Ask Continental Tyres a question...

[mark.s]

Hi Forum members,

Some of you will be aware that we’ve worked with the team at Continental Tyres UK for a number of years now. In a new development, we have organised for Steve Howat, Continental’s General Manager for Technical Services, to answer a number of key tyre-related questions raised by the MBO forum members.
Maybe you’re unclear on whether winter tyres would suit your car, or your tyres need replacing and you want some advice. It might be you want a different puncture repair solution, or you want to dial up certain aspects of your vehicle’s performance.
Whatever it is, we want to hear from you! Please add your questions below before the end of this month. We’ll then share them with Continental, before publishing a selection with answers on the forum, on social media and in the Mercedes Owner magazine.

Many thanks

 

[Chrishazle]

Why does no-one make 245/40 R17 all season tyres? They're a popular size on MB cars, both mine have the same staggered set-up with 225/45 R17 front and 245/40 R17 rear, no problem getting the 225/45 all season but although I'm told I could fit the same on the 8J rears I'm not keen on loosing 20mm of contact patch on the driven wheels and quite possibly rim protection as well! I'm not the only member who has asked about this on here or t'other side.

 

[Blobcat]

Why does no-one make 245/40 R17 all season tyres? They're a popular size on MB cars, both mine have the same staggered set-up with 225/45 R17 front and 245/40 R17 rear, no problem getting the 225/45 all season but although I'm told I could fit the same on the 8J rears I'm not keen on loosing 20mm of contact patch on the driven wheels and quite possibly rim protection as well! I'm not the only member who has asked about this on here or t'other side.

Altering width doesn’t alter the contact patch...

Narrower tyres means the contact patch is more fore and aft, wider tyres means it’s more side to side.

Wider tyres can run cooler as less sidewall deformation, which is good for summer

 

[mioba]

Clear up alot of debate:

Do winter tyres do anything better in winter and how

 

[Chrishazle]

Simple answer - yes. My S203 I had difficulty getting off my swept driveway in reverse when it snowed here, and had all sorts of fun getting the car turned around to reverse back into our driveway. Following year, with winter tyres fitted, did not even have to sweep the driveway and had no problem getting off and back into our driveway when it snowed.

 

[sonic]

Simple answer - yes. My S203 I had difficulty getting off my swept driveway in reverse when it snowed here, and had all sorts of fun getting the car turned around to reverse back into our driveway. Following year, with winter tyres fitted, did not even have to sweep the driveway and had no problem getting off and back into our driveway when it snowed.

Same here a massive difference. I went to Europe skiing once 20 years ago on summer tyres couldn't get anywhere. After that always on winter tyres, its a different world. You have traction & breaking.

 

[T5R+]

Do Continental "hand cut" any tyres for specialist cars.

Summer vs Winter debate - is it dependant on both temperatures but also equally on tyre composition and pattern.

Does the general public have any appreciation of the simple materials used within a tyre - as opposed to the science/technology/R&D employed by manufacturers to create a winning product.

 

[V6Matty]

What is the true difference between a premium product and a budget tyre (get as technical as you like)

 

[alexanderfoti]

I would love to know what direct factors affect perishing. I see new tyres that are very perished and old tires that look new. Obviously UV has a big deal to do with it, but what other factors are at play?

 

[eman]

Clear up alot of debate:

Do winter tyres do anything better in winter and how

In the Shetland Islands they run winter tyres all year round as high speeds and hot weather are the downside to changing them down here seasonally. Shetland has one road that is 60 mph and their temperatures are always 10+ degrees cooler in the summer. If your lucky enough to experience snow up there it’s like being in the Antarctic

 

[brandwooddixon]

Some people advise that tyres are changed once they are 5 years old, irrespective of actual wear.

As we are also told that UV light exposure is the main main factor in tyre compound degradation when not in use, would storage of tyres away from UV light or sun exposure extend this time period?

