Motorcycle Forum / Country Specific / Australian Group / September 2008

From memory, at the same time they changed to radial mounted calipers
(I think it was on the ZX10R), they 'downgraded' from 6 piston to 4
piston calipers because they reckoned the improvement in braking with
radial mounting was so great that an improvement in braking could still
be achieved while a further weight saving was realised.  Discuss.

Nev..
'07 XB12X

And not only that - it's a vile misnomer; a set of radial anything needs
to converge to a common centre point. As the mounting bolts on a
radial-mount caliper are parallel to each other, they don't qualify.
They should call them parallel-mount, or something, referrring to the
orientation of the caliper mounting bolt relative to the plane of the
brake disc... under that convention, normal calipers would be
transverse-, perpendicular- or orthogonal-mounted... or just
regular-mounted.

Thoroughly true, and very rarely acknowledged.

*yoinck* Ah, the advantages of living like a slob. Reach down from the
couch to the floor, retrieve December 2006 issue of "Performance Bikes"
featuring a large pic of Carl Fogarty next to his 1998 WSB title-winning
 996. The regular-mount caliper mounting arm on the Ohlins fork, cast
integral with the magnesium fork bottom (now there's a component
drastically in need of a rename[1]) and milled out for lightness,
features two sets of caliper mounting bolt holes, spaced what look to be
~20mm apart.

The following year, factory Ducatis (and GP bikes running Ohlins) got
parallel-mount calipers for the first time.

Some of that'll be attributable to Chinese whispers... the first bits of
gumpf about parallel-mount calipers acknowledge that the benefits are in
the greater stiffness of the mounting of the caliper to the fork...
because the caliper is fixed at both the leading and the trailing end
(with respect to disc rotation - and, note, there's no reason why this
can't be done with regular mounting), rather than just the trailing end,
if the disc flexes from side to side, it doesn't take the caliper with
it, and because there are now two shorter, spaced-out mounting arms
instead of a single longer one, there'll be less azimuthal movement of
the caliper... get on the picks, the disc tries to take the caliper with
it, caliper mounting arm doesn't let it, there's less flexion with the
parallel-mount arrangement.

The mounting can be made more compact, lighter etc... the difference in
performance might be SFA, but it makes for inherently better
engineering, like mounting the calipers behind the forkleg instead of in
front, or stacking the gearbox shafts on top of one another, so why not
do it?

[1] If you're Caucausian, and you let one go in the company of some
Native American, then lie about it, would they be correct in stating
that white man speaks with fork bottom?