Choosing the right go-kart frame or chassis size can be daunting as a beginner, but as long as you know a few basic things it becomes a much easier decision to make. It helps to check out a go-kart frame size guide to pick the right one for your next kart.
What size of go-kart frame/chassis you need varies depending on your age, the engine you are using, and the type of go-karting you plan to take part in. As one example, Senior (age 15+) go-kart frames are either made of 30 mm tubing or 32 mm tubing, but their dimensions don’t tend to vary much.
With all of the potential options and combinations out there for go-kart frames, otherwise known as a chassis, there are a few different things to consider to allow you to make the right choice. We take a look at all of these different factors in detail below.
Sprint, Oval & Enduro Karting Chassis Sizes
Your thoughts of what go-karting is will vary depending on what your background is and where you’re from. But typically, most people will think of sprint-style karts, which have a straight chassis where the driver sits in the center of the rig and races in short stints.
Although go-karts come in all shapes and sizes, the racing variety are largely the same. Sprint and oval kart chassis will typically meet the standard measurements of 78” long, 25” tall and 52” wide. Enduro karts are a different story altogether! Let’s take a closer look at each one.
Sprint Racing: Straight Chassis
Go-karts designed for sprint racing are the most common you’ll likely encounter when you go out looking for go-kart frames. Most chassis will adhere to the standardized measurements without much deviation except in specific circumstances (for example, Margay started to produce chassis for tall drivers, which were longer than usual).
One big difference you need to be aware of is the size of the tubing used for composing the frame itself. Although the differences between them is in mere millimeters, I can assure you that there are major drivability differences between the two!
Chassis tubing also varies in size between racing classes and age ranges, and we recommend you keep it in mind when choosing your engine too. But at the most basic level, you will have to choose from 30 mm or 32 mm moly tubing for Senior-level racing (the adult classification).
The frame is designed to keep the driver central and to assist in keeping good balance on the track. That’s why the measurements are always kept the same as per IKF (International Karting Federation) regulations.
Oval Racing: Offset Chassis
The frames of karts designed for oval racing are specifically engineered to accommodate constant left turns. This involves the driver being seated on the left and so the sizes vary slightly when compared to sprint karts.
You’ll see more deviation with chassis length and width in this classification of racing, but not by much. A couple of inches added to length will keep more downforce, which is good for cornering.
The biggest difference is seen in the tubing size of these karts. Everybody you speak to in oval racing will recommend that you choose a larger measurement in order to keep the chassis more rigid and to be more resistant to the higher g-forces experienced only on one side of the kart.
Some people use a mixed amount of tubing, with 30 mm being used on the right side and 32 mm used exclusively on the left.
Enduro Racing: Specialized Chassis
This specific classification of kart racing is a lot more niche than sprint or oval racing, and the chassis are unique to match. They’re notably longer than the standardized measurements, and they’re almost entirely enclosed inside, with the driver lying down to race.
The chassis of enduro karts are designed to last, and as such are typically made of 32 mm or even 34 mm moly tubing at its base before additional reinforcement is attached. Because races are of an endurance variety, the kart doesn’t need to be as lightweight as sprint or oval rigs, hence the thicker tubing.
Driver Age & Racing Classes
Although every track will offer different classes, these are the most common karting categories:
- Kid Karting – Age 5-7
- Cadet Karting – Age 7-12 (Mini & Max)
- Junior – Age 12-15
- Senior – Age 15+
- Master – Age 35+
Note: These categories only really pertain to sprint and oval karting, as endurance racing is typically reserved for adults
Kid & Junior Karting
Kid karts are notably shorter and a bit narrower than adult karts, and they are typically made with 26 mm moly tubing. Cadet karts are a step-up from these and you’ll find 28 mm moly tubing as a common choice for them. Junior karts are the last of the smaller kart types, and you can expect 28 mm or 30 mm moly tubing on these.
Senior Kart Racing
In the Senior kart classification, you will be choosing between 30 mm and 32 mm chassis tubing. As far as measurements and the physical size of the frame goes, there won’t be any deviation from the standardized figures I mentioned earlier ( 78” long, 25” tall and 52” wide).
The Master racing classification is designed for more experienced kart drivers with a higher upper weight limit, and as such, you’ll start to see some notable deviation compared to the bulk of the pack in the Senior area.
Tubing will be exclusively 32 mm to better support a heavier driver without losing the suspension characteristics of the kart’s chassis. Depending on the race organizer, modifications can be made to the length and width of your frame, provided they’re still within certain parameters. This can help with extra, more reliable downforce to give competitive racers a better edge.
KEY POINTS• Go-kart chassis sizes vary depending on the type of karting you plan on participating in
• The ideal go-kart chassis size for you largely depends on your age
• The physical dimensions of the kart usually don’t vary too much between classes
How Engine Power Affects Go-Kart Frame Size
Every racing classification will have an engine classification too, in order to create further divisions and allow all go-karting to be as equal as possible. For example, a Comer C51 engine can only compete against other Comer C51s. It usually can’t go up against a Honda GXH50, even though they’re of the same displacement (50cc).
There is little nuance in kid karting and cadet karting in terms of types of tubing to be used for different advantages/purposes, due to how their karts are made specifically to reach certain safety requirements, but you’ll start to see the differences appear in Junior or Senior karting.
50cc engines are used in kid karting and can often be found on rental karts at outdoor tracks. In order for a proper balance to be reached, kid karts are not only smaller to accommodate smaller drivers, but they’re also made with more lightweight moly tubing so that the engine can properly propel the vehicle. This is why only 26 mm tubing is used with 50cc engines.
100cc & 125cc
Junior and Senior karting will each be split into 100cc or 125cc engine classifications. If you’re racing 100cc karts, your chassis should generally be made of the more lightweight, flexible 30 mm moly tubing. However, 32 mm moly tubing can be used for extra rigidity.
When you look at 125cc engine racing, the choice of moly tubing and therefore the size of your frame is a lot more dependent on your personal preferences. These engines have the extra power needed to propel a 32 mm chassis easier than a 100cc engine, so getting extra rigidity doesn’t come with the same speed penalty.
Matching Your Engine With Your Chassis
Not all kart engines offer the same horsepower and they all have their own little quirks. This can influence your decision of frame size as well. A notable example is comparing IAME engines, which are mechanically-friendly and familiar, and ROK engines, which are plucky and feisty.
IAME engines typically have lower horsepower, and although they can be tuned for higher output, they are favorites of drivers with smaller, lighter frames. By comparison, ROK engines tend to be more powerful out of the box, and as such, drivers with heavier, more rigid frames often prefer these.
Choosing the right kart chassis/frame size largely comes down to the type of karting you plan to participate in, your age, and the engine you want to use in your kart. While physical dimensions don’t usually vary much between kart chassis, the moly tubing will usually vary between 30 mm and 32 mm.
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