The Heavy Hitter 420 Primary Chain Drive Conversion Kit replaces the stock primary belt on the Sur Ron Light Bee, Segway X160/X260, E Ride Pro, Ventus ONE+ and 79Bike Falcon with a 30-tooth 7075-T6 rear sprocket, a nitrided 52100 steel front sprocket and a Japanese non-O-ring chain. Made by Heavy Hitter, sold here at GritShift, 1.37 lb.
Specs verified September 2026 against the live GritShift product page and the Heavy Hitter tech sheet.
Specifications
| Type | 420 primary chain drive conversion, replaces the stock primary belt |
|---|---|
| Rear (jackshaft) sprocket | 30-tooth 7075-T6 billet aluminum |
| Front (motor) sprocket | 13-tooth Nitrided 52100 tool steel |
| Chain | Japanese non-O-ring 420 chain, master link included |
| Hardware | Mounting bolts for the 30T sprocket are not included; reuse the OEM bolts |
| Weight | 1.37 lb |
| Dampers | None; no rubber dampers |
| Gear ratio | Maintains the OEM gear ratio and motor alignment |
| Front sprocket orientation | Sur Ron Light Bee X: Surron / #1 face outwards. E Ride Pro: E-Ride / #2 face outwards. E Ride Pro 3.0, 4.0 and SR: Surron side outwards |
| Chain tension | Loose, never tight |
| Motor note | EBMX XLB series motors must be properly shimmed to avoid side wear on the sprockets |
| Tech sheet | Heavy Hitter 420 Primary Chain Drive Conversion Kit assembly guide (PDF) |
What bikes does the Heavy Hitter 420 primary chain kit fit?
- Sur Ron Light Bee X and S (2017 to 2025 model years only)
- Segway X160
- Segway X260
- E Ride Pro-S
- E Ride Pro-SS
- E Ride Pro-SS 2.0
- E Ride Pro-SS 3.0, Pro-SS 4.0 and Pro-SR (must use the Surron side outwards)
- Ventus ONE+ (non-spline shaft motors)
- 79Bike Falcon Pro and GT (non-spline shaft motors)
Why swap the primary belt for a 420 chain?
Heavy Hitter built this kit for riders who have pushed stock belts past their limits with upgraded motors and controllers. A chain has no rubber dampers, so there is no efficiency loss, no extra heat and no debris shelf for chain links to pack into, while the kit maintains the OEM gear ratio and motor alignment. Precision machining of the sprockets extends their life and keeps performance smooth at high RPM. Heavy Hitter calls it the lightest 420 primary kit on the market for these platforms and is direct about the trade-off: it is louder than a belt, though no louder than any other chain kit.
What is in the box?
- 1 x 30-tooth 7075-T6 billet aluminum rear sprocket
- 1 x 13-tooth nitrided 52100 tool steel primary drive (front) sprocket
- Japanese non-O-ring 420 chain with master link
Mounting bolts for the 30T sprocket are not included; reuse the OEM bolts. The Zero XB shim shown on the tech sheet is not included in this kit; Zero XB owners need the separate Heavy Hitter Zero XB 420 Primary Chain Drive Conversion Kit.
Which way does the front sprocket face?
The tech sheet names the two faces of the primary drive sprocket. On a Sur Ron Light Bee X, fit it with the Surron / #1 face outwards; on an E Ride Pro, fit it with the E-Ride / #2 face outwards; then install and tighten the output shaft nut. The E Ride Pro-SS 3.0, Pro-SS 4.0 and Pro-SR must run the Surron side outwards. Both orientation diagrams are in the assembly guide (PDF).
How tight should the primary chain be?
Loose, never tight. Heavy Hitter states that any chain drive should run with loose chain tension, and that EBMX XLB series motors must be properly shimmed before installation or the sprockets will show side wear. The master link makes chain swaps and maintenance simple. Ventus ONE+ and 79Bike Falcon fitments apply to non-spline shaft motors only.
Where can I buy the Heavy Hitter 420 Primary Chain Drive Conversion Kit?
Right here. We sell the Heavy Hitter 420 Primary Chain Drive Conversion Kit at GritShift.
