Ohseem Blog

There's no substitute for trail time in terms of drilling down to the practical side of bike performance. We use a diverse test team to make sure we’ve lived with each brake for months in as many environments as possible.

From the grinding grit of the Yorkshire Moors, Dales and Peak District, to the mountain descents of the Alps, the Spanish Sierra Nevada and Whistler in Canada, the brakes in our latest test have been put through their paces in full-on freeride use, epic marathon day races and day-in, day-out trail riding.

If you’re likely to do it, these brakes have seen it, regardless of price, because low cost shouldn’t mean low performance. We also note the performance of the hundreds of brake sets we use on complete bikes that come in for testing to broaden the spread of data collection. This is crucial to determine whether a problem is isolated to an individual brake or one we see time and again across the same type.

This means we can comment on something in context with reference to a solid knowledge base. In most cases it’s the on-trail use that sorts out the brakes we’d recommend and those that need more tweaking before they’re truly ready for the hardest riding situations

Once the dirty data is sorted we hit the lab at Fibrax with the help of its resident engineers and our specialist bike boffins. The ability to replicate the same test for a fresh unit of each brake gives us the perfect platform to calibrate the stopping performance of a brake against its peers. It also gives us mechanical data to put alongside our subjective assessments.

As Fibrax don’t make any brakes themselves, just spare pads for them, they’re totally independent in testing terms. Massive thanks to them for letting us use the facilities. The test rig itself uses a full bike chassis with the front wheel on a powered rolling road. Hydraulic arms at wheel axle level push the front tyre down to replicate 100kg of rider weight being thrown forward as the brake is applied.

A hydraulic ram with articulated lever blade cradle is bolted onto the dummy handlebar to provide totally accurate, repeatable load brake pulls. Water sprinklers can also be sprayed onto the calliper and rotor to simulate brake use in wet conditions. The braking power on the ‘road’ drum is then cross referenced with the lever pull (in newtons) to give the performance graphs.

For consistency, all brakes ran a 180mm rotor or nearest equivalent. However we ran one brake with 160, 180 and 200mm rotors to check what difference they made to the power output. The results were pretty clear, with a roughly 20 percent increase in power for every 20mm extra diameter. You’re looking at around 50g extra in weight for each step too, though.

We ran the exact same protocol as last year’s tests (you can view a video of the 2010 testing below). On the advice of Fibrax main man Mark Morris, this started with a cycle of 10 four-second pulls at 50N (1N is the amount of force required to accelerate 1kg at 1m/s2) with a 30-second rest between to bed each brake in and ensure maximum performance.

The dry test cycle saw each brake deliver three pulls of four seconds on, 30 seconds off at 50N, three at 100N and then three at 150N. This gave us average power ratings simulating gentle, reasonably firm and full-on, must-stop-right-now lever pull.

We then switched the water sprinklers on and ran the same test cycle. While you’d expect wet stopping performance to be worse (it generally is on trail), by cooling the brake down the water can actually increase its ultimate stopping power, which is why some brakes show better results on the wet run than the dry.

The comparison overlays below let you see how each model compares. For individual results, see the graphs attached to the brake reviews, which will begin appearing here onBikeRadar soon (there's a list at the bottom of this page). The vertical axis is calibrated in terms of decelaration in metres per second squared (m/s²). The higher the brake is on the graph, the more power it produces.

The horizontal axis shows the average output of the 50, 100 and 150N pulls. This lets you spot which brakes put out a lot of power at low lever forces, and which need a good squeeze to get the best results. The straighter the line between the three pulls, the more consistent the relationship is between how hard you pull the lever and how hard the brake stops.

You’ll notice that the lines for some of the brakes droop slightly between 100 and 150N. This is a result of increased heat build-up across the three hard pulls and a resulting reduction in pad ‘grip’ that simulates intensive mountain use. Where there is no reading after 100N, that's because the brake locked up.

It’s worth noting that fine control levels of each brake at the moment the pad contacts the rotor are hard to assess except by very careful studying of individual pull spikes. This means it’s a lot easier to feel that through your fingertips.