Hi Whats the benifit of a floating rear caliper mount,
outher than its easier to ajust the chain ?
As I dont have room between the S/A for one due to the width of the rear hub.
I can make one that floats but just wondered what the benifit is.
Thanks.

Brakes fixed to the swingarm have the effect of transferring the braking torque into the swingarm, thus lifting the rear suspension under braking. Floating calipers are generally fixed to the frame or engine by a torque arm, so no impact to suspension.

Here's an article by Tony Foale. At the end of it he discusses the braking forces on the rear suspension. Basically, the floating rear caliper helps to avoid wheel hop.
Bill
http://www.tonyfoale.com/Articles/Dive/DIVE.htm

Thanks guys food for thought there.

Exactly the other way around

Brakes fixed to the swingarm do not induce any effect on the suspension characteristics. Moreover it is the brake torque transferred from the tire contact patch via the swingarm geometrie into the chassis which is creating the rear rise effect. Depending on your wheel and swingarm weight, swingarm lengts, mounting points, bike weight ect. it can create those wheel hop issues , but not necessarely have to. Just ask your self would it make any difference where your support the brake caliper mount on your swingarm. No not at all. you could even do a floating caliper mount fixed to the swing arm, it all will be the same. Saying that a brake caliper fixed to the swingarm is transferring brake torques into the swingarm creating a lift effect, is just like saying you would be able to pull yourself out of a swamp on your own hairs.

On the other side a floating brake caliper mounted with a brace to the chassis is indeed transferring brake torques into the chassis and by thus is influencing the swingarm geometry behaviour under braking usually making it stiffer and depending on the mountig point of the strut inducing strong or soft antirise effects.

TOM