuster, but it still goes funny just in one part of the range, the symptoms can be as described and there isn't much else that can go wrong I think, other than guide wheel to sprocket spacing possibly.

I had it before after a crash, and it took a bit of trial and error to realign everything so it shifted smoothly across the range.

Did you have a crash on the bike perhaps?  Otherwise, I could only think of some wear, crud or damage in the cassette which has caused some inconsistent gear spacing or alignment.

Thanks! Need to look elsewhere, then.

CB

Chain is new, sprockets almost new, no discernable wear. Proper mystery...

CB

Not really, but will check once I get my work stand back to where the bike is....

Thanks,

CB

Stiff chain link? 

Is the cable routed and clamped in the correct position at the pinch bolt on the derailleur? Any wierdness here can affect the pull ratio.

No, new chain and I checked the link. CB

Unlikely, worked nicely with the old cassette...

It really is a mystery!

Anyway, thanks for all the comments!

CB

I suppose an obvious question ( and not knowing that particular cassette), has the cassette itself been put together properly with all the necessary spacers between cogs?

Looks fine by eye. I will take my calipers and make sure on the weekend....

CB

Check hanger isn't bent. That's more likely than bent cage as its designed to be a sacrificial bender to prevent damage to derailleur. I usually keep a spare hanger partic for gravel bike as it tends to get hammered more!

I never  had a crash, and the problems appeared as soon as I changed the cassette, so probably related to something there.

Thanks,

CB