quote:
Originally posted by Primus:
Looks like our discussion went into the channel of a theoretic dispute. But may be, CapriRacer, as a tire industry representative, could share his knowledge and experience and give us more simple example of tires behaviour using some test results of H, V, W and Y rated tires in areas like handling, braking and comfort ? If there are no net figures available, may be just a percentage difference from a reference tire ?
Index . Handling . Braking . Comfort
. H
. V
. W
. Y
Since this is kind of a generalization and there aren't going to be any tests that actually do this type of comparison - kind of an apples and bananas sort of thing that is of little value to someone trying to design the next generation of a particular tire line - which is usually around one speed rating and a limited range of sizes.
So what I did was sit down with a colleage of mine and developed a list. Interestingly we were really close on our first assessments:
Speed Rating....Handling/Grip...Ride Comfort
S................40 to 60........90 to 100
T................50 to 70........85 to 100
H................60 to 85........70 to 90
V................70 to 90........60 to 80
W, Y.............85 to 100.......50 to 70
Z................90 to 100.......40 to 60
First this is a scale of 1 to 100. The reason there is no 1's on the list as a "1" implies a truly terrible situation and we both felt that even a tire at an extreme has some "good" in any given category.
I lumped handling and grip together. Handling to me means responsiveness (although I frequently include grip in that classification) and grip is more along the lines of braking and cornering power. But as a general rule, these 2 go hand in hand - with the exception of T rated tires, where "Touring" tires are generally found (or ought to be found!). Touring tires are generally more responsive all season tires, but not necessarily better grip - but there's a lot a variation here.
Ride comfort means impact harshness - the reaction a tire has to an impacting object, like a small pot hole. This equates quite well to overall ride quality (excluding vibrations)
Anyway, that's the list.
While speed rating has nothing to do with handling or ride comfort, the types of tires that get certain speed ratings determine what most of the other properties are going to be.
For example a 4 door luxury sedan is more likely to have an S rated all season tires on it (and therefore ride is important), while a high powered, 2 seater coupe is more likely to have V or Z rated tires (and therefore have high grip and responsive handling).
Where this gets sticky is where you have a 4 door luxury sports sedan. Is this a "Luxury" car or a "sports" car that has 4 doors?
Hope this helps.
