Kart Setup: Basic Chassis Setup Tips

Kart Setup: Basic Kart Setup.

Here are some some changes that can be made to kart setup, and what these changes should do to the handling of you kart - in theory. There's never one set rule for every chassis for every track though, so these should only be taken as guidelines. Experimenting with the setup by yourself and taking note of how the changes affect handling is the best way to find out what best works for you and your kart. In addition to the kart chassis setup your engine and carb setting play an important role in your speed. The most important factor however is the nut behind the wheel - and most attention should go into improving your driving rather than spending all your time worrying about the kart.

You should really only start to fool around with your kart setup when you can consistently lap within 2 tenths or so every lap for 10+ lap stints. This way when you make a setup change you should be confident enough that an improvement in lap time was caused by the change and not by the driver. Another important point to remember is that you should only change one thing at a time. If you change two or three factors you will have no idea which change did what. In last-ditch efforts during race weekends it is of course understandable to go for several changes at once - when you are way off on the setup.

An important part of setting up a kart is understanding the handling problems. Often drivers go to try to add grip to the rear of the kart because they are oversteering through a corner. Closer analysis may however reveal that the oversteer is actually caused by understeer earlier in the corner. The understeer makes the driver turn the front wheel more than desired and as the front regains traction the kart snaps into oversteer. It is very important to think what in your driving may improve the handling of the kart.

Tyre Air Pressures:

The air pressure in the tyres is one of the most important things to get right. Starting with manufacturer recommended pressures is best, and then experimenting with lower or higher pressures. An important point to remember is that for example 12psi might be absolutely perfect during your first three laps but your times might quickly start getting worse (often a sudden .5 tenths per lap slower). This means that your tyres were at the optimum pressure when you started but as tyres heat up the pressure builds up and the tyres will start underperforming when the pressure gets higher than optimum. Being fast right out of the pits is what you need for 3 laps of qualifying, but not for a race.

I find that a good way to find tyre pressures that work is by looking at your times. If you are able to consistently drop your times by a tenth per lap for example over the first five laps and then your times stabilise or still improve slightly at a slower rate for the next 10 laps you have found good pressures for a 10-15 lap race. You can try slightly higher pressures until you reach the point where your times get worse after a few laps.

Generally You would use lower pressures for a long race, high ambient/track temperature, and when there is a lot of rubber on the track. For the opposite conditions you would reduce tyre pressure. In wet weather the more water there is on track the more pressure you should run. On a drying track it is important to run low pressures in wets to prevent them overheating as much as possible, or if possible use an old set of wet tires that have been hardened and will be able to maintain grip on a drying track.

Track (Front/Rear Width):

Widening the rear track stops the kart from binding as easily and in theory makes the rear of the kart looser. If your kart is hopping in the corners or you can feel your engine severely bogging coming our of corners widening the rear track might help (only change rear track about 10mm each time though, as it can have a very large effect on handling).

Going narrower on the rear track in theory makes the kart stick to the track better. So if you have lots of oversteer narrowing the rear should help keep it in line.

Karting Setup Tips

In general widening the front track should give more front end grip and improve responsiveness. Narrowing it makes the front end less responsive. Sometimes however it may feel like the front end needs to be widened out but the front tyres may actually be overworked and doing the opposite will solve the problem. There is a small difference in feedback to the driver between the tyres being overworked or being underworked - with time you should be able to distinguish the difference, I am unable to explain it with words.

Ride Height:

Changing the ride height of your kart makes a big difference to handling. When there isn't a lot of grip on the track and the kart is sliding all over the place raising the chassis can help a lot by raising the center of gravity. Normally you would want to run the chassis low for a low center of gravity to maximise overall grip. On bumpy street tracks having the chassis higher is a good idea because street tracks usually aren't very grippy and you will avoid any ground clearance issues with the brake disc and sprocket - and on a street track its better to have a kart which binds a little than to have one which slides a lot to avoid oversteering into curbs. You can also try to change just the front or the rear ride height to affect handling. If you are experiencing lots of understeer for example you may want to raise the front end and see if you can generate a bit more front end bite.

For wet weather you would want to set the chassis high if you have the time. Raising the seat also results in a similar effect by raising the overall centre of gravity.

Toe-in/out:

Setting the front end alignment is important to have a kart that handles predictably, and should be checked often. On karts you will mainly be looking to have 0mm toe to about 2mm toe-out. Having toe-out will make the kart more responsive to steering movements and will improve turn-in. The more your tyres are pointing away from dead-ahead however the more rolling resistance you are introducing. In wet weather you would be looking to run 2mm or more toe to reduce understeer which is common place because not as much weight is transfered forward under braking.

I will try to add more to this article in the future - stay tuned.

Books with info on Kart Setup:

Listed below are three books. Drive to Win is an excellent book dealing with a lot of areas related to racing including setup, driving technique, rain racing, safety, and technical aspects of cars - which can to a certain extent be applied directly to karts. The other two books are specifically related to kart setup however I have neither of them so you will have to trust the reviews on the amazon site.

Drive to Win

Kart Chassis Setup Technology

Go-Kart Chassis Setup

Kart Setup and Tech Tips Links:

Here are some good resources on the web which explain different aspects of kart setup and other tech tips some in a more simplistic way than i have here and others go more in-depth and cover completely different areas. Clicking on the links will open the website in a new browser.

Karting Asia Forums

Tech Talk and Driving Technique
Ask questions you have about kart setup and driving technique on the KartingAsia.com forums.

Arrow Karts Setup Guide

www.arrowkarts.com.au/files/arrow_setup_guide.pdf
Great karting set-up guide with many problem-solution set-up scenarios.

UK Karting - Tech Tips

http://www.karting.co.uk/KandK/Tech/KartSetup.html
Kart Steering, Physical Forces and Setup - Theory and Practice

Getfaster.com - Tech Tips

http://getfaster.com/gftechtips.html
A lot of non-karting articles which provide an intersting read.