[stm32disco]

I ended up getting my tween a Rock Mountain Soul. https://www.bikes.com/en/bikes/soul/2019

The bike comes with a Sunrace 8sp 11-40 cassette and Shimano Altus long cage RD-M370-SGS. Shimano says this derailleur has a large cog capacity of 34T. The front chain ring is a 28T narrow wide.

She's popped the chain off a couple of times on some rough and fast terrain and she complains about chain slap.

I think the chain length is OK though I haven't measured it properly. To me, it seems like the RD is underspec'd. Is there a better RD I can put on there? Or should I put a smaller cassette on it?

 

[stm32disco]

I found a couple of other threads:

https://forums.mtbr.com/drivetrain-...ks/wide-range-8x1-sunrace-csm680-1040600.html

https://forums.mtbr.com/drivetrain-...railleur-8-speed-11-40t-cassette-1039658.html

A derailleur with a clutch would make this cassette a lot more usable, but there aren't any 8 or 9 speed derailleurs with a clutch. I'm thinking that chain slap and the occasional drop is just a limitation of this low-cost drive train. It probably makes more sense to start collecting parts to convert to 10 speed.

 

[OneTrustMan]

I found a couple of other threads:

https://forums.mtbr.com/drivetrain-...ks/wide-range-8x1-sunrace-csm680-1040600.html

https://forums.mtbr.com/drivetrain-...railleur-8-speed-11-40t-cassette-1039658.html

A derailleur with a clutch would make this cassette a lot more usable, but there aren't any 8 or 9 speed derailleurs with a clutch. I'm thinking that chain slap and the occasional drop is just a limitation of this low-cost drive train. It probably makes more sense to start collecting parts to convert to 10 speed.

The Microshift Advent is a 9sp with a clutch and can handle up to 46t max.