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Any - Tyres - wantstolearn

Researching for new tyres. How accurate are the tyre gradings ? How much weight should I give to them ? thanks

Any - Tyres - badbusdriver

Researching for new tyres. How accurate are the tyre gradings ? How much weight should I give to them ? thanks

Depends on where your info is coming from. If you are looking at a 'controlled' test (by which I mean the same size and spec on the same car*) of a variety of tyres being tested on things like dry acceleration, cornering and braking, wet acceleration, cornering and braking, nis levels and economy, there is no reason you should doubt them.

But if you are just looking at owners reviews, you need to be full aware of the limitations of this. The vast majority of owners will never have found themselves in the kind of situation that separates a good tyre from a poor, or just average tyre. Such as an emergency stop from speed on a wet road, having to violently swerve to avoid an accident. For most, owners reviews are going to be based on noise levels, economy, purchase price, and how they handle normal everyday driving.

*Auto Express Magazine publish these from time to time, though they can be found online.

Edited by badbusdriver on 13/02/2022 at 18:26

Any - Tyres - Engineer Andy

I would use them as a general guide rather than a rigid one.

The weight rating is for the absolute maximum loading per tyre, which you'd likely never get near, but you HAVE to follow as per your car's handbook / inside door plate. A tyre can be fitted that has a higher load index rating than the minimum stated there; similarly with the speed rating.

The noise rating is externally measured noise, not in the cabin, and thus what you hear is more dependent upon your own car's soundproofing, or your driving style and what roads you drive on, plus the weather conditions.

I do recall someone here previously noting that the mpg one essentially saying the difference between each band (at the mid point) is a small percentage, so realistically you might only notice a difference between tyres 2 or more bands apart. Don't quote me here, but I think the difference between an A and an E or F rated tyre for mpg was about 20-25% - for the same test vehicle.

I suspect the same would apply with wet weather performance, noting that the actual mpg and wet (and dry) performance of you car is as much dependent on the car itself and your driving style as it is the tyres.

Some tyres, despite them being A/A or A/B rated, often work poorly on certain cars, but very well on others, hence why they are subjective ratings in my view.

The wear or traction rating (on the sidewall only these days) is more of an American thing, and again is a general guide like the others - a large difference in rating between tyres would likely be noticeable; a small one would likely not be.

For that reason, it's why I always take note of as many user (us) reviews of tyres*, particularly matching my own car (or failing that similar ones) and a tyre I would look to buy as much as just a car magazine tyre test. Luckily for me, most of the latter use a VW Golf, Audi A3 or Ford Focus car, which reasonably matches my Mazda3 in most respects.

* See the Tyre Reviews website - Jon there is very knowledgeable and often carries out his own group tests as well as republish car magazines' ones, plus he will always respond to queries via his YT channel or the TR comments area below each article (the site uses Disqus for a comments platform)

[update] If the OP is possibly referring to tyre group test 'ratings' by car mags and others (like Tyre Reviews), again, they are subjective because they are almost always carried out on (nice smooth) test tracks and using new(ish) cars, mostly VW Golfs or similar. What works well for them may not for the OP's car, or vice versa.

Hence why the user review on Tyre Reviews can be just as useful. Just take note of the variable each person states when uploading their review scores, because many upload them with only a few hundred miles/km on the clock after the tyre change, or their driving styled (which should be listed) may not match ours; similar the car they drive can make a big difference, or the region / country (weather, road quality).

Edited by Engineer Andy on 13/02/2022 at 18:54

Any - Tyres - RT

The Uniform Tire Quality Grading (UTQG), eg 400AA, moulded on most tyres is an American standard but isn't a direct comparator across different brands - it's also not moulded or removed on certain tyres sold in Europe.

The EU Tyre Label Grading is a reliable comparator but very restricted in scope.

I don't use either when selecting tyres, preferring a consensus of multiple online tests.

Any - Tyres - wantstolearn

Thanks for prompt and informative replies. I have often said this forum is outstanding.

I do appreciate people taking the time and trouble to help me. I will now follow up suggestions.

