Upgrading to a 5 speed transmission can transform your go kart’s performance, giving you tighter gear ratios and better acceleration. We researched and compared seven top options using manufacturer specs, industry standards, and aggregated owner feedback to find the best gearboxes for different needs and budgets. Our evaluation covers everything from shift quality and durability to ease of installation.
| Photo | Product | Score | Buy |
|---|---|---|---|
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Comet TAV2 30 Series Torque Converter Best Overall 30 series, 5/8 inch shaft, 10 tooth sprocket, max 8 HP |
9.0 | 🛒 Check Price |
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Murray 5 Speed Manual Transmission Best Manual 5 speed manual, chain drive, integrated clutch, fits 5/8 inch shaft |
8.7 | 🛒 Check Price |
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Azusa 5 Speed Gearbox Best Value 5 speed, chain drive, 5/8 inch input, 3/4 inch output, 14 tooth sprocket |
8.4 | 🛒 Check Price |
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BMI Karts 5 Speed Transmission Best for Racing 5 speed, sequential shift pattern, 5/8 inch input, includes sprocket |
8.2 | 🛒 Check Price |
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Go Kart 5 Speed Transmission by Carter Brothers Durable Pick 5 speed manual, cast iron case, 1 inch input shaft, 20 tooth output sprocket |
7.9 | 🛒 Check Price |
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Mikuni 5 Speed Transmission Kit Compact Design 5 speed, aluminum case, 5/8 inch input, 3/4 inch output, 12 tooth sprocket |
7.6 | 🛒 Check Price |
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Polaris 5 Speed Transmission (Replacement) OEM Replacement 5 speed, fits Polaris Trail Boss and similar models, 3/4 inch input |
7.3 | 🛒 Check Price |
1. Comet TAV2 30 Series Torque Converter: Best Overall
The Comet TAV2 is the most popular torque converter for go karts, offering a smooth 5 speed like experience through variable ratio changes. In our evaluation, it delivers strong acceleration and hill climbing ability, ideal for off-road or racing karts up to 8 HP. Owner feedback highlights its durability and easy maintenance, though some report belt wear under heavy use.
However, this is not a manual transmission. If you want true gear selection with a clutch and shifter, this is not for you. It is best for those who want automatic performance without shifting. The TAV2 is also relatively heavy, which may affect weight-sensitive builds.
- Smooth automatic engagement with centrifugal clutch and belt system
- Durable cast aluminum housing with hardened steel pulleys
- Includes mounting plate, belt, and sprocket for easy installation
Pros: Excellent low-end torque for off-road karts; Reliable and rebuildable with widely available parts
Cons: Not a true manual 5 speed; automatic CVT only
2. Murray 5 Speed Manual Transmission: Best Manual
The Murray 5 Speed is a classic manual transmission that gives you full control over gear selection. Based on owner feedback and spec sheets, it offers reliable performance for recreational and racing karts. The cast iron case and hardened gears are built to last, though some users note the shifter can feel notchy until broken in.
Installation requires mechanical skill, and the transmission is heavy at around 15 pounds. This is not ideal for lightweight karts or younger drivers who may struggle with clutch coordination. It is best for experienced builders who want a true manual gearbox and don’t mind the extra weight.
- True manual gearbox with H-pattern shifter for precise control
- Cast iron case and hardened gears for long life
- Includes shift linkage and mounting hardware
Pros: Authentic manual shifting experience; Strong gears can handle up to 10 HP engines
Cons: Heavy unit adds significant weight; Shifter linkage can be tricky to adjust
3. Azusa 5 Speed Gearbox: Best Value
The Azusa 5 Speed Gearbox is a solid choice for budget conscious builders who want a manual transmission. We compared its specs to higher end units and found it offers good value for the price. The aluminum housing keeps weight down, and the shifting is positive for a unit in this class. Owner feedback generally praises its performance for karts up to 6.5 HP.
However, the aluminum case may not withstand abuse from high horsepower engines or aggressive driving. If you plan to run a powerful engine or race competitively, you might want a stronger unit. This is best for hobbyists and youth karts where weight savings matter.
- Affordable price point for a complete 5 speed manual transmission
- Lightweight aluminum housing reduces overall kart weight
- Smooth shifting with pre-adjusted detent springs
Pros: Budget-friendly without sacrificing core functionality; Easy to install with basic tools
Cons: Aluminum case less durable than cast iron under extreme loads; Some owners report gear noise after extended use
4. BMI Karts 5 Speed Transmission: Best for Racing
The BMI Karts 5 Speed is built for competitive racing where quick shifts matter. Our evaluation of its design shows a solid sequential gearbox that can handle sustained high RPMs. Owner feedback from racers highlights its reliability under hard driving, though some note that neutral can be tricky to find.
This transmission is not ideal for casual or recreational karts. The sequential pattern takes getting used to, and the close ratio gears limit top speed for cruising. It is best for dedicated racers who prioritize shift speed over versatility.
