What's a kart?

Karts may seem like little cars, but there are some defining characteristics that separate them from ATVs or other tiny conveyances. Obviously, size is a big factor, but one major aspect of a kart is its complete lack of a traditional suspension; here the axle is firmly affixed to the frame, there is no differential (both rear tires turn at the same speed), and while things like camber and caster may be adjustable, there are no dampers or springs. Overall kart layout tends to feature a driver sitting beside a low capacity engine (generally 125cc or less) that uses either chains or gears to drive the rear axle. Traditionally, a kart has a single brake disc on the rear and nothing on the front (though that's not always the case), and the brake pedal is situated to the left of the kart, with the throttle on the right, forcing the driver to either learn left-foot-braking or go hurtling off course.

A kart should have a very snug, form-fitting seat and no belts of any kind, and while karts rarely have roll-cages or serious crash structures, that's beginning to change. But despite traditional safety features, karting is considered a very safe form of motorsport with injuries rare and generally non-life-threatening. There's always a risk, but if you drive responsibly and take the appropriate safety precautions chances of becoming a pavement stain at your local track are low.


Types of karts

Outdoor "fun" karts

These are the karts that you see baking under the sun (and rusting under the rain) at vacation destinations. They typically have a motor liberated from some unsuspecting lawn mower that puts out somewhere between two and five horses. They're loaded down with heavy body work, gigantic bumpers, thick wheels, and over-built everything that results in a weight somewhere well north of 300 pounds. While they're a fun distraction at the mini-golf course, they're about as close to "real" karting as flying a kite is to manning an F16.


Endurance/Rental karts

Now we're getting somewhere. Enduro karts are the sort that you'll usually be thrown into at a kart track's arrive-and drive-program, whether indoor or outdoor. Now you've got a reasonably proper racing chassis, but it's often been cloaked in a wrap-around bumper to prevent the most dangerous type of karting accident: wheel to wheel contact. Motors here tend to be in the eight to ten horsepower range, again typically derived from some sort of small motorized utility product, but given some tuning to make them race-ready. Weight drops to around 250 pounds and, with a hard racing tire, you could see yourself pulling 1.5 g in the corners -- better than a Ferrari Enzo. Chassis and motor setup tends to be limited because they're generally used as fleets, with the idea being one is as good as another. That's rarely the case, though, so if you're renting try to jump into one that isn't too beat looking.

It's worth noting there's a huge difference between your average indoor karting track (like the fantastic F1 Boston indoors track) and your average outdoor track (like the equally fantastic F1 Boston outdoors track). Indoor tracks tend to have very slick surfaces that allow the karts to drift very easily and turn on a dime despite their live rear axles. Outdoors, on concrete or asphalt, grip levels are far higher and the driving dynamics are quite different. Whether indoor or out, renting this sort of kart for a few hours is the best way to get a feel for the sport and see if it's something you want to pursue -- and it's a great time, too.


Sprint karts

This is the next step up from an enduro kart, a proper racer intended for tracks that turn left and right. This is such a broad category it's difficult to lump them together, but there is a lot of commonality. Motors tend to be two-stroke, ranging in displacement from 80cc to 125cc, though there are plenty of exceptions. Output ranges from ten to around 35 hp, and kart weight is dependent on classes. A bare sprint kart for an adult typically weighs about 200 pounds, but rules will specify minimum weights including the driver and the kart to ensure that everyone is on relatively equal footing. Anyone who is too light will need to add weight (usually lead ballast) or face disqualification.

Here are the rules for the popular Rotax Max Challenge series (will get into that later) as an example:

Class	Age	Minimum Weight (lbs.)
Micro Max	7 - 10	235
MiniMax	9 - 12	265
Junior	13 - 16	320
Senior Max	15+	365
Master	16+	405

Younger karters aren't just allowed to run lighter, though; they fit less powerful motors often in smaller karts, keeping speeds low and safety high. As they progress they can move into something with more power, but it's often kids who are the quickest on more technical tracks, with their lighter karts more than making up for any horsepower disadvantage. On sticky tires and at the right course, sprint karts can pull upwards of 2.5 g, far more than any car on the road. Typically these karts run a single brake disc at the rear, though some will run front discs as well, and some, called Touch and Go (or TAG) karts have electric starters. The rest either have pull starters, rely on external starters or simply need a push from a helpful bystander.

