Micro compact chainset compatibility

graemevet wrote:

I'm confused by various standards and I hope that someone can help. I'm only little and in order to help on super steep hills I want to change the chainset on my 2015 Canyon Endurace. I'm currently running a 105 5800 34/50 chainset. Press fit bottom bracket (?BB30?).

I want to run one of these in 30/46 spec:
https://www.suginoltd.co.jp/us/products/road/ox.html

Am I correct in thinking that the Shimano 5800 chainset shares the same 24mm spindle diameter as the Sugino one or would I require some sort of adapter for the bottom bracket?

Does anyone know if this would cause any issue to the 5800 Front Mech? FYI I have a GS 5800 rear mech and an 11-32 cassette.

Thanks

Graeme

I think so. Clicking on their BB link takes you to their BB30 to ID24 bottom bracket. Says to me that this has a 24 mm axle. Lovely looking chainset BTW.

That looks like it would just be a straight swap, so you could leave whatever BB you have in there (it won't be bb30. Shimano press-fit in a BB86 bottom bracket shell I'm guessing)

You'll likely need to shorten your chain and drop the front mech down a bit.

The front mech is the only thing you need to check. Will it be feasible to lower it a bit? If a braze-on mount, is there room in the slot to slide it down? If a band-on, does the shape of the seat tube allow you to loosen it and slide it down?

On my winter bike I've fitted a 46/36 CX chainset and the band-on mount would only drop a bit before it fouled the lower bottle cage boss, so the mech sits a little higher than I'd like. It still shifts sweetly though and I've never dropped the chain

graemevet wrote:

Thanks everyone - I think you've all uncovered the incompatibility that I didn't spot - Looking at the braze-on mount I don't think it'd drop much lower that it already does so I'd run the risk of dropped chains and poor shifting.

Looks like plan B (keep current chainset):
Shimano XTR M-9000 SGS rear mech
11-40 or 11-36 casette
JTEK Shiftmate 8a

As a bonus it means I can continue to use my Stages power meter.

I think its time I went to see my local bike mechanic!

The new R8000 rear mechs can take a 34 sprocket officially, and I wouldn't be surprised if a 36 would be fine. That would work with your 5800 shifters with no shiftmate.

Just noticed similar thing from Sugino:

https://www.suginoltd.co.jp/us/products ... #pnH4MT-OX