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What Size Go-Kart Frame/Chassis Do I Need?

One of the best parts about go-karting is how variable it is, and how many options you have when getting started. A lot of people ask me about go-kart frames and their sizes, so it’s only right that I share my knowledge on the matter!

So, what size go-kart frame do you need? What size of go-kart frame or chassis you need varies heavily depending on the age of the driver, the engine they are using, and the type of go-karting they do. As one example, Senior (age 15+) go-kart frames are either made of 30mm tubing or 32mm tubing.

With all of the potential options and combinations needed to be considered before deciding on a specific frame, otherwise known as a chassis, this question can’t be answered just like that! Let’s look at how driver age, engine choice and type of go-karting should influence your decision.

Types Of Go-Karting: Sprint, Oval & Enduro

Your thoughts of what go-karting is will vary depending on what your background is and where abouts you’re from in the US of A. 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 race in short stints for the chance to be crowned victorious.

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 start with sprint chassis specifically and I’ll go through each racing type one by one to illustrate the differences between them. The size of your chassis and most importantly, the type of chassis, will largely depend on which types of race you will be entering.

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. As I mentioned previously, most chassis will adhere to the standardized measurements/size without much deviation except in specific circumstances (Margay started to produce chassis for tall drivers, for example, which were longer).

One big difference you need to be aware of, however, 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 the drivability is like night and day!

Chassis tubing also varies in size between racing classes/ age ranges, and it’s recommended to keep it in mind when choosing your engine, too. But at the most basic level, you will have to choose from 30mm moly tubing or 32mm 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

As you can likely tell from the explanatory chassis description, the frames of karts designed for oval racing are specifically engineered to accommodate for constant left-turning. This involves the driver being seated on the left and as such, a somewhat different size comparatively to Sprint racing.

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 30mm being used on the right side and 32mm used exclusively on the left.

Enduro Racing: Specialized Chassis

This specific classification of kart racing is a lot more niche than Sprint or Oval, and the chassis are unique to match. They’re notably longer than the standardized measurements, and are almost entirely enclosed inside which the driver will lay down to race.

Superkarts are very similar to enduro karts and it’s here that a large deviation happens in terms of frame size.

The chassis of enduro karts are designed to last, and as such are typically made of 32mm or even 34mm moly tubing at its base before added 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 used on average.

Driver Age / Racing Classes

After discussing the three types of kart racing and the typical sizes of their frames, plus the construction of their kart chassis, it’s important to next look at how driver age and racing classifications will also influence your decision about go-kart frames.

This is mainly dependent on Sprint and Oval racing types, as Enduro racing is typically reserved for adults only.

In the world of go-karting, racing is split into different categories based on the age of participants in order to keep a level playing field. Although every track will offer different classes, these are the most common:

  • Kid Karting – Age 5-7
  • Cadet Karting – Age 7-12 (Mini & Max)
  • Junior – Age 12-15
  • Senior – Age 15+
  • Master – Age 35+

It’s rather obvious why frames and chassis are differing sizes between these classifications, right? You wouldn’t put a 6-year-old in the same kart as a 22-year-old because they simply wouldn’t be able to reach the controls!

Kid karts are notably shorter and a bit narrower than adult karts, and are typically made with 26mm moly tubing. Cadet karts are a step-up from these and you’ll find 28mm moly tubing as a common choice for them. Junior karts are the last of the smaller kart types, and you can expect 28mm or 30mm moly tubing on these.

In the Senior kart classification, you will be choosing between 30mm and 32mm chassis tubing. As far as measurements and physical size of the frame goes, there won’t be any deviation from the standardized figures I mentioned earlier.

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 noted deviation compared to the bulk of the pack in the Senior area.

Tubing will be exclusively 32mm to better support a heavier driver without losing the suspension ability of a kart chassis. Depending on the race organizer, modifications can be made to the length and width of your frame provided they’re still within parameters. This can help with extra, more reliable downforce to give competitive racers a better edge.

So, as you now know, the size of your go-kart frame is hugely dependent on which racing classification you’ll be taking part in. To add onto this variable and truly expand upon it, let’s have a look at what engines have to do with it, too!

Engine Power

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 the same type. It 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 this come into effect for Junior or Senior karting.

50cc engines are used in kid karting and can otherwise 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 for the smaller driver, but are also made with more lightweight moly tubing so that the engine can properly propel the vehicle. This is why only 26mm tubing is used with 50cc engines.

As I mentioned previously, Junior and Senior levels of karting are where you can start to make some decisions on moly tubing thickness/weight for your advantage.

For example, Junior and Senior karting will each be split into 100cc or 125cc engine classifications. It’s a well-known fact in the go-karting world that if you’re racing 100cc karts, your chassis should be made of the more lightweight, flexible 30mm moly tubing. But on a personal level, 32mm 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. It has the extra power needed to propel a 32mm chassis easier than a 100cc engine, so getting extra rigidity doesn’t come at a cost of your speed.

Although all engines of the same displacement can compete in their brackets, not all engines offer the same raw horsepower and they all have their own little quirks. This can influence your decision of frame size, too!

A notable example is comparing IAME engines, mechanically-friendly and familiar, and RoK engines, plucky and feisty to a fault.

IAME typically have lower horsepower on average and although they can be tuned for higher output, they are favorites of drivers with smaller, lighter frames. By comparison, RoK engines have a naturally higher horsepower out of the box and as such, drivers with heavier, more rigid frames much prefer these.

Final Thoughts

There we have it! Who’d have thought that such a simple question could be answered so easily and yet with so many variables?

This is go-karting in a nutshell; it works for so many people from so many different walks of life that the options for racing are pretty much infinite. Even the easier questions on offer, such as which engine to choose, can take weeks of research!

I hope that you’re able to find a good go-kart frame size for your purposes; whether you’re a sprint or an oval racer, a kid karter or a master. There truly is a kart out there for everybody, with all kinds of frames and nuances to consider!