Guest Post by Giles Kirkland who is a professional mechanic with a love for motoring history and classic cars.
For many classic car owners, getting the right size tire is absolutely vital. However, as mainstream production services more modern cars, owners of older vehicles have to resort to alternative means to keep their cars in order.
For some people, it’s a question of aesthetic while, for others, it’s a matter of maintaining the ride’s original performance and design. Of course, no matter what your reasons are, it’s also important to ensure a road safety standard if you’re planning to take your car for a spin on public roads.
Finding The Right Size
If your car happens to be more recent, such as from the late 1970’s onwards, when tire sizes started to become more standard. If this is the case, then a simple tire size calculator should help you find a product with the right dimensions.
However, if you have a car that uses a size no longer in circulation, you will have to go to a specialist vintage supplier. While you can find conversion guides online, these offer an approximate fit at best and this is far from ideal.
It’s also worth noting that, as far as this part of the car is concerned, you should not use original equipment. Car tyres generally do not last more than 10 years – and you should ideally not use a tyre more than 6 years old, anyway – so today’s “vintage tyres” are produced to fit vintage cars but are much newer and less likely to wear down.
Cross-Ply Or Radial?
While cross-ply tires were popular in the early days, modern vehicles have all but switched to radial tires. This is because the softer tire wall, thanks to the design, allowed the tire to be much more flexible, especially when changing direction. Similarly, cross-ply tires rarely handle the higher speeds of today’s motoring, lacking a high enough speed index.
As such, it is often advised to switch from cross-ply to radial tyres and, in most cases, this is entirely possible. Radial tyres, in the vast majority of cases, can be identified by the “R” on the tire markings, which labels them as such.
However, there is a slight difference in how much tire pressure these tyres need. When switching to radial tyres, you may want to increase the pressure by around 0.3 or 0.6 bar to account for the extra fluidity that radial tyres offer.
What About The Whitewall?
If you’re driving a truly classic – or even vintage – car, then the chances are it was originally equipped with whitewall tyres. The very earliest tyres were, in fact, completely white, as they used both natural rubber (which had an off-white hue) and zinc oxide (which was also white) for additional properties.
Later on, this was replaced with carbon black, which is still used today. At first, this was just applied to the treads, with zinc oxide still used on the sidewalls. This is how the classic whitewall aesthetic originated and many drivers often wish to recreate this for the vehicle.
Today, there are numerous whitewall products available, but it is worth investing in products that were manufactured this way. This is because the alternative – where purely black tyres have been treated post-production – only uses a white outer layer that can be easily worn away.
You should also be aware of the maintenance required for whitewall tyres. Since aesthetic appeal is their purpose, you should avoid typical commercial cleaning solutions and favour something formulated with whitewalls in mind. This is because typical solutions can ruin the colour, giving your beautiful white wheels a less appealing, yellow tinge.