This is particularly pertinent to those drivers who cycle through summer or winter tyres depending on the season and yet don't do enough mileage to require tyre replacement due to wear within a 5 year time period.

 

[Blobcat]

Some people advise that tyres are changed once they are 5 years old, irrespective of actual wear.

As we are also told that UV light exposure is the main main factor in tyre compound degradation when not in use, would storage of tyres away from UV light or sun exposure extend this time period?

This is particularly pertinent to those drivers who cycle through summer or winter tyres depending on the season and yet don't do enough mileage to require tyre replacement due to wear within a 5 year time period.

Often Caravan and Motorhome owners use tyre covers as their vehicles spend most of the time sitting around - it does reduce the UV damage

 

[brandwooddixon]

Often Caravan and Motorhome owners use tyre covers as their vehicles spend most of the time sitting around - it does reduce the UV damage

Yes, but does the advice to replace tyres once 5 years old irrespective of wear still stand? If so then a low mileage driver would only get 2 and a bit seasons out of a set of tyres e.g. say 15 months mileage.

Not an issue for me as I'm always replacing tyres due to wear, but if your mileage is such that you replace a set of tyres due to wear every 3 or 4 years, you may expect a set of summers and a set of winter tyres to last upto 8 years.

Is this a safe expectation?

 

[AndySlade]

We should ask exactly what is the difference between your ‘normal tyres and ones branded with an OEM mark?

 

[mark.s]

Hi All,



Steve Howat, Continental’s General Manager for Technical Services has been answering tyre-related questions posed by MBO forum members over the last couple of months, and some key themes have emerged where it’s clear there’s real appetite for information – especially summer vs winter tyres, tyre
perishing, vehicle manufacturer approvals, and premium vs budget. After passing these over to the Continental team, we hope this content will be as informative for you as it is for the forum members who posed the questions.
Maybe you haven’t paid much attention to your tyres before or maybe you have, but you’re keen for more technical insight, to help you make the right tyre purchasing decisions and get the best out of your car. Either way, you’re in the right place. If there’s one thing we’ve learnt over the years of our relationship with Continental, tyres are an awful lot more than just ‘black and round’.

Q1:
What does it mean when tyres are branded with an OEM mark?

A1: Every new car comes with pre-installed tyres. These are the original equipment (OE) tyres chosen by the vehicle manufacturer (OEM), which meet their exact requirements having undergone a series of rigorous tests.
Mercedes owners should look out for tyres with MO, MO1 (AMG models) or MOE marked clearly on the tyre wall – this proves they are homologated (or approved) by Mercedes. A tyre submitted to an OEM for homologation and type approval can require many submissions and design changes before
meeting the OEM’s stringent requirements. This can involve construction or compound changes over a period of years. The approval process starts long before a new vehicle make or model comes to market, to ensure that the tyre is perfected in time.



For many drivers, picking OE tyres for their vehicle is a simple, fuss-free option. It also means the car remains as the OEM intended – so all the things you read about it online or were told in the dealership before you bought the car, covering anything from safety to performance or emissions, remain relevant
and true.
It makes sense that OEMs pay huge attention to tyres – and that’s why drivers who care about their cars should, too. The tyres are the only part of the car that’s in contact with the road – so they’re essential to the whole driver or passenger experience. The car isn’t the car without them.

Q2: What are the key differences between summer and winter tyres?

