maximum brake size for 15" rim

[karolko]

i have searched for a while now and i haven't found a real answer.

what is the largest brake you can stuff under a 15" rim.

i would love to get 13" rotors in the front and 11-12" in the rear. but i want to see what everyone else has run.

the plan is to use a cts v brake set up or a c5-c6 zo6 setup or get a set of brembo's from a wrx sti.

any ideas would help


thanks

 

[novaderrik]

you aren't going to get the CTS or C5 stuff behind anything less than a 17" rim- and probably an 18" rim will be required.
i had 15" rims on my Nova with 12" C4 Vette brakes, but those were early 70's Z/28 rims that only cleared by about 1/8". standard steel wheels and regular ralley wheels wouldn't clear, and i never tried any aftermarket wheels.
every B body (Caprice, etc) from the mid 70's- 96 that had 12" brakes had 15" wheels on them, as well as older GM 1/2 ton pickups with 12" brakes.
but anything with 13" or bigger brakes takes at least a 16" rim, but most need 17's.

 

[turbov6joe]

I wonder if the Caprice police package rotors would work? I'm in the market for some drilled and/or slotted rotors for my TR and would not mind going to a larger rotor diameter if they would work.

 

[Adam Connell]

The blazer brake conversion works with 15s and there are drilled/slotted rotors out there for them.

 

[novaderrik]

I wonder if the Caprice police package rotors would work? I'm in the market for some drilled and/or slotted rotors for my TR and would not mind going to a larger rotor diameter if they would work.

other than the bigger studs and 5X5 bolt pattern, i think they will bolt up to a stock spindle with the proper bearings. but i might be wrong on that point..
if that rotor will fit, then get the late 80's/early 90's Camaro 1LE rotor that is the same as the Caprice part, but with smaller studs and the same 5X4.75 bolt pattern as your Regal. of course, then you need to figure out how to hook up a caliper to a 12" rotor on a spindle made for 10.5" brakes..

 

[karolko]

the caliper would just recieve a simple bracket to offset the caliper the specified distance.

i guess the next question is how well do 12" discs brake compared to the factory's. i would be keeping the electric brake setup and not converting to vacume assist.

 

[POWERBRAKEBOB]

Hydroboost Conversion

It Always Comes Down To Pressure. Pressure Is What Stops The Car. Larger Pads, Maybe Larger Dia Rotors Will Give More Torque, But They Usually End Up With Smaller Caliper Pistons When The Rotor Is Larger, To Clear The Wheels. Pressure Against The Pads Is The Line Pressure Supplied By The Booster/master, Multipied By The Square Inches Of Piston Area In The Caliper. The Stock G/n Or S10 Caliper Is 2.5" Diameter. The New Calipers Need To Be Larger Than That To Help. The Great Thing About The Hydroboost Is That Is Has So Much Pressure, You Can Even Feel The Calipers Expand. (they Are Cast Steel) It Has The Power, And Doesn't Rely On Larger Dia Rotors And Wheels To Stop. Most Larger Calipers, Including The Baer/corvette Units Have Smaller Pads, And Approx 1.375" Pistons. The Stock G.n Pads Are Larger. As You Increase The Wheel Diameter, You Decrease The Brake's Effectivness. It Just Keeps Getting Farther To Reach What You Are Trying To Do.

 

[novaderrik]

i dunno about that- i had the C4 front brakes in my Nova running off a manual master cyliner, and it stopped better than any car i've ever had before or since, and with less pedal pressure.
i still had the stock rear drums, and used a Wilwood adjustable prop valve to limit the pressure to the rear to prevent lockup. once i got the rear wheels to not lock up, the whole car just squatted down and came to a really fast, really undramatic stop.
that car only weighed about 200 pounds less than my T Type- 3200 vs 3400- so i've been thinking about ditching my leaky hydroboost and adapting the C4 brakes to the front and using the same 77 Chevelle manual master cylinder i used in the Nova. i might step up to th 13" Vette brakes instead of the 12" brakes, just for tha extra little bit of leverage.

 

[Roger]

I have Baer 12" brakes up front. I had to go to the '84 - '85 15" GN wheels. I blasted the black paint off them & it is difficult to notice these wheels are not '87 TType wheels. The original '87 T wheels cleared with a 5/32" spacer, however I dislike spacers.

I was able to get my Baer 12" from Jack Cotton for a price which made the Baer decision a no-brainer.

I wanted the TR to appear original.

I'm at a loss attempting to understand why GM went with drilled rotors on the Z06 Vette - I have been led to believe drilled rotors are prone to crack. Does GM have the crack problem under control or is this a $ issue per the drum brakes on the rear of the newer Silverados????

 

[TR Custom Parts]

It Always Comes Down To Pressure. Pressure Is What Stops The Car. Larger Pads, Maybe Larger Dia Rotors Will Give More Torque, But They Usually End Up With Smaller Caliper Pistons When The Rotor Is Larger, To Clear The Wheels. Pressure Against The Pads Is The Line Pressure Supplied By The Booster/master, Multipied By The Square Inches Of Piston Area In The Caliper. The Stock G/n Or S10 Caliper Is 2.5" Diameter. The New Calipers Need To Be Larger Than That To Help. The Great Thing About The Hydroboost Is That Is Has So Much Pressure, You Can Even Feel The Calipers Expand. (they Are Cast Steel) It Has The Power, And Doesn't Rely On Larger Dia Rotors And Wheels To Stop. Most Larger Calipers, Including The Baer/corvette Units Have Smaller Pads, And Approx 1.375" Pistons. The Stock G.n Pads Are Larger. As You Increase The Wheel Diameter, You Decrease The Brake's Effectivness. It Just Keeps Getting Farther To Reach What You Are Trying To Do.

What's the story on the caps at the beginning of each word? Real hard to read your posts.