15 inch rims want big brakes wilwood if possible

[Danny57]

I need your advice on upgrading my 57 front brakes. Currently CPP 2 piston disk w/power kit & stock spindles.

I see ads for wilwood 4 piston that say "will work with 15" rims." My front rims are Rocket Launcher 10 spoke. Rocket technical say I have 12.8" diameter clearance.
When I called wilwood, a tech said they don't make kits that work with 15" rims.

Can anyone tell me they have successfully installed 4 piston wilwood (preferably) or other calipers/rotors with 2" dropped spindles utilizing 15" rims the dimensions noted?
thanks,
Danny

[NickP]

There are Wilwood units that fit but with a minimum of machine work depending upon the wheel application. In the Wilwood catalog, pick out what you want and then look for their clearance template. Print it out and see if it works. I have used 12.19 on the front of an 69 El Camino but with skinny wheel/tire combo.

[Maddog]

Did you look at the Wilwood site? They have 3 kits with 4 piston calipers. The 11.75" rotor version will fit, they also have a 12.19" rotor but that may or mat not fit your wheels.
11.75":http://www.wilwood.com/BrakeKits/Bra...Air&option=All

I'm not sure which CPP kit you have and am not sure why you're specifying 4 piston, 2 piston and 4 piston are essentially the same, ones rigid mount the other is a floater. A floating caliper only uses pistons on one side while a rigid mount must have pistons on both sides of the caliper body, no difference in force if piston diameter is the same, don't be fooled by the "more is better" concept. Wilwood will be much better quality then CPP but I doubt there's any stopping difference.

[chevynut]

I don't see how/why the number of pistons in the caliper drives the size of wheel you can use. I have some 4-piston 68 Corvette/Camaro calipers that work with 15" wheels. What determines if the wheel will fit is the rotor diameter, not the number of pistons.

[Rick_L]

The caliper's dimensions affect the fit just like the rotor diameter. The caliper's "bridge" thickness essentially adds to the rotor diameter. The "safe" rule of thumb is that the rim should be 4" bigger than the rotor.

The C3 Corvette fudged everything just a little bit, using a 11.88" rotor rather than 12", and used 15" wheels. Similarly, the early Chevelle/Camaro/Nova setup was 10.88" rotors and could wear a 14" wheel. Also those wheels were the new (at the time) "disc brake wheels).

[markm]

I don't see how/why the number of pistons in the caliper drives the size of wheel you can use. I have some 4-piston 68 Corvette/Camaro calipers that work with 15" wheels. What determines if the wheel will fit is the rotor diameter, not the number of pistons.

The 4 piston Camaro caliper is smaller than the C3 Corvette and actually works with the correct 14 inch 67/68 Camaro rally, I own one of each car. Camaro went to single piston calipers in 69. D53 calipers I think. The Camaro started using the single piece rotor that is common to 55-57 disk conversion then also.

[markm]

The caliper's dimensions affect the fit just like the rotor diameter. The caliper's "bridge" thickness essentially adds to the rotor diameter. The "safe" rule of thumb is that the rim should be 4" bigger than the rotor.

The C3 Corvette fudged everything just a little bit, using a 11.88" rotor rather than 12", and used 15" wheels. Similarly, the early Chevelle/Camaro/Nova setup was 10.88" rotors and could wear a 14" wheel. Also those wheels were the new (at the time) "disc brake wheels).

Rick is your 4 inch rule for 4 piston only, I was thinking of 72 Chevy trucks and Impalas 12 inch roters with single piston. Both have 15 inch wheels.

[NickP]

Rule of thumb for me is to review known data and requirements surrounding that which is being considered if available.

[Rick_L]

It's a generic rule, recognizing there are exceptions, like the ones noted. And I'm sure there are others. I was unaware of the two that you stated, but they almost certainly have similar dimensions to the C3 stuff, even if the parts are different.

You should always check some way to see if they'll fit if you are under the 4" rule. Maybe even always no matter what the wheel size is. Calipers can also hit the wheel center. That's why some billet wheels have optional mounting pad thickness so you can fine tune that part of the fit.

[Mike56]

My front wilwood brakes on my 55 will not fit in a 8 inch vette rally wheel. Some wheels, on the back of the wheel, have a step up as it goes toward the mounting surface, and this creates the problem. Book said I need a 13 1/16 clearance, I made a 13 3/16 cardboard pattern to test future purchase wheels. note: The 8 inch rally fit my back wilwood brakes with no problem.