Best Reverse Gearbox For Go Kart: Compare 30- and 40-Series Kits

#1 · Best Overall

1. maXpeedingrods Gearbox Kit

• Weight: 12.35 lb
• Dimensions: 7.87 x 7.87 x 7.87 in

Best for: 30 Series chain-flexible builds.

Why it ranks #1: The 30 Series kit covers engines up to 14HP and specifies a 5/8-inch shaft, 3/16-inch keyway, and sprockets for two chain sizes.

Both included sprockets let this maXpeedingrods 30 Series gearbox work with #35 chain at 12T or #40/41/420 chain at 10T. That gives go-kart and utility-vehicle builders a choice of listed chain setups, with forward and reverse gearing for maneuvering in either direction.

The 5/8-inch shaft with a 3/16-inch keyway defines the clutch-side connection, while the stated engine limit of 14HP identifies its power range. Its gearbox speed is 5/13 of clutch speed, and the listed forward and reverse ratios are 1:1:3 and 1:2:6. A 1540mm shifter cable is specified, giving the installation a stated cable length; the kit is explicitly for 30 Series use, not a universal gearbox fit.

Skip it if you need a 40 Series gearbox; the GXYWADY 40 Series replacement is listed for that application.

Choose this kit for a 30 Series go-kart or utility-vehicle build that benefits from the included chain-sprocket options. Check the 14HP ceiling, shaft dimensions, and converter series against your setup before selecting it.

Listed on Amazon as: maXpeedingrods Go Kart Forward Reverse Gearbox Kit 212cc 30 Series

#2 · Clear Ratio Specs

2. Silscvtt 30 Series Gearbox

• Weight: 12.35 lb
• Dimensions: 11.81 x 10.24 x 7.87 in

Best for: 30 Series three-mode control.

Why it ranks #2: Its 30 Series limit, 13HP maximum, 5/8-inch shaft, 3/16-inch keyway, and forward and reverse ratios are clearly stated.

Forward, reverse, and neutral selection combines with a specified 1540mm shifter cable on this Silscvtt 30 Series gearbox. Those details help builders plan both directional control and cable routing, while the listing sets a clear engine ceiling of 13HP.

The 5/8-inch shaft and 3/16-inch keyway define the stated connection, and 35-chain 12T or 40/41/420-chain 10T compatibility gives two drive-chain configurations. Its 1:1.3 forward and 1:2.6 reverse ratios are paired with a listed 2300 RPM. The gearbox is explicitly for 30 Series use and will not fit 40 Series, a meaningful boundary when choosing a replacement for a kart or utility vehicle.

Skip it if you have a 40 Series setup; GXYWADY's 40 Series replacement is listed for engines up to 18HP.

This fits buyers seeking neutral as well as forward and reverse on a 30 Series build up to 13HP. The stated chain options add flexibility, but the explicit 30 Series-only limit rules out 40 Series installations.

Listed on Amazon as: Silscvtt 30 Series Go Kart Forward Reverse Gearbox

#3 · Three Shift Modes

3. GXYWADY 30 Series Gearbox

• Weight: 12.45 lb
• Dimensions: 7.87 x 7.87 x 7.87 in

Best for: 30 Series chain-choice builds.

Why it ranks #3: This 30 Series replacement specifies engines from 2HP to 13HP, a 5/8-inch shaft, and forward, neutral, and reverse.

Included mounting hardware accompanies the GXYWADY gearbox, giving assemblers specific pieces for attaching the unit rather than a gearbox alone. Its listing supports 2–13HP engines and names both 35-chain 12T and 40/41/420-chain 10T configurations for 30 Series torque-converter applications.

The 5/8-inch shaft with a 3/16-inch keyway identifies the drive interface, while the two stated chain and sprocket combinations let builders match either of the listed setups. Three shift modes—forward, reverse, and neutral—add a neutral position for maneuvering and stopping. The package details include two mounting pieces, and the listing specifies 4-stroke engines from 2HP to 13HP; together, these facts help frame both installation and engine fit.

Skip it if you are fitting a 40 Series converter; Blast's gearbox is listed for 11–18HP, heavier applications.

Consider this for a 30 Series, 4-stroke kart within the 2–13HP range when the stated shaft and chain options match. Its 4-stroke-only specification is an important boundary for other engine types.

Listed on Amazon as: GXYWADY Forward Reverse Gearbox Kit Replacement for 2HP-13HP Go Kart

#4

4. labwork 30 Series Gearbox

• Weight: 5600 g

Best for: Assembly-focused 30 Series owners.

Why it ranks #4: The 30 Series kit is listed for 2HP–13HP engines and includes a 1540mm shifter cable, with replacement sprockets for two chain sizes.