Any - Tyres - edlithgow

"Don't quote me here, but I think the difference between an A and an E or F rated tyre for mpg was about 20-25% - for the same test vehicle."

25% seems an awful lot

(Oops! I quoted you. Apologies)

Any - Tyres - Engineer Andy

"Don't quote me here, but I think the difference between an A and an E or F rated tyre for mpg was about 20-25% - for the same test vehicle."

25% seems an awful lot

(Oops! I quoted you. Apologies)

That's ok (mine was a figure of speech anyway, as I wasn't 100% sure of the information as I was remembering what someone else here had said).

It's rare for tyres, especially new ones, to be F rated for mpg. Most on sale are older design tyres, often for unpopular / unusual tyre size combos, e.g. 13in tyres or older designed winter / all-season tyres, and/or from cheapo makes.

Some are also for ultra high performance tyres, because they are designed for grip rather than rolling resistance. Most of those now are E rated rather than F.

Any - Tyres - mcb100
Make sure new tyres are the correct width/aspect ratio/diameter/load/speed rating, and if it’s a brand you’ve heard of, and you’re not planning track days, you’ll be fine.
Anything from a mid-price upwards will provide enough grip in 99% of conditions to do the job.
Any - Tyres - Johnmo89

Of all the things I traveled in the summer, I liked the Michelin Pilot Sport 3 the most. From the budget ones, I would take Formula or something like that, but never buy a Nokian (micro hernias constantly appear, the steering wheel starts to hit at a speed of 100 km, just balance it goes normally, time passes again the same)

Edited by Johnmo89 on 14/02/2022 at 09:29

Any - Tyres - badbusdriver

Of all the things I traveled in the summer, I liked the Michelin Pilot Sport 3 the most. From the budget ones, I would take Formula or something like that, but never buy a Nokian (micro hernias constantly appear, the steering wheel starts to hit at a speed of 100 km, just balance it goes normally, time passes again the same)

Eh?

Any - Tyres - Terry W

The other point to consider is what type of tyre - depending on where you live, having better wet and snow grip could be useful - I usually fit all season, not summer tyres.

Premium makes do cost a little extra but £20 a tyre (£80 a set) spread over 2-5 year (depending on mileage) is not a high cost to pay.

A good review site which seems authoritive and thorough:

2021 Auto Bild All Season Tyre Test - Tyre Reviews and Tests

Any - Tyres - wantstolearn

Many thanks. This is the place to learn !

Edited by wantstolearn on 14/02/2022 at 10:15

Any - Tyres - Engineer Andy

The other point to consider is what type of tyre - depending on where you live, having better wet and snow grip could be useful - I usually fit all season, not summer tyres.

Premium makes do cost a little extra but £20 a tyre (£80 a set) spread over 2-5 year (depending on mileage) is not a high cost to pay.

A good review site which seems authoritive and thorough:

2021 Auto Bild All Season Tyre Test - Tyre Reviews and Tests

Indeed (I'd also thoroughly recommend the tyre Reviews website), and where the local climate and/or road conditions (e.g. living on high ground or more rural / northern areas), a set of decent all-season tyres could easily make the difference between having and not having an accident in winter, even without snow.

That in itself - just one time during the ownership period of a car, would easily pay (and more) for the difference in cost over a set of (decent) summer tyres, given insurance penalties from having a fault accident (paying the excess, more chance in losing a protected no claims bonus, a higher starting premium, etc, etc).

The difference in lifespan (for similar quality tyres) between all-season and summer tyres in far less than it used to be, as is the capital cost. Add to that far better 'summer' (above 7degC external temperture) performance and the availability of different grades of summer and winter bias on the performance front means they can be bought to tailor them to the driver's circumstances for location as well as the car itself.

Normally, the more winter-biased all-season tyres are of a softer compound and, in general, give a softer ride than those more summer-biased all-season tyres, but at the expense of some warmer weather grip / handling ability, which is always a trade-off.

