Tyre size /aspect ratio.

Much has been written in recent years about the benefits of fitting bigger wheels with lower profile tyres.

Almost counter-intuitively, the contact patch of a tyre is much the same regardless of tyre size.

A high aspect ratio tyre (say 70) has a long and narrow “footprint” – low aspect ratios reduce the length and increase the width of the contact patch.

Higher cornering forces are generated by the shape of the contact patch, and the generally softer compounds of the wider tyres.

Remember that the crisper handling that results will be to detriment of ride and ability to resist aquaplaning.

The suspension geometry will change when cornering, inducing greater roll steer, raising the COG. Increased weight transfer can lead to sharper break-away.

Remember also that greater grip will inevitably mean higher stresses on the wheel hub and suspension system.

If you wish to increase wheel size – there is a simple standard formula:-

(in order to maintain rolling radius)

20mm increase in tyre width and 10% lower aspect ratio for each 1” increase in wheel diameter.