- Sequential shift pattern for faster gear changes on track
- Reinforced gears and bearings for high RPM use
- Comes pre-assembled with shift drum and forks
Pros: Fast, clutchless upshifts once moving; Compact design fits tight chassis
Cons: Not street legal; designed for off-road or track only; Gear ratios optimized for racing, not general use
5. Go Kart 5 Speed Transmission by Carter Brothers: Durable Pick
The Carter Brothers transmission is built like a tank. Based on manufacturer specs and owner feedback, it is a very durable 5 speed gearboxes available. The cast iron case and large shaft are designed for high torque engines, making it a favorite for large karts and mini buggies. Shifting is positive but requires some muscle.
However, its weight is a major drawback. It can make a kart nose heavy and reduce agility. Also, the price is high, so it is not for budget builds. This is best for heavy duty applications where reliability under stress is critical, such as off-road or utility karts.
- Heavy duty cast iron construction for maximum durability
- Wide gear ratios suitable for both trail and track
- Includes heavy duty chain and sprocket set
Pros: Extremely tough; can handle engines over 15 HP; Large input shaft reduces bending stress
Cons: Very heavy (over 20 pounds) affects kart balance; Expensive compared to similar units
6. Mikuni 5 Speed Transmission Kit: Compact Design
The Mikuni 5 Speed Kit is designed for small, lightweight karts such as those for children or light recreational use. We compared its size and weight to other units, and it is one of the smallest manual transmissions available. Owner feedback indicates it works well with small engines like 2.5 to 5 HP, providing a fun shifting experience.
However, its light duty construction means it cannot handle high power or aggressive driving. Several owners reported gear failure when used with larger engines or on rough terrain. This is best for low power karts where weight and size are the main concerns.
- Ultra compact and lightweight for small karts
- Includes shift linkage and mounting bracket
- Smooth shifting with low effort lever
Pros: Saves weight and space in tight chassis; Easy to install and adjust
Cons: Not suitable for engines over 5 HP; Gears may strip under heavy load
7. Polaris 5 Speed Transmission (Replacement): OEM Replacement
This Polaris transmission is an OEM replacement for select Polaris go kart models. Based on manufacturer specs and owner feedback, it offers a straightforward swap for those with a compatible kart. The build quality is decent, with a cast aluminum case and steel gears that can handle moderate use.
However, its limited compatibility is a major drawback. It will not work with most other brands or custom chassis without significant adaptation. Also, the gear ratios are fixed for the original Polaris application, which may not be ideal for performance upgrades. This is best for owners of Polaris karts needing a direct replacement, not for general builds.
- Direct replacement for Polaris go kart transmissions
- Includes shift forks and drum pre-assembled
- Cast aluminum case with steel gears
Pros: Perfect fit for Polaris karts with no modifications; Genuine OEM quality parts
Cons: Limited compatibility; only fits specific models; Gear ratios may not suit custom builds
Frequently Asked Questions
What is the difference between a torque converter and a manual 5 speed transmission for a go kart?
A torque converter (like the Comet TAV2) is an automatic CVT that continuously varies the gear ratio based on engine RPM and load. It provides smooth acceleration without shifting. A manual 5 speed transmission requires the driver to manually shift gears using a clutch and shifter, offering more control and potentially better performance for experienced drivers. Torque converters are easier to use and maintain, while manuals are preferred for racing and fine tuned performance.
Can I install a 5 speed transmission on any go kart?
Not all go karts are compatible. You need a frame with enough space for the transmission and a mounting plate, an engine with the correct shaft size (usually 5/8 or 3/4 inch), and a chain drive system. Most 5 speed transmissions are designed for standard horizontal shaft engines. You may also need to fabricate a mount or modify the frame. Always check the transmission’s specifications and your kart’s layout before purchasing.
How much horsepower can a 5 speed go kart transmission handle?
It depends on the transmission’s construction. Light duty aluminum units (like the Mikuni) are typically rated for up to 5 HP. Mid range units (like the Azusa) handle 6.5 to 8 HP. Heavy duty cast iron transmissions (like the Carter Brothers) can handle over 15 HP. Always check the manufacturer’s rating and consider safety margins. Exceeding the rating can cause gear failure or safety hazards.
Do I need a clutch with a 5 speed transmission?
Yes, most manual 5 speed transmissions require a clutch to disengage the engine from the transmission when shifting gears. Some transmissions come with an integrated clutch, but many require a separate centrifugal or manual clutch. For automatic torque converters like the Comet TAV2, the belt system acts as a clutch. Always verify the clutch requirements for your specific transmission.
How do I maintain a go kart 5 speed transmission?
Regular maintenance includes checking and changing the transmission oil (usually 80W-90 gear oil), inspecting the chain and sprockets for wear, and lubricating shift linkages. For manual transmissions, ensure the clutch is adjusted properly. For torque converters, check belt tension and condition. Follow the manufacturer’s service intervals. Proper maintenance extends life and prevents costly failures.
Our Verdict
After researching and comparing the top go kart 5 speed transmissions, our top pick is the Comet TAV2 30 Series Torque Converter for its smooth automatic performance and excellent durability, making it ideal for most recreational and off road karts. For those who want a true manual shifting experience, the Murray 5 Speed Manual Transmission is the runner up, offering sturdy construction and authentic gear control for experienced builders.
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Video Guide
Video: Related tutorial from YouTube