Disc brake-Caliper brake comparison
Summary and editing by Phil Coleman
Disclaimer: Myke and Ken are local bike shop owners and bike mechanics. As with any technology, refinements are ongoing and obsolescence is inevitable. The observations and recommendations made are applicable today. Contact your local reputable bike shop for any further technical refinements in the months and years ahead.
Ken Bradford, Ken’s Bike-Ski-Board Davis, CA. http://kensbikeski.com/
Myke Berna, Velocity Bicycles, Winters, CA http://velocitybicycles.com/
Disc brakes now taking center stage. Less than a week before the start of this year’s Tour de France, the UCI governing body authorized the use of disc brakes for entrants. Three years of study of disc brakes in road racing events preceded this authorization. Several TDF teams are fully or partially using disc braking and this has brought more world-wide interest in his form of bike braking. This article examines the utility of disc brakes and includes tips on purchase, operation, and maintenance.Cycling News Article
advantages of disc brakes over rim brakes
Earlier versions of disc brakes had complaints about squealing, causing more difficulty in tire changes and frequent adjustments. There was no uniformity in manufacturing standards, they were expensive and added extra weight.
These issues have been corrected. By every objective standard of measurement and performance, today’s disc brakes are superior to calipers. Their advantage is most apparent when cycling in inclement weather and on steep descents but is immediately noticeable on any ride. Disc brakes are a must have for any tandem bicycle.
A disc brake assembly moves the braking action away from the outer diameter of the wheel (found with rim brakes) to the wheel’s center axis or hub where braking a rotating wheel is most efficient. In addition, the rotating weight of the wheel is reduced, improving both braking and acceleration.
Rim manufacturers now don’t have to build extra strength in the outer rim edge or add a costly heat resistant coating to accept the stress and heat of rim brake placement. Wheelsets built for disc brakes are more elegant, lightweight, and aerodynamic. Also, disc brakes—not being close to rotating tires– are less likely to getting deposits of dirt and debris in the brake assembly.
Caliper brake are mounted on the frame’s front fork and seat stays and compete for clearance with the tire and wheel assembly. With disc brakes, this area allows more versatility in tire width selection and the optional placement of fenders.
Disc brake recommendations
Myke carefully monitors the disc brake development, adding his many years’ experience with retail sales, attendance at various trade shows, and mechanic for professional racing teams. Below Myke recommends these particular specifications in the selection of disc brake options:
- 140 mm rotors
- 12mm x 100 front axles
- 12 x 42 rear axles. The “R.A.T through axle” allows wheel changes that are easier in many respects to changing a wheel on a bike with wide tires & rim brakes.
The argument for hydraulic disc brakes
Mr. Bradford is an unabashed proponent of hydraulic braking. This form of braking, Ken argues, is smoother, more efficient, requires less effort by the rider, is more powerful and needs less maintenance than mechanical brakes. Hydraulic brake systems have no wire cables that stretch, fray, and corrode. The necessary cleaning, lubricating, inspecting, and periodic replacement of cables and housing is replaced by occasional pad adjustment and infrequent bleeding of brake lines.
Some skeptics of hydraulic brake systems say they fear a catastrophically fail were they to have a hydraulic line rupture at a critical moment. A mechanic brake system, with a severed cable, produces the same result. These same cynics have no trust crisis for hydraulic brake systems in every automobile on the highway today; mechanical brakes on cars disappeared over 80 years ago. With hundreds of millions of vehicles using hydraulic braking, hydraulic line failures are very rare.
Disc brake maintenance
All disc brakes take some “breaking in” (mating the pads to the rotors) so a brand-new bike on a test ride won’t have the advantages found with the same bike a week later. Quality bike shops know this and provide post-sale adjustments as part of the purchase. Overall, disc brakes are fully reliable and need less maintenance than caliper brakes.
The adage, “You get what you pay for,” applies to bike brakes as with anything else. However, even the cheapest hydraulic disc brakes are far superior to the least expensive caliper brakes.
Were we to arbitrarily divide cost ranges into Low, Medium, and High, the prices for all are dropping due to increased production and sales. As consumer use increases, the unit price will continue to drop. Last year’s high-end brakes become next year’s medium range. Ken and Myke suggest most disc brake buyers gravitate towards the Middle price range, current offerings are robust, smooth & effective with little weight penalty.
While rim brakes continue to remain in mass supply and use, they are being replaced by the refined disc brake. The recreational cyclist can continue to use rim brakes with confidence and familiarity until a new bike is desired. For cyclists now seeking greater performance while having a greater margin of safety, bicycles equipped with hydraulic disc brakes have no equal.