A 1540mm shifter cable is a concrete fit detail on this labwork 30 Series gearbox, helping builders plan the control run as they assemble a kart. The listing covers 2–13HP engines and specifies replacement sprockets for both 10T 40/41 and 12T 35-chain setups.

The stated 5/13 clutch-speed relationship describes how the gearbox speed relates to the clutch, while the 1540mm cable length helps establish the shifter routing needed during assembly. Compatibility is listed for 2–13HP four-stroke engines and a 30 Series torque converter. Because both 10T 40/41 and 12T 35 sprockets are specified, the kit offers chain-choice flexibility within those setups; buyers should still verify the shaft interface for their build.

Skip it if you need the shaft and keyway measurements stated up front; Silscvtt lists a 5/8-inch shaft and 3/16-inch keyway.

Choose this for a 30 Series assembly where the stated engine range, cable length, and chain options suit the build. Shaft dimensions are not supplied in the provided facts, so that interface is the main fit boundary.

Listed on Amazon as: labwork Go Kart Forward Reverse Gearbox Kit Replacement for 2HP-13HP Engine

#5

5. marddpair 30 Series Gearbox

• Weight: 12.28 lb
• Dimensions: 7.09 x 7.09 x 7.09 in

Best for: Cable-measured 30 Series swaps.

Why it ranks #5: This 30 Series unit states a 5/8-inch shaft, 3/16-inch keyway, 2300 RPM, and fitment for engines from 2HP to 13HP.

A listed 130cm shifter cable sets a practical routing measurement for this marddpair 30 Series gearbox. Its 5/8-inch shaft, 3/16-inch keyway, and chain options for 10T #40/41 or 12T #35 give builders several concrete interface details to check against a replacement setup.

The gearbox is specified for engines from 2HP to 13HP and for TAV30 Series applications, which narrows the intended engine and converter pairing. Its 1:1.3 forward and 1:2.6 reverse ratios are accompanied by a listed 2300 RPM, while three positions provide forward, reverse, and neutral selection. The 130cm cable length helps with control-routing plans, and the stated shaft and chain details support a more focused compatibility check.

Skip it if you need a longer listed cable than 130cm; labwork specifies a 1540mm shifter cable for its 30 Series kit.

This suits a 2–13HP TAV30 Series replacement where the stated shaft and chain dimensions match. Its 130cm cable is a useful routing reference, but buyers needing more reach should account for that limit.

Listed on Amazon as: ALL-CARB Go Kart Forward Reverse Gearbox Replacement for 2HP-13HP

#6

6. JNDO 30 Series Gearbox

• Weight: 12.1 lb

Best for: DIY builds needing neutral.

Why it ranks #6: Its listing identifies forward, neutral, and reverse modes and support for engines up to 13HP, though shaft and chain details are limited.

Forward, neutral, and reverse shift modes give the JNDO gearbox an explicit neutral position alongside two drive directions. That arrangement can make repositioning and stopping a go-kart easier to manage, while the listing specifies support for engines up to 13HP, including 420cc applications.

The 30 Series designation narrows the intended converter pairing, so this is not simply a gearbox for any engine setup. Its stated support up to 13HP and 420cc gives builders a defined engine range to compare against their project. Three shift modes add neutral between forward and reverse, a practical control choice for maneuvering. The listing also describes rugged aluminum alloy construction, but supplies no shaft or sprocket dimensions in the provided details.

Skip it if you need confirmed shaft and sprocket dimensions from the supplied listing; maXpeedingrods YW65 gives both chain sprocket options.

This suits DIY builders adding three-position shifting to a 30 Series setup within the stated 13HP and 420cc range. Since shaft and sprocket dimensions are not supplied here, those details remain a key fit boundary.

Listed on Amazon as: JNDO Go Kart Forward Reverse Gearbox Kit 30 Series for 212cc 420cc Engine

#7

7. SEBLAFF 30 Series Gearbox

• Weight: 12.35 lb
• Dimensions: 7.87 x 7.87 x 7.87 in

Best for: Compact 30 Series replacement.

Why it ranks #7: This 30 Series option is listed for engines from 2HP to 13HP, with 35-chain 12T and 40/41-chain 10T fitment.

A compact assembly with listed 35-chain 12T and 40/41-chain 10T fitment makes the SEBLAFF gearbox a flexible option for 30 Series go-karts. Its stated engine range runs from 2HP to 13HP, covering a broad range of the listed small-engine applications.

The 30 Series torque-converter fitment sets the main compatibility boundary, while the two specified chain-and-sprocket combinations give builders options for matching their drive chain. SEBLAFF describes the gearbox as light in weight, wear-resistant, and compact, characteristics that can help keep an installation manageable in a constrained kart layout. Its listing also states convenient installation, but does not provide shaft dimensions or a shifter-cable length in the supplied facts.

