Thanks for the reply, I was going to say I had a 44t chain ring but then realised the BBS02 has its own chainring and O didn't know how many teeth it had.Other factors required.
Wheel size? Tyre size? Number of teeth on front chain ring?
I have aBBS01 250W set up with an Alfine 8 with 16 tooth sprocket and 42 tooth chain ring on the motor. 26x1.35 Marathon plus tyres at 65psi.
Top speed is about 30 on the flat.
Put a 52 tooth chain ring on and I guess it could push beyond 40?
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What speed would the BBSHD be capable of with a 48v 17ah battery,there are videos on youtube of bikes doing 45mph on the flat with this setup or would you need 52v,the rider is pedalling.You can gear a crank-drive as high as you like but the higher you go, the less torque you have, so you get to the point that wnen you change to top gear, there's not enough torque to maintain that speed, so you'd slow down.
Assuming that you set the controller to 25 amps and that you have a 48v battery, power from the battery would be 1200w, which would equate to about 900w at the back wheel. You need 1000w to maintain 30 mph on a mtb-type bike, so with perfect gearing, the top speed would be 28 mph, though more downhill and/or with the wind behind you.
A motor makes it's maximum power at about 75% maximum RPM, so the perfect gearing would be 28 mph at a cadence of 75 in top gear.
Now you need to do some sums based on what you've got.
As others have mentioned, depending on software, chainring and final cog ratio, 45 mph is achievable.What speed would the BBSHD be capable of with a 48v 17ah battery,there are videos on youtube of bikes doing 45mph on the flat with this setup or would you need 52v,the rider is pedalling.
He has one of those cycle analysts on the bars to show the speed is accurate.