#TechnicalTuesday

#TechnicalTuesday

Follow our regular reports for hints and tips from our technicians to help you care and maintain your classic.

This week we are talking tyres…

Tyres are fundamental to the performance and safety of your classic. The very simplest of maintenance tasks like keeping your tyre pressures correctly set, can have a dramatic effect on not only the ride and handling of your car but also tyre wear, fuel consumption and can even reduce the wear and tear of the cars steering and suspension!

We recommend you check your tyre pressures weekly if your car is in regular use. If your classic has been in storage over the winter period, over-inflating the tyres to close to the tyre manufacturers maximum recommended pressure will help prevent a flat spot forming on the tread of the tyre. This is a common problem when cars are stood for an extended period and leads to unpleasant vibration when the car is driven.

Of course you must remember to reset the tyres to the recommended pressures before you use the car!

Tyres obviously wear. UK law states that passenger car tyres must have a minim of 1.6mm of tread across the centre ¾ of the tyres tread. In reality we would recommend at least 3mm of tread as an absolute minimum for good wet weather grip. Under normal use they should wear evenly across the width of the tread. The pattern of wear is a good diagnosis tool when trying to identify issues with wheel alignment and suspension geometry.  Excessive wear on the centre of the tread pattern is often indicative of over inflated tyres for instance. Wear to the edges can be caused by under inflation or if only present on one edge of a tyre, excessive toe angle or camber issues possibly caused by wear in the suspension.

Good suspension geometry is essential to tyre life and the road holding of your car. Having your cars suspension geometry checked and adjusted as part of your normal maintenance schedule will not only help preserve your tyres but will enhance your driving experience by keeping the car handling as its designers intended.

Tyres not only wear but they degrade with time. There are currently no laws in the UK concerning passenger car tyre age other than the condition of the tyre, cracks, perishing and tread depth. However as a good rule of thumb even if a tyre appears to be in good condition, 10 years would be a good point to replace with new.

There are two main types of tyres used on classic cars. Radial and the older Cross-ply type. These descriptions refer to how the carcass of the tyre is constructed. Radial tyres have a stronger more ridged construction which in turn produces a tyre which runs cooler, lasts longer and ultimately gives significantly more grip and predictability. Very often Radial tyres can be retro fitted to older cars fitted with cross-ply tyres and can provide significant improvements in road holding and safety  however some consideration must be given to the extra loads that these tyres are capable of inducing in the cars suspension and steering.  

It is not unusual to see wider tyres fitted to classic cars that were originally fitted with “skinny looking” cross-ply or narrow radial tyres. This can increase the amount of available grip but again caution is required and other modifications may be required to get the best out of the tyres and maintain the handling characteristics of the car.

Looking after your tyres is one of the simplest and most effective maintenance items you can invest time into. And better still, in most cases, the air that fills them is free!