Go kart calibration manual – tire / tire pressure

The tire is the only part that touches the ground. It and engine horsepower are the most important factors determining the speed of the car. CTCC’s Super Group car is actually equivalent to WTCC’s specification. However, the single lap is 3 seconds slower, which is caused by different tires.
The adjustment of tire pressure is relatively simple. Basic parameters of dry tire: the ideal tire pressure of hot tire is generally 0.8bar ~ 1.0bar, or about 11.5psi ~ 14.5psi. (I haven’t seen one with more than 0.9bar) the difference from cold tire to working temperature is generally between 0.2 ~ 0.4. (there will be slight difference according to the temperature) this parameter will not change when using tires of different brands.
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① Driving experience, advantages and disadvantages of high tire pressure and low tire pressure
Higher tire pressure can make the tire enter the working state faster and obtain enough grip in a short time. However, as the number of turns continues to increase and the tire temperature continues to rise, when the tire pressure is too high, it will feel jumping during steering. The grounding area caused by excessive tire inflation will become less, which will affect the grip and cornering stability.
If the tire pressure is lower, the tire will enter the working state slowly, but under the condition of appropriate adjustment, the tire pressure will not be too high for long-time driving, and it can run in the ideal working range for a long time. However, when the tire pressure is too low, the tire does not rise sufficiently when reaching the working temperature, which will lead to rapid tire wear.
So it’s a question of trade-offs. In the race, the temperature of many tires is higher than that of normal cars. If you follow the car behind you, this phenomenon will be more obvious.
If you choose a lower tire pressure, you will suffer a loss in the last few laps of the departure. However, as the race continues, the working conditions of tires with higher tire pressure will slowly decline, so your advantage will appear in the later stage of the race. According to your ranking in this round, the choice of tire pressure is very important.
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② Precautions for tire pressure measurement
One is to measure before playing, and the other is to measure after completing a training session.
(1) If you want to measure before playing, you need to predict the pressure of the four tires on the track in advance. For example:
Beijing Ruisi high-speed track has an average number of left and right big turns (the first turn, the second left turn in front of the longest straight road and the last low-speed U-turn are left turns; the slow turn in the low-speed section and the re braking U-turn after the longest straight road are right turns)
The front tire pressure can be higher, the rear tire pressure can be lower, and the left and right sides can be configured equally for the first test. In high-speed curves and heavy braking curves, the power wheel (i.e. the rear wheel) will be subjected to greater pressure than the front tire, so the temperature of the rear wheel will be higher than that of the front wheel. If the rear tire pressure is too high, it may lead to jumping and unable to cross the curve smoothly, resulting in the delay of the exit throttle point.
There are several points to note:
When the tire has just been inflated, or when the tire is full, you need to measure the tire pressure twice. Because the air in the tire has not run well after just pumping, you can carefully observe the change of the measured value on the tire pressure gauge at this time, which will show a slow upward trend. This also happens when you let out too much gas at one time.
Therefore, the first measurement should be roughly adjusted, and then wait for a while. After the air in the tire runs evenly, it can be measured again to obtain the accurate value. And when deflating, don’t put too much in one breath. Only by putting it bit by bit can we measure the accurate value.
In order to improve the measurement accuracy, the air is usually discharged after the new tire is installed, and then inflated again, and then placed for a period of time before measurement.
(2) If you want to measure the tire pressure after a training / competition, be sure to talk to your technician and prepare the tire pressure gauge in advance. Be sure to measure at the first time after you get off the court. You should run normally before you get off, so as to reduce the error as much as possible. When the tire is hot, the tire pressure of the four tires shall be consistent. Do not inflate the tire when it is hot. Push it to a cool place and inflate it after the tire cools naturally.
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③ Tire pressure adjustment in rainy days
If the track is already wet but not enough to use wet tyres, a higher cold tyre pressure is required in order to make it easier for the tyres to remain in operation. For example, use 0.7 bar or even more than 1.0 bar.
The tire pressure of wet tire is different from that of dry tire. Generally, we need to go according to the manufacturer’s requirements, and there will be a lower limit. If it is lower than that lower limit, the tire will not rise sufficiently, which will lead to the insufficient function of the drainage groove on the tire tread. Sometimes you will encounter excessive wear of rain tires due to slow rain. At this time, it is an empirical problem whether to use high tire pressure to ensure the performance of the drainage channel or low tire pressure to ensure its grip.
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Other details:
1. When you use rear tires of different sizes, you need to adjust the gear ratio at the same time. The wider the width, the greater the torque required.
2. There will be a little deviation between the tire pressure gauges. If possible, it is recommended to equip yourself with an electronic tire pressure gauge and keep it by yourself at ordinary times so as not to knock it.
3. When you find that the tire is leaking, but you don’t find the leakage of three screws and air ports on the wheel hub, it may be that the tire is not installed properly or it may be pierced. If you get stabbed, you can only admit bad luck
4. Due to different tire formulations of different brands, the tire pressure selection may be somewhat different, but they are generally in the range of 0.8 ~ 1.0bar. It’s best to know before buying.