,
 |
| The ST22 rear caliper also has correctly proportioned pistons and dust boot protected seals. |
At MotoIQ we have plenty of experience with poorly proportioned big brake kits. Prior to Stoptech’s developing correct proportioning, it was typical for a big brake kit to have a longer stopping distance to stock. Although the brake might be bigger, more fade resistant and more powerful than stock, the big brakes almost always had too much front brake bias. Incorrectly functioning ABS, a long mushy brake pedal and premature front wheel lockup were common faults of your typical aftermarket kit. Fortunately back then most cars stock brakes were so bad, it was better to put up with the bad proportioning than to have a car that would have no brakes at all after a few laps!
 |
| Stoptech calipers feature full length and full width stainless steel abutments. Most race and OEM calipers either don’t have these or have very small ones that are just on the upper edge of the caliper body. The abutments helps keep the steel backing plates from wearing into the softer aluminum of the caliper body, making grooves that the pads can get hung up in. They are also a hard sliding surface for the pads that helps smooth and consistent operation, even when the pads are loaded up under torque. |
Stoptech calipers use common standardized FMSI pad shapes shared with Brembo, AP, Alcon and other common racing brakes. This means that there are many pad choices from many manufactures in this size so the end user can select pads from a pool of at least 15 different compounds. We ended up using Performance Frictions most excellent carbon metallic PFC-01 compound pads in the front and PFC-97 pads in the rear. The Performance Friction pads have excellent fade resistance with good bite and release characteristics. They are also easy on the rotors. The slightly less aggressive 97 compound gives a little more stability under turn in so it was chosen for the rear. Performance friction pads are one of our favorites.
 |
| The big front ST60 caliper features this bridge over the center gap. The bridge is held in place with 4 cap screws and significantly stiffens the caliper which helps ensure a firm pedal. |
The front ST-60 calipers have a bolt in bridge to span the open area of the caliper where the pads are inserted which greatly contributes to caliper stiffness without contributing to additional bulk and weight. The ST-60 calipers are also equipped with stainless steel abutments that the brake pad backing plates can ride upon to prevent them from gouging into the softer aluminum caliper body in long term use. The smooth hard stainless also makes the brake action smoother with a more consistent pedal as the pads can move more freely when the brakes are applied.
 |
| The ST60 also has full length stainless abutments and inserts on the bridge. Everywhere the pad rubs, is protected by stainless. Also note the proportioned pistons and the dust seals. The leading pistons are smaller than the trailing ones to prevent taper wear of the brake pads. The brake pad is affected by a tipping moment which puts more load on the leading edge of the brake pad. This causes it to wear out faster. To compensate, the leading edge gets a smaller piston for less clamping load. |
