Big wheels / Big Brakes

[TRMALLY]

Can anybody give me advice on increasing the front brake sizes and wheel sizes.
I have a rally replica TR7 V8 that i am going to sprint/trackday eventually.
If i put the big brake conversion on the fronts poss hi-spec 325mm discs i will have to go from 13 to 15inch rims.
Am i going to really feel a difference with 325mm discs and would i benefit from 15inch wheels anyway.
With my current wheels i have compomotive ML 8inch fronts and 10 on the rear but am unable to get road legal tyres to fit the 10,s correctly.
Now i seem to be able to get 15x9inch Compomotive wheels - Any ideas i dont know which way to go? Have you any experience or Your thoughts please.

[Raider]

So at the moment you haven't done any sprints or hillclimbs?

Do you currently have the standard brakes?  Hopefully not, with a V8 in the car!

I would suspect that you don't need massive brakes or at least ones so big that you must go to 15" wheels.

A sprint or hill climb is too short a distance to suffer any brake fade for example.

I am taking part in Historic tarmac rallies and the MSA rules & regs means I must use 13" wheel, no wider than 6".

Actually I use 5 1/2" wide wheels as the rules and regs also say I can only use a 70 series tyre - a 185/70R13 tyre doesn't need a wider wheel ;)

So - 13" wheels can still be used in tarmac rallying which will have stages much longer than a sprint or hill climb.

[Beans]

Always difficult in giving advice as it all depends on your car's setup, use and driving style.
A few points to bear in mind though;

• Most important thing when choosing brakes is heat dissipation;
• So first thing to do is make sure your brakes won’t overheat easily, so go for something vented with decent pads;
• Make sure there is at least an inch clearance between outside of disc and inside of (alloy) wheel;
• It is said that you can’t over brake a car, but be careful with big brakes as it is not just a matter of bolting something on;
• The rest of the car has to be up to it (decent suspension set up and grippy tyres ) otherwise you will lock up the brakes rendering them useless;
• Make sure the brake cylinder has the correct inside diameter (small ø gives more clamping force at the calipers but also a longer pedal stroke0;

B.t.w. I do have a HiSpec set upon my car ...



More info here ...
http://tr7beans.blogspot.com/2007/03/braking-t-kreng-part-2.html
and here ...
http://tr7beans.blogspot.com/2007/12/t-krengs-front-suspension-upgrade-old.html