Seth
Whoops, typo - you are correct, the conversion is 2.54cm (not mm) per inch.
The offset is 10mm, not cm. This is the offset, not backspacing. Wheels are,
or at least were, measured by offset, not backspacing. When changing wheels,
you want to maintain the same offset so that you do not change suspension
geometry. So, when you change to an 8" wheel, maintain the offset and you will
get 1/2" more inside and 1/2" more outside. Watch your tire clearances! But,
why go to an 8" wheel when the 7" will take a tire several sizes larger than
original?
I measured front and back spacing (to compute offset) on both wheels. Note that
these are to the 1/4", so measurements are not exact to the mm. Also note that
I measured to the rim, not the bead seat (as would be correct), but since we are
going to subtract, it makes no difference in computing the offset.
Original wheel
front 3 1/4"
back 4 1/2"
offset = 4.5 - 3.25 = 1.25 then div by 2 = .625" (5/8") = 15.875mm
Compomotive wheel
front 3 3/4"
back 4 1/4"
offset = 4.25 - 3.75 = .5 then div by 2 = .25" (1/4") = 6.35mm
note that the wheel is nominally 10mm, so that tells you how (in)accurate these
measurements are
So, there is .625 - .25 = .375" (3/8") difference in my wheels from the
original. You can not tell this difference visually, so, no my tires do not
stick out. Even the 4" backspacing you mention is not that different from the 4
1/2" of the original wheel and would not cause the tires to stick out.
Another very important thing to consider when buying new wheels: The original
wheels are centered by the lug nuts, not the hub. This, and the poor quality,
are why the original wheels are hard to keep balanced and ride poorly. Buy a
wheel that centers on the hub - most quality wheels do. I had to take a wire
brush to the brake hubs to clean off the rust to get the new wheels to go on the
hubs. This does not take long, but don't think your new wheels don't fit the
hubs because of a little rust.
Mike
#2039 - original owner
> I'm assuming you meant 10cm (2.54cm per inch). With only a 10 cm backspacing
> which is just shy of 4", don't your tires stick out of the wheel wells?
>
> Seth
> #1544
>
>
> On 11/8/01, at 5:21 PM, Mike and Candy Joehrendt <Joehrend@bellsouth.net>
wrote:
>
>
> >I ordered :
> >15x7 wheel
> >10mm offset (2.54mm per inch)
> >5 on 4.5" bolt pattern
> >72mm centerbore
///
/// bricklin@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
///
|