If you’ve no upper limit on your brake budget, then SRAM really has iced the cake and slapped a cherry on top to create a truly ‘Ultimate’ version of its already excellent Guide RSC brake.
The most obvious change at the lever end — especially on properly freezing days where the reduced heat conductivity is clear through your gloves — is the use of a carbon fibre rather than alloy lever blade.
It sits on the same cartridge bearing pivot as the RSC for ultra-smooth action and ultimate control sensitivity. It connects to the master cylinder using the same Swing Link leverage changing cam to bring the pads in fast at the start of the stroke then boost clamping pressure and power when they contact the rotor.
The bolts for the handlebar clamp (and the brake mounting bolts themselves) are titanium to shave a few more grams out of the system and if you add the mass missing from the alloy centre ‘Centerline X’ rotor it saves 37g over a Guide RSC with the same sized but all steel 180mm ‘Centreline’ rotor.
As the brakes are sold in a modular format (brakes, mounts and rotors are sold separately and titanium bolts are available from multiple suppliers) there’s nothing to stop you building your own lightweight version of whatever Guide you want.
SRAM has also pulled the carpet out from under the Ultimate since its launch, by trickling all of its initial unique features lower down into the Guide range. The very neat ‘buried in the body’ bite point adjustment dial now appears on the Guide RSC brake.
The swing link cam between lever blade and master cylinder for clean, quiet running rotor clearance with no loss of contact speed and then increased lever as the pads begin to clamp onto the rotors now appears on Guide RSC and RS.
The brilliant S4 caliper is now used throughout the Guide family too. That doesn’t mean that its heat proof stainless steel shielding, alloy interfaces and new supple seals on the four separate pistons don’t still provide benchmark control sensitivity in a neat, lightweight package though. Obviously the so simple it’s brilliant ‘Bleeding Edge’ purging circuit that moves the fluid injection port to the far end of the brake system so it flushes past the pistons to minimise the risk of trapped air is no less effective either.
Unlike a lot of top-end brakes relying on exotic materials our Ultimate brake samples have been utterly reliable too. Plus, while they may not be the most cost effective option in the Guide family (I’d put RS in that slot) the blissful richness of control they put under your fingers even in the craziest trail situations and the knowledge that you can’t get that performance in a lighter or more user friendly format really does make them the Ultimate trail brake.