> Moore, John wrote:
> > Just for comparison purposes, the 225/50-15 BFG is 8.4" tread where
> > the Kumho is 8.66". When talking 205/55-14, then the BFG is 7.1" and
> > the Kumho is a whopping 7.64".
> >
> > 225/45-15 Hoosier Radial is 8.8" Tread width, 225/55-125 Hoosier
> > Radial is 8.5", 225/50-15 Kumho is 8.66" and 225/50-15 BFG R1 is 8.4".
>
> Are you comparing apples to apples?
>
> What exactly are these numbers? Is this the width of the tread that
> touches the ground when the tire is mounted on a reference rim (how
> wide?), inflated to reference pressure (how much?), and loaded with
> the weight of a car (how heavy?)
[Moore, John] I just gave some basic number for comparison. You
want the full story, then go out to the TireRack sight and look for
yourself. For those who may not have web access, here goes more of the
story:
Tire Overall Diam
Section Width Tread Width Rim Width
______________
Kumho 225/50-15 23.62"
9.17" 8.66" 7.0"
BFG R1 225/50-15 23.8"
8.8" 8.4"
7.0"
Hoosier Radial 225/45 22.7" 9.2"
8.8" 7.5"
Hoosier Radial 225/55 24.4" 9.3"
8.5" 7.0"
From measuring my Kumho 225/50-15's the Tread Width numbers are the
actual manufactured width of the tread. All of it may not actually contact
the ground, but most of it should with proper inflation. I don't know how
the others where measured. As far as section width, the Kumho Section Width
numbers for a 225/50-15 on a 7" rim, match almost exactly to my 225/50-15's
which are mounted on 7" rims, inflated to 32 psi and are NOT on the car. The
section width will increase some when the tire is on the car, but that is to
be expected.
The above data does not give all the answers as far as tire fit, but
at least it's gives some clue. And remember, manufacturing tolerances may
make for some tires being wider, or narrower than the specs show. My MR2's
previous owner ran with Kumho 225/50-15's on the front. I bought some new,
shaved, 225/50-15's and put them on the front and they constantly rubbed the
strut tower. They seem slightly taller, probably because the old ones are
worn, but also the section width seems about .2" wider which took away all
the clearance. Luckily the rears are also 225/50-15's so I put the new ones
on the rear and got some 205/50-15's for the front.
> Or are these just the width of the "tread pattern", regardless of how
> much touches the ground? Is it the linear width (as measured with a
> ruler), or the circumferential width (as measured with a string which
> can round the corner)?
[Moore, John] I measured my Kumho's with a string. Don't know how
the charts creators got those numbers.
> Furthermore, that the tread width of a tire may be wider than another
> doesn't necessarily mean that the overall tire is wider at the widest
> point, which is what most people care about when they're concerned
> about rubbing.
[Moore, John] See the above section width numbers.
> Does anyone have any real-world measurements of these tires, or can
> anyone empirically determine what the tread widths on the spec sheets
> actually represent?
[Moore, John] All I tried to do was to give some information on the
differences that the manufacturers data shows in the tires. I don't
appreciate being basically flamed for simply answering someones question
with the information that I thought they where looking for. I just happenned
to have the charts printed and sitting on my desk handy when the question
came in. Since the original question mentioned that the Kumho's seemed about
1/2" wider and the Tread width data shows exactly that, the numbers where
provided.
John "Useless Information Collector" Moore
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