Frank X said:Quoted message said:Cheaper, larger platform, release in both directions.
Frogs only release when foot is twisted in one
direction (heels outwards, I think) -- which I find a
scary prospect for the event of crashes, where feet or
bike could twist in either direction.
My current SPDs release only in one direction and I'm
happy with that.
Are you sure? I thought all SPDs can release by twisting
inwards as well as outwards, even if that feels unnatural
and more force is required. I think some multi-directional
versions also release simply by pulling upwards -- that's
not what I mean.
But in any case, you may be perfectly happy in normal use
with one-direction but you won't always have the opportunity
to deliberately twist feet in a crash. Getting stuck to the
bike or tangled up in it can result in greater injury. I
know of one case where a rider seriously injured his leg
because of this problem. The rider or the bike tends to
twist to one side naturally during a fall but it can be to
either side!
Quoted message said:What does larger platform mean,
Simply that the pedal is larger, with a larger area for the
cleat to contact. This just tends to feel more comfortable
efficient, even I find with extremely rigid soles (which
doesn't make sense according to the theories but seems to be
the case in reality with me).
Quoted message said:is that likely to be better for my knees?
I don't think so. That's where the large amount of float of
Speedplays could indeed help you, although Look pedals
provide up to 9 degrees* which is quite a lot. You get about
5 degrees with SPD. Time pedals also have more float than
SPD--another option for you to consider: I think they have
models compatible with SPD shoes.
* albeit with quite some friction with standard setup, but
this can be vastly improved with grease and altering cleat
rubber thingy (please see other reply).
~PB