How important to rideability is fore-aft balance?

[Nehmo]

For the sake of comfort, I'm considering using handlebars that extend significantly to the rear. To compensate for the consequent cramping of the rider's space, I'll also use a seat post that moves the seat a few cm to the rear too. Since the pedals remain in their original place, this gives the rider a more inclined seating attitude, and it also moves the center of mass to the rear. A greater proportion of the overall weight will now rest on the rear wheel too.

This balance question is answered differently for an ebike opposed to a human-powered bike. The engineering trade offs would be different. Ebikes are supposed to be ridden while the motor supplies the power; human-powered bikes are supposed to be peddled. In a human powered bike rider position is optimized for leg expansion/contraction, and in an ebike, the primary issue is rider comfort.

Usually, people experiment to find the desired balance, but I'd hope to get some idea in advance. How important is fore-aft balance? I suppose it doesn't matter much in the going-straight-down-the-road state, but what's the difference in maneuvers? I don't know much on the subject. What's the ideal mass distribution? What do ebikes typically have?

 

[nutnspecial]

I'm having trouble with the correlation to bikini's and zero g planerides :lol:
Hmm, I don't think I've seen zero g experiments with about 5% or so water released into the air. That would be interesting trying to avoid breathing water?

Anyway, sure, a lower center of g, and more aggressive rake/ weight dist would be great. These are things most bicycles seem to sacrifice because of pedal stroke, ground clearance . . . power application. Just look at the differences going to dh or fr bikes that rely more on g. Unless you want more of a cruiser experience, which you'd also look to make the rider more upright or even laid back.

Step too far?


Yeah, definitely

If you wanna get all technical, there's enough here
https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry
https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics

I couldn't resist . . . . V :lol:
https://www.google.com/search?q=zero+g+water&biw=982&bih=429&source=lnms&tbm=isch&sa=X&ved=0CAgQ_AUoA2oVChMI25_pqLX8xwIVglQ-Ch246AYu#imgrc=gnDfmdxmyiRKqM%3A

 

[Punx0r]

I think you're OK as long as the centre of mass isn't too far to the front or rear. Otherwise you end up doing wheelies under power or endos under braking, bearing in mind that slopes will worsen the effect.

 

[dogman dan]

Uhh, it depends....

Going from a forward handle bar like a flat bar or racing drop bar to a back sweeping bar won't ruin the handling of the bike. Not even big cruiser bars. Bottom line, the majority of your weight is still in the same spot. on the saddle, or if standing on the crank.

But yeah, do other changes to the frame geometry, like a much much taller fork, and you can get a strange riding bike. Or load enough cargo on the rear of a bike, and the frame can start to look like a cooked noddle as you pedal. The whole frame bending with every pedal stroke.