Large diameter phenolic replacement piston (18 mm) for Hope V4 brake calipers: the essential spare part to maintain your Hope hydraulic brakes at their optimal performance level. This maintenance component ensures precise and durable operation of your high-performance braking system.

Technical Summary

This 18 mm phenolic piston is specifically designed to replace the large pistons in Hope V4 calipers (2013 models and later). Manufactured from phenolic resin, a material renowned for its thermal resistance and low conductivity, it prevents heat transfer to the brake fluid during intensive braking. Each V4 caliper incorporates an asymmetric configuration with 2 large 18 mm pistons (reference HBSP298) and 2 small 16 mm pistons (reference HBSP136 or HBSP432), thus offering progressive modulation and optimized braking power. Sold individually with a weight of only 4 grams, this genuine Hope piston ensures a perfect fit and reliable operation.

Technical Highlights

• High-temperature phenolic material: exceptional thermal resistance that limits heat transfer to the brake fluid, thus preserving consistency and performance during prolonged descents or repeated braking.
• Exclusive V4 compatibility: designed specifically for Hope V4 calipers from 2013 onwards, this piston integrates perfectly into the 4-piston asymmetric configuration (2×16 mm + 2×18 mm) that characterizes this flagship model from the British brand.
• Large piston dimension 18 mm: this specific diameter ensures the braking power necessary for aggressive disciplines (DH, enduro, freeride) while preserving excellent modulation thanks to the combination with the small 16 mm pistons.
• Genuine Hope part: manufactured to the exact specifications of Hope Technology in Barnoldswick (England), guaranteeing quality, machining precision and maximum durability.

Maintenance and Installation

Regular maintenance of caliper pistons is crucial to preserve the integrity of the hydraulic braking system. Worn pistons can lead to reduced braking power, inconsistent lever feel and potential leaks. Replacing this HBSP298 piston restores the original performance of your Hope V4 brakes. During installation, it is imperative to lubricate the pistons and seals with Hope silicone oil reference HTTLUBE to ensure smooth movement and prevent premature wear. For a complete replacement of a V4 caliper, you will need 2 large diameter pistons (HBSP298) and 2 small diameter pistons (HBSP136). Corresponding piston seals are available separately (reference HBSP299 for large pistons, HBSP68 for small ones).

Range Evolution and Compatibility

This HBSP298 pure phenolic resin piston equips Hope V4 calipers from 2013 to generations prior to Tech 4. Hope has since developed an evolved hybrid version (reference HBSP433) combining a stainless steel body with a phenolic insert, used on recent Tech 4 V4 brakes. This new hybrid design offers even smoother movement, requires less maintenance and handles extreme temperatures better without heat transfer. If you own a Hope Tech 4 V4 brake, check the appropriate reference: HBSP298 for standard V4 models (approximately 2013-2020) and HBSP433 for the most recent Tech 4 V4. Both references share the same 18 mm diameter but differ in their material construction.

Available Variants

• Variant HBSP298 (current product): EAN 5055168048406 — Pure phenolic piston 18 mm for standard V4 caliper — Weight 4 g
• Variant HBSP433 (Tech 4 hybrid version): EAN 5056454909692 — Hybrid stainless steel piston with 18 mm phenolic insert for Tech 4 V4 caliper — Evolved construction for smoother movement and reduced maintenance