Winter Tyres - Part 2. Selecting the tyres

What types of tyres are there? 

The M+S mark requirement – to comply with legislation on the Continent – reduces the choice down to either the full winter tyre, a so called “four season” or all-season tyre, or surprisingly, in the case of the Michelin offering, a “Camper” tyre.

It could be argued that all-season tyres are a misnomer; they are just “grippier” tyres more suitable for wet and muddy conditions – there being no substitute for a dedicated winter tyre for use in the ice and snow. But for us, the legal requirement is the thing; everything else, as so much in this life, is a compromise. All-season tyres are unlikely to be as good as the best specialist winter tyre but can be expected to work better on wintry roads than a summer tyre, and you will avoid the hassle and cost of swapping wheels/tyres twice a year.

It must also be remembered that modern winter tyres are not just for snow and ice, advances in compound technology and tread pattern design mean that they provide higher levels of safety in cold and wet conditions too; as we ourselves have now found, the improved levels of grip even with an M+S tyre can be remarkable over a standard summer tyre. 

I did at one stage contemplate fitting a full winter tyre, and Continental is one source that says if you are unable to swap tyres, you can use winter tyres all the year round, but there are issues here. 

Winter tyre compound contains a higher percentage of natural rubber and is designed to remain flexible below +7 degrees Centigrade, as this is the temperature below which – research has shown – potentially hazardous conditions are most likely to be encountered. However it will wear faster and run warmer, compromising the handling in the summer, possibly even making the vehicle feel unstable – such as through small steering movements on long corners – because the rubber has become so soft. 

But, opinions differ as to what is a safe upper limit for these compounds, 15° C is one recommended figure, though the performance of compounds will vary from one manufacturer to another, and tyre type to another.

Secondly, there are trade-offs on grip and braking distances as well. Winter tyres will always out perform summer tyres on snow and ice covered roads, but what you gain in superior grip with a winter tyre under braking in wet and wintry conditions, you will lose in the warm and dry compared with a standard summer tyre. The reductions in stopping distances for winter tyres in the summer though, are smaller than for the opposite case of summer tyres in winter conditions. 

On wet roads the differences will be much smaller or insignificant, the summer tyres losing out to the winter tyres at 5°C, but coming marginally on top at 20°C. Thus, winter tires on a wet road in the summer show only minor disadvantages compared to summer tires.

However, on dry roads the summer tyres will beat the winter tyres on braking distances by an increasing margin with rising temperature. This is hardly surprising as modern tyres are highly developed for their designed task. As most accidents happen in wintry conditions however, you may consider this to be a compromise worth making.

Thirdly, a softer, more open, “blockier” tread is likely going to be noisier, wear faster and give rise to higher fuel consumption, despite reassurances to the contrary – see the section on EU label ratings.

Some or all of the above comments maybe applicable to four-season tyres as well and you will have to seek out assurances from the manufacturer as to their suitability for the conditions in which you intend to drive.

Finally, another conundrum. Winter tyres lose their suitability - and legality - for winter conditions when the tread depth falls below 3 or 4mm (depending on the countries’ legislation), but the partially worn tread blocks no longer deform so much when braking and so their performance in the dry actually improves. This has led to owners with worn winter tyres “using up” their winter tyres in the summer, albeit accepting the reduced performance in the wet and longer braking distances compared to summer tyres. 

So, it makes sense to buy your winter tyres at the beginning of the winter season, however long you keep them. Remember though, every year the rubber compound will have matured and hardened a little more, reducing its grip at low temperatures! Michelin say it is impossible to predict the usable life of a tyre as there are so many variables affecting its condition, but after 5 years they should be inspected by a professional every year.

However, for motorhomers like us, the all important issue is the M+S symbol for compliance with the Law in continental countries.

What are the new Euro label markings?

The new Euro label ratings came into force on 1st November 2012. They measure three factors: Fuel Efficiency and Wet Grip (on a descending alphabetical scale, similar to the efficiency/environmental ratings on washing machines, etc,) and also Rolling Noise in decibels. They quickly and easily indicate distinctive differences between regular “summer” and “winter” tyres, and the performance of tyres at the cheaper end of the market!

