Shimano 10sp cassette uneven spacing and shifting issues

[wafter]

Thanks folks

If ever I need something analysed in some detail, I am giving you a shout. 😁

Cheers - perhaps "OCD by-proxy" is an untapped service industry waiting to be exploited

Can you measure the spacers and see if they are consistent or not?

Not any more than I already have as the first eight sprockets are riveted together in a single block.

Is it a genuine cassette ?

To the best of my knowledge - it appears to be the original that came with the bike although is Covid-era so anyone's guess as to its provenence. Actually I've not explicitly checked that it's a Shimano item (certainly looks like it) but it should be according to the specs and regardless of brand should bloody work!

If you've had it a few years I'd just get a new one and replace the cables with SP41 Optislick.

It's all nearly new - bet it's not done more than 200 miles in its life.

10s cassettes aren't that expensive. Must be worth buying one to see if it solves the problem.

Worst case: you've got a spare ready when the current one wears out.

True, although the bike's already turned out to be a massive money pit, it should be right and I'm not really keen on accumulating any more "spares" i I can help it; having taken the "replace it and see" route more times than I probably should have in the past..

Counterfeit cassette?

As above, to the best of my knowledge OEM-fitted to a branded bike so should be right.

I’ve been working on a 9 speed Specialized Cirrus at work which we couldn‘t get to shift properly after fitting a new chain and cassette, after swapping inner and outer cables then the shifter, I then removed the rear mech degreased it and still no improvement. In desperation I fitted a brand new rear mech and that solved it.

Thanks - in this case the issue with the cassette seems obvious however and it's behaved the same way with two different RD's fitted..

A quick Google search suggests the bigger cogs on a 10sp Shimano cassette are spaced further apart than the smaller ones.

I believe I read years ago the extremes (low and high) are spaced further apart to compensate for the derailleur movement describing an arc, rather than a straight line.

Thanks; while that makes sense the sprocket pitches look much more like a fecking lucky dip:

Unsurprisingly shifting problems are experienced at positions 2-3 and 9-10..

Yeah, that is a weird one. A bent cassette spacer behind the big sprockets could cause that issue at both ends. It's a cheap and easy thing to check first.

Do you mean the spacer that fits between the sprocket and hub on 11sp hubs? Im not sure how this would work as IIRC all of the sprocket are separated by plastic spacers, with the exception of 1-2 which from memory are just separated by the main steel / alloy cassete spider more outboard nearer their teeth, and 8-9-10 which are deeper / have integral spacers (not-very-helpful exploded diagram here).


For an idea of the cassette's construction the video below shows one being stripped (rivets drilled out) - looks like it's 10sp and might be the same model although 11-42 while mine's 11-34: