On 26 Oct 2004 16:59:55 -0700, Jan Wysocki wrote:

Do you mean you need a 'crash' gearbox to be able to do clutchless
gearchanges like you can on a motorbike?

If you want to make a habit of it.

I'd assumed that a synchromesh gearbox would make it even easier,

Easier, yes. But it doesn't help reliability.

I have no idea how synchromesh works.

There's a bronze ring with a cone clutch on it and tapered lead-ins
for the splines on the sliding member.. When you try to engage the
dogs, the ring gets there first. Once the cone has spun to the
matching speed, it allows the dog splines to slide freely.

Do too much of it, you wear the nose off the dogs. then the blunt nose
jams in the socket, locks solid, there's a bang and the ring breaks
into fragments. You're now left with a rather sloppy crash box. On
some gearboxes, the exploding clutch can get caught in the works on
the way out and do more damage.

Porsche's gearbox design is different and doesn't use the same sort of
bronze cone. They're more robust for being used clutchless. OTOH, I
believe that if they break, they always lose that ratio.
--
Smert' spamionam