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

#1 · Best Overall

1. maXpeedingrods 30 Series Kit

• Weight: 12.35 lb

Best for: 30 Series 212cc Builds.

Why it ranks #1: Its 30 Series fit, up-to-14-hp range, 5/8-inch keyed shaft, stated ratios, cable length, and included sprockets offer unusually useful fitment detail.

A 30 Series gearbox rated for engines up to 14HP gives compatible go-karts and utility vehicles a forward-and-reverse transmission option. Its included 12-tooth and 10-tooth sprockets cover listed #35 and #40/41/420 chain choices, helping buyers match the chain setup without sourcing those sprockets separately.

The 5/8-inch shaft with a 3/16-inch keyway defines the mounting interface, while the five-foot shifter cable gives a stated length for planning the control route. Forward and reverse ratios are listed as 1:1.3 and 1:2.6, and gearbox speed is 5/13 of clutch speed. Those details help buyers assess drivetrain and shifter fit before assembly. Use is limited to a 30 Series torque converter, so the engine rating alone does not establish compatibility.

Skip it if you need a gearbox for a 40 Series converter; GXYWADY DY-9714498-731076-GX is listed for 40 Series applications.

Choose this for a 30 Series go-kart or utility-vehicle build within the 14HP limit, especially when the included chain sprocket options suit your setup. Check shaft, keyway, chain, and converter compatibility before installation.

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

#2 · Best Shift Modes

2. GXYWADY 30 Series Kit

• Weight: 12.45 lb

Best for: Three-Position 30 Series Builds.

Why it ranks #2: It specifies forward, reverse, and neutral, a 5/8-inch shaft with 3/16-inch keyway, and compatibility with 35 and 40/41/420 chain.

Three shift modes—forward, reverse, and neutral—give this GXYWADY 30 Series gearbox a useful maneuvering range for compatible go-karts and utility vehicles. Its stated 2–13HP engine range and sprocket choices for #35 or #40/41/420 chain help buyers narrow both engine and chain fit before installation.

The 5/8-inch shaft with a 3/16-inch keyway provides a defined mounting interface, and the 30 Series torque-converter restriction helps prevent choosing it for a different converter family. Sprocket options are listed as 12 teeth for #35 chain and 10 teeth for #40/41/420 chain, supporting chain selection for compatible builds. Forward, reverse, and neutral modes offer more control when maneuvering, while the stated engine range is 2–13HP for four-stroke applications.

Skip it if you have an 11–18HP engine and 40 Series converter; GXYWADY DY-9714498-731076-GX is listed for that range and series.

This fits buyers adding three-position shifting to a 30 Series, four-stroke build in the stated 2–13HP range. Match the keyway and one of the listed chain options, and do not select it for a 40 Series converter.

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

#3 · Best Ratio Detail

3. Silscvtt 30 Series Gearbox

• Weight: 12.35 lb

Best for: 30 Series Ratio-Specific Builds.

Why it ranks #3: The listing gives forward 1:1.3 and reverse 1:2.6 ratios, a 5/8-inch shaft, 2300 RPM, and an up-to-13-hp range.

Specified forward and reverse ratios of 1:1.3 and 1:2.6 make this Silscvtt gearbox useful to buyers comparing drivetrain behavior for a 30 Series build. It is listed for engines up to 13HP, with forward, reverse, and neutral positions, a 5/8-inch shaft, and chain options for #35 or #40/41/420 setups.

The 5/8-inch shaft and 3/16-inch keyway provide mounting dimensions to check, while the 1540mm shifter cable gives a stated length for planning control routing. Forward and reverse ratios of 1:1.3 and 1:2.6, plus a listed 2300 RPM, help buyers evaluate the gearbox against their drivetrain needs. Its 12-tooth #35 and 10-tooth #40/41/420 chain options broaden chain selection, but the product is explicitly limited to 30 Series use.

Skip it if you need a 40 Series gearbox for an 11–18HP engine; Leyuncot 40 Series 11-18hp 420CC 530 chain is listed for that application.

Choose this for a 30 Series build up to 13HP when the stated ratios, cable length, and chain options fit your plan. Its 30 Series-only restriction rules it out for 40 Series converters.

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

#4 · Broad Chain Fit

4. SEBLAFF 30 Series Kit

• Weight: 12.35 lb

Best for: Compact 30 Series Setups.

Why it ranks #4: Its stated 2–13-hp range and options for 35 chain 12T or 40/41 chain 10T suit buyers comparing common 30 Series configurations.

Compatibility with 2–13HP engines gives this SEBLAFF 30 Series gearbox a broad stated range for go-karts using a 212cc-class setup. It supports #35 chain with a 12-tooth sprocket or #40/41 chain with a 10-tooth sprocket, giving builders two listed chain configurations to consider during drivetrain planning.

