Touring and Mini Car Tire Tips

Many of these tips come from Bill Martinez, an HPI factory driver, and Akira Kogawa, head of HPI Research and Development. Between them, they are able to explain the benefits of each tire HPI produces, and can explain best when to use a particular style of tire.

Bill uses Super Radials only when the track is very dirty or on a completely unprepared street or parking lot. The directional treads kick out dirt and small rocks.

The X-Pattern Radials are best on semi-prepared tracks, that is, lots that are swept or blown off but not sprayed with a traction additive.

He uses belted slicks almost exclusively, especially on tracks that have been fully prepared (swept or blown off and sprayed with sugar water or soda), or permanent R/C tracks.

For more steering, Bill suggests using belted rear tires and non-belted fronts, while staying with the same tread design. The belted tires are slightly harder than non-belted because of the nylon belt inside each one, and the softer tire in front will give more steering response.

You can also get more steering by using a wider track in the rear. You can do this by using the 2mm or 1mm spacer that come with most of the HPI wheels. Put the spacer in the rear wheels only, and you will see how much more steering you get. You can also use 26mm tires in the rear with 22mm tires in the front for a similar effect.

Belted tires wear more evenly than non-belted tires, and provide more grip through the turns because the sidewalls flex a little bit less and have less of a "squirm factor" than the non-belted tires. Non-belted tires will flex more and have a less exact feel than than belted tires.

If the track is warm and the sun is out, Bill uses slicks if the track is blown off sufficiently. The tires will warm while running and hook up better if the surface of the track is hot. Asphalt can reach 220 degrees Fahrenheit in most locations at the peak of summer, and the rubber in the tires will soften considerably, improving the grip of your car.

Super narrow tires, with their smaller contact patch, are a good companion to small, tight tracks. This is because they respond quicker to turning input from the driver. The reason for this is twofold: the super narrow tires have less rotating mass than a standard width tire and the weight of the car is concentrated on the smaller contact patch of the super narrow tires. So, while you have less weight overall on the car, the average weight per given unit of area in the contact patch is increased. This higher concentration of the car's weight on the four contact patches of the car results in better turning response, making the car handle better for twisty tracks.

Super narrow tires also allow you to accelerate to top speed quicker and slow down faster, because there is less rotating weight for the motor to move. Lowering the weight of the car is nice, but a lower rotating weight is three times as good.

Standard width tires are used by Bill on medium to large tracks, because of the better acceleration afforded by the larger contact patches as compared to super narrow tires.

For a good commentary on touring car tires, check out this site: http://ourworld.compuserve.com/homepages/Avitaliti/techrepo.htm. Anthony Vitaliti has good suggestions for what to use, and when.