Tim Pettenati writes >
>I am looking to upgrade the wheels on my J-H. I would like to change from the
>stock 13" rims to 14" or 15" rims. The bolt pattern is 4 X 4". Do you know
>of any other car that would have a 14" or 15" rim in a 4 X 4" pattern?
The bolt pattern is MG Midget. Since this is a British car, the offset may be
the same. Other cars that used this pattern include the Chevrolet Monza and
companion Sunbird, etc. (rear drive cars) I don't know of any 14" or 15" rims,
but I am no expert. Why do you want a larger diameter wheel?
>I don't know the offset .... but
>don't think it is that important as long as the wheels come off a rear drive
>car.
Bzzt. I put a set of wheels on the Midget that had a different offset and they
required serious flares to fit. The British rear drive cars tend to have
offsets more like a front drive car than like a rear drive Yank car.
>and I'm really not sure how to measure it,
The right way is to measure from the inside of the rim, where the tire meets
the metal. This is difficult if there is a tire mounted on the wheel.
It is easier, and damned near as accurate, to measure from the outside of the
rim. If the tire is on a symmetrical casing, as most are, you can measure
from the outside of the tire using a flat floor and a carpenter's square.
Remember, the offset is defined as the distance between the hub face of the
wheel (the plane where it touches the car) and the center of the wheel (the
plane halfway between the insides of the rim).
Flop the wheel-tire on a flat floor, outside down.
Use a straightedge accross the top and a ruler to measure the total section
width of the tire (this is your rim width plus two tire bulges). Take half of
that and write it down (this is half the rim width plus one tire bulge).
Now measure from the straightedge down to the hub face of the wheel (this
distance is your backspace plus one tire bulge.)
offset = backspace - (rim width / 2) so it follows that
offset = (backspace + tire bulge) - ((rim width / 2) + tire bulge)
as long as the tire is symmetrical so the tire bulges are equal.
If you suspect that your tire is asymmetrical, you can measure the drop to the
rim from a straightedge on each side.
backspace
|<- ^ ->|
->| |<- offset
|<-rim width ->|
| ||
|| (outside of rim to right)
| ||
__________||_
/ ___________ \
/ / | \ \
|/ \ |
|| | ||
^ ^ ^
rim center rim
line
I *think* that the type of wheel shown (wherein the backspace is more than half
the rim width) is most common and that this it called POSITIVE offset, but I
keep getting confused on that.
>I've heard that minilite is back in
>business or someone is building "minilite" style wheels for $99 each.
Select Sales
FL
305-888-2828
the new Minilite wheels
>Any other company that can supply or build
>unusual size wheels for $150 or less?
Darryl Seefeldt
Sierra Pacific Racing
Lodi, CA
209-369-8546
7.3 lb 3-piece wheels, ~$135
I think that Sierra Pacific is the outfit that made the wheels for autox list
netter Bob Fogt's Renault. You can call or Email Bob on this. He does not
check his mail real frequently, so don't be surprised at a slow Email
response.
Bob Fogt
bobf@pnet51.orb.mn.org
612-454-9199
Phil Ethier, THE RIGHT LINE, 672 Orleans Street, Saint Paul, MN 55107-2676
h (612) 224-3105 lotus@pnet51.orb.mn.org (infrequent mail checks)
w (612) 298-5324 phile@pwcs.stpaul.gov (lists go here)
"The workingman's GT-40" - Anthony Colin Bruce Chapman
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