CSX4910 I started with 15" wheel and tires. The 11" setup for The BFG tires was almost too much when stopping. Lockup was easy to do and flat spot the tires. I added a proportianing valve to help with bias of front to back. This helped on lockup.With poor tires that car still stopped in 115 ft of 60mph. Straight line was optional. I thought the same thing and went to the ERA 12" brake kit and 4 piston setup. THis system is way to much for 15" wheels unless you have an abs system in the car. The braking will put you through the windshield if your lap belts are loose. I went to a Dunlop tire with a softer 260 wear and this helped again with stopping and braking. A have been tracking and auto crossing the car and went to 17" wheel and Pilot tires. I found a balance with the 335 tires on the back. 275 on the front. New down side was the brake pads where for street and not high temp of track abuse. I added the ducting for the fronts and this helped. Serious guys have added fans to cool pads and rotors. I can run 3-4 laps without over heating the pads and rotors too much. I have not added the heat temp paint to the rotors to find out what temp they run hot. This is the real test for setup of braking system. I don't flush the system after every race, some guys have too. Dot 5 brake fluid for high temps.
Tires, Avon are about the best for 15" unless you go to billboards. Have to check out the price on them. Side note, if racing only a couple of older guys where running 15" wheels. Dick smith was one and drifted the car alot. This was his driving style. The newer guys are running 17-19" wheel combos. I have nitto 05 tires with 200 wear. I am happy with them. There is an article about 17" tires in one of the Hot rod or car craft that tested these tires. The test car was a full size boat and weights alot more than a cobra. BFG some how came out on top. Look into these. I know my nittos where 1/2 the price of BFG. Side note, Jack up car after every track run. Billboards get flat spots if left on the ground when hot. IF you are serious get a pyrometer for checking tires temps after a run and learn about alignments and what the car and tires like. I know of Only Morris, Cobra 3170, and Kirkham Having the knowledge to setup a cobra for the best handling. The rest is a learning curve of the driver. Rick L. Ps bring a couple pair of underwear in the beginning.
Love this subject! LOL
The largest practical diameter rotor you can run in a typical 15” Halibrand/Trigo wheel is
12.720 x 1.25 thick but there are a lot of variables. The inside contour of the wheel and caliper profile dictate the location. Caliper with opposed pistons (Wilwood, Brembo etc) require a lot more push-back that a sliding caliper (GM or PBR types) Try not to get “Diameter Envy”. These cars are light and the typical use (even on the race track) just don’t generate the heat load that would require large rotor (over 12.5)
It should be noted that a a 12.19 x.810 rotor weighs about 9.5lbs
my 12.720 x 1.25 weighs 13.4 and a 14.25x1.25 comes in at a whopping 18.7lbs each! You will feel the difference in rotating mass just like going to an aluminum flywheel.
IMO, 12.19 x 1.0 or 1.25 with a Superlite size caliper (4 or 6 piston) is the best fit for 99.5% of the group with a few exceptions.
JASON
How much braking do you want??
Linear Mode
