Best Gear Box For Go Kart: 10 Forward-Reverse Options

#1 · Best Overall

1. maXpeedingrods Go Kart Gearbox

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

Best for: 30 Series chain flexibility.

Why it ranks #1: Fits 30 Series applications up to 14HP, specifies a 5/8-inch keyed shaft, and includes sprockets for #35 and #40/41/420 chain.

Two included sprockets let this maXpeedingrods gearbox work with either a #35 12-tooth chain or a #40/41/420 10-tooth chain. That gives builders a choice of listed chain setups while adding forward and reverse to a 30 Series go-kart using an engine up to 14HP.

The 5/8-inch shaft with a 3/16-inch keyway provides a defined connection point for compatible driven-clutch setups, while the 1540mm shifter cable gives the operator a remote shift control. Forward gearing is 1:1.3 and reverse is 1:2.6, so the two directions have distinct ratios. Both sprockets are included, reducing the need to source one of the specified chain options separately. Its engine limit and 30 Series designation narrow the fit.

Skip it if you need a 40 Series gearbox for an 11–18HP engine; GXYWADY’s 40 Series replacement covers that stated range.

Choose this kit for a 30 Series go-kart or utility vehicle build where either listed chain sprocket is useful. Check the engine rating and shaft setup, since this gearbox is limited to 30 Series applications.

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

#2 · Best Three-Mode Kit

2. GXYWADY 30 Series Gearbox

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

Best for: Three-position 30 Series upgrade.

Why it ranks #2: Lists forward, reverse, and neutral modes, a 5/8-inch shaft with 3/16-inch keyway, and compatibility with 2HP–13HP engines.

Forward, reverse, and neutral shifting gives this GXYWADY kit three operating positions for a 30 Series go-kart build. The listing covers 2–13HP engines and both #35 12-tooth and #40/41/420 10-tooth chain options, combining maneuverability with a choice of specified chain setups.

The three shift modes allow the operator to select neutral in addition to forward and reverse, which supports easier maneuvering around a garage or track area. Its 2–13HP engine range and 30 Series torque-converter specification help narrow compatibility, while the two listed sprocket options cover #35 12T and #40/41/420 10T chains. A 5/8-inch shaft with a 3/16-inch keyway provides a defined interface. The verified information limits this kit to four-stroke engines.

Skip it if you have a two-stroke engine; this kit is specified for four-stroke applications only.

Choose this for a four-stroke, 30 Series kart where three shift positions and chain flexibility matter. Its stated 2–13HP range and four-stroke-only limitation are the key boundaries to check.

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

#3 · Best Ratio Details

3. Silscvtt 30 Series Gearbox

• Weight: 12.35 lb
• Dimensions: 9.06 x 7.68 x 7.68 in

Best for: 30 Series three-mode control.

Why it ranks #3: Provides 1:1.3 forward and 1:2.6 reverse ratios, 2300 RPM, three shift positions, and compatibility with engines up to 13HP.

Three shift positions—forward, reverse, and neutral—give the Silscvtt gearbox a useful control range for maneuvering a go-kart. It is rated for up to 13HP and lists a 5/8-inch shaft with a 3/16-inch keyway, plus a 1540mm shifter cable for reaching the operator position.

The 1:1.3 forward and 1:2.6 reverse ratios provide distinct direction gearing, while the listed 2300 RPM specification gives another operating reference for a compatible build. Its 5/8-inch shaft and 3/16-inch keyway define the clutch connection, and the 1540mm cable helps place the shifter away from the gearbox. The unit supports #35 12T or #40/41/420 chain setups and engines up to 13HP. It is expressly limited to 30 Series use.

Skip it if you need a 40 Series gearbox for an 11–18HP engine; Leyuncot lists a 40 Series unit for that range.

Select this for a 30 Series kart within the 13HP limit when three modes and a long shifter cable suit the layout. Its explicit 30 Series restriction excludes 40 Series conversions.

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

#4 · Best Higher Displacement

4. JNDO 30 Series Gearbox

• Weight: 12.1 lb

Best for: Three-mode DIY builds.

Why it ranks #4: Specifies support for engines up to 13HP and 420cc, with forward, neutral, and reverse modes for maneuvering.

Forward, neutral, and reverse modes give the JNDO kit a clear advantage for maneuvering a go-kart that otherwise lacks reverse. It is specified for 30 Series setups and engines up to 13HP, including the listed 420cc ceiling, making it a functional option for a DIY assembly project.

