On Wed, 23 Apr 1997 17:00:57 -0600 David Councill <dcouncil@inetco.net>
writes:
>Is there a benefit to the larger tires?
>
>I have always believed that smaller tires yielded better handling. But
..... I may have to go to a 175 or even a 185 (gasp) ..... Should I
worry? And what would a 195 do to my car in terms of handling?
a.) Your car will handle well if the tires are not overloaded.
b.) As a matter of economics, stock size tires on many cars are very
near the minimum size required to carry the load. MGs are no exception.
c.) Tires one size large can yield a nice improvement in handling
because they won't get overloaded in severe maneuvers.
d.) Tires of larger sizes will yield progressively smaller improvements.
The law of diminishing returns applies here.
e.) Tires a few sizes larger than stock can be detrimental to the
handling on wet or snow covered roads. Hydroplaning gets worse as the
footprint gets bigger.
f.) When the manufacturer specifies a minimum rim width for a tire, they
mean it, in spades. When the tread width gets wider than the rim width
the tire wants to roll over on the shoulder on hard cornering. When this
happens the inside part of the tread gets lifted off the surface while
the outside shoulder of the tire takes a terrific beating, and handling
goes down the tubes.
g.) The optimum tire/wheel combination matches the wheel width to the
tire tread width. If you can't afford both new tires and new wheels, a
little larger tire will show more advantages than disadvantages, but
three sizes wider than stock is pretty far out on the limb.
>From someone with lots of experience in this area. I run 195 tires on 4
inch wide wheels to stay in stock class with SCCA. With a lot of hard
cornering they wear through to the tire cords on the outside shoulder
when only about 2/3 of the tread is used up. The grip also gets very
unpredictable when they get right up to the hairy edge. When then tread
starts to roll over the car can change ends very quickly. The only way
to prevent the roll over is add more air pressure, which gives a smaller
foot print which yields a lesser grip. It gets to be a real art trying
to pick the optimum tire pressure for any given pavement and temperature
condition.
For the curious, 195 is the narrowest tire available in race rubber
compound for a 15 inch wheel. That's the only reason I don't go to a
smaller size.
Barney Gaylord
1958 MGA with an attitude
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