The 30 Series designation limits the converter type to check, while the listed 2–13HP range helps screen engine suitability. Sprocket choices of 12 teeth for #35 chain and 10 teeth for #40/41 chain let buyers plan around either listed chain size. The gearbox is described as compact and lightweight, which may help with installation space and handling during assembly. The supplied facts do not state shaft dimensions or gearbox ratios, so assess those needs separately.

Skip it if you need listed shaft dimensions and ratios before assembly; Silscvtt TR-2321445-184880-SS gives shaft and ratio specifications for a 30 Series gearbox.

Consider this for a 30 Series go-kart or utility-vehicle build in the stated 2–13HP range when one of its chain options matches. Check your shaft and ratio requirements, which are not detailed in the supplied specifications.

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

#5

5. JNDO 30 Series Kit

• Weight: 12.1 lb
• Package Dimensions: 8 x 7.8 x 7.5 in

Best for: Three-Mode 30 Series Builds.

Why it ranks #5: It offers forward, neutral, and reverse for a stated up-to-13-hp application, but the supplied details omit shaft and chain specifications.

Forward, neutral, and reverse shift modes give this JNDO 30 Series kit a practical maneuvering option for go-karts that need more than forward drive. The listing specifies support for engines up to 13HP, including 420cc engines, and describes rugged aluminum-alloy construction for DIY assembly projects requiring a reverse gearbox.

Three shift positions allow a driver to select forward, neutral, or reverse, helping with maneuvering and disengaging drive in a compatible build. The stated 13HP ceiling and 420cc reference give buyers an engine-range starting point, while the 30 Series designation narrows the converter type to check during planning. Aluminum-alloy construction is specified, but the supplied details do not provide shaft, keyway, or chain dimensions, so verify those against the rest of the drivetrain before assembly.

Skip it if you need listed shaft and chain dimensions before choosing; maXpeedingrods YW65 specifies its shaft, keyway, and chain sprocket options.

This is a candidate for a DIY 30 Series go-kart build up to 13HP where three shift modes matter. Treat the 420cc reference as a fitment cue, and check drivetrain dimensions before committing to installation.

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

#6 · Best 40 Series Fit

6. GXYWADY 40 Series Gearbox

• Weight: 20.8 lb
• Package Dimensions: 13.3 x 9.85 x 9.75 in

Best for: 40 Series Predator Builds.

Why it ranks #6: Its 11–18-hp fit, 3/4-inch keyed jackshaft, 12-tooth sprocket, and 530 chain details target larger-engine 40 Series setups.

A 40 Series replacement gearbox specified for 11–18HP engines gives higher-powered go-karts and utility vehicles a forward-and-reverse option. Its 3/4-inch jackshaft and 12-tooth sprocket for 530 chain make the shaft and chain interfaces explicit, with Predator 420CC and Duromax 11HP-and-over applications named in the fitment details.

The 3/4-inch jackshaft with a 3/16-inch keyway gives builders a concrete shaft interface to check against their engine and drivetrain. A 12-tooth sprocket for 530 chain supports planning around that chain size, while the stated forward ratio of 1:2 and reverse ratio of 1:2.6 clarify the gearbox ratios. The listed 40 Series application and 11–18HP range help narrow engine fit; this is not the 30 Series option for smaller setups.

Skip it if you have a 30 Series converter or need a listed 35-chain sprocket; maXpeedingrods YW65 specifies those 30 Series chain options.

This suits a 40 Series build using an 11–18HP engine, a 3/4-inch shaft interface, and 530 chain. Confirm those drivetrain dimensions and the stated application before choosing it for a go-kart or utility vehicle.

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

#7

7. Blast 40 Series Kit

• Weight: 22 lb

Best for: 40 Series Gearbox-Only Builds.

Why it ranks #7: It covers 11–18-hp applications and lists both 12T 530-chain and 10T 420-chain sprocket options, but excludes driver and driven clutches.

A gearbox-only 40 Series kit for heavier 11–16HP applications lets builders add forward and reverse gearing while sourcing their clutch components separately. It offers a 3/4-inch jackshaft with a 3/16-inch keyway and a choice of 12-tooth 530-chain or 10-tooth 420-chain sprocket configurations, making chain selection part of the fit decision.

The 3/4-inch jackshaft and 3/16-inch keyway specify the shaft interface for a drivetrain check, while the two listed sprocket configurations let buyers match either 530 or 420 chain. The product is described for 11–18HP engines and names Predator 420CC, Honda, Briggs & Stratton, and Duromax applications. However, the driver and driven clutches are expressly excluded, so assembly planning must include separately sourced clutch components rather than treating this as a complete drive system.

Skip it if you need a kit that includes the driver and driven clutches; Leyuncot 40 Series 11-18hp 420CC 530 chain is listed as a gearbox kit.

