27.5+ Conversion

[Warwick]

I found this: http://www.ebay.co.uk/itm/130-BCD-Spider-Chain-Ring-Adapter-for-8fun-Bafang-Mid-Drive-Motor-BBS01-02-/331976513887?hash=item4d4b57995f:g:MfcAAOSw1KxXMriE
I have a 40t chainring in that size. I presume it will fit the BBS01 kit...?

 

[anotherkiwi]

The Chinese ones don't have very good press which is why you have CNC shops making them in the USA, New Zealand and this company here in France.

 

[Warwick]

Hmm, I need to get something to fit my 9-speed Carrera Kraken with a BBS01. Being a bit of a numpty in these things, which adaptor and/or ring would I need to have the best chainline?

 

[anotherkiwi]

It looks like a 104BCD chainring from the photo. If the GSM chain line is anything to go by (it is a clone of the BBS) it isn't too bad, not perfect but not way off whack. This will of course vary with each and every bike.

The adapters tend to improve the chain line slightly by bringing the chainring inboard a little more.

 

[Warwick]

Thanks for the quick replies. Bearing in mind I am a reasonably fit cyclist, would a 36t or 42t ready-made ring be best with the 11-32 cassette on my Carrera?

 

[D8ve]

It depends on where you are cycling and how you pedal. For me I avoid the big hills around here. So I went for 48 *16 with an 8spd Aldine hub so very high gearing but I am a grinder not spinner. And I can still climb 7% in first with no power if nessisary.

 

[Warwick]

Thanks. I'm at the other end of the scale. My dodgy knees mean I'm a spinner, and I'm going to stick with the derailleur set up on the rear (though my Orbit has an Alfine 8-speed rear hub).

My commute is undulating, but I have the Orbit for that. This bike is for off-road use and as the occasional substitute on the commute.

 

[D8ve]

Well I think your answer is 36 then, or even the 32 for hill climbing spinning and reduced knee pressure

 

[anotherkiwi]

Thanks for the quick replies. Bearing in mind I am a reasonably fit cyclist, would a 36t or 42t ready-made ring be best with the 11-32 cassette on my Carrera?

36 for unfit offroad or very steep very technical and 42 for a strong fit rider. 42:32 is 37.2 gear inches.

Next step would be an 11-34 cassette. I had a 42-32-22 crankset and with a 14-34 rear cog the bike could climb walls in 42:34 bottom gear.