GREHUA Rear Disc Brake Caliper Kit for Razor MX500 MX650 SX500 — Metal Alloy Replacement with Mounting Hardware

GREHUA rear disc brake caliper kit is a direct-fit replacement assembly engineered to restore reliable stopping power on Razor MX500, MX650 and SX500 dirt bikes and compatible electric off-road machines.

If your Razor dirt bike or similar electric motocross vehicle has a worn, damaged or seized rear brake caliper, this GREHUA kit provides the core metal caliper plus mounting hardware needed for a straightforward swap. Made from durable metal alloy, the caliper resists deformation and cracking from repeated use while matching the factory mounting points and cable interface for quick installation.

How simple is installation on a Razor MX500 or MX650?

Installation mirrors the original factory procedure and requires basic hand tools. You remove the two caliper mounting screws and the brake cable pinch bolt, replace the caliper, then reinstall the mounting screws and reattach the cable to set the tension.

• Remove two frame-mounted caliper screws and the brake cable
• Take out old caliper and install GREHUA unit in same orientation
• Use included screws and shims to secure and re-pin the brake cable
• Adjust cable tension and test brake engagement before riding

What vehicles and parts is this caliper compatible with?

This rear brake caliper is designed for many Razor models and fits other small electric and gas off-road vehicles with similar mounting. It is a functional replacement for OEM part W15128190009 and suits a variety of scooters, pocket bikes and ATVs that share the same mounting layout.

• Compatible with Razor MX500, MX650, SX500 and McGrath Dirt Rocket
• Fits Dirt Quad 500 ATV and E500S electric scooters where mount matches
• Works as a universal rear caliper for some pocket bikes, go-karts and e-bikes
• Replaces Razor part number W15128190009 (front/rear fitment)

What are the material and durability features?

GREHUA uses a premium metal construction to minimize compression deformation and resist aging or fracture under typical off-road stresses. The robust build ensures long-term reliability when properly installed and maintained.

• Premium metal alloy resists wear and mechanical fatigue
• Designed to avoid deformation under braking loads
• Corrosion-resistant finish for extended service life
• Dual-pad style compatible with common brake pad configurations

What comes in the box and what additional parts might you need?

The kit includes essential mounting hardware to replace a like-for-like caliper. If your original brake pads, mounting bolts or cable are excessively worn, consider replacing them as well to ensure optimal braking performance.

• Package includes: 1 x GREHUA brake caliper, 2 x screws, 2 x shims
• May require brake pads if worn or not transferred from old caliper
• Basic hand tools needed: socket or wrench set, screwdriver, pliers
• Brake cable adjustment and a test ride recommended after install

Who is this for: Riders or technicians restoring or maintaining small off-road and electric motocross vehicles — especially owners of Razor MX500, MX650, SX500 and similar models — who need a durable, direct-replacement rear caliper that matches OEM mounting and provides long-lasting braking performance. This kit is ideal for DIY mechanics comfortable with basic brake work and for repair shops servicing recreational electric vehicles where a reliable, metal-bodied caliper is required.