>I don't have all your answers, but I had to respond anyway. Isn't a 245/45
>the same 245mm wide regardless of wheel diameter? Therefore, I wouldn't
>think there should be any question. Lighter, cheaper, and same amount of
>rubber on pavement?
Don't confuse nominal sizes with reality. They may very well be the same
width (section width, anyway) but you have to look at their specs for
actual widths and tread widths. Be aware of what they are measuring -
there is a design rim width, which is what the specs are shown for. If you
have a different rim width than that, you will have a different result
(section width in particular is effected by rim width; tread width
probably changes relatively little). Then you have to factor in sidewall
heights (in general, we like smaller overall diameter, but on some cars or
some courses that could just lead to lots of shifting). And you also have
to consider what effect that sidewall height has on spring rates - the
sidewalls (especially on a DOT tire) are a significant part of the total
spring rate, so a shorter sidewall at the same OD could be a good
thing. Then you have to consider how one or the other will fit your
driving style. Then look at prices - if they are all equal, but the 17"
stuff costs 50% more, then the 16" package is probably the way to go.
Now, to the weight issue. Is a 17" package (at the same ODa and same
width) actually heavier than a 16"? Depends. There is considerably less
rubber. With decent rims, you may find that the 17" package weighs less
than a 16" package (I'm making some logical leaps here - you'd definitely
have to weight some wheels and tires). Then you have to take into
consideration the rotational inertia of each package, and again, it is
possible that the 17" package has the advantage. Or not. This exercise is
left to the student....
As always, none of this is to be taken as official in any way, shape, or form.
Paul Brown
Isotope Racing Wheels - I will have a set of white 15X6 Volk TE-37s to fit
the late Miatas
available at Topeka. 9 lb, 6 oz each!
Paul and Meredith Brown
MR2: "Not the easiest car in the world to work on"
|