restomod67

How much difference is there exactly in stopping power between 11 and 12 inch disc brakes ? Let's say they both use 4 piston calipers are both slotted. Pretty much an "all else being equal" type question.

The reason I ask is that I'm planning on purchasing a Heidt Mustang II IFS which comes standard with 11" rotors but there is an option to upgrade to 12" rotors. Also, I'm going to have 11" drums in the rear. Trying to get as much info as possible to make the decision. Thanks.

raven_ghostwolf

I don't know where to get exact figures but the 12" would more than likely give you a larger swept area and that would give you more friction for more stopping power. I have 11" non slotted non drilled on my 87 and they stop plenty fine as they where ment to stop Lincoln LSC's! All drilling and slotting do is help the disk cool faster between stops unless your going to road race or just want the look I guess I would say how deep are your pockets?

restomod67

Pockets aren't that deep so I'm trying to find a good balance for how much I'm going to put into the braking system. Right now on the rear I have 10" drums with 1.5" wide shoes. If I upgrade to 11" drums the shoes are 2" wide. Given that the front brakes do a dispraportionate amount of the work I'm just wondering if it would be better to go to 12" rotors on front. I'm all about just making it 11"' all the way around ... so would like to hear from those with brake experience. It will be power brake system for a 67 mustang. I'm trying to get a general techie view of cons and pros of mixing and matching sizes and types of brakes.

So basically I have three different setups in mind that I need to choose:

1) 10" drums in rear, 11" disc in front
2) 11" drums in rear, 11" disc in front
3) 11" drums in rear, 12" disc in front

Colorado_Mustang

The larger disc doesn't give the larger swept area/friction. What it does is give the brake pads more leverage on the disc. The 1" more will give about 9% more stopping power.

I have factory 11" disc/10" drum setup on my '71 with sticky tires and you'll eat dash pad. There are other components that would give benefits. A higher power master cylinder and steel braided brake lines will make quite the difference.

I would go with the 11"/11" setup.