Speaking personally, for cars of standard performance and living in the UK (except areas that get a lot of snow in winter, where I'd go for a set of summer+winter to cater for the more extreme conditions, if I could store the other set), I'd now always fit all-season tyres to my car, because the small trade off in summer performance (grip / handling) is in my view far smaller than the gains in colder weather, and especially snow and icy conditions, particularly (as you say) the cost penalty of buying them over summers only is normally about £20 for an average car.

Any - Tyres - mcb100
Of all the things I traveled in the summer, I liked the Michelin Pilot Sport 3 the most. From the budget ones, I would take Formula or something like that, but never buy a Nokian (micro hernias constantly appear, the steering wheel starts to hit at a speed of 100 km, just balance it goes normally, time passes again the same)

No idea what that means - I’ve used both Nokian all season and Winters without any issues.

Edited by mcb100 on 14/02/2022 at 11:16

Any - Tyres - Engineer Andy

Of all the things I traveled in the summer, I liked the Michelin Pilot Sport 3 the most. From the budget ones, I would take Formula or something like that, but never buy a Nokian (micro hernias constantly appear, the steering wheel starts to hit at a speed of 100 km, just balance it goes normally, time passes again the same)

Eh?

Lost in translation perhaps? I have no clue what they were on about either, but Nokian tyres are normally good, though they are far better on all season and especially winter/studded tyres because that's their speciality.

Any - Tyres - Brit_in_Germany

>Lost in translation perhaps? I have no clue what they were on about either, but Nokian tyres are normally good, though they are far better on all season and especially winter/studded tyres because that's their speciality.

I don't think even google would be that bad - more like random text.

Any - Tyres - Xileno

Probably some spam on its way but the registered email looks ok. We will see...

Any - Tyres - blindspot

XL for stronger ,better weight carry.

Any - Tyres - RT

XL for stronger ,better weight carry.

plus more puncture-resistant - but the downside of XL tyres is harsher ride due to stiffer sidewalls.

Any - Tyres - wantstolearn

Thanks. Priorities comfort and quietness.

Any - Tyres - industryman

We should be wary of tyre reviews from the the general public. As a rule they will be comparing old well worn tyres to brand new replacements. The new tyres should perform much better than the worn out tyres in most respects. Can they remember how the old tyres performed when they were new? Unlikely.

EU product labels were introduced to promote environmental improvements and are typically based on energy consumption and factors such as noise emission rather than the ability of the product to perform its function. For tyres the label rates fuel efficiency ( = energy consumption), external noise ( = airborne noise, an environmental factor), and braking ability. The latter is a measure of product performance which is not usually the subject of these labels but was included after intense lobbying by a major tyre manufacturer. The external (drive-by) noise rating cannot used as an indicator of interior noise as they are not related.

Tyres designated as XL (= extra load) do not necessarily have stiffer sidewalls than their "normal" equivalents. The load a tyre can carry depends on its inflation pressure and XL tyres can be inflated to 0.5 bar higher pressure than "normal" tyres to enable them to carry higher loads. The carcass cords in an XL tyre might have a higher tensile strength than those in normal tyres but can be just as flexible. With the exception of "run flat" tyres, tyre sidewalls are not designed to carry load and a tyre with no inflation pressure will support very little weight.

Any - Tyres - Manatee

Tyres designated as XL (= extra load) do not necessarily have stiffer sidewalls than their "normal" equivalents. The load a tyre can carry depends on its inflation pressure and XL tyres can be inflated to 0.5 bar higher pressure than "normal" tyres to enable them to carry higher loads. The carcass cords in an XL tyre might have a higher tensile strength than those in normal tyres but can be just as flexible. With the exception of "run flat" tyres, tyre sidewalls are not designed to carry load and a tyre with no inflation pressure will support very little weight.

I'm aware of the above as far as it goes, but...My MX-5 uses 84V tyres. Many if not most replacements offered are 'XL' 88V. I've been led to believe that these tyres would need higher pressures, maybe 2-3 psi, to achieve the correct shape and even the load rating of the 84 rated tyre. The car is very sensitive to tyre pressures so I stick with 84 load rating despite the much wider availability of XL rated ones.