The three shift positions let the operator select neutral as well as forward or reverse, supporting easier low-speed maneuvering in tight spaces. JNDO lists support for engines up to 13HP and 420cc, so buyers can compare the stated limit with their engine before assembly. Its aluminum-alloy construction is described as rugged, and the kit is aimed at DIY assembly enthusiasts. The listing does not specify chain sizes, so chain selection is less clearly established here.

Skip it if you run an engine above 13HP; GXYWADY’s 40 Series replacement lists support for 11–18HP engines.

This suits DIY builders who want three shift positions on a 30 Series kart with an engine within the stated 13HP limit. The listing does not give chain sizes, so chain-specific builds need extra scrutiny.

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

#5

5. labwork 30 Series Gearbox

• Weight: 5600 g

Best for: Assembly-focused 30 Series kit.

Why it ranks #5: Targets 2HP–13HP four-stroke engines and lists a 30 Series, 2300 RPM setup with replacement sprockets for 10T #40/41 and 12T #35.

A 1540mm shifter cable and stated 5/13 clutch-speed relationship give the labwork gearbox useful setup details for an assembly project. This 30 Series unit is specified for 2–13HP engines and lists replacement sprockets for 10T 40/41 and 12T 35 chain arrangements.

The 30 Series torque-converter designation and 2–13HP engine range help define the intended application before installation. Its 1540mm cable gives a stated length for planning shifter placement, while the 5/13 gearbox-speed relationship explains how gearbox speed relates to clutch speed. The listing names both 10T 40/41 and 12T 35 sprockets, letting builders match one of those chain configurations. labwork describes installation as easy for people assembling karts, though the engine and chain limits still govern fit.

Skip it if you run an engine above 13HP; GXYWADY’s 40 Series replacement lists applications up to 18HP.

This suits kart assemblers seeking a 30 Series gearbox with a specified cable length and two listed chain options. Keep the 2–13HP engine range and 30 Series designation in view.

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

#6

6. ALL-CARB 30 Series Gearbox

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

Best for: 30 Series short-cable layouts.

Why it ranks #6: Lists a 5/8-inch shaft, 3/16-inch keyway, 2300 RPM, and compatibility with 10T #40/41 or 12T #35 configurations.

A 130cm shifter cable gives the ALL-CARB gearbox a specific reach for compact 30 Series layouts. It is listed for 2–13HP engines and supports 10T #40/41 or 12T #35 setups, with a 5/8-inch shaft and 3/16-inch keyway defining the connection.

The 1:1.3 forward and 1:2.6 reverse ratios give the operator different gearing in each direction, while the stated 2300 RPM offers a reference for the intended setup. A 5/8-inch shaft with a 3/16-inch keyway specifies the shaft interface, and the 130cm cable provides a known length for shifter placement. Its 30 Series listing covers 10T #40/41 and 12T #35 arrangements, with engine use limited to the stated 2–13HP range.

Skip it if you have an engine above 13HP; Leyuncot’s 40 Series gearbox lists an 11–18HP engine range.

Consider this for a 30 Series go-kart or utility vehicle where the 130cm cable suits the shifter layout. The 2–13HP limit, shaft dimensions, and listed chain options define its fit.

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

#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: Covers 2HP–13HP engines and lists 12T #35 and 10T #40/41 chain options for 30 Series torque-converter applications.

A compact assembly with two stated chain-and-sprocket options makes this SEBLAFF kit adaptable across listed 30 Series setups. It is specified for 2–13HP engines, with a #35 12-tooth option or a #40/41 10-tooth option, covering common 212cc go-kart configurations within that range.

The two chain choices let a builder match the gearbox to either a #35 chain with 12 teeth or a #40/41 chain with 10 teeth. Its stated 2–13HP engine range gives a clear boundary for selecting an application, and the 30 Series torque-converter fit identifies the intended system. SEBLAFF describes the assembly as compact and convenient to install, which can help in a constrained build area. Confirm the model and pictures against the intended setup before installation.

Skip it if you have a 40 Series, 11–18HP setup; GXYWADY’s 40 Series replacement lists that engine range.

This is a practical candidate for a 30 Series 212cc kart within the stated 2–13HP span, especially when the chain option matters. Its 30 Series restriction rules it out for a 40 Series conversion.

