Rotor Size Question

[pitts64]

I'm thinking about switching to the new Scarebird disc brake set up. Both use the GM D-52 Caliper. This how they compare.. Do you guys think it would be worth it? The difference is around $300...

The new set up uses this 77 Bonneville Wagon Brake Rotor;

Diameter : 11.86"
Brake Rotor Discard Thickness : .97"
Brake Rotor Thickness New : 1.04"
Brake Rotor Type : Disc Brake Rotor & Hub
Height : 4.65"


The old set up I have now uses this 77 Seville rear Hat Rotor on the stock front hub;
Brake Rotor Diameter : 11.16"
Brake Rotor Discard Thickness : .91"
Brake Rotor Thickness New : .98"
Height : 2.2"


Thank you...

[pitts64]

Since the bigger rotors are only.70 bigger (11.86 vs 11.16) and the brake pads allready fully ride on the smaller rotors, I'm figuring there would be no benefit to swapping. Would this be correct?

[dipren443]

It depends on how you look at it Pitts...

In theory, due to mechanical advantage, the farther away the clamping force is from the axis of rotation, the greater that mechanical advantage is... It is a linear relationship.

However, you also have to look at the fact that by using a larger rotor, the rotor itself carries more inertia. Meaning it takes more clamping power to overcome. And rotational inertia doesn't increase with linearity. It increases exponentially as the diameter increases...

So, without answering, there are several considerations or variables which play in to this.

[pitts64]

Thanks Nick...

I'm going to have my 11.16 rotors cut and install the Hawk HPS pads I have sitting here.. Best to try the least expensive route first....