Tyres - Brands And Speed Ratings

[Falchoon]

I've been window shopping for new wheels and tyres (19s) and was pricing some tyres. I was keen on Falken 'cause I know a couple of people that have them in this size and they are happy with them. Tyre shop said they will sell me Falken 235/35/19 for $450ea but offered Kuhmo same size for about $100 less and claim they are just as good except they have a lower speed rating, Falken Z vs Kuhmo V.

Anyone care to comment or share their experiences?

[justind]

There was an article in yesterdays herald Sun (Melbourne) about the cost of replacement tires for performance vehicles. One thing I did get from the article was that the load rating was more important. Speed rating is important when it is the difference between 140 and 200 but when the speed rating is 200 or 270 why pay the extra if you are not going to do those speeds. Just a thought.

[Mondie]

l am no expert, but dont you have to stick with the same speed rating (z) for the car to remain legal? Or at least stay with the same speed rating as the tyre placard states?

Not sure Ross, but its something to check on.

[Falchoon]

Thanks for the tip Mondie, that was something I hadn't considered.

What is the actual speed rating difference between V & Z does anyone know?

[justind]

That is what I was saying the article stated that the load rating must be maintained but speed rating could change. Along with slight size changes etc. If the load rating is different then it could have long term effects on suspension steering and the like.

I don't belive everything I read but it did make sense to me and is probably worth investigating further.

Edited 24/01/04 10:20 AM by justind

[mickq]

I believe that your car must have at least the speed rating which it was released with (which should match the top speed of the car, at least). I know that rule applies to car manufacturers. But putting your own tyres on it may be different.

A tyres rating means that the tyre can function at that speed, with a certain load (weight), and not deform for at least 1 hour at that speed.

V rated tyres, worst case, are meant for use on cars which do not exceed 240kmh. (ie if you were to keep it floored for an hour). This may explain partially why the XR6T is artificially limited to 230kmh. Letting it run to 260kmh would have added up to a couple of hundred dollars to the manufacturing price of the car, as (likely) more expensive tyres would have to be used.

Z rated tyres are also rated to 240kmh, but are denoted as being "240+". They are not limited, but often used in conjunction with another letter to limit the max speed it can cope with (eg WZ or 235/50ZR15 91W) to indicate the car has the ability to run for 1 hour at 240kmh BUT must not go over 270kmh max speed.

Interestingly, all new tyres sold in Oz must be rated at least to 180kmh!

Getting a tyre rated much above what your car can do is a waste. It wont necessarily perform any better. (Could even be worse and ride and cornering could suffer although high speed straightish line stuff may be better and more safe as the tyre is made much stronger).

Being sensible, Id limit the rating you choose for your car to at most 1 rating above the cars max speed, so nothing more than a W rating (or WZ or similar).

Edited 24/01/04 10:32 AM by mickq

[100%]

I have 19's with the Falkens on the front and Hankooks on the back and I reckon the Falken get a bit 'skaty' when hot and the Hankooks are much better in all conditions. Once the Falkens are worn I will be replacing them with Hankooks.

[whatever]

I was been told load rating has to be maintain, too. speed rating can be changed.

Load rating is depended on the weight your car is design for. so using lower load rating tyre is dangerus. whereas speed will only matter if you are planning on racing.

[BATRB-6]

My 19's have 245x35x19 Hankooks all round and I think they are great in all conitions. Prices are around the same figure as Falkens

[aaronmihe]

Speed rating can be changed - hence why re-treads can be legally sold/fitted to any car....

BUT

Load rating must be maintained otherwise bye bye roadworthiness and bye bye insurance...

The load rating for a Falcon is quite high....

A.