Hope RX4+ SL Postmount Complete Caliper - Mineral Version 2026

HOPE RX4+ SL Postmount - 4-piston power for Postmount frames and forks
Hope's benchmark caliper evolves for 2026 to become the RX4+ SL. Entirely CNC-machined from a 2014 T6 aluminium block, this Postmount (74.20mm spacing) caliper combines exceptional lightness with increased structural rigidity. Its monobloc design eliminates the "fuzzy" lever feel to offer surgical braking precision on modern road and gravel bikes.

Why upgrade to the RX4+ SL (Mineral Version)?

The RX4+ SL caliper uses 4 phenolic resin pistons of different diameters (2x14mm and 2x16mm) to guarantee perfect modulation and consistent braking power. This version is specifically designed to work with Mineral oil brake fluid, making it perfectly compatible with SRAM Road/Gravel levers.

What's new in the SL version:

• Slimline Design: New bore caps reduce the overall width of the caliper, offering better compatibility with frames and forks where space is limited.
• Simplified Maintenance: New bleed screw compatible with SRAM fittings or Hope bleed tools (HTTBLRXMIN syringe - specific - available separately).
• Monobloc construction: Increases overall stiffness, reduces pad rub, and improves heat dissipation.

Key features:

• Monobloc CNC machining: 2014 T6 Aluminium for an optimal weight-to-strength ratio.
• Pads included: Delivered with two types of compounds (Blue for road use, Red for CX/Gravel).
• Customisation: Available in 7 Hope anodised colours (Black, Silver, Red, Blue, Purple, Orange, Smoke).

Specifications

• CNC-machined 2014 T6 aluminium monobloc caliper
• 4-piston caliper (two 14mm and two 16mm pistons)
• Postmount fitting (74.20mm spacing)
• Compatible rotor diameters: 140mm, 160mm or 180mm depending on the setup
• Compatible braking system: Mineral only
• Colour: Black, Blue, Red, Orange, Silver, Smoke or Purple
• Reference: HBSPC104
• Note: Not suitable for IS (International Standard) mounts

Lever compatibility:

• SHIMANO
    - Dura Ace Di2 R9270 / R9170 / R9120 / R9200
    - Ultégra Di2 R8170 / R8100 / R8070 / R8170 / R8020
    - 10S Di2 R7170 / R7020 / Di2 R785 / RS685
    - GRX RX820 / RX810 / RX600 / RX400 / RX815 Di2 / RX817 Di2
• CAMPAGNOLO
    - Ekar
    - Record
    - Super Record
    - Campagnolo H11

In the box

• RX4+ SL Postmount brake caliper
• Blue pads for Road use
• Red pads for Cyclo Cross/Gravel use
• Hydraulic fittings: copper washer, brass insert and olive, shroud nut
• Bleed pad spacer

Documentation:

Guide to determining which RX4+ caliper you need
Guide to determining which adapter you need
RX4+ SL caliper exploded view

Pro tip: Ensure you use exclusively Mineral oil. The use of DOT 4.0 or 5.1 fluid would irreversibly damage the seals of this version.