Paddock Innovations: Scholtz Is Pumped About His Bike’s Thumb Brake, But Not In His Arm

Mathew Scholtz uses a thumb brake on his Westby Racing Yamaha Superbike, and it’s changed his whole riding style.

In a “Paddock Innovations” story that we posted last year right after the Utah round of the Championship, we reported that a couple of the EBC Brakes Superbike teams were experimenting with the use of a left-hand-operated mechanism to apply the rear brake.

The Monster Energy/Yamalube/Yamaha Factory Racing team installed a rear brake lever on the left clip-on of Cameron Beaubier’s Yamaha YZF-R1 Superbike, and Westby Racing tried out a left-thumb-actuated rear brake mechanism on Mathew Scholtz’s R1 Superbike.

The Yamaha Factory team abandoned the rear brake lever setup because Beaubier ultimately felt that it was too complicated for him to have a clutch lever AND a brake lever on his left clip-on. It was kind of a “more trouble than it’s worth” scenario, so Beaubier hasn’t been using the setup at all this year, and there are no plans for him to start using it again any time at least in the near future.

As for Westby Racing, Scholtz and the team did find some merit in the left-thumb-actuated rear brake mechanism they tried out last year, but they couldn’t find a setup that provided the right ratio and feel for Scholtz’s liking.

The thumb brake setup is manufactured by IMA in Italy, and it’s available through Superbike Unlimited, which is one of Westby Racing’s team sponsors.

This year, thanks to Freddy Carswell and his company Superbike Unlimited, which is one of Westby Racing’s team sponsors, the team has found a setup that Scholtz really likes and is now using regularly on his Superbike.

According to Westby Racing team manager Chuck Giacchetto, “Freddy connected us with a company called IMA that provided us with the setup that Mathew’s been using this season. We fabricated a couple of little things for it ourselves, but the system is essentially available over-the-counter from Superbike Unlimited. It’s like everything else on our bike. There’s no ‘unobtanium’; everything on the Westby Racing R1 Superbike is available to the public, and we keep no secrets about that.”

When Westby Racing added Superbike-level Marelli electronics to Scholtz’s bike for 2019, Scholtz’s riding style changed pretty significantly. He transformed from a rider who hardly ever touched the rear brake to a rider who now uses the rear brake quite frequently. “Now that Mat’s using the rear brake so much, we had to switch to a thicker rear rotor than the one we were using last season,” commented Frank Shockley, who is one of Westby Racing’s team technicians. “The thinner rotor we used last year kept getting hot and warping from all the rear brake that Mat’s using this season.”

Scholtz himself said, “Being a taller rider, I really like the whole idea of a thumb brake because it’s difficult for me to use the rear brake pedal when I’m leaned over, particularly in right-hand corners. Now, with the thumb brake, going into the corners, I can tuck in my elbows and just use it. And the thicker rear rotor generates a lot more stopping power than what we had last year.

Just below the left handgrip on Scholtz’s Superbike is the little thumb-operated solution to his chronic arm pump problem.

“The thumb brake still doesn’t have quite the same power or feel as the brake pedal does, but with the Marelli electronics system, we can now put more intervention in, like wheelie control, to help the rear braking.

“I never used to use the rear brake, ever, and now, I am definitely using it a lot. It’s changed my whole riding style and given me a lot more confidence. Also, last year, I was getting really bad ‘arm pump.’ I was coming out of the corners, and the bike was wheelying, and I was just holding on with my fingertips. Now, I can just keep myself forward, and use the thumb brake, and I’m not sliding back in the seat. So, the thumb brake, combined with the Marelli system, has helped my arm pump problem. I was considering having the surgery to relieve the arm pump even though I would prefer not to. Well, so far, this year, with the changes we’ve made to the bike, arm pump is no longer a problem for me. Last year at VIR, I had a huge problem with arm pump. This year, when we were at VIR, it wasn’t a problem at all. Sonoma Raceway is another track where I had huge arm pump last year, so I expect that it won’t be a problem at all this year.”


Arm Pump, also known as Chronic Exertional Compartment Syndrome affects many athletes who use their grip in their sport. Motorcycle road racers are especially prone to the condition due to the stress they experience when accelerating and braking aboard their high-horsepower bikes. Arm pump occurs when blood pools in a rider’s forearm instead of flowing to the hand and back to the heart. This pooling of blood creates pressure in the forearms that counters the mechanics of the muscles that control the throttle, brakes, clutch, and the ability to hold onto the bike. Any rider who gets arm pump will tell you that it is the single most debilitating issue they encounter as road racers.