Pick this for a heavier 40 Series build when you already have, or will source, the driver and driven clutches separately. Match its shaft, keyway, chain option, and engine range to the vehicle before assembly.

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)

#8

8. Leyuncot 40 Series Kit

• Weight: 23.1 lb
• Package Dimensions: 13.8 x 10.3 x 10 in

Best for: 530-Chain 40 Series Builds.

Why it ranks #8: The 3/4-inch keyed shaft, forward and reverse ratios, 12-tooth sprocket, and 530 chain are specified for 11–18-hp engines.

A 12-tooth sprocket paired with 530 chain gives this Leyuncot 40 Series gearbox a clearly specified chain interface for higher-powered go-kart and utility-vehicle builds. The listing covers 11–18HP engines, names Predator 420CC and Duromax 11HP-and-above applications, and specifies a 3/4-inch intermediate shaft with a 3/16-inch keyway.

The 3/4-inch intermediate shaft and 3/16-inch keyway provide concrete dimensions for checking the engine-side connection, while the 12-tooth sprocket and 530 chain define the listed chain setup. Forward and reverse ratios of 1:2 and 1:2.6 help builders account for the gearbox in drivetrain planning. Its stated 40 Series and 11–18HP application range, including Predator 420CC and Duromax 11HP-and-above engines, helps separate it from smaller 30 Series options.

Skip it if you use 420 chain and want that option listed; Blast BL-40S-FRG offers a 10-tooth sprocket configuration for 420 chain.

Choose this for a 40 Series build within the stated engine range that uses a 3/4-inch shaft interface and 530 chain. Its listed setup is specific, so match the chain and keyway before assembly.

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

#9

9. Woosphy 40 Series Gearbox

• Weight: 20.4 lb
• Package Dimensions: 13.58 x 9.06 x 7.87 in

Best for: Predator 420CC 40 Series.

Why it ranks #9: It identifies a 3/4-inch keyed jackshaft, 12-tooth sprocket, 530 chain, and an 11–18-hp fit, though fewer operating details are provided.

A 40 Series replacement listed for Predator 420CC engines gives this Woosphy gearbox a clear target for higher-powered go-kart builds. Its 3/4-inch jackshaft with a 3/16-inch keyway and 12-tooth sprocket for 530 chain specify two important drivetrain interfaces, while the stated engine range covers 11–18HP applications.

The 3/4-inch jackshaft and 3/16-inch keyway give builders dimensions to compare with the engine-side connection, while the 12-tooth sprocket for 530 chain sets the listed chain arrangement. Its 40 Series designation and stated 11–18HP range help distinguish it from smaller-series gearboxes, and Predator 420CC and Duromax 11HP-and-over applications are named. These details support fitment planning for go-karts and utility vehicles, but the 530-chain setup must match the rest of the drivetrain.

Skip it if you need a 420-chain option for a 40 Series kit; Blast BL-40S-FRG lists a 10-tooth sprocket for 420 chain.

This suits a 40 Series go-kart or utility-vehicle build in the stated 11–18HP range, particularly one using a Predator 420CC and 530 chain. Check the shaft, keyway, and chain interfaces against your drivetrain.

Listed on Amazon as: 40 Series Forward Reverse Gearbox Replacement for Predator 420CC 530

#10

10. HSCJMEHT 30 Converter Gearbox

• Weight: 14.1 oz
• Package Dimensions: 0.39 x 0.39 x 0.39 in

Best for: TAV2 30 Converter Owners.

Why it ranks #10: It is intended for 30 torque converters and small or medium go-karts, but the listing supplies few shaft, chain, ratio, or engine-limit details.

Compatibility with TAV2 Series 30 torque converters is the central fit point of this HSCJMEHT reverse transmission, giving owners of compatible go-karts a stated route to reverse capability. The description also names small and medium go-karts equipped with 5.5- and 6.5-engine setups, making its intended use more specific than a general gearbox listing.

The stated 30 torque-converter application gives buyers a clear first compatibility check, while the TAV2 Series 30 reference narrows the converter family further. Its description identifies small and medium go-karts with 5.5- and 6.5-engine setups, which helps owners assess whether the intended vehicle class matches. The product is described as a reverse transmission, not as a three-position forward/neutral/reverse kit, so buyers needing those additional modes should choose accordingly.

Skip it if you need forward, neutral, and reverse modes in a stated 2–13HP range; GXYWADY GXYWF8-025357 lists all three.

This is for owners of a small or medium go-kart with a TAV2 Series 30 converter and a listed 5.5- or 6.5-engine setup. Its stated function is reverse, so consider mode requirements before buying.

Listed on Amazon as: Reverse Gearbox Transmission for Go-Karts with 30 Torque Converter