A rear brake kit that swaps a stock e-bike caliper for a four-piston-style Ultra Bee caliper on a MaceMX adapter bracket, with a thickened 220mm or 240mm rotor and sintered pads. It is aimed at riders of Super73, Ridstar, Macfox, P-51, Juiced Scrambler and similar e-bikes who want stronger, more consistent stopping than the stock single-piston setup. The kit arrives pre-bled with mounting hardware, so it is a bolt-on upgrade rather than a build. Compared with stock brakes it adds pad area, heat capacity and a larger rotor; the trade-off is that fitment depends on your frame's caliper mount and rotor size, and some Macfox frames need a separate 180mm post-mount adapter.
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Riders rate it well overall and mostly praise the added stopping power and the pre-bled setup. Complaints center on fitment surprises, especially on Macfox frames, and on the work needed to get the caliper aligned and the lever feeling right.
The Ultra Bee Brake Upgrade is a rear brake kit for e-bikes with a standard caliper mount, including Super73, Ridstar and Macfox models. It is not for e-motos, because the brake rotor does not fit them. A bracket adapts the rear caliper. The V2 has a new caliper design and sintered brake pads.
The kit includes everything required for installation. The rear brake assembly comes pre-bled. A minor bleed may still be needed after installation or transit, since small air bubbles can get into the system during shipping or handling. If the brake feels spongy or underperforms, a quick bleed should restore full performance.
Some e-bikes, including some Macfox models, require replacing the stock brake post with a standard 180mm post mount adapter. Bikes with dual rear shocks may have clearance issues, so confirm there is room for an enlarged rotor before ordering. The Ultra Bee brakes need a brake disc about 40mm wider than the stock rotor.
