BBSHD vs cassette: Is skipping common?

[onemorejoltwarden]

I have a BBSHD on a Cannondale Quick, I weigh 170 and have had progressive skipping in the 2 highest gears.
I have replaced the chain and freehub, the Acera RD and adjusted B-screw maximally and checked RD alignment.
Does not appear to be coming from the relatively new BBSHD. (~100 m)
No problems with other gears.
I have a new cassette on order, but old one appeared on inspection to be OK.

Is chain slip common on the 11 and 12 tooth cogs (Sunrace 11-32) ?

Any other places to think of? It is smooth and other wise problem free.
I may just need to avoid those gears, but it makes pedaling at speed , then slowing a bit overly distracting

 

[Bengy22]

Just depends on how worn you cassette is. I will always recommend a all steel cassette for a mid drive motor, can take more power and last longer for not much extra weight. A while back I upgraded my hub on my bbshd bike and I had no issues with any skipping before hand and a visual inspection of my cassette showed no need to replace. I believe I might have also taken this time to install a new chain. Instantly had huge skipping problems, mostly in 3rd and 4th (this was a big hint because its my most used gears). Because the hub I bought had a higher engagement I was convinced it was that skipping so I reversed all my work just to find out it was still skipping after. Then realized it was the cassette and swapped on a spare I already had, issue was gone.

The 11 and 12 tooth gears have very little material and chain wrap, this is why a lot of manufactures make these gears replaceable without replacing the whole cassette as even on a non ebike they can wear fast. On ebikes its recommend to avoid these gears as much as possible due to this, and if you do use them to not start out from a stop on them, only use once up to speed.

 

[Chalo]

Mid drives eat up cassettes and chains. For reliable service, replace both of them as soon as the chain elongates 0.5% or as soon as the first sprocket starts skipping. Replace them together, because worn parts transfer their wear to new parts almost immediately.

 

[onemorejoltwarden]

Thanks GOT IT FIXED
New cassette (last thing replaced) did the job. Motor has only about 350-500 miles on it (Not the 100 first supposed)
First did chain , alignment, and RD adj and then replace RD (all within spec) then freehub , then cassette which I will have to do a closer exam of , as it looked fine , by all recommendations, except function.
Realize I should have done chain and cassette as a piece , but cassette looked good.
Didn't act like the internal BBSHD gearing, but was hard to localize.
Went with a steel Shimano CS-HG200-9 and Shimano chain. Chain line OK with small sprockets, but poor on the bigger ones, so may replace factory front sprocket for one with with better offset,
Sounds like best to avoid softer aluminum ones
Current factory one has 46t, 8mm clearance to chain stay and 50mm to seat tube center 22mm dish /offset on chainwheel.
'Till then avoid high and low sprockets.
Learned a bunch in doing it, that I need to know in the process.
Thanks for the info on small cogs, Bengy. Will double check them against a new one before reusing.
and thanks once again to Chalo, an ever present source of good stuff.