BMX 3-Piece Crank Upgrade Kit, Mid BB + US Cups

BMX 3-Piece Crank Upgrade Kit

Unless you want a balance bike...

The single best upgrade for an entry-level BMX. Three-piece cranks are stronger, lighter and smoother than the one-piece cranks most starter bikes come with. This kit has everything to make the swap in one box: you would usually spend over £20 just on bearings that fit three-piece cranks, and entry-level cranks start around £50 on their own.

It works on our C1 BMX, on other brands' bikes, and on high-end custom builds.

Will it fit my bike?

• Mid bottom bracket frames: the sealed Mid bottom bracket fits straight in. Mid is the standard on most modern BMX frames.
• American (US) bottom bracket frames: the larger shell found on most entry-level BMX with one-piece cranks. Use the included Mid-to-US cups.
• Sprocket: reuse yours or fit a new one. A sprocket pinch bolt is included.
• Pedals: three-piece cranks take 9/16 inch pedals, not the 1/2 inch pedals used on one-piece cranks. Pick up our 9/16 inch BMX pedals or PX1 alloy pedals.

Not sure which bottom bracket your frame has? A Mid shell is about 41mm inside; an American shell is about 51mm inside. Ask us with your frame model if you're unsure. We recommend fitting by a bike shop.

In the kit

• 2 crank arms
• Splined axle
• Sealed Mid bottom bracket (with spacers)
• Mid-to-US bottom bracket cups
• Sprocket pinch bolt
• Crank bolts