With over 25 years of experience designing and building hydraulic disc-brake systems for mountain bikes, Hope is targeting road, cyclocross and gravel bikes with the RX4+ hydraulic disc calipers.
To simplify your decision-making, the RX4+ calipers are compatible with all common Shimano, SRAM and Campagnolo drop-bar hydraulic brake levers.
Because Shimano and Campagnolo systems use mineral oil, and SRAM brakes use dot fluid, Hope makes calipers specific to each type, with a letter ‘M’ or ‘D’ etched onto the bore cap.
Hope RX4+ Disc Calipers specifications
The calipers are CNC machined from solid 2014 T6 aluminium in Hope’s Barnoldswick factory, and come in six colours.
Versions for either post-mount or flat-mount road disc brake setups accept 140mm, 160mm and 180mm rotors.
Each caliper comes with two pairs of Hope disc brake pads, recommended for road and gravel use, a caliper bleed kit, and the necessary fittings for your frame and brake line, plus instructions.
Including pads and spring, my Flat Mount Front +20mm caliper (for 160mm rotor) weighed 119g, and the Flat Mount Rear 101g, both lighter than Shimano’s GRX400 calipers.
Their cost puts them between Shimano’s Ultegra and Dura-Ace, and similar to SRAM’s Red calipers.
Hope RX4+ Disc Calipers performance
The RX4+ is termed a monobloc design, because it’s formed from a single piece of aluminium, making it stiffer than a two-part caliper and allowing its four pistons to squeeze the pads firmly and squarely against the rotor every time.
During setup, Hope’s bleeding process was a little more involved than the big brands and required the syringe to be fitted and removed several times during the routine. That wastes a small amount of oil, and requires a bit more cleaning up afterwards, but Hope does provide all the necessary kit.
This was, however, the first bike I’ve built with Hope’s hydraulic disc brakes and I expect the process will become simpler with repetition, as it has when working on Shimano, SRAM and Campagnolo products previously. Many riders will also rely on a bike shop for bleeding.
In terms of performance, despite weeks of road and off-road muck and grime regularly coating just about everything through the testing period, the brakes kept working well.
Brake rub was a rarity, occurring only when water or liquid temporarily filled the gap.
Brake feel via Shimano’s excellent GRX levers is at least on a par with any road disc brake, with superb fine control and phenomenal power when needed.
Whether on tarmac, gravel or wet trails, the RX4+ gives enormous confidence, and pad wear is no worse than its rivals.
Hope RX4+ Disc Calipers bottom line
Hope has poured all of its experience into the RX4+ calipers.
The result is dependable performance for both road and gravel riding.