Which bike to convert

[Sivy]

Hi all,
I've more or less decided on a conversion kit for my commute which involves some back roads and trails, bafang mid motor,
I have 2 bikes one a Trek Roscoe 9 hardtail 27.5 2.8 tyres 36 tooth single front 11 speed,
And a pinnacle arkose X 650b 2.1 tyres 42 tooth front SRAM rival
Now the Trek could be a fiddle as the BB is 83mm so the motor would have to be 100mm and I'd have to fiddle with spacer's
I think that the trek would have been better with the front suspension, etc albeit id have to get a bigger front sprocket for better road use.
I was worried the mid motor would be overkill for the gravel bike but it would be easier as its standard 68mm BB
I live in a very hilly area and I'm 96kg so didn't think the hub drive's would be ideal?

 

[Bonzo Banana]

Hi all,
I've more or less decided on a conversion kit for my commute which involves some back roads and trails, bafang mid motor,
I have 2 bikes one a Trek Roscoe 9 hardtail 27.5 2.8 tyres 36 tooth single front 11 speed,
And a pinnacle arkose X 650b 2.1 tyres 42 tooth front SRAM rival
Now the Trek could be a fiddle as the BB is 83mm so the motor would have to be 100mm and I'd have to fiddle with spacer's
I think that the trek would have been better with the front suspension, etc albeit id have to get a bigger front sprocket for better road use.
I was worried the mid motor would be overkill for the gravel bike but it would be easier as its standard 68mm BB
I live in a very hilly area and I'm 96kg so didn't think the hub drive's would be ideal?

Legal hub motors won't match the hill climbing ability of the most powerful mid-drive motors but its really about how much hill climbing ability you need. I think the average human produces a consistent amount of torque between 20-50Nm with older less fit riders closer to the 20Nm figure and very fit younger riders close to the 50Nm figure. I think the weakest hub motor I've seen was a very tiny geared hub motor typically used on 20" wheel folding bikes and that was about 12Nm but geared hub motors can go up to about 65Nm I think and direct drive hub motors perhaps 30-45Nm and then you have mid-drive from 40-95Nm approx. You do lose about 2-3Nm with a mid-drive motor as it delivers its power through the drivetrain which isn't 100% efficient so you will lose a little bit there but it will also scale with the gears.

No question if you are a very weak cyclist or someone who really doesn't want to assist the motor that much perhaps wants to arrive un-sweaty for work then mid-drive could be a good option. I personally much prefer the reliability and low running costs of hub motors but that does come at the expense of reduced hill climbing ability compared to the more powerful mid-drive motors. If you have a hub motor of 30Nm and you produce 30Nm yourself you can understand roughly that you will be able to get up hills much easier. Imagine a second person on the bike who weighed nothing and yet provided as much power as you. Pretty much all the speed gains of ebikes are going up hills and start/stop cycling where the motor kicks in to speed up your movement away from junctions. On the flats and downhill where you would normally easily go beyond 15-16mph you get no assistance.

 

[Nealh]

Of course legal hubs won't match hot rod mid drive bikes, one correctly outputs temporary 400 - 500w and the latter over 700w and some quoted at 800/850w. As we know mid drive brands are puuling the wool over someones eyes regarding true legality.

 

[Sivy]

Thanks for the input guys do you think a hardtail with fat tyre's makes a better commuter than gravel with fat tyre's, I'm not a strong cyclists but do climb the various steep long hills around here its just commuting I didn't want to make it too much of a drain

 

[guerney]

Of course legal hubs won't match hot rod mid drive bikes, one correctly outputs temporary 400 - 500w and the latter over 700w and some quoted at 800/850w. As we know mid drive brands are puuling the wool over someones eyes regarding true legality.

The likes of Bosch and Giant (and possibly Bafang?) are clearly taking the p*ss, look at this post from @Zlatan - 460W!

Hello from LaVita Boost

Hi :) I'm Nick, I designed the Boost kit in 2021 and we're starting to roll out to bike shops now. Our kit is rear wheel, has the crank sensor built into the wheel (so no external crank sensor) and is less expensive than Swytch even when fitted by a shop. Excited to learn from the forum...

www.pedelecs.co.uk

How are Bosch and Giant motors producing so much power anyway? According to @soundwave his BMS is limited to only 20A. Are they using capacitors to increase amps? Or are they using more efficient motors?

If I didn't give a damn about my battery's lifespan, I'd up the amps from 15 to 20 and call it legal, because 250W is engraved on my motor and that's what Bafang has rated it as. I expect the Police would disagree.