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

#8 · Best 40 Series Fit

8. GXYWADY 40 Series Gearbox

• Weight: 20.8 lb

Best for: Higher-power 40 Series karts.

Why it ranks #8: Designed for 11HP–18HP applications, with a 3/4-inch keyed jackshaft and 12-tooth sprocket for 530 chain.

A 3/4-inch jackshaft and 12-tooth sprocket for 530 chain distinguish this GXYWADY 40 Series replacement. Its listed engine fit spans 11–18HP, including Predator 420cc and Duromax 11HP-and-over applications, giving higher-powered go-kart and utility-vehicle builds a gearbox option matched to that setup.

The 40 Series designation and stated 11–18HP range point this kit toward engines beyond the limits of many 30 Series listings. A 3/4-inch jackshaft with a 3/16-inch keyway defines the shaft interface, while the 12-tooth sprocket is specified for 530 chain. Forward ratio is 1:2 and reverse is 1:2.6, giving buyers concrete gearing details for planning a replacement. The listed 20.8-pound weight is worth accounting for during handling and installation.

Skip it if you need a lighter 30 Series gearbox; Silscvtt lists a 12.35-pound 30 Series unit for engines up to 13HP.

Consider this for a 40 Series kart or utility vehicle using a listed 11–18HP engine and 530 chain. Its 3/4-inch shaft and 20.8-pound weight are important installation considerations.

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

#9

9. Leyuncot 40 Series Gearbox

• Weight: 23.1 lb

Best for: 530-chain 40 Series builds.

Why it ranks #9: Targets 11HP–18HP engines including Predator 420CC, and specifies a 3/4-inch shaft, 12 teeth, and 530 chain.

A 12-tooth sprocket for 530 chain gives the Leyuncot 40 Series gearbox a defined match for higher-powered kart builds. It is listed for 11–18HP engines, including Predator 420cc and Duromax 11HP-and-above applications, with a 3/4-inch intermediate shaft and a 3/16-inch keyway.

The 40 Series designation and 11–18HP rating help identify the engine class this gearbox targets, while the listed Predator and Duromax applications give concrete examples. A 3/4-inch intermediate shaft with a 3/16-inch keyway defines the connection dimensions for planning installation. The 12-tooth sprocket and 530 chain pairing also give the build a stated chain specification. Forward ratio is 1:2 and reverse is 1:2.6, useful details when comparing gearing for a replacement.

Skip it if you need a lighter 30 Series unit for an engine up to 14HP; maXpeedingrods lists a 12.35-pound kit for that class.

This fits a 40 Series build where the engine rating, 530 chain, and 3/4-inch shaft match the stated setup. Account for its 23.1-pound weight when handling and installing the gearbox.

Listed on Amazon as: 40 Series Forward Reverse Gearbox 11-18hp Fit for Predator 420CC 530 chain

#10

10. MOOTINGMOTO Reverse Gearbox

Best for: Vertical-engine shaft conversions.

Why it ranks #10: Its stated fit is for CG-series vertical motorcycle engines and a 6-spline input with universal-joint output, rather than the common 30 Series setup.

A 6-spline female input and 20mm output shaft with a universal joint set this MOOTINGMOTO reverse gearbox apart from common chain-driven kart kits. It is listed for CG-series 150cc–250cc vertical engines, making its shaft-transfer layout relevant to compatible trikes, motorcycles, quads, and go-kart applications.

The stated CG-series 150cc–250cc vertical-engine fit identifies the engine family and orientation this transfer case targets. A 6-spline female input connects to the listed drive side, while the 20mm output shaft and universal joint describe the output arrangement for a shaft-driven installation. The listing also refers to 150cc, 200cc, 250cc, and 300cc vehicles, but its key feature specifies a 150cc–250cc range, so use that narrower stated range when assessing fit.

Skip it if you need a conventional 30 Series chain-driven gearbox; maXpeedingrods’ 30 Series kit lists sprocket and chain options for that setup.

This is for a shaft-driven conversion using a compatible CG-series vertical engine, not a general chain-drive replacement. Check the engine range, spline input, and 20mm output arrangement against the vehicle.

Listed on Amazon as: Transmission Reverse Gearbox, Go Kart Forward and Backward Converter Transfer Gear Case for ATV 150cc 200cc 250cc 300cc Engine Trike Motorcycle