Hi Tom,
I read your commentary with great pleasure. You made some good points.
First, let me preface this with my R&D? :-)) being oriented toward the 15"
wheel.
Your question regarding the "frontal measurement" is a good one. If we have a
7" rim, for example, and the backspace is 4.5", then the "frontal" is 2.5"
(4.5+2.5=7). This given (with the rim diameter = 15") we know where the front
lip of the rim is and can determine if there will be any interference, I built
a model of the dimentions on my hub. (I found with this combination,
interference came from the tie rod ends scuffing on the inside of the wheel
rim when the suspension was unweighted and at full lock, but not a problem in
service.)
Remember that, in my R&D, I was considering the 7"x15" wheel with a 4.5
backspace and use of a 205x50-15" tire. For this application there was
clearance. BUT, my car is lowered in front and has 1.5 degrees of negative
camber, all of which affects body interference. Also know my Tiger has a
>very< small amount of valence rolled up so the shoulder of the tires clear as
the front wheels are turning. Some people run 16" wheels but I don't know how
they do it. I spent about three weeks taking measurements 20 ways to Sunday
and couldn't make it work.
In today's market place we are blessed with on-line information. When I did
my R&D I got the specs on wheels & tires, built a model representing the
inside of the rim, the inside shoulder of the wheel and went from there.
If you are looking for maximum rubber on the road them you may consider this
approach. Otherwise there are vendors who have done the R&D for you and would
be glad to make recommendations.
Hope this info helps.
Darrell
Date: Wed, 16 Mar 2005 10:47:51 -0600
From: "Tony Someone" <tonythetiger@onecliq.net>
Subject: Re: offset vs. backspace
We could get into tire specs, which would be the missing link to actually
determining if a wheel/tire combination would fit the space we have
available
in our wheel arches, but that's another story...
Darrell
Hi Men and Ladies too-
Much talk about offset, negative and positive etc etc. I always use the"lay
wheel on its face, lay straight edge across back of wheel and the distance
between the line created by the srraight edge and the measurement I read from
it to the mating surface of the inside or back side of the wheel"- then I know
if it will work BUT some wheels have an offset(wrong word but we are now
educated in its meaning) that may work on a Tiger but it has a frontal
measurement that makes it hit the wheel wells unless the car has flares et.
IF someone on the LIST has the measurements of
the extreme ammount allowed on front and back, then he/she will have sent
the best information available for someone looking at used wheels or odering
a wheel for a Capri ,as an example, because Sunbeam isnt listed. Perhaps
telling a wheel salesperson the wheels you want fit a Mustang2 but you need
X ammount of offset etc, so they will fit your car. In Ca. there are tons of
places to buy or order from, in pahrump or n Benton, there are only a few
car dealers and a junk yard or two, so an actual "acceptable wheel size"
chart would be handy to have in my Tiger folder. Thanks for lisitening to my
weak mind pushing my arthretic fingers across the keyboard and have a
wonderful hump day. warmest regards, Tony the Tiger
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