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Long Live the Disc Brake

Posted: August 1, 2014 by Steve Rock

Why have air disc brakes never reached the same level of popularity on our shores as they have in Europe? Perhaps because, like most things in life, we prefer to stick with what we know. But it might be time to change-up.

The Day the Disc Died

Discs did get a look-in back in the 70’s but didn’t really catch on. This was partly due to them being too small for the vehicle that they were trying to stop, plus they were made from inferior materials that were prone to rust and corrosion. Not at all good for one of the most important components on the truck. Parts were relatively expensive and a poor distribution network was the final nail in the coffin; consumers stuck with the cheaper and readily available drum brake. The disc was dead.

New Stopping Regs

Fast forward to summer 2013, that’ s when OEM’ s will have to ensure that all of their class 8 tractors conform to new stopping distance regulations, as laid down by The National Highway Traffic Safety Administration. Even though required stopping distances will be reduced considerably, braking systems will not need to be drastically re-designed. They will however need an increase in applied braking force and this can be achieved by various means. Larger drums on the front axle for one, wider shoes front and rear, larger chambers, or longer brake adjuster arms will all help to increase the applied force and therefore meet the new requirements. Other components may also need reinforcing to cope with the added strain, as well as possibly increasing air pressure to the front axle, to take advantage of the larger capacity drums and chambers.

There is of course another option that manufacturers could take, and that is a return to the disc brake. I’ m not going to hold my breath as these kind of major changes need two things before they happen: demand and time. Be patient though, as I’ m confident that once word gets around as to just how good they are, demand will be sufficient to ensure that they become the norm rather than the exception. Take a look across the pond at European trucks. Granted the style of driving there is quite different with lots more stop-start traffic, but most manufacturers now fit air disc brakes as standard on all axles.

Some Canadian companies are already ahead of the game, like J&R Hall Transport in Ayr, ON. They’ve been using air disc brakes for the better part of five years. During a recent interview, General Manager Paul Knill gave me an insight as to how the company thinks and operates. This is a company that likes to look after it’ s drivers as they only keep tractors for about three years, and after an experiment with xenon headlights (during which drivers reported feeling less tired while running at night) they fitted them to the whole fleet.

J&R is Bringing the Disc Back

But I digress, back to brakes. Paul says that initially, drivers were a little reluctant to accept this ‘new’ technology, but once word got around as to how good the new discs were performing, drivers actually approached Paul and asked when they’ d be getting an air disc equipped truck. J&R’s drivers now love them, especially in the mountains where they report their chances of getting slowed down, if an absent minded moose or tourist should cross their path, as being much better than it used to be with drum brakes. Drivers also say that pedal feedback is steadier, and the application feels progressive and constant on all wheels.

Longer Brake Life, Quicker Brake Jobs

Paul told me that all new equipment is now spec’ d with air discs, and the entire fleet of 70 tractors has them, with around half of the 145 trailers that they own stopping on discs, too. Their main reason for spec’ ing discs was quite simply safety; they are known for their superior performance which comes largely from the ability to dissipate heat, which in turn virtually eliminates brake fade.

Paul also reports that to date, they have not had any go out of adjustment and so the maintenance guys like them, too. Although the initial cost can be up to $4000 more per unit for the upgrade, they get approximately three times the life over one that is equipped with drums. Not only that, but a brake job now takes half the time that it used to, and is actually more cost effective even though parts are a little more expensive.

So where will manufacturers go from here? Likely nowhere fast, but I truly believe that drums are yesterday’ s technology and that the way forward for trucking is with the disc. When I put this to Paul, he replied“Why would you not go with disc brakes? If you’ re serious about safety then they are the obvious choice. Over the course of our equipment life the pay back on the initial expense is through lower maintenance costs and a higher resale value. Plus, if they save just one collision then they would have paid for themselves several times over.”

The only question left about disc brakes is: what’s stopping you from making the switch?

Steve Rock is a driving instructor with DriveWise in Barrie, ON. He immigrated from the U.K in 2003 and has driven on local, national and cross-border routes. He was also an in-cab instructor with Bison where he coached numerous Canadian drivers.


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