A2: Composition and tread pattern are among the fundamental differences between summer and winter tyres, and they go hand in hand with changing temperatures and weather conditions. The operating temperature range of a tyre’s compound depends on the ratio of materials it’s made from, designed to achieve the ideal blend for the intended environment and use.
The glass transition point is the temperature at which the tyre gets harder because the molecules within start to move less freely. When you leave a plastic bucket outside during the winter, it will crack or break more easily compared to when you leave it outside in warmer weather. It’s not that different with
tyres…
When temperatures approach freezing, winter tyres contain more natural rubber and remain more pliable and softer than summer tyres, meaning better traction and performance, and reducing your stopping distance when you brake. Conversely, summer tyres become hard and brittle at low temperatures, with consequences for grip and wear.
And the same is true in reverse. The winter tyre compound is too soft for dry asphalt, meaning it will wear out quicker in summer – not to mention the increased rolling resistance increasing your fuel consumption and road noise. Summer tyres on the other hand are designed to deliver excellent grip on wet and dry roads when it’s warm.
Now, onto the tread pattern. It’s deeper on a winter tyre, to clear away slush and dig into snow for greater traction. Summer tyres have a more streamlined tread in comparison, with fewer grooves for water clearance, maximising the contact patch with the road and delivering superior traction and braking during drier, warmer weather.
A last word, just to throw all-season tyres into the mix – a hybrid solution which combines the benefits of both summer and winter models. They’re less tailored to the specific conditions at either extreme but can be an excellent compromise in climates like ours, with relatively mild winters.

Q3: What factors affect tyre perishing, and how should tyres be stored to maintain their condition?

A3: Many tyre manufacturers will use advanced anti-ozonic chemicals in both the tread and sidewall compounds. These chemicals reduce the ageing/hardening effect caused by both UV and heat, which can usually be seen as cracking.



To ensure that these anti-ozonic chemicals continue to work and are effective over the life span of the tyre, it’s important that the tyre is ‘worked’ or driven on. The process of the tyre flexing as it rotates under load ensures the anti ozonic chemicals remain on the surface of the tread and sidewall and prevents
premature age cracking.
There is a direct link between tyres that are used irregularly and the effects of premature age cracking. If you can, our recommendation is to store tyres away from UV light and heat when you’re not using them – which is especially relevant if you cycle winter and summer tyres throughout the year.

Q4: What’s the difference between a premium product and a budget tyre?

A4: One of the key factors that pushes the performance of a premium tyre forward is the ever increasing technical requirements from the vehicle manufacturers (OEMs). OEMs have to meet stringent emissions requirements – like WLTP regulations – which has a direct impact on the technical
requirements of the tyres they specify. Rolling resistance – and its effect on fuel economy and range – is a key consideration from an environmental point of view, but at the same time wet grip performance and other safety requirements cannot be compromised. A high level of technical capability is required to find the right balance and achieve on all fronts.



At Continental we have more than 150 years of experience in developing tyres, which gives us a wealth of knowledge and experience that budget tyre manufacturers can’t compete with. Car manufacturers in Europe trust our products so much, they use our tyres for every third new car, in more than 800 models.
We use advanced polymer technology and innovative materials in our tyres, to enhance their performance, and to deliver sustainability benefits. As an example, we were the world’s first tyre manufacturer to launch recycled polyester yarn which is obtained from PET plastic bottles. This high-performance material is known as ContiRe.Tex.
Whatever your primary motivation – safety, performance or sustainability, or a combination of the three – you’re far more likely to get what you’re looking for if you invest in a premium product.
Some people advise that tyres are changed once they are five years old, irrespective of actual wear. With vehicles that are used infrequently – like caravans and motorhomes – this is good advice, although there is no specific age limit to bear in mind when it comes to tyre replacements. We recommend that all
vehicle tyres that are 10 years from date of manufacture should be replaced, which is in line with the legal requirement for truck steer tyres.



Regular inspection is key, to check for cracking or the early signs of significant ageing – like small superficial cracks or the colour looking grey and dull – so you can determine when your tyres need changing.
It’s easy to focus on a car’s Interior, style and fuel economy, without paying the same level of attention to its only contact with the road.

Big thanks to Steve and the team at Continental for their efforts to change that, and for answering real questions posed by our MBO Forum members. If you’ve enjoyed this content, let us know in the post.! And if it’s sparked more questions, get in touch at: info@mercedesclub.org.uk.

For more information, visit www.continental-tyres.co.uk