I've never been able to find "official" advice on this. The shape thing sounds logical to me - if they are designed to be the right shape at 36psi then they won't be the right shape at 29psi, will they?

Any - Tyres - wantstolearn

Thanks for the additional posts which are extremely helpful. Wish I'd started to learn decades ago and would have avoided many mistakes !

Any - Tyres - industryman

Tyres designated as XL (= extra load) do not necessarily have stiffer sidewalls than their "normal" equivalents. The load a tyre can carry depends on its inflation pressure and XL tyres can be inflated to 0.5 bar higher pressure than "normal" tyres to enable them to carry higher loads. The carcass cords in an XL tyre might have a higher tensile strength than those in normal tyres but can be just as flexible. With the exception of "run flat" tyres, tyre sidewalls are not designed to carry load and a tyre with no inflation pressure will support very little weight.

I'm aware of the above as far as it goes, but...My MX-5 uses 84V tyres. Many if not most replacements offered are 'XL' 88V. I've been led to believe that these tyres would need higher pressures, maybe 2-3 psi, to achieve the correct shape and even the load rating of the 84 rated tyre. The car is very sensitive to tyre pressures so I stick with 84 load rating despite the much wider availability of XL rated ones.

I've never been able to find "official" advice on this. The shape thing sounds logical to me - if they are designed to be the right shape at 36psi then they won't be the right shape at 29psi, will they?

The inflation pressure a tyre needs depends on the vertical load imposed on it and its speed of rotation (ie road speed of the vehicle). Higher loads require higher pressures, and higher sustained speeds require additional higher pressures. Also, if the wheel/tyre is cambered more than 2 degrees a further pressure increment needs to be applied. These pressure increases are essential to prevent the tyre overheating which will result in a sudden failure (commonly called a "blow-out"). This heat is generated by the tyre flexing as it rotates through the road contact patch. A tyre fitted to a road vehicle (particularly a passenger car) will be subjected to a wide variety of loads and speeds so the specified inflation pressure must be that which will be sufficient for the highest loads and speeds of the vehicle, or a range of pressure settings related to specified load/speed conditions. The latter is more common for passenger car applications.

The "basic" inflation pressure required by a tyre fitted to a particular vehicle application can be calculated using industry standard formulae and data tables. This will be the pressure needed to prevent tyre overheating. However, it is usual to specify actual running pressures above the "basic" pressure to give a margin of safety for lack of maintenance, optimise vehicle handling, reduce rolling resistance etc....

In answer to your specific question, the data tables for an 84 load index standard tyre and an 88 load index XL tyre give load carrying capabilities which do not differ by more than 5kg over the range of pressures applicable to the 84LI tyre up to its maximum load of 500kg. I would therefore recommend the same pressure setting for both in an application that does not need tyres loaded by more than 500kg per tyre. For higher tyre loadings the 84LI tyre must not be used but, by means of pressure increments above that required for 500kg, the 88 XL can loaded up to a maximum 560kg. Your MX5 will obviously not need more than 2000kg capability but, for example, an estate car derivative of a saloon/hatchback can carry higher loads on the same size tyres if the XL versions are fitted.

Any - Tyres - Engineer Andy

Thanks. Priorities comfort and quietness.

One other thing to note is that the tyre pressures can also make a big difference to ride quality and mpg.

When Honest John himself used to own this website and penned his Daily Telegraph column, he often recommended that drivers only use the handbook's (cold fill, i.e. not after use where the tyres and air inside will be warmer) as a guide, not rigidly stick to them, especially when fitting all-season and/or XL (higher load-rated) tyres.

Where the cold fill pressure for low (weight) loads may be 32psi (as mine is) and (say) 46psi for a fully laden (including full boot) car, the former might be for 'up to the driver plus 2 passenegers', thus you might find the ride is more comfortable at 31psi, maybe even 30 if you are the only occupant for the vast majority of the time (it's a good idea to alter the pressure if the load changes for a reasonable length journey).

