"Up-Stepping" by Fitting Low Profile Tyres

Vehicle performance can be improved without the necessity of changing wheels simply by selecting a tyre with a lower profile. This means maintaining overall diameter while lowering aspect ratio and correspondingly increasing the tyre width. Put simply, a tyre with a lower section height and wider tread has better cornering force and grip, thus improving steering stability.

In order to attain the maximum performance out of your vehicle, larger and wider wheels are recommended. Although high performance is our goal, there are certain safety guidelines that must be observed. This means that wheel size and type, and tyre height and width must fall within certain limits. When selecting a high performance tyre the following must be observed.

Clearance
Wheel well clearance must be maintained. Failure to do so would most likely severely cut the tyre when turning, if not lead to a puncture. The vehicle manufacturer can provide the maximum tyre width permissible. Otherwise consult a specialist high performance tyre dealer.

Speedometer Error
With a constant wheel diameter, overall tyre diameter will decrease proportionately with aspect ratio. This smaller overall diameter will result in speedometer error.

Wheel Selection
Wheel Selection It is often the case that new wheels are required. This can be because either a larger rim width and/or larger rim diameter is called for. When choosing high performance wheels ensure that they have the correct offset and pitch circle diameter (P.C.D.) for your vehicle.

Up Stepping to High Performance
Up Stepping to High Performance Maximizing your car's performance by selecting a lower profile tyre/larger size rim combination is referred to as "up-stepping." Plus-one or plus-two tells you how much larger the rim size is. This "up-step" approach to improving performance came into being because, although it is possible to get higher performance without changing rims, it is often necessary to increase tyre width to the point that steering geometry is affected, with the result that a change in driving style or habits becomes necessary.

So to fully maximise your vehicle's performance (which includes preserving the steering geometry) the "up-step" approach is highly recommended. By fitting a larger rim, increases in tyre section width are properly managed while correct overall diameter is maintained. This maximizes cornering force and grip without sacrificing any other handling parameters.

Information courtesy of Yokohama.