Joe West
05-30-2005, 05:46 PM
------------------------------
Date: Wed, 27 Dec 2000 16:43:19 -0500
From: Joe Curran <espace@MIT.EDU>
Re: <VV> Wheel Backspacing
> I am planning a Corvair hauler, based on GMC Transmode rear airbag
> suspensions. To maximize the width between the airbags, I need wheels with
> a large offset. (I don't have hubs or wheels for the Transmode.) I don't
> recall from previous discussions which direction is "positive" and which is
> "negative." The direction I need is the direction that puts the wheel
> deeper into the wheelwell. I measured some early 70's Toronado wheels at
> a junkyard yesterday, and they have the desired offset, but a couple inches
> too much of it.
> Is there a wheel reference that includes the offset amount and direction?
Ryon,
You pointed out exactly why the term "offset" is pretty much useless.
The term you want is "backspacing", and is a measure of the distance from
the inside rim to the hub mouning plate. (See Bryan Blackwell's site,
http://www.geocities.com/MotorCity/9164/tires.html,
if you need a diagram). You should still know the wheel width, but
backspacing is much more intuitive.
What you want is a wheel with a lot of backspacing. Modern GM cars seem
to be headed in this direction. FWD cars tend to have lots of backspacing
(as a percentage of the total wheel width). Also the latest generation of
Camaros, among others.
Good luck,
- -Joe Curran
espace@mit.edu
'66 Corvair Monza coupe w/'67 110, '66 PG/3.55 posi diff
Gen II F-body wheels, 15x7", 3.75" backspacing.
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Date: Wed, 27 Dec 2000 16:43:19 -0500
From: Joe Curran <espace@MIT.EDU>
Re: <VV> Wheel Backspacing
> I am planning a Corvair hauler, based on GMC Transmode rear airbag
> suspensions. To maximize the width between the airbags, I need wheels with
> a large offset. (I don't have hubs or wheels for the Transmode.) I don't
> recall from previous discussions which direction is "positive" and which is
> "negative." The direction I need is the direction that puts the wheel
> deeper into the wheelwell. I measured some early 70's Toronado wheels at
> a junkyard yesterday, and they have the desired offset, but a couple inches
> too much of it.
> Is there a wheel reference that includes the offset amount and direction?
Ryon,
You pointed out exactly why the term "offset" is pretty much useless.
The term you want is "backspacing", and is a measure of the distance from
the inside rim to the hub mouning plate. (See Bryan Blackwell's site,
http://www.geocities.com/MotorCity/9164/tires.html,
if you need a diagram). You should still know the wheel width, but
backspacing is much more intuitive.
What you want is a wheel with a lot of backspacing. Modern GM cars seem
to be headed in this direction. FWD cars tend to have lots of backspacing
(as a percentage of the total wheel width). Also the latest generation of
Camaros, among others.
Good luck,
- -Joe Curran
espace@mit.edu
'66 Corvair Monza coupe w/'67 110, '66 PG/3.55 posi diff
Gen II F-body wheels, 15x7", 3.75" backspacing.
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