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Overview

Factory pre-bled rear braking from the Shimano GRX ST-RX825

The Shimano GRX ST-RX825 Disc Brake Set Rear is built for gravel and adventure bikes that need complete, factory-ready rear braking, pairing the GRX Dual Control lever with the BR-RX820 flat mount caliper as a pre-bled J-Kit. The RX825 lever delivers GRX ergonomics built for gravel: a textured hood and lever blade for secure control on rough terrain, with the reach and power dialed in for confident braking deep into a ride.

This is the rear assembly, featuring a right lever, the BR-RX820 caliper with a 25mm flat mount and no adapter, resin pads with cooling fin, and a longer 1700mm SM-BH90 hose with connector insert already installed to reach the rear caliper. The pre-bled J-Kit design means clean, consistent braking with minimal setup time, ideal for shops and builders who want reliable GRX stopping power without bleeding the system from scratch.

All the specs

Series
Shimano GRX
Generation
RX825
Position
Rear (right lever)
Lever
ST-RX825 (R)
Caliper
BR-RX820 (R)
Caliper Mount
25mm flat mount, no adapter
Pad Type
Resin with fin
Hose
SM-BH90, 1700mm, connector insert installed
Pre-Bled Kit
Yes (J-Kit Direct)
Caliper Material
Aluminum
MPN
IRX8251DRRDSC170A

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Good questions

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Is this the front or rear assembly?

This is the rear set: right lever with the rear caliper on a 25mm flat mount, and a longer 1700mm hose to reach the rear of the bike. The front set is sold separately.

Does it come pre-bled?

Yes. The J-Kit Direct design ships pre-bled with the hose and connector insert installed, so it is ready to mount with minimal setup.

Why is the hose longer than the front?

The rear caliper sits farther from the lever, so it uses a 1700mm hose versus the 1000mm hose on the front set.

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