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Generic · Complete Brake Sets

BR-MT420 Quad Piston Rear Disc Brake Set with Left Lever

Four-piston Shimano rear brake set with a left-hand lever.

$99.99

Only 2 left · Ready to pick up from Ashburton Cycles

Ashburton Cycles

Open until 6 pm · Ashburton

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Call03 9885 1•7•1•6•
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Rear, left-hand lever
Position
BR-MT420, 4-piston, post mount
Caliper
BL-MT401, 2-finger alloy, 75 mm minimum reach
Lever
D03S-RX resin or D02S-MX metal
Pad options

Overview

Riders fitting or replacing the rear brake on an entry-level mountain bike who want more stopping power and control than a two-piston brake gives.

This is the rear set: a BR-MT420 four-piston caliper with a BL-MT401 two-finger lever for the left-hand side and an SM-BH90-SS hose. Shimano quotes 90% of the braking power of its BR-MT520, 20% more braking power than the two-piston BR-MT400 and 150% better wear resistance than the BR-MT400.

The lever has an anodised alloy blade, funnel bleeding and a reach that adjusts down to 75 mm for smaller hands. The caliper mounts to a post-mount frame, takes D03S-RX resin or D02S-MX metal pads (both without fin) and runs on Shimano mineral oil.

Four-piston caliper

Shimano says it brings greater confidence and control on descents, with 20% more braking power than the two-piston BR-MT400.

Better wear resistance

Quoted at 150% better than the BR-MT400.

Resin or metal pads

D03S-RX resin and D02S-MX metal pads both fit, so choose a rotor that suits the pad type.

Short-reach lever

The two-finger BL-MT401 adjusts by tool down to a 75 mm minimum reach.

Ask about this product

Specifications

Caliper (BR-MT420)

Pistons
4
Mount type
Post type
Pad options
D03S-RX resin or D02S-MX metal, both without fin
Compatible rotor sizes
140, 160, 180, 203 and 220 mm
Recommended rotors
SM-RT30, SM-RT54 and SM-RT56 (resin pads only), SM-RT64
Fluid
Shimano mineral oil
Bleeding
One-way bleeding
Caliper bolt
5 mm tool size, snap ring anti-loosen

Lever and hose (BL-MT401)

Lever
BL-MT401, 2-finger anodised alloy
Reach adjust
By tool, 75 mm minimum reach
Compatible shifter mount
Clamp band
Lever bleeding
Funnel bleeding
Hose
SM-BH90-SS, black, straight joint
Position and side
Rear, left-hand lever

Who it's for

Great for

  • Rear brake replacement or upgrade on a mountain bike with a post-mount rear mount
  • Riders who want a step up in braking control on steep descents

Maybe not for

  • Frames with a different rear disc mount standard, which need a separate mounting adapter
  • Anyone who needs a front brake, as this is the rear set with the left-hand lever

Takes 140, 160, 180, 203 and 220 mm rotors (rotor not included). Shimano's SM-RT30, SM-RT54 and SM-RT56 rotors are for resin pads only, and the SM-RT64 is also on its recommended list. This set has the left-hand lever.

Worth knowing

Match the pads to the rotor

Shimano marks the SM-RT30, SM-RT54 and SM-RT56 rotors as resin-pad only. If you want to run the D02S-MX metal pads, pick a rotor without that mark, such as the SM-RT64 on Shimano's list. The system uses Shimano mineral oil, never DOT fluid, and a qualified mechanic should fit and bleed it.

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