[EVDL List]

This is exactly correct. Large torque spikes come _up_ the drivetrain
in the opposite direction than normal, from the road. When you go
over a pothole, the tire decelerates quickly, stops, then accelerates
quickly (almost instantly) as it comes back out again. If there is
not a complaint ("springy") element in the drive line, then the
torque spike is enormous from this.

Fatigue failure is caused by repeated brief torque spikes.
It won't happen the first day, but will happen after, say, 50 pothole
crossings. It is like bending a coat hanger in half. You can do it
once and it won't break, but if you bend it in half ten times it will
break in two.

There is a compliant element in every commercial
highway-capable vehicle. They won't make 20,000 miles without one.
BMW cars have the rubber "guibo" on the tail of the transmission
(pronounced "gweebo".) Motorcycles have that rubber thing in the rear
hub. Cars have a loooong drive shaft and the springs in the center of
the clutch. Tesla transmissions had no compliant element, so they
failed routinely.

Basically, you need to have a "guibo" in the driveline to
soak up the torque pulses that come from potholes, etc.

Bill Dube'

At 04:51 AM 3/14/2010, you wrote:
>Jon,
>
>Just do it like this (see photo at 23/02/09, 18th one down) ...
>
>http://www.winlow.co.uk/html/ev_conversion.html
>
>... and you wont get that problem but still have a fairly simple and
>cheap coupler solution. It's just a cut down friction plate from the
>clutch (buying one new or used should be cheap and easy - even a badly
>worn one) mounted to a taper-lock hub via an adapter ring. The key is
>keeping those springs in the driven plate which absorb all those drive-
>line shocks.
>
>Regards, Martin Winlow
>Herts, UK
>http://www.evalbum.com/2092
>www.winlow.co.uk
>
>
>[quote] Jon Glauser wrote:
>
> > I've taken it all apart and figured out whats going on. The coupler is
> > wearing itself out. Consulting with my mechanic, we've decided it's
> > caused by the extra torque and impulses of the transmission. With the
> > clutch, it absorbed the shocks. After I took out the clutch, all the
> > force went into wearing the splines off.
> >
> > The worn shaft coupler splines:
> > http://picasaweb.google.com/lh/photo/mIMiUZ2SUwuSs6ffXBoOWg?feat=directlink
> >
> >

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