This new StopTech C43 kit weighs less than 21 pounds per corner. The racer’s creed promotes and encourages reducing weight, and reducing unsprung weight is even more important. Unsprung weight is anything that rises and falls with the changes in the road or grounds surface. Brad Abrams is StopTech’s Program Development and Account Manager. In other words, he is responsible for ensuring that the weight reduction does not detract from the braking power of this new, lightweight caliper. He has been very involved with James and getting the best braking system possible for the Type R and he was very helpful in understanding the brake system changes that the Type R has gone through in the last three years. The C43 Competition Caliper is all new and was derived from the ST43 caliper. In 2016 James was running the ST40 caliper. In 2017 we introduced you to the STR43 kit that James was running (In fact, that article was delayed by a few days while MotoIQ confirmed that there actually was such a kit from StopTech). That kit was a prototype that was used to develop the C43 competition setup. James has the Type R out for three to five laps at a time and he is seeking that optimum flyer lap. The large thermal mass of a standard big brake kit would be a significant weight penalty. The C43 caliper incorporates design changes from ANSYS FEA software (oh wow, this is really cool software that enables the user to explore component capability in simulation mode) that allowed StopTech to remove weight from the design while maximizing caliper stiffness. This C43 kit is optimized for the time attack style of racing that James participates in by giving him reduced weight – see one of any number of articles here on MotoIQ that encourage reducing unsprung weight – and concentrating on a properly balanced brake system. The 13.3 lb non-directional slotted pillar vane rotors (309×32) are about three pounds lighter than last season’s 300×32 directional vane rotors. An essential component of dissipating heat generated through braking is the brake pads. The Type R runs G-LOC Brake Pads.
The 16mm thick G-LOC Brakes GPW7416 R16 brake pads are a necessary part of the braking systems ability to absorb and manage heat. This R16 compound has a temperature range from 255°F to 2000°F. James runs pre-bedded pads. Talking with Danny Puskar at G-LOC Brakes about pre-bedding he says, “We have a programmable super-oven that bakes the brake pads at certain temps for a specific amount of time, before hitting their cool down cycle. This allows the pads to go through their final curing and out-gassing cycle and then they are ready to be installed and run a race straight away.’ For 2019 James will be going back and forth between the R16 compound and the more aggressive R18 compound. The R18 takes more time to heat up but will offer more – James wants to see how they feel and will be watching the data! In 2018, while running on 315 Hoosier A7’s the K-Tuned Type R boasted a peak -2.9 G under braking! When we asked Brad at StopTech if there were any changes in clamping power we got a bit more schooling (which we needed!). The STR43 kit actually has slightly more clamping power as its front caliper piston sizing of 38/42 versus the C43’s 36/42 piston. However, this was scaled with rotor sizing with the end result being that the force output of the two systems is nearly identical. The slightly larger diameter, lighter weight rotor allowed StopTech to decrease the force slightly which in turn helped manage temperatures, service life, and component wear while decreasing rolling inertia. James went through two sets of brake pads and is still on the original rotor. The Konig Dekagram wheel was chosen for their strength and design. With 18″ by 10.5″ on the front and 17” by 9 on the rear, wrapped with Hoosier A7 rubber, this setup completes the unsprung weight assembly on each corner.