Want the best car tyre tips, tricks and advice? Then look no further than our tyre FAQ!
Here At FC we’re constantly asked all sorts of technical stuff via the mediums of Facebook, email and being shouted at in petrol stations. Now, although we like to think we’re a knowledgeable lot, we don’t actually have the answer to everything.
So we thought we’d get onto the industry experts to find out the definitive information to clear up any of your niggling questions. We speak to Davanti Tyres armed with all your FAQs about those inflated black circles to give you the best tyre tips, tricks and advice.
What is the main difference between a performance and an all-season tyre?
A ‘performance’ tyre is designed to operate at peak performance when the temperature is over 7℃. They are optimised for the highest possible levels of both wet and dry handling and braking performance in what is generally referred to as ‘summer’ conditions. Tyres of this type make up the vast majority of those sold in the UK – over 90%.
An all-season tyre is designed to perform all year round – even when the temperature drops. All-season tyres therefore offer the convenience of one tyre that performs adequately all year round, but it will typically lack some of the capabilities of a focused summer performance tyre near the limits. A true all-season tyre will feature the Three Peak Mountain Snowflake (3PMSF) symbol – this signifies that it meets the standards required of a ‘winter’ tyre in Europe.
It is still most common for Ultra High Performance cars to recommend separate focused summer and winter tyres in order to maximise the vehicle’s performance as conditions vary. All-season tyres are better suited to vehicles where summer performance demands are not as extreme.
What is a low-profile tyre?
A low profile tyre has a sidewall height that is considered to be relatively slim compared with the overall diameter of the tyre. Historically, radial tyres had a standard profile of ‘80’ – meaning the height of the sidewall was 80% of the tyre’s tread width.Through the 1970s and 80s, profiles began to get lower. These days, profiles of ‘55’ and lower make up the majority of tyres sold. As tyre technology moves on, and wheels get larger, what is considered ‘low profile’ has evolved and is a matter of opinion – probably ‘40’ or below.
Why do road tyres have a tread but race tyres (slicks) don’t?
Slicks provide excellent grip as they place as much rubber in contact with the road as possible. However, they have no capability to displace water. As road cars encounter wet surfaces on a regular basis – and can’t pull into the pits to swap to wet weather tyres – they have to be prepared for whatever the weather throws at them!
How important is tyre pressure? Does it really matter if my tyres are out by a couple of PSI?
Tyre pressure has a significant effect on vehicle handling, tyre life and fuel efficiency. It is estimated that a tyre under inflated by 10% will use 1% more fuel, and the tyre will achieve just 90% of its expected life. Under inflation will also impair handling, and potentially make the vehicle unsafe to drive.
Is it true that performance tyres don’t last as long and aren’t as good in the wet?
No tyre will have better levels of performance in the wet than it will on a dry road – the water acts as lubricant and reduces the tyre’s ability to transmit the driver’s inputs to the road. That said, a good tyre’s performance in the wet will be as close as possible to its dry performance, and will still provide assured levels of grip. It is possible that a driver can cause more tread wear in wet conditions by allowing the wheels to spin more.
My friend says he has stretched tyres? What does he mean and is this legal?
‘Stretched’ refers to tyres that are relatively narrow, compared with the width of the wheel they have been fitted to. This results in the tyre being stretched across the rim. This is mostly done for aesthetic purposes – especially in the most extreme cases. Stretching tyres puts them in a state that they are not designed or tested for, and it is therefore not advisable and potentially unsafe.
What’s the difference and benefits between asymmetric and directional tyres?
Asymmetrical tyres have a tread pattern that varies across the width, meaning they have an ‘inner’ and an ‘outer’ side. Each side of the tyre will be tuned for different aspects of performance.The ‘outer’ is typically designed for cornering and steering, with the ‘inner’ being more focused on providing traction.
Directional tyres typically have some form of ‘V-shaped’ pattern. They are designed to run in a certain direction.The V-shaped tread is ideal for providing traction – especially in wet and wintry conditions – and is therefore more commonly found on winter or all-season tyres.
Asymmetrical tyres have been more common than directional tyres in recent years as they are better able to meet the requirements set out by the EU for tyre efficiency.
What’s the minimum tread depth of a tyre for it to be legal?
At least 1.6mm throughout a continuous band in the centre 3/4 of the tread and around the entire circumference of the tyre.