Developing the BMC Timemachine Road rear brake caliper covers

Developing the BMC Timemachine Road rear brake caliper covers

When I was working at BMC, I found myself in an environment that was very conducive to pushing the envelope. We were constantly looking for what great opportunities existed for making bikes faster, more usable, more enjoyable to ride, and sexier to look at. But being part of a big company means that you're most likely to end up developing the solutions that will attract most buyers. When I founded, I set out to create solutions that were more specific in their application. Sure, I'd probably not have many customers, but that mattered less. It would be a while before this company would start to pay the bills, so for now, I was set out to design and develop the bike solutions that we couldn't dream of bringing to fruition when I was part of the BMC team.

One of the scenarios that would be very interesting for certain riders would be that of using their second generation BMC Timemachine Road as a triathlon hybrid. This means that people would be able to convert their fast road bike into a triathlon worthy bike with relative ease, and convert it back again when the race is done. With the Timemachine Road being a disk brake only platform, it would become much more of a hassle to swap the stem or handlebar for a different setup. So to balance the versatility of the platform with conversion ease, the decision was made to keep the aero road handlebars, and to add some proprietary clip-on extensions, now available from BMC with part number 30000749.

I personally felt that not everything had been squeezed out of the Timemachine Road in order to turn it into a triathlon monster. Some of the more recent pure triathlon bikes come with brake caliper covers, to trade brake cooling performance for better airflow. I felt like this was achievable for the Timemachine Road as well, given that we had already made a start with a subtle front caliper cover. I knew I could do better.

It started with a front caliper cover, since this would be a modification of the existing caliper cover. Basically, the redesigned caliper cover would extend past the outer surface of the fork blade, in an effort to reduce turbulence caused by the brake caliper. On flat courses where braking rarely happens, this would be a great trade-off, as the calipers don't heat up to the point where cooling becomes a problem. The same could be developed for the rear caliper. However, this would be significantly more complicated for a number of reasons:

1. The bike comes with two different seat stay angles. Which one your bike has, depends on the frame size. Sizes 56 - 61 have a much steeper seat stay angle than the smaller frame sizes, for the simple reason that the seat stays need to fit in within the UCI technical regulations. This means, two different caliper covers have to be developed

2. The bike can be equipped with either a 140 mm or a 160 mm rear brake rotor. This means that choices have to be made whether I would now develop four different caliper covers, again doubling the development time. In the end, I stuck with the argument that if the rider would ever wish to upgrade to a 160 mm rear brake rotor, they would have to replace the caliper cover if it already accommodated the caliper at that position.

3. Unlike for the front caliper cover, there are no provisions to mount a rear caliper cover by means of a retaining bolt. I'd have to look for alternative ways of mounting the caliper cover to the frame. I settled on double sided tape by 3M, which is specifically designed for these type of applications, as well as bonding well with the PA12 Nylon 3D printed material. Tests will be done to determine several factors that influence proper and simple mounting of the rear brake caliper, as well as riding the bike in harsh conditions to test longevity.

What you can see in this picture, are the renders of the final parts before testing. I've ordered them at my 3D print supplier, and test fitting will commence as soon as I receive them. When the weather allows for it, I will start riding the bike around with the caliper covers, to see how well they hold up.