Connor Iseli
2007 NTK Spring Champion
2006 NTK Season Champion
2006 KART Southern Regional Champion
2004 NTK Most Improved Driver
2003 NTK Rookie of the Year
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Connor Iseli
2007 NTK Spring Champion 2006 NTK Season Champion 2006 KART Southern Regional Champion 2004 NTK Most Improved Driver 2003 NTK Rookie of the Year |
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| Kid Kart Tire TipsA lot of your choice in tire selection will be related to the driver's experience, ability, and preference. This class is all about reducing friction, including rolling resistance of the tires and preserving momentum around the track. Keep this in mind when choosing tires.
Since you aren't allowed to change gear ratios, you want to get the maximum legal tire diameter in the rear for maximum speed. This isn't that easy since standard tires don't come close. The maximum roll out (tire circumference) specification is 33.75 inches. Tires typically come in either 10" or 11" diameters, 10" is 31.4" circumference and 11" is 34.5". So 10" is way under the limit and 11" is too large. We were only allowed to run 5" wheels, there is a 10.5" tire available but only for 6" wheels. If you can run 6" wheels I would buy these 10.5" tires. This is one area that we did not optimize, we just ran 10x4.5x5.0 inch tires unmodified. Another situation of it not being worth the expense to us to try it. However if we were going to stay in class this is what I would do: Make some narrow wheels - by this I mean buy two piece rim halves to make a wheel about 3.5" in width, put your 10x4.5x5.0 tire on it and measure circumference. With the narrow rim it should push the center of the tire out, thus increasing diameter. You may have to experiment with different rim widths to get it right. Some people report stretching tires by mounting them on a rim, inflating to high pressure (never exceed the maximum rating for the tire), and leaving them in the sun for a few days. I have never tried this. If you try it be very careful - a hot tire at high pressure could explode. Front tires don't matter as much, although longer rollouts will reduce rolling resistance. We were limited to using only 10x4.50x5.00 tires per rules so there wasn't much we could try different here. If you can use narrower tires I would try that, just to reduce the friction between the tire and track.
We ran at the maximum legal limit of 20 psi. This helped maximize tire diameter and the reduced center contact patch reduced rolling resistance. This also makes the kart loose in the turns. The driver must be able to drive and handle the loose kart to effectively run this much pressure. You may want to work up to this for less experienced racers.
We ran a very old (several years) set of Bridgestone YGCs. This is a medium compound tire, but after years of aging and countless heat cycles they were very hard. Durometer measured around 78 at end of season. Harder tires will be faster, due to lower rolling resistance, but just like high tire pressures, your driver must be able to handle it. If I were buying new tires for an experienced driver I would get the hardest compound I could find. There is a trade off here if you are going for maximum diameter. The harder compounds won't stretch as much and will have a flatter contact patch. Only your stopwatch and lots of testing will optimize between the two.
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