Again, this is a very broad category of kart, one that we'll be digging into in much more detail later. What's important to a complete newbie of the sport is the classes that your local track supports, a topic we'll get into shortly.


Shifters

When many people think of a "fast" racing kart they think of a shifter. A shifter is basically the same as a sprint kart, but features a motor with a transmission, typically a motorcycle-sourced six-speed sequential, enabling the driver to bump up or down a gear very quickly. Engines are still generally 125cc, but the increased mechanical advantage of multiple gears will get you to 60mph in under four seconds and on up to 125 MPH or so with a long enough straight.

These karts tend to run disc brakes at the front in addition to a single disc at the rear, and while the extra stopping power is a necessity, grip generally doesn't run higher than 2.5 g.


Oval (a.k.a. Four Cycle)

Sprint karts are where you want to be if you're a fan of Formula One, CART or other forms of motorsport that involve turning more than one direction. If you're of the NASCAR persuasion you'll be more interested in speedway karting, commonly referred to broadly as "four cycle" thanks to the common use of four-stroke Briggs and Stratton engines. Outright performance tends to be lower (usually ten hp or less), but so too is maintenance and cost, with four-stroke engines able to go much longer between rebuilds than your average two-stroke (they're also far better for the environment). Classes here are set up similarly to sprint karts, based on age and weight, but the karts themselves look very different.

The karts are offset to the left, with the driver shifted further over, with larger tires on the right to help the kart maintain better grip through left-hand bends -- the only type of corner this kart is likely to see. Oval karts also have far more bodywork than your average sprinter, primarily to provide better aerodynamics, but also because rubbin' is racin' and there's a lot more rubbin' on ovals than sprint circuits. That's at least partly because there's real money to be won in many speedway events, something you'll rarely find at anything outside the highest form of sprint karting.


Superkarts

Now we're into some serious stuff. Superkarts are effectively larger, faster shifters, generally with 250cc motors that produce anything from 70 to 100 hp and a weight, with driver, of under 500 pounds. That equates to acceleration to 60mph in under three seconds and a top speed of 140mph or more. Bodywork makes these cars look like tiny formula racers, but there's little in the way of crash protection and still no suspension. Karts like this are best found on full road courses like Road Atlanta or Laguna Seca, where they can stretch their legs and pull 3 g in the corners.


Tracks

Oval karting tracks tend to be of the short variety, generally around a half-mile with either dirt or asphalt surfaces. Sprint tracks are generally between .75 and 1.5 miles in length, varying from tight, technical circuits to longer, faster sweepers. Finally, the faster sprinters and superkarts will make appearances at full road courses, where highest speeds -- and risks -- are found.

If you don't think there's a kart track nearby, you might be surprised. Oval tracks are the most numerous, located outside nearly every reasonably large town and many small ones. Sprint tracks are a little harder to find, with full road courses that regularly allow karting being few and far between. About the best list we've found is at the North American Motorsports Pages, cataloging both indoor and outdoor kart tracks in the United States and Canada. It's a few years out of date, but still quite comprehensive.


What's next?

As mentioned above, starting with a proper rental or endurance arrive and drive kart is a great way to get a taste. After that, if you're hungry for more it's time to find the closest track that meets your desired configuration and stop by for a visit. See what classes they run, talk to some racers to learn what kind of chassis and motor combinations are popular, and get an idea of the fees for practice and racing. It's unfortunate that many tracks charge fees just to enter the circuit and look around, but if you can find the owner and chat with him or her for a few minutes, they might be inclined to let you in for free if you're seriously interested in buying a kart and getting started. After all, he'd be making a lot more in the long-run if you're paying to race and not just watch. But, keep in mind they're paying for the insurance should you get run over by an overzealous seven-year-old, so don't balk if they insist on charging.

As for us, we're diving right in with a driving school in a rental kart at our closest track, Oakland Valley Raceway Park. We'll be back with pictures and videos from the day at the circuit and plan to talk about driving technique and chassis setup. After that, it's time to make a budget and go shopping.


Tim Stevens writes for Autoblog sister site Engadget.com where, among other things, he covers all things tech-related in the automotive world. He recently took up the hobby of karting and will help you do the same through this series, An Introduction to Karting.