Final Solution to Brake Lever Travel

by Gregory D. Girard

- We solved the problem of excessive and inconsistent lever travel by installing a Brembo Grand Prix Radial Pump brake master cylinder (Model Number: 10.4760.60). Please see included pictures below.

- The stylish $250 USD (retail) unit utilizes a 19mm piston with 20mm maximum leverage. It was fitted with a pressure-sensitive banjo switch made by Brembo for street applications that require brake lights. The unit was installed with only a minor amount of fitting effort (filing of 2 mm groove in plastic kill-switch casing on right handlebar). A small aluminum bracket was fabricated with a hacksaw and file to raise the stock brake fluid reservoir to a level that would prevent a kink in the feed tube.

- The Brembo GP unit has larger plunger piston (19 mm versus 12 mm used in Triumph), thus approx. 50% more fluid is moved with each stroke.

- The Brembo GP adjustment for the fully-extended brake lever position utilizes a continuous screw mechanism not unlike that used by Honda. The Brembo GP adjustment screw has soft "stop" settings every 1/2 turn. The entire adjustment range encompasses 26 stop settings, offering a precisely configurable fully-extended lever position range that extends from further than any human hand could reach to within 1cm of the grip.

- The stopping power of the Sprint RS with this enhancement is "world class" under all conditions mentioned. Brake lever action is very firm with a very short distance between the fully-extended lever position and the point at which the caliper engages. The larger fluid volume in the pump more than compensates for affects of pad wear i.e. the lever travel is not as much a product of the distance the pistons in the caliper need to travel. Affects of atmospheric pressure and temperature are rendered negligible at worst and undetectable in most cases.

- The adjustment of the fully-extended lever position (distance from the grip) may be finely adjusted according to the discrete stop settings, and can be easily and safely changed while riding (requires a simple turn of the fingers without a need to look down or "set" the pin in the adjustment hole). Thus, if one finds that the current fully-extended lever position is not quite right after changing to cold weather gloves, rather than pull over, one can simply turn the adjuster a few turns while riding to compensate.

- We conducted a trial of almost 6500 miles with one of our bikes (after 1500 mile breaking with stock unit). The braking performance remained dramatically superior in virtually every performance metric to the stock unit, and performance did not degrade in any detectable way over time. The same modification was made to a second and third bike with the same results.