They are crude yardsticks however, not taking into account other important factors such as handling and driving stability; resistance to aquaplaning; braking performance on dry roads; and durability. 

Winter tyres are designed to perform to their highest abilities in temperatures below 7°C, and the rubber compound is able to retain its elasticity – unlike a summer tyre, which is prone to solidifying in freezing conditions!

Caution is therefore also required in reading too much into the differences in EU Tyre Label scores for winter tyres, as the tests are carried out in the same conditions as all-season and summer tyres i.e. relatively warm. Winter tyres do not perform to their best abilities in these conditions, so it is very likely that they will continually score poorly against summer tyres.

When selecting a winter tyre it is more important to investigate and take into account the type of compound used in the tyre's construction, the size of the tyre's contact patch, the tread pattern and the sipe design, and of course, how the tyre has scored in the specific winter driving tests.

Can I just fit winter tyres on the driving wheels?

One consistent piece of advice I came across was always put your best tyres on the rear, even if you have front wheel drive. However, it is definitely not recommended to fit winter tyres on just two wheels – and some tyre fitting companies may refuse to do so – because of the unbalancing effect on the cars handling.

The logic behind this is to avoid “oversteer”, or the rear wheels overtaking the front, rather than “understeer” when the front tyres are slow to respond to the turn. If you think about it, oversteer is more likely to be disastrous if carried to its ultimate conclusion in a spin, especially with a rear-heavy motorhome, than if the front wheels just ploughed on a bit when they should be turning. Either way, having different tyres front and rear is likely to upset the proper handling of the vehicle.

What makes of tyre are available?

Knowing that I needed an M+S marked tyre, and thinking along the lines of an all season tyre, my research started by sending the same email enquiry to six of the major tyre companies: Continental, Dunlop, Goodyear, Hankook, Michelin and Vredstein. 

Interestingly, Continental, Dunlop and Hankook responded immediately with useful information and Vredstein 10 days later (having been forwarded from Holland to their UK office). Goodyear and Michelin did not respond at all, which is very disappointing for Michelin as they produce a very specific tyre to our needs.

After a preliminary look at the tyre ranges, three brands appealed to me: The Continental Vanco series - a huge German company with a well deserved reputation, the Vredestein Comtrac series - a Dutch company with an excellent reputation, and the ubiquitous Michelin Agilis series. I liked the look of the Continental and Vredestein tread patterns on their all-season tyres, less so the Michelin range.

Michelin produce a specific motorhome tyre, the Agilis Camping, which is often categorised as a summer tyre, but magically it has the M+S symbol and hence would apparently be acceptable as a winter tyre in the above countries. Michelin do not make an all-seasons tyre, neither do Dunlop or Hankook.

Continental also make a “Camper” tyre, as does Pirelli. However the Continental “Vanco Camper” and Pirelli "Chrono Camper" tyre do not carry the M+S marking and so fell out of the running. 

I discarded the Continental Vanco Winter, the Vredestein Comtrac Winter and the Michelin Agilis Alpin winter tyre for the reasons of uncertain performance in high summer temperatures.

That left me with the Continental Vanco Four Seasons, the Vredstein Comtrac All Season and the Michelin Agilis Camping, that meet the winter legislation requirements.

Continental Vanco Four Season (215/75 R16 113R)

The Continental Vanco Four Season tyre, with the M+S symbol, has a softer compound and a coarser tread pattern, but is suitable for summer use, and was for me the leading contender. In the words of their technical representative: “it has some great benefits: high safety in the summer due to improved handling characteristics, high safety in winter due to reliable traction and braking on wintry roads, good grass contact and is very quiet. This tyre works to the same level as a summer tyre and has no limit on temperature, so you don't have to worry like you would a winter tyre.” 

