Hope RX4+ Road/Gravel Disc Brake Caliper Description:
The Hope RX4+ Road/Gravel Disc Brake Caliper is a robust, yet lightweight, disc brake caliper that has been designed to provide upgraded braking feel, modulation, and power for hydraulic disc braking systems found on drop handlebar bicycles. Every Hope RX4+ caliper starts with a one-piece Monobloc caliper body design that is CNC machined out of a chunk of 2014-T6 aluminum, which provides a stiff platform that when set up correctly will minimize vague feeling brakes and will also eliminate caliper flex induced brake pad rub. Four opposing pistons push against large brake pads for a very easy to modulate and powerful brake; when it comes time to replace those pads, the pad shape is shared with the Hope Tech E4 MTB disc brake caliper to make it easier to source replacement pads, and the pads can be removed and installed through the top of the caliper for a very fast and user friendly pad change. Hope has gone the extra step by designing two separate varieties of these calipers that can either use DOT hydraulic fluid or mineral oil, and additionally there are four different caliper mounting shapes that mean these brakes can be used on a wide range of bikes, with many shifter/brake levers, and can fit many rotor sizes. Add in the availability of several attractive anodized colors to the machined finish plus the awesome performance and available fitment options, and the result is a very easy upgrade to the appearance, feel, modulation, and available braking power for any adventure, cyclocross, gravel, or road bike.
Notes: Calipers designed for braking systems that use mineral oil are not compatible with braking systems that use DOT brake fluid, and vice versa, so please select the right caliper for the braking fluid used. Brake/Shift levers and hydraulic brake hose are not included with these calipers.
Features:
- Mineral oil specific variations utilize mineral oil as the hydraulic braking fluid and are designed to work with either Shimano or Campagnolo gravel and road bike shifter/brake levers (Hope recommends using Shimano mineral oil if using a Shimano brake/shift lever with these calipers, and for Campagnolo, use either Magura Royal Blood or Campagnolo Mineral Oil)
- Slim profile one-piece Monobloc caliper body design is CNC machined from 2014-T6 aluminum to create a stiffer caliper which will reduce a fuzzy, or vague feeling, brake lever feel and will reduce brake pad rub caused by caliper flex
- Slimline 4 piston design was inspired by the brakes Hope designed for MTB and e-bikes, and this unique design provides powerful stopping capability with impressive modulation
- Brake pads are the same ones used in the Hope Tech E4 MTB disc brake caliper to make it easier to source replacement pads, and they can be accessed from the top to make the removal and installation process much easier and faster
- Available in configurations to fit both post mount and flat mounts, as front and rear models, and even two specially designed flat mount versions that allow clearance for a 20mm larger rotor without the need for special adapters (see resources tab for help determining what mounting option/model is needed for the size rotors being used on the bike)
- Standard Flat Mount and Flat Mount Direct +20 calipers will directly mount to a frame or fork with a flat mount attachment point with bolt holes that are approximately 34mm apart, or can attach to a flat mount style brake mount on a fork that has the holes 70mm apart with the correct adapter for the disc rotor size being used (adapters are not included)
- Front Flat DM +20 will directly attach to a flat mount style brake mount on a fork with bolt holes that are approximately 70mm apart without the need for an adapter
- Post Mount calipers attach to frame and fork post-style mounts or to adapters with a bolt spacing of approximately 74.20mm (adapters are not included)
- Each caliper includes hydraulic brake hose fittings, pad spacers, caliper bolts, (1) set of blue brake pads for road bikes or for riding mostly in dry conditions (these will also be quieter), and (1) set of red pads for cx/gravel bikes and/or riding in more varied trail and weather conditions (ultimately more stopping power and longer life in foul conditions, but may be a bit noisier as a trade-off)
Specifications:
- Brake Type: Hydraulic Disc
- Brake Fluid: Mineral Oil
- Brake Mount: Flat Mount | Post Mount
- Brake Pads: Organic/Resin
- Pistons: 4
- Color: Black
- Weight: -
This product is expected to become available for purchase on Saturday, March 1, 2025
RX4+ Caliper Selection Help For Frame/Fork Mounting Interface and Rotor Size:
Notes: Please consult the frame and/or fork manufacturers for recommendations on the maximum safe disc brake rotor size. Exceeding the maximum recommended size can result in frame or component failure, which can lead to crashing the bike and the potential for serious injuries.
Fork Mount Disc Rotor Size Compatibility:
- If the fork flat mount bolt holes are 70mm apart, and centerline of bottom caliper mounting bolt is approximately 23.50mm above the centerline of the axle in the dropout:
- For 140mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMXN (rotor and adapter sold separately)
- For 160mm rotor: Front Flat DM +20 Caliper (no adapter needed; rotor sold separately)
- Alternative for 160mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMZN (rotor and adapter sold separately)
- If the fork flat mount bolt holes are 70mm apart, and centerline of bottom caliper mounting bolt is approximately 32.0mm above the centerline of the axle in the dropout:
- For 160mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMXN (rotor and adapter sold separately)
- For 180mm rotor: Front Flat DM +20 Caliper (no adapter needed; rotor sold separately)
- Alternative for 180mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMZN (rotor and adapter sold separately)
- If the fork flat mount bolt holes are 34mm apart, and centerline of bottom caliper mounting bolt is approximately 45.0mm above the centerline of the axle in the dropout:
- For 160mm rotor: Standard Flat Mount Caliper (no adapter needed; rotor sold separately)
- For 180mm rotor: Flat Mount Direct +20 (no adapter needed; rotor sold separately)
- Alternative for 180mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMYN (rotor and adapter sold separately)
- If the fork post mount bolt holes are 74.2mm apart, and bottom most brake post is approximately 55.90mm long, measured from center of hub axle in the dropout to end of post:
- For 160mm rotor: Post Mount Caliper (no adapter needed; rotor sold separately)
- For 180mm rotor: Post Mount Caliper w/ Hope post mount caliper adapter part number HBMLN (rotor and adapter sold separately)
Rear Frame Mount & Disc Rotor Size Compatibility:
- If the frame flat mount bolt holes are 34mm apart, and centerline of rear most caliper mounting bolt is approximately 36.50mm from the centerline of the axle in the dropout:
- For 140mm rotor: Standard Flat Mount Caliper (no adapter needed; rotor sold separately)
- For 160mm rotor: Flat Mount Direct +20 (no adapter needed; rotor sold separately)
- Alternative for 160mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMYN (rotor and adapter sold separately)
- If the frame flat mount bolt holes are 34mm apart, and centerline of rear most caliper mounting bolt is approximately 45.0mm from the centerline of the axle in the dropout:
- For 160mm rotor: Standard Flat Mount Caliper (no adapter needed; rotor sold separately)
- For 180mm rotor: Flat Mount Direct +20 (no adapter needed; rotor sold separately)
- Alternative for 180mm rotor: Standard Flat Mount Caliper w/ Hope flat mount caliper adapter part number HBMYN (rotor and adapter sold separately)
- If the frame post mount bolt holes are 74.2mm apart, and rear most frame tab is approximately 47.50mm tall:
- For 140mm rotor: Post Mount Caliper (no adapter needed; rotor sold separately)
- For 160mm rotor: Post Mount Caliper w/ Hope post mount caliper adapter part number HBMLN (rotor and adapter sold separately)
- If the frame post mount bolt holes are 74.2mm apart, and rear most frame tab is approximately 55.90mm tall:
- For 160mm rotor: Post Mount Caliper (no adapter needed; rotor sold separately)
- For 180mm rotor: Post Mount Caliper w/ Hope post mount caliper adapter part number HBMLN (rotor and adapter sold separately)
