Groupset manufacturer SRAM has today announced a new range of hydraulic disc brake calipers that use the Flat Mount open standard introduced by Shimano last year. With brakes to match all three of the company’s hydraulic road groupsets (Red 22, Force 22 and Rival 22, including their 1x variants), we’re taking this as a wholehearted endorsement of the standard.
Flat mount versions of red, force and rival: SRAM / Immediate Media
Flat Mount allows for neater, more space efficient calipers, reducing the brakes’ footprint on the frame and making life easier both for bike designers and riders who work on their own bikes. The caliper mounting bolts thread into the calipers themselves rather than the frame as on a post-mount setup. At the rear, the bolts actually pass through the chainstay, while front brakes are bolted to a thin mounting plate, which itself is bolted to the fork. While Flat Mount frames can mount standard brakes with adapters, Flat Mount calipers are not backwards compatible with existing IS and post-mount frames. On native Flat Mount frames the brakes make for a clean, uncluttered look as demonstrated on the new Izalco Max Disc from Focus.
Side by side with a standard force caliper, the flat mount red version is a lot more elegant: side by side with a standard force caliper, the flat mount red version is a lot more elegant Matthew Allen / Immediate Media
The rear brakes use 140mm discs by default, or 160mm with an adaptor, while the fronts can be switched between the two sizes by flipping their mounting plate 180 degrees. SRAM recommends that all but the lightest riders run 160mm rotors front and rear, and given the minimal weight penalty there’s little reason not to. On the subject of weight, SRAM hasn’t made any great claims about the new brakes and the claimed figures look quite similar to the standard models, at 459g, 489g and 496g for Red, Force and Rival respectively. (Front brake, 160mm rotor, 800mm hose, full mounting hardware.)
xx: xx Matthew Allen / Immediate Media
The care and feeding of disc brakes are still a relative novelty for many roadies, but SRAM’s Flat Mount brakes don’t present any new challenges for the home mechanic. Apart from relocating the caliper bleed port from the side of the brake to the top (or rather the front, on the rear brake), SRAM hasn’t made any fundamental changes to the way the system functions. SRAM tech Jan Mueller gave us a demonstration of the bleed procedure, which he says a competent mechanic can complete in around 5 minutes (per brake) with a bit of practice. It’s a two-syringe affair, with fresh brake fluid being introduced to the system at the caliper end.
The bleed procedure is unchanged with flat mount: Matthew Allen / Immediate Media
New standards always elicit collective groaning but if first impressions are any indication, there’s no real downside to Flat Mount. BikeRadar got the chance to ride the Red version of the new brakes in brain-addling heat at the launch event in northern Italy, and braking performance was indistinguishable from existing products – which is to say, very good indeed.
Some high speed descents didn’t reveal any inherent weaknesses in the new brakes: Gruber Images / Immediate Media
After one particularly rapid descent both rotors and calipers were noticeably toasty, with slight discolouration of the discs evident, but braking performance did not appear to suffer afterwards. The smaller Flat Mount calipers do naturally offer less surface area to dissipate heat than their post-mount counterparts and we’d need to spend more time with them to give a definitive verdict, but at face value there’s a lot to like.
The brakes are expected to be available in September, and will be fitted as standard to some 2016 bikes. Pricing (per wheel, in other words one lever and one brake) is as follows, with the sterling and Euro amounts being inclusive of VAT.
|Red 22 (shift-brake)
| Force 22 (shift-brake)
| Force 1 (brake)
| Rival 22 (shift-brake)
| Rival 1 (brake)