Tuesday, July 16, 2013

HIPARI TYRE-STRETCH TYRE



In Japan, the word Hipari refers to a tire style that is achieved by stretching a narrow tire over a wider wheel like a 215 35 18 inch tire on a 9.5 wide wheel. The difference in widths causes the sidewalls to stretch from the lip to the tread giving the tire a unique low profile stance and increased sidewall rigidity. In drifting, less sidewall flex means smoother weight transitions, improved throttle response, better steering feel, and less body roll when cornering. There are higher end tires that can provide these same handling characteristics when drifting without the sidewall stretch, but they are expensive and herein lies another advantage of the hipari style tire – narrow tires are cheap.

Stretching a thin tire onto a wide rim decreases a wheel’s standard tire width resulting in a smaller contact patch and less traction. When learning how to drift this can be advantageous since you can get the car sliding sideways at lower speeds. However in pro level drifting events, drifters need as much traction as possible out of their tires to control their drift cars at 100+ mph so initially it seems that hipari tire would not be the best choice but pro drifters found a solution. D1 Grand Prix drifters get around the traction loss issue by using super wide wheels that fit tires they would usually use on their car so the overall contact patch stays the same. This gives the hipari look without loosing traction.
Stretched tires can be used on all four corners of a car but up front, usually you don’t stretch the tires to the same extent as they are stretched on the back. For example, a car with 8.5 inch wide wheels all around, would use 210-220 tires up front and 195-205 tires in the rear. This gives the drift car good grip up front for steering while maintaining the hipari style and handling advantages.
Another thing to note is that stretched tires require a higher psi than normal. 40+ psi is recommend for stretched tires.
The history behind hipari style stretched tires is two fold as poor people have been stretching tires onto wheels they don’t belong forever while euro tuners in Germany and Belgium started stretching their tires out of legal necessity. Local laws there require that the tire tread be within the fender line and with wider or lower offset wheels that can cause problems. To maintain the wide wheel fashion and keep the car street legal, narrow tires are stretched over the wide wheels.
Popular Tires for Stretching:
  • Toyo T1-S
  • Dunlop SP9000
  • Dunlop SP8080E
  • Falken FK451
Other tires will work. Find a tire with a rounded shoulder and lip protector. If you want to get the tire outside the fender, use wheel spacers.
Most wheel and tire shops will be willing to stretch tires and it will take a professional air compressor to help seat the tire as it can take up to 90lbs of pressure to pop the bead.
Critics of the hipari tire style say it’s all about fashion and anything that reduces a car’s contact patch is dumb. Some go further to say that stretching tires increases wear because of uneven heat dissipation and that may increase the potential of tire failure. As far as safety goes, there is little evidence that stretched tires are any more dangerous than regular tires. One problem though is that your wheels are closer to street and damaging potholes but you should stay away from holes in the ground anyway!



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