Tyres again - Vredestein 155 HR13 78H Sprint

[Ross Robbins]

OK guys, I am taking off the gloves

What we have here is a technical guideline from a global application perspective being applied as a hard rule to a specific situation. On the theoretical level I wholeheartedly agree with the "nothing less than H rated" argument, because it includes overloaded Ford Explorers in the Arizona heat at 80 mph for ten hours at a time. In other words exactly the conditions that lead to all the Firestone Wilderness AT failures in the '90's through 2004. But, and this is a bigger but than JLo has, we are driving cars that weigh 1,400 Lbs.over distances that are less than a couple hundred miles. The load rating for an S rated 155 X 13 tire is about 950 Lbs EACH. That is a load capacity of 3,800 Lbs for a 1,700 Lb load with two people aboard or 1,900 with all the junk you can imagine and the load pictured below.That is a two to one safety factor folks We did over 1,750 miles like this by the way.

Now if I were Barry and putting out generalized advice that might come back to haunt me, I too would make the statements he has made. But c'mon folks, these tires are not dodgy, old, bias ply, rim protectors from the '60 that we ran around on with careless abandon in our misspent youth. The capability of a low price S rated tire is far greater than the requirements for even enthusiastic driving for a few hours. And the nature of these tires matches the design goal of the Elan perfectly, yielding gentle breakaway at the limit with a very predictable nature. And, with the just adequate grip they offer, I am not over-stressing the 45 year old suspension either

So, to conclude, I suggest we all take a deep breath and allocate our tire (tyre) budgets as we see fit. As for me, I will buy inexpensive S rated radials every three or four years rather than seeking out H rated tires and keeping them twice as long.

Happy motoring whatever your tire choice. Get the car out of the garage and use it as Colin and Ron Hickman intended.

[pereirac]

The only caveat I have is, watch out for your insurance.
I would imagine some companies will try anything to get out of a claim should you have an accident and if they can claim that you had the wrong speed rated tyres ... I think countries like Germany are very strict about what tyres you can fit, if the manufacturer say H rated then I would imagine you have to fit H rated Tyres? I think other countries may be more flexible. Whatever you fit it might be worth talking to your insurance company first, just in case.

Carl

[Galwaylotus]

By all means put whatever you want on your own cars. I reiterate what was said on my earlier post however, "What about the speed capability of tires that are inflated to a lower pressure, but properly loaded for that pressure?

John Baldwin (again) also tested this and found a 2 step drop there as well. This was also not an exhaustive study and more work is needed. Ref: J. M. Baldwin, "High Speed Testing Of Tires and the Use of Constant Deflection," presented at a meeting of the Tire Society, Akron, OH, September 23-24, 2003.

Hopefully by now you will realize that the speed capability of a tire could be quite less than the speed rating. If you add up what is known, you could be looking at a 6 step drop - and those are just the issues that are known!"

Yes the load rating is higher than we need - AT THE MAXIMUM INFLATION PRESSURE - but it isnt rated to carry that load at the pressures we are likely to run (not sure I'd want to ride in an Elan where the tyres are at 40 psig!!)

When the only thing between me and the road is a bit of fibreglass and four tyres I want to be as sure as I can that a tyre won't fail probably destroying the fibreglass and potentially landing me in hospital or worse. I won't pay the prices for Michelin XAS but I will try to get H-rated tyres iin a known brand and type approved for the market where I'll be using them.

As I said though, to each his own.