Not sure I agree with this Chris. The width across the points you
describe will vary depending on various other factors, e.g. width of
rim it is fitted to ( I know there are recommended rims for any given
width of tyre, but the recommendatuion is usually a range of rim
sizes); pressure the tyre is run at and weight of vehicle.
The actual tread width is a fixed amount for any tyre size, and seems
to me to be more accurate.
Still, I'm being pedantic I guess!
I agree your version of the profile % calculation.
What we need is someone running a 205 tyre to go and measure it!
Guy
----- Original Message -----
From "Chris King" <cbking at alum.rpi.edu>
To: <spridgets@autox.team.net>; "Guy Weller"
<guy@weller-lakes.freeserve.co.uk>
Sent: 15 November 2002 13:23
Subject: Re: rubberized hieroglyphics
> A little of both - the description is a little off. If you imagine
cutting a tire in half across its diameter, you'll get a revolved "U"
shape. What the 205 measures is the maximum width of the "U". The
tread with can be fairly close to this (usually in low profile tires),
or a little narrower, due to the bulge that usually happens in the
middle of the "U".
> The 205 doesn't include the sidewall height (the sides of the "U"),
that is described by the "55". As stated below, it's a percentage of
the 205, so in this case 55% of 205 is 112.75mm.
>
> Hope I haven't confused you more!
>
> -=Chris
>
>
>
> Chris King - cbking@alum.rpi.edu
> http://mywebpages.comcast.net/kvcbk/
>
>
>
> ---------- Original Message ----------------------------------
> From: "Guy Weller" <guy@weller-lakes.freeserve.co.uk>
> Reply-To: "Guy Weller" <guy@weller-lakes.freeserve.co.uk>
> Date: Fri, 15 Nov 2002 08:10:13 -0000
>
> >I think that the description of the first number is wrong.
> >The example of 205 measures the tread width only, i.e. the width of
> >rubber that contacts the road and with no element of the tyre wall
> >height. 205 is about 8 inches and if you included the tyre wall
> >height in this, say 2 X 3 inches, it dosn't leave much width of
tyre
> >for the road does it?!
> >
> >Or have I misunderstood your description?
> >
> >Guy
> >
> >----- Original Message -----
> >From: "Bill Bryant" <bryant@sonic.net>
> >To: <spridgets@autox.team.net>
> >Sent: 15 November 2002 04:22
> >Subject: rubberized hieroglyphics
> >
> >
> >> Anyone with a little knowledge and a printed copy of this
> >> article, can decode the rubberized hieroglyphics on the side of
> >> tires!!
> >>
> >> The best way to understand tire markings is to take an
> >> example and break it down. We'll start with the most
> >> important numbers found on a sidewall.
> >>
> >> Take, for example, the numbers: 205/55R 16 89V
> >>
> >> 205.... The first number in this series, refers to the tire's
> >> section width, or distance from sidewall edge to sidewall edge
> >> (in millimeters) when measured up and over the tire's tread.
> >> Generally speaking, the larger this number is, the taller and/or
> >> wider the tire will be.
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