Q. What does Shimano mean by the new 'Servo Wave' braking on the new XT brakes?
Marc Walnut, York
A: Servo Wave isn't new wave, it's just the re-introduction of a technology used in their old cantilever brakes. Basically, the leverage of the brake changes through its pull. It moves the pads a lot but with less power at the start and then moves them less, but with more force just as they bite on the rotor. This means that they can be spaced well away from the rotor so they don't drag even when dirty, but the actual braking action is more powerful (20-25 per cent) according to Shimano.
The 'Servo' feel takes some getting used to, but they've certainly got more bite than older Shimano brakes for a given rotor size. The lever shape isn't to everyone's taste though, and the need to bleed the brakes multiple times before they work consistently is also a real pain.
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