48 replies to this topic

[Mister H]

Blue Louis, on 24 July 2012 - 01:27 PM, said:

I don't know if it is still the case but in former years when conducting wet road braking distances it was always done with a vehicle with the ABS turned off so that the wheels were actually locked, it was done so because that was what the test regulations said ! MAD

Quite often it was found that when the ABS was turned on again, the very same vehicle would stop a whole lot sooner on one of the other brands being tested.

Why mad? It makes sense to test with the ABS off as the vehicle the tyres are fitted to may not have ABS or may have a faulty system thus preventing the ABS from operating. Testing the tyres in the worst case scenario makes perfect sense.

[Blue Louis]

Well Ritchie my answer to that is Yes and No.

The reason for me passing this thought is that in years gone by when I was working with several different tyre technical departments of the worlds tyre manufacturing industries, there were a large number of their technicians who new only too well that tyre '1' would work superbly when fully locked in the test and yet tyre '2' would look as though it were on ice when locked and yet when rotating and the tread in general and more importantly the sipes were working to their fullest extent, then tyre '2' could stop in a far shorter distance.

Now this in my most humble opinion is mad and shows how stupid and lacking the basis of testing is, it also goes in some way to emphasise the very valid post made by Stuartggray made earlier.

It is exactly the same when it comes to the government fuel consumption figures when vehicle 'A' has technically a far lower fuel consumption than vehicle 'B' and yet in the real world the answers are so very often very significantly reversed.

[Mister H]

Clearly you have a lot of experience in this area, which I don't. I guess that with more and more vehicles are being fitted with ABS as standard, if the test is as you have said, it probably needs to be looked at.

As for the economy figures - I imagine they're about as accurate as showroom MPG/MPL figures for new cars i.e. not very.

[Blue Louis]

Yes Ritchie it is a sad fact that these days there are not all that many people who do anything other than climb into a car and drive it, for what it is worth and so these international tests have to reproduce the lowest possible factor of repeatable result.

If you were to get rid of ABS and all similar systems and to very significantly improve the capability and performance of the drivers of the World then other tests showing real world performance figures might be more justifiable.
It is for this reason why I like the tests conducted by Autocar where cars are driven by highly skilled drivers over the same track, time after time and lap after lap under repeatable test conditions where the track can be flooded or dry (etc.) and it is then that you can see very significant differences in the achieved lap times because car 'A' is far more capable than car 'B' and yet in the real world out on the open road the opposite can be the case.

So I suppose the current test are OK, but dramatically improve the collective lot of the capability of the drivers of this World and some other kind of test might become more relevant.