You do, however, have to not go too far in reducing the pressure, as it will increase mpg (as you're increasing the contact patch size and thus frictional grip) and wear on the tyres, especially the driven wheels and on the outer edges.

Similarly in the other direction, pumping the tyres up to above the standard (say to 34psi on mine) means higher wear on the central part of the contact area, lower grip, but a bit higher mpg. I would do this (for my car only) if the car was carrying a couple of passengers.

It's always best to have the tyres pumped up to a level than evens the wear over the contact width area of the tyre. What that is will depend on what load (weight of the driver, passengers, boot contents) and the conditions. In warmer weather, the measured tyre pressure will be higher than in colder weather because the air heats up a bit and expands.

Tyres under very low pressures (20%+ lower) give a nice ride, but will wear a LOT more quickly and will be far more susceptible to damage, and especially blowouts, which can obviously cause serious accidents.

Any - Tyres - wantstolearn

Thanks Andy for helpful information.

If I may add another strand to the thread. My personal min tyre depth is 3mm .

Is this sensible ?..Any arguments to make it more ?

Any - Tyres - badbusdriver

Thanks Andy for helpful information.

If I may add another strand to the thread. My personal min tyre depth is 3mm .

Is this sensible ?..Any arguments to make it more ?

Very sensible IMO, that is what I change at. Don't think there is much, if any, argument to changing before 3mm, but some may argue to leave it later. For example, my wife has a Motability car, and apparently 2mm is what they deem the point where the tyre should be changed.

Apparently some tyre makers reckon their tyre will work fine down to the legal minimum, but I really can't see how that could be possible when it comes to very wet roads. You'd be far more likely to aquaplane down at 1.6-2mm because such a shallow tread depth would not be able to shift anything other than a small amount of surface water.

Ultimately it is up to you though.

Any - Tyres - wantstolearn

Many thanks bbd. I appreciate the confirmation, especially since we have had a lot of rain and I regularly visit the Lakes !!

Any - Tyres - Engineer Andy

Thanks Andy for helpful information.

If I may add another strand to the thread. My personal min tyre depth is 3mm .

Is this sensible ?..Any arguments to make it more ?

Very sensible IMO, that is what I change at. Don't think there is much, if any, argument to changing before 3mm, but some may argue to leave it later. For example, my wife has a Motability car, and apparently 2mm is what they deem the point where the tyre should be changed.

Apparently some tyre makers reckon their tyre will work fine down to the legal minimum, but I really can't see how that could be possible when it comes to very wet roads. You'd be far more likely to aquaplane down at 1.6-2mm because such a shallow tread depth would not be able to shift anything other than a small amount of surface water.

Ultimately it is up to you though.

Diito - change by tread left, condition of the tyre and age. My own personal gauge for tread depth has always been, like you, 3mm min, age used to be around 6 years old (because that's what Honest John used to recommend when he was running ths ite and had a Telegraph column), though now I'd go to 10 years but ONLY if the other two categories were still fine.

With condition, it's very subjective other than seeing a good number of cracks, physical damage / cuts or excessive wear on one part of the tyre (rather than even across the width). Plus, of course, how the tyre feels when driving (especially in poor weather), which is normally the most obvious way of spotting that a tyre is nearing the end of its useful life.

Case in point when my previous car's OEM set caused it to not stop in time for the same set of lights within the space of a few days, and my current car (also OEM tyres, different make, both 'premium' brands though) experiencing similar grip problems (the back end partially letting go) but on cornering on roundabouts.

Both happened in wet / damp conditions, the former when the front tyres were at a shade under 3mm and the latter when the tyres were around 6 years old, still 4mm+ of tread left (5mm on the rears) but had got firm and noisy. Both were fine in the dry grip-wise.

My latest set are, according to the manufacturers, designed to last 10 years if wear is taken out of the equation, which at the moment would be the case. I'm always keeping an eye out in case of damage as well as noting how the car feels, in case something changes for the worse and significantly enough to warrant a change. No problems yet though.

Any - Tyres - wantstolearn

Thanks Andy for an informative and clear post.