>Actually they are 5.5" wide wheels.
>Could they have a 120mm backspace and the 12 in there also means 12mm
offset?
'S'not possible (mathematically). A 5.5" wide wheel with 122mm backspace
would have a 40mm negative offset (that is, centerline offset 40mm towards
the car).
IOW, *that* particular combination is obviously possible -- what's'not
possible is to have a 5.5" wheel with 122mm backspace AND a 12mm offset.
Think about it: if the nominal width of the wheel is 5.5", then the
measured width of the wheel c/b 6.5" including the lip; if the backspace is
~4.75", then the centerline is clearly well over 12mm towards the car (12mm
is 1/2"). Actual negative offset would be on the order of 1" more, or
1-1'2".
Reasonable minds can disagree about whether the correct way to measure
backspace is from the rim edge or from the bead edge (which would net a
somewhat smaller backspace) but it wouldn't account for the difference.
Personally I'd go with your backspace measurement as being the correct one!
Backspace is a much more useful measurement for buying and discussing
wheels, 'cause it's almost always a negative number and so there's a lot
less confusion; and because usually what we're most concerned with is --
will it clear the suspension, and then will the wheel width clear the
fenderwells? (and offset doesn't really say much about that).
Richard Nichols
rnichol1@san.rr.com
San Diego, California, USA
86 Mustang SVO-1C: SM Class Autox
Team SVO -- "Bred to race, not show"
SVOCA Member
1972 Ford Pinto Sedan -3J (Original Owner - Restored)
On display at the San Diego Automotive Museum
12 June 1999 through 31 January 2000
-----Original Message-----
From: Robert & Katherine Seamon <forestg@ionet.net>
To: richard nichols <rnichol1@san.rr.com>
Date: Tuesday, June 01, 1999 7:37 AM
Subject: Re: Wheel Backspace measurement and NeOkla