Fast Legal Bike

[4bound]

Tony - OK, I was initially responding to a post by selrahc1992 which referred to "slightly illegal" bikes which I took to refer to the EC defined S-Pedelec which is limited to 350 watts. You have widened the field now by talking about 1000Watts - in fact if you read my post to the end I did say "Of course the 1500W bikes are a different matter".

Of course neither of us have mentioned gears - even if the bike was being ridden by Sir Chris Hoy, the commercially available S-Pedelecs do not have the gearing to do much over 30mph.

You certainly were a strong young man!

 

[anotherkiwi]

You certainly were a strong young man!

I am guessing there were some bumps in that road, it looked and felt flat back then (no more than 1 or 1.5%). The bike had been in the Tour de France in the '60s, bought at the after Tour sale by my father in law, lovely piece of kit, he had another even better one...

Thanks to your post I am off into the wonderfull world of speed/power simulators: for my grungy free MTB - factoring in the frontal area, drag coef etc. it would require 750W to climb a 10% gradient at the legal 25 kph of a pedelec. With 250W + 150W (me on a good day?) the speed would be 12.4 kph. Now I have some numbers to live up to when the conversion is done!

Just for fun a road racer with a Bafang 750W mid drive and a big sprocket could be a real sunday morning terror machine! At least these days you would be able to stop the damned thing. And the tyres wouldn't explode every two weeks...

Cheers

Tony

 

[Deleted member 4366]

Don't forget that that's output power. You have to also consider motor and driveline efficiency. Motor efficiency depends on speed for a hub-motor and crank-speed for a crank-drive, so it all gets a bit complicated.

 

[anotherkiwi]

Another motorist kindly looked at his speedo for me yesterday. I was pedaling briskly down a small (2%) hill when I heard "putain il est a plus de 40 ce con!" coming from a truck window as he passed me... (yes that is 40 kph not mph)

Tony