Classic Motorcycle Brake Upgrades

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Glimmerveen, John. "Classic Motorcycle Brake Upgrades." ThoughtCo, Nov. 10, 2013, thoughtco.com/classic-motorcycle-brake-upgrades-743527. Glimmerveen, John. (2013, November 10). Classic Motorcycle Brake Upgrades. Retrieved from https://www.thoughtco.com/classic-motorcycle-brake-upgrades-743527 Glimmerveen, John. "Classic Motorcycle Brake Upgrades." ThoughtCo. https://www.thoughtco.com/classic-motorcycle-brake-upgrades-743527 (accessed October 21, 2017).
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Of all the changes made to motorcycle design over the years, the braking systems must rank near to the top for effective improvements. Ride a modern bike with dual four-piston caliper front brakes, then ride a classic with a single leading (narrow) shoe front brake and the difference is staggering. (Obviously this is not comparing apples to apples, but this does represent the advances.)

Besides the difference in designs that have dramatically improved braking systems, materials have also played a major part.

When the early Japanese superbikes became popular in the 70s, their braking systems were adequate at best, but were dangerous in the wet at worst. Changing the pad materials improved the braking performance on these machines considerably. However, it was not a sudden improvement as aftermarket pad makers developed their products slowly but surely.  

As development continued, drum brakes were, generally, consigned to low performance machines such as those used for commuting. Even manufacturers of off-road dirt bikes eventually used rotors and caliper type braking systems.

Classic Brakes

For owners of classic motorcycles, the choice of braking system is limited if he or she wishes to keep the bike original. However, there are a number of upgrades that will improve the overall braking efficiency of classic bikes. 

For owners of machines with drum brakes, the improvements are limited by two factors outside of their control: the leverage ratio between the levers and brake arm, and the brake shoe width.

Nonetheless, improvements can be made by 1) ensuring the drum is perfectly round, 2) ensuring  the shoe pivots and cams are positioning the shoes correctly and 3) using quality braking materials. This latter point is very important as the marketplace is becoming flooded with cheap brake shoes from Asia (Taiwan and China primarily).

 

Owners of classic bikes with rotors and caliper type braking systems can improve their braking systems easily by fitting modern (quality) pads and, in some cases, rotors. However, many of the early rotor brake systems had poorly matched master cylinder sizes to caliper piston size. This resulted in brake lever pressures that were very high to get a reasonable retardation, and often felt solid at a certain point. 

Replacing the master cylinder with one that utilizes a smaller piston can give a dramatic improvement. However, there are limits. If the pressure generated at the handlebars is too great, the lines will straighten dramatically (all rubber hoses do this to an extent under heavy braking)  and in some extreme cases the caliper will flex as the pressure will try to force the two halves apart.

Aftermarket Brake Specialists

With something as critical as the braking system on a motorcycle, making changes or improvements must be based on known principles and the experience of the part supplying company. One company in particular that specializes in classic bike brake parts is Vintage Brakes operated by Michael "Mercury" Morse out of Sonora, California.  

With a background in national road and dirt track racing (including winning a national championship), nineteen years working for Yamaha, and experience as a factory race mechanic for Triumph, Norton and Rickman, Morse has the background.

Having improved the braking systems on his race machines, Morse began his business specializing brake parts and updates. For the most part, he relies on the product range of Ferodo, a company he has found to offer excellent products combined with an R & D department that keeps the company at the forefront brake design.

Specialist Manufacturers

Unfortunately, companies like Ferodo do make brakes (particularly brake shoes) for some of the older classics as the volume demand is not there. To meet this demand, Morse offers a realigning service using his own designed and developed braking materials. This material offers the coefficient of friction that will work with the early drum brakes, giving good stopping power without overheating the drums.

The process of applying the new shoe material is one developed by Morse.

The friction material is initially flexible.  This helps to form it to the shoe radius. The friction material is then clamped to the aluminum shoe for further curing. After curing, the friction material and shoe are drilled for the locating rivets. The final phase is to bond and rivet the shoes to the aluminum shoe. 

Having made the brake shoes, it is very important to position them inside the drum correctly. To ensure the shoes are radiused properly, the new shoes are fitted to the shoe backing plate which is then mounted on a fixture, before having 20 thousandths of an inch (0.5-mm) machined off of the friction material in a lathe.

This mounting of the shoes onto their backing plate must be done carefully because, as Morse explained in a recent interview, "early Commando brakes are a problem as the spindle hole is over size some 30 thou. We machine and fit a bush to tighten up the clearance."

Notes: 

Another problem with the early Commando front brakes was that the backing plate can flex under heavy braking pressure which reduces the stopping power just at a point when the rider requires it most! 

In addition to owning the Vintage Brake company, Morse also operates 650 Central, a company specializing Yamaha 650 motorcycles

    Format
    mla apa chicago
    Your Citation
    Glimmerveen, John. "Classic Motorcycle Brake Upgrades." ThoughtCo, Nov. 10, 2013, thoughtco.com/classic-motorcycle-brake-upgrades-743527. Glimmerveen, John. (2013, November 10). Classic Motorcycle Brake Upgrades. Retrieved from https://www.thoughtco.com/classic-motorcycle-brake-upgrades-743527 Glimmerveen, John. "Classic Motorcycle Brake Upgrades." ThoughtCo. https://www.thoughtco.com/classic-motorcycle-brake-upgrades-743527 (accessed October 21, 2017).