[Steve Jarvis]

I thought I would add this information. I saw people adding front rotors/calipers without a rear upgrades and worried about the brake bias implications. I've done in excess of 10,000 track miles with half of those in a heavily modified MKIV Supra. I went through several brake configurations over the years and have a basic understanding of some of the pitfalls. Adding larger rotors and pads help with heat management and rotor/pad life, but adding more front brake bias is not good. You spend a meaningful amount time at less than 100% braking (trail braking) and this puts a greater load on the front brakes and reduces rear brake pressure. This uses less of the rear tire contact patch and can actually lengthen stopping distances. In most cases you want to add more rear bias to reduce stopping distances. Because of this, I decided to run some basic calculations to understand the impact of the BMW 135 front brake "upgrade" used by many. Don't get to caught up in the actual numbers as I used some basic assumptions for the pedal ratio, master cylinder piston diameter and resulting line pressure. The differences are more important. The good news is though the 135 front brakes have larger diameter rotors (more leverage) and visually larger caliper, the actual brake torque is less than the stock 35i front brakes. This means 135 front brakes and 35i rear brake are a nice street setup with the ability to dissipate more heat than the stock brakes and still have good brake balance. Using the 135 front brakes with the stock 35is rear brakes actually keeps the bias almost identical to the stock 135 and Z4 35is setup. Please let me know if I have any of the specifications for the rotor or piston diameters incorrect and I will update the sheet.