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Old 03-06-09, 02:33 PM
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I haven't used the Shimanos you're asking about, but I do have the "Avid Code" 4pots on a freeride bike which should be about the equivalent, if the XT756 were the previous Saints. IMHO I would say that would be overkill - but not unusable. But if you want them on your bike for no other reason than you like them, then why not?

My understanding is that 4 pots have smaller pistons and they engage in succession. The idea is to have a smoother, more gradual modulation with the increased stopping power rather than ending up with a sudden wheel-locking thud if 2pots were just made bigger. 4pots also allow a larger brake-pad area profile, which theoretically should last longer, handle heat better, and be more gentle on the rotors. The downside is that there are more parts and seals to maintain, or to replace - and are a bit heavier.

Technically speaking, your brakes (and rotor combination) should be matched more to the size of your tires and the overall weight of bike+rider - rather than your riding style. At the defining moment where whatever tires you use - "lets go" of the terrain, all the stopping power in the world is no longer any good to you.

4pots are in their element when installed on heavy-ish bikes (35-45 lbs), with deep thread tires 2.5 and wider, which require larger rotors 185 - 203mm, and are used on trails with exceptionally long braking sections. Quick-release front axles are not going to be able to handle these braking forces, so a fork with 20mm thru axle at the front is a "must have."

If you can deliberately "lock" your wheels whenever you want with 2pot calipers on 165mm rotors and have never turned a rotor "dark-blue" from overheating... you really don't need anymore unless you just want them for the bling.

Pocko is offline