h a l f b a k e r yOn the one hand, true. On the other hand, bollocks.
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One of the cardinal principles of ground-contact vehicle design is
to
mimimize the unsprung mass; that part of the system outside the
influence of the suspension. |
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On vehicles with pneumatic tyres, the unsprung mass is low
because the tyre itself is a deformable suspension element. |
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The smaller the unsprung mass in proportion to the total mass of
the vehicle, the better the ride. Look at F1 cars; big tyres,
lightweight alloy hubs, tiny thin (but very strong and stiff)
suspension arms. |
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Adding mass to a hub is a Bad Thing. |
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Not just a better ride 8th, better fuel economy and
acceleration. |
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8th, solid point, but the F1 example is way off.
Wheel/tyre
sizes are fixed by stagnant regulations. Pretty much
every
other motor sport runs bigger wheels, it allows bigger
brakes for a start. The size and nature of the tyre as a
spring is problematic to designers and the engineers who
have to set the car up according to conditions. The sheer
volume of gas in there is why they whine about tyre
temps
constantly. When Adrian Newey designed the no-limits
car
for Gran Turismo 5 (X2012?) it has noticably bigger
wheels
than a standard F1 car. |
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As for the idea, nah. There's only 3 components in a ebike
kit anyway. Battery, motor and controller. You WANT the
battery to be detachable so you can take it inside to
charge, and if the whole thing is easy to remove, it'll get
stolen easier. What ebikes need is a cleverer brake
arrangement. The disk brakes I see seem like a wasted
opportunity for some clever ABS regenerative set up. |
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The main problem with regenerative braking is that it's not
possible to dump the energy back into the battery in such a short
time without damaging it. There needs to be a supercapacitor to
act as a buffer, and a charge controller- all of which add bulk,
mass, and cost for relatively small benefit. |
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We cited F1 because the suspension is typically open to view.
A motorbike might be a better analogy. Only the wheels
themselves, the lower part of the forks, and the swingarm are
unsprung mass. |
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Oddly reminiscent of the F1 regenerative system, via ratchet. To slow the F1 car, a roller is pressed against the tyre, the rotation is fed into elevating the driver and seat upwards. When wishing to accelerate again, the ratchet is released, the roller reapplied, and the driver and seat drops down again. |
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Obviously the controls would be run by wifi. Would also be handy for looking over the other cars. |
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NB Having spent 20 minutes working out how to encrypt stuff in an online database, and then 4 hours and 8 minutes working out to decrypt it again, I'm allowed to talk crap for the whole day, as an alternative to committing mass murder. |
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heh, of course that leaves you at a stop... your feet
dangling impotently 8 inches from the ground shortly before
you topple from an artificially lofty position onto the
ground. |
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Normal bicycles don't have suspension, save for the rider's limbs, and luggage is usually mounted on the unsprung frame, so really I don't see the problem. Also on the Copenhagen Wheel (linked, which completely bakes this idea) the battery is both integrated into the hub, and removable. |
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In the copenhagen wheel you have to buy their whole
thing. A round battery turns any hub wheel into a
Copenhagen wheel. And in my experience, and as seen in
the wheelstick example (I have two EBikes, one with hub
motor in front and one in back) the extra battery weight
will only be for the benefit. |
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Here's my [-] for 8th's quoting physics problems that in fact
do not apply here. The hub motor (in particular for a front
wheel) is purposefully made heavy in order for it to do its
job. The extra weight could be sheered off and replaced
with the battery, making the whole bike lighter!! |
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Here's a [+] to offset technically irrelevant ramblings about F1, suspensions, and the like. Tuners <rolls eyes>. |
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Allan Staniforth link, inventor of string "computer" for suspension jommetry design |
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hardly applicable to bicycles. Especially ones with a hub
motor. |
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