Two identical DT Swiss P1800 wheels… but different cassette position.

[Oms]

Hiya.

I've two P1800 disc wheel sets.

Despite having identical 105 R7000 11-32 cassettes on them, the indexing is off when I swap wheels (off to the point where I have to re-adjust the hi/low derailleur screws, as well as re-adjust the cable tension substantially). Clearly they sit in quite different positions.

I swapped one cassette for an 11-34 - same problem. So it's not the cassettes causing the issue.

I can't get my head round why this might be happening. I've taken the cassettes off to inspect and they both seem fine... look the same... and fit onto the free hub the same at first appearance.

Seems odd - any suggestions as to what might be causing it?

Fankoo.

[alcatraz]

That sounds odd but for a different reason. The 11-34t cassettes are narrower and require a spacer to fit onto 11s freehubs. It's because the big cog clears the spokes so well they managed to make it 10s freehub compatible for old wheelset compatibility with 11s.

So the 11-34 should definitely sit differently (or not clamp completely) on the 11s freehub. If you look at the back of it, the freehub stop is recessed. On the 11-32t cassettes it shouldn't be. (if my understanding of this is correct).

I can't explain why the two 32t are different. Compare the cog clusters. Some have A/B/C stamps on them. Meaning they're meant to be used with different jumps. Also it's possible you have some cogs from other cassettes mixed into a 105. That's one problem with shimano cassettes that if you dump them carelessly in a box with other cassette parts, it's going to be really hard to find the right parts again. Clusters, spacers, cogs. As mentioned, shimano make several kinds of cogs/clusters with the same tooth counts.

[Oms]

Hi Alcatraz,

Thanks for the reply.

I did find the 11-34 spacer a bit strange (particularly as it was branded as an ultegra cassette), but I did as I was told and popped the spacer in there.

It looks like I'm going to have to disassemble both wheels again and get measuring to see what's what. I'll also check the cassettes (both shipped pre-assembled on the wheels from Rose, but you never know!).

Out of interest, could the axle be slightly off on one of the wheels (some oddity in the way that the bearings/axles are assembled)?

[alcatraz]

Here's an odd idea.

Maybe you got the endcaps mixed on one of the wheels. (if they're directional) left/right.

It's unlikely but I'm just brainstorming here...

Pull the freehub off and compare the inner sleeve sizes. Maybe one is slightly longer for a different model hub. Sometimes people swap freehubs and just get the wrong spacer sleeve.

[Cleaner]

Have you checked the dish of the rims? Even though the wheels are identical the dish will vary and this will shift the cassette position relative to the hanger in the frame. It is not likely the only issue here but it is worth checking. Measure the position from the frame dropout to a cog on each wheel and compare the values.

Have you tried using the same rear wheel and only swapping the cassette? This would narrow down the root cause potentially.

[alcatraz]

I'm pretty sure the dish doesn't affect the cassette.

[ghostinthemachine]

Dish is the hub/rim relationship, not hub/cassette.
It might help to highlight if the end caps are reversed though.

[Oms]

Thanks for the replies.

Definitely not the cassette - I do wonder whether the caps were muddled up at the factory though. I'll have a good look/measure after it's had a clean.