BBS01 with 28T cluster? and 42T chain ring?

[chibi-sphere]

Hi,


I'm in the middle of the long and expensive process of converting my racer to an ebike and wondering why the heck I didn't buy a bike off the rack?

Anyway, I was planning on putting a 34 or 36T cluster on, and a leckie bling ring, when I realised my derailleur only accomodates 11-28T. So would 42/28 be too big a gear with 700CC wheels? There are a lot of hills around here, which is why I wanted an ebike.

thanks
-s

 

[vk4bxi]

with (only) a BBS-01, a 34 tooth gear on the back is the least I would go to.

I run a 42:34 with a BBS-02 750 watt and have to peddle some on the steepest grades. When I did my conversion I did some calculations and actually measured the grade of my steepest local hill ! (inclinometer). And decided that I wanted the largest cog on the back that I could get. With my free wheel hub that came out to be a 14: 34 seven speed (steel and cheap Shimano) gear set. The rear derailleur (which was supplied for a 14:28 seven speed with three front gears) managed the 34 gear OK but I had to seriously up the spring tension (added a longer (B ?) screw) to make it work. If you have a cassette set up on the back then aim for larger than 34 i.e. 11:36 or even 42.

Bob

 

[tipsy13]

If you haven't bought the bling ring yet, get an adapter and a smaller chainring if you don't want to pedal on steep hills. But if you've already bought the bling, i do think it'll still work with the 28T but you'd have to pedal on steep hills. No matter what you decide on, it will still beat unpowered bikes anyday on any hill

Sent from my SM-N920C using Tapatalk

 

[chibi-sphere]

Thanks. Definitely want to pedal on the hills, strange as it might sound, part of the point of the conversion it to enable me to use the bike for exercise. I just don't want to half kill myself on the hills.

Have resigned myself to buying a new derrailleur and getting a 30T cluster, which will make a small difference and give me the same gear ratio as the bike I was riding yesterday.

 

[vk4bxi]

Yes same here ! Brisbane also has got hills !! my wife rides with me but without a motor, but she has to get off and walk the worst ones.
As you said the bike is for exercise, and for fun, but hills are not fun.

Bob

 

[notfatjustbigboned]

Hi,
Just for reference - I am 20 stone and have the bling ring 42t front and 12 - 28 tooth cassette with a 250W BBS01. It gets me up all my local hills with little effort, max around 10% gradient. I was surprised at how powerful it is around 60rpm.