OT(ish) - tyre rating labels

[David]

I'm looking for a replacement tyre for the spare which (I think) must be around 10 years old (if not older; we have had the car for about 10 years and I don't remember changing the spare at any time). Out of sight, out of mind. Just noticed that it doesn't look good.

I am now doing the web search for tyres, and one one site

they show a tyre label similar to the labels you get on domestic appliances.

From the symbols they seem to be for fuel efficiency, and use in the wet (presumably grip and braking) plus road noise in dB.

Does anyone have any idea how accurate these are?

As the rating is from A (best) to G (worst) I am not attracted to the cheapest tyre on offer at F (fuel) and G (wet weather) for £41.99 when you can get a C/C for £56.89.

Also, does anyone check the label ratings before buying?

Further puzzling stuff; my car has a rated maximum speed when new of 140 mph but the recommended tyres are not V (good for up to 148 mph) but Z (150 mph+) or higher. Not sure why apart from safety margin.

As usual, once you get into searching the Internet the amount of choice is enormous.

Cheers

Dave R

[Scott M]

It's far easier just to assume that the names you've heard of (Pirelli, Michelin, Goodyear etc) are better than the endless stream of chinese crap (Ling Long, Triangle, Runway.)

For a spare you may as well buy a cheap one and then buy a decent replacement should you ever actually get a blowout/puncture/pot hole damage.

Similarly, if you're likely to need new tyres at any point soon, simply replace the spare with one of the worn-but-much-newer ones.

8 to 4 they're fairly low profile then. Z-rated tyres are often a catch all in certain sizes.

[Huge]

This ^

[Roger Mills]

Tyres die of old age even if not used - which is probably what happened to yours.

On that basis, if the tyre you're about to buy is going to sit in the spare wheel well for ten years until its turn comes to be thrown away, there's little point in spending more than you have to on anything too exotic.

Load and speed[1] ratings *are* important, and you need a tyre which would be legal if you *did* have to use it. Apart from that, I wouldn't worry about the other parameters.

[1] Car makers tend to overdo the spec beyond what is really required - but you may invalidate your insurance if you use something of a lower spec than the original equipment. [I think that winter tyres are allowed to have a slightly lower speed rating - but not standard tyres]

[Davidm]

The spare wheels supplied with many modern cars are described as "space savers" - usually narrower than the tyres fitted to the 4 road wheels, and are usually restricted to 50mph and for emergancy use only. Nothing to stop you using the same approach, and fit a lower rated speed tyre to the spare.

[GB]

Even one which will do 70 (well, ok, 100) is not really a problem on UK roads. However, it would be a modification that you would need to notify your insurers about.

[T i m]

I think the load rating is an interesting one. On daughters Transit Connect, because it's not rated at whatever level that *requires* a specific (minimum) load rating, she could have left on the pair of new tyres it came with on the front, even if they didn't meet the minimum suggested rating, *as long* as they were never actually used past their maximum rating (or more accurately, never tested by VOSA to be carrying above their maximum load rating). ;-)

eg, If someone is using a van (or any such vehicle potentially) and never actually loads it above the tyres maximum load rating, they aren't (as I understand it) breaking any rules.

So, if you are only ever filling the van up with say, polystyrene foam sheets, you can get away with whatever tyre load rating tyre as long as it's load rating is never exceeded.

Now, because daughter can't predict what load she might have in the van on any trip, she replaced all 4(5) tyres with ones that met the maximum permissible load of the van (even those the fronts may never get near that ... assuming the tyres that were fitted to the front weren't then used on the back ... )

I'm not saying these are the rules, just what I (and many others, some supposedly in the know) understand them to be.

Cheers, T i m

[Brian Gaff]

Is this one of those get you home thin wheel thingies? I've never really been convinced of their safety, and considering the difference in width wonder how they get away with it. Also, what would make a tyre go off so to speak, it surely should stay pristine. Its all a bit of a black art. Another reason I'm glad I can't drive. Brian

[David]

Rubber rots eventually, especially if it has been used enough to get contaminants off the road, and then is stored.

There is a similar problem with trailer and camper tyres. As I understand it, constant use keeps the rubber flexible and it can go brittle if just standing in one position (again especially with the bottom permanently deformed). Pays to give them a run now and then.

Cheers

Dave R

[Dave Plowman (News)]

The speed rating is rather more than just a speed rating in practice. A tyre designed for a higher speed is generally better made, like for like. So your car maker has specified the best tyres in their opinion.

[charles]

[Snip]

But are car tyres made of rubber these days?

[harry]

After a while, cracks appear in tyres.

Even if unused.

[bert]

In article , T i m writes

My Land rover has max axle loading specified which presumably determines the max load on each wheel and hence tyre.

[bert]

In article , charles writes

No but they do have a shelf life (AFAIK 7 years).

[T i m]

Yup. However, unless your Landy is one of the vehicles that *must* have a minimum load rating tyre fitted (like an HGV etc) then you are only committing an offence if you actually *overload* any of it. eg, if an axle is rated at 1 tonne and the tyres only 300kg each then you will still be ok (legally) as long as the load on each tyre doesn't exceed 300kg.

Common sense however would probably suggest you had tyres capable of supporting the full max load of each axle, just-in-case. ;-)

Cheers, T i m

[Huge]

Neoprene, and it is degraded by ozone & sunlight, so little used tyres such as those on trailers & caravans should be replaced every 5 or 6 years, no matter how little they're worn.

Not so sure about spares, since they're protected from sunlight, at least.

[Roger Mills]

Plus a safety margin to allow for asymmetric loading.

[T i m]

And that, good point. ;-)

Cheers, T i m

[Richard]

Good luck with neoprene only tyres.

[The Natural Philosopher]

Used em on a few model aeroplanes :-)

IIRC its a butyl rubber polymer of sorts for tyres.

Oh. You have to smile at the armchair theorists.

Here is a more definite statement

A common-sized all season passenger tyre made by Goodyear, weighing about 10 kG (22 lbs) new, contains:-

30 kinds of synthetic rubber 8 kinds of natural rubber 8 kinds of carbon black steel cord for belts polyester and nylon fibre steel bead wire 40 different chemicals, waxes, oils, pigments, silicas & clays.

:-)