The EU ratings for Vanco Four Season are: 

Fuel Efficiency: (E)

Wet Grip: (C)

Rolling Noise: (72 dB)

When I raised the issue of the EU ratings, he responded:

“The Four season tyre will give you all the applications you are looking for annually, this tyre is great all year round. The EU ratings measure three aspects only, wet braking on a 1mm of water on a particular flat road surface, rolling resistance, and external noise levels measured in decibels, there are so many other factors which make up a good premium tyre. The EU label is just a guide and should not be used for the only decision when purchasing a tyre.”

http://www.conti-online.com/generator/www/uk/en/continental/transport/general/home/index_en.html 

(for some reason this link does not show the Four Season tyre, but it is easily found on supplier’s websites)

VREDESTEIN COMTRAC ALL SEASON (215/75 R16 113R)

The Vredstein Comtrac All Season also greatly appealed to me, particularly as it carries the mountain/snowflake marking, which means that you are absolutely sure it will be accepted as a “winter tyre” by the authorities. The fact that there is no regulatory control over manufacturers applying the M+S symbol to their tyres means that in the future only the certified snowflake symbol may be acceptable.

The specification reads: “The Vredstein Comtrac All Season is a van tyre that offers both summer and winter performance in equal measure. This tyre suits van drivers that want to benefit from enhanced winter safety without having to run 2 sets of tyres and avoid the costs of swapping these over each season. The Comtrac All Season has a carefully designed sipe structure, which is a key feature of winter tyres and offers great traction on snow and ice. This tyre has the mountain/snowflake and therefore fulfils the requirements for designation as a winter tyre in countries where winter tyres are mandatory. It has a directional tread design that is great at clearing slush in the winter and rain any time of year. The tyre offers comfort, excellent handling and stable road holding. The compounds in the Comtrac All Season are balanced for both winter and summer use and allow for a high degree of wear resistance for a long life span. As with the Comtrac it benefits from a steel reinforcement strip, making it suitable for all modern delivery vans”

The EU ratings for Comtrac All Season are:

Fuel Efficiency: (E)

Wet Grip: (E)

Rolling Noise: (71 dB)

http://www.vredestein.co.uk/car-tyres/light-truck?Lang=en-UK

Michellin Agilis Camping Green X (215/75 R16 113 Q)

The Michelin Agilis Camping is a one off, it is the only “Camping” designated tyre to carry the winter M+S (Mud and Snow) rating. How Michelin managed this, I don’t know, as neither the Continental Vanco Camper or the Pirelli Chrono Camper achieve the same feat. This is classed as a summer tyre with a more “grippy” tread suitable for light snow and wet, muddy surfaces, but Michelin would have you believe that the compound is something special as well.

“The Michelin Agilis Camping is designed especially for motorhomes, for long tyre life and very safe journeys! Product benefits include: Long life, Robustness & Versatility (M+S marked) The design and technology is derived from the new Michelin Agilis van tyre range. New technology, such as the DCP (Durable Contact Patch), equals a long lasting tyre capable of use over several seasons. The reinforced construction using two casing plies enables the use of higher inflation pressures to provide resistance to heavy loads (up to the tyre's rating). Protected sidewalls: 8 kerbing protectors have been positioned on each sidewall to increase resistance to sidewall scuffing. A tread pattern with 30% more sipes and 20% more grooves, combined with a rubber compound capable of operating over a wide temperature range, provides sufficient grip for occasional use in difficult conditions. Simply the best tyre on the market for camper vans or motor homes.”

The EU ratings for Agilis Camper are:

Fuel Efficiency: (C)

Wet Grip: (B)

Rolling Noise: (70) dB)

http://www.michelin.co.uk/ 

Other Factors

The manufacturer's claims for reinforced construction and protected sidewalls open up another can of worms when it comes to the difference between “Camper” designated tyres and “Commercial” LCV tyres – there really is a fog of contrary information as to the real and important differences. 

Suffice to say, perhaps, that the old 8 and 10-ply designations have fallen into disuse (they only really applied to cross-ply tyres anyhow), and that the manufacturers’ are well aware of the abuses that “white van man” puts their tyres to, so the technology going into “Camper” tyres is unlikely to be significantly different to LCV tyres, other than a few tweaks aimed more at the marketing angles for motorhome owners.