Skip it if you need stated shaft dimensions before planning installation; maXpeedingrods YW65 specifies a 5/8-inch shaft and keyway.

This is worth considering for a 30 Series kart within the stated 2–13HP range when either listed chain setup fits. The absence of shaft and cable measurements in the supplied details limits installation planning.

Listed on Amazon as: 30Series Forward Reverse Gear Box Kit 35Chain 12T 2300rpm

#8 · Higher-Power Fit

8. GXYWADY 40 Series Gearbox

• Weight: 20.8 lb

Best for: 40 Series higher-power builds.

Why it ranks #8: The 40 Series replacement targets 11–18HP engines and specifies a 3/4-inch jackshaft, 12-tooth sprocket, and 530 chain.

A 3/4-inch jackshaft and 12-tooth sprocket for 530 chain distinguish this GXYWADY replacement from smaller 30 Series gearboxes. Its stated fitment covers 40 Series applications with 11–18HP engines, including Predator 420cc and Duromax 11HP-and-over use, giving those builds a defined starting point.

The 3/4-inch jackshaft with a 3/16-inch keyway specifies the shaft interface, while the 12T sprocket and 530 chain identify the listed drive-chain setup. Fitment is stated for 40 Series go-karts and utility vehicles, with engine applications spanning 11–18HP; that range helps screen out smaller builds. Forward is listed at a 1:2 ratio and reverse at 1:2:6, providing the stated gearing for directional operation.

Skip it if you need a listed 35-chain option for a 30 Series setup; maXpeedingrods YW65 includes a 12T #35 sprocket.

Pick this replacement for a higher-power 40 Series build using the stated 3/4-inch shaft and 530-chain arrangement. Its fitment is not the 30 Series setup, so match the converter and chain configuration carefully.

Listed on Amazon as: GXYWADY 40 Series Forward Reverse Gearbox Replacement for Go-Karts

#9

9. Blast 40 Series Gearbox

• Weight: 22 lb

Best for: Heavier 40 Series applications.

Why it ranks #9: This 40 Series kit is for 11–18HP engines and offers 3/4-inch jackshaft fitment, but its driver and driven clutches are not included.

This Blast gearbox is specified for 11–16HP use and offers a 3/4-inch jackshaft, positioning it for heavier 40 Series go-kart applications. A 10T sprocket for 420 chain is listed, making the chain configuration explicit for builders planning a compatible drive setup.

The 3/4-inch jackshaft with a 3/16-inch keyway defines the shaft interface, and the listed 10T 420-chain sprocket offers one specified chain arrangement. The description also identifies a 12T sprocket with 530 chain, providing another stated option. A major installation consideration is that the gearbox kit ships without the driver or driven clutch; those components are sold separately, so this listing is not a complete clutch-and-gearbox assembly.

Skip it if you need a gearbox kit that includes both clutches; maXpeedingrods YW65 lists a complete forward/reverse gearbox kit.

Choose this for a heavier 40 Series build whose shaft and chain setup match the listed specifications. Plan separately for driver and driven clutches, which are expressly excluded from the kit.

Listed on Amazon as: Go Kart Forward Reverse Gearbox Kit Compatible with 11-16 hp Engines, Predator 420CC- 3/4" jackshaft (10T Sprocktet 420 Chain)

#10

10. Vital All-Terrain Gearbox Kit

• Weight: 11.12 lb
• Dimensions: 8 x 8 x 8 in

Best for: Trail Master and Cheetah owners.

Why it ranks #10: Its listed fitment names Trail Master Mid XRX-R and Cheetah 200E, making it a more model-specific choice than the general-purpose options.

Named fitment for Trail Master Mid XRX-R and Cheetah 200E models makes this Vital All-Terrain gearbox distinct from broadly specified replacements. It also lists 12T #35 and 10T #40/41/420 chain sprocket options, helping identify the intended chain configurations for those applications.

The 5/8-inch shaft with a 3/16-inch keyway specifies the connection, while the two chain-and-sprocket combinations offer defined alternatives for matching the drive chain. Listed ratios are 1:1:3 forward and 1:2:7 reverse, giving buyers the stated gearing information for a replacement decision. The listing cautions that named models are potential matches, not a guarantee, so compatibility depends on confirming the actual part requirements for the vehicle.

Skip it if you need guaranteed fitment from model name alone; maXpeedingrods YW65 provides shaft and chain specifications without named-vehicle claims.

This is aimed at Trail Master Mid XRX-R and Cheetah 200E owners matching the listed shaft and chain setup. Treat those model names as potential matches, and verify the vehicle's required part details before choosing.

Listed on Amazon as: Go Kart Forward Reverse Gear Box Kit for Trail Master Mid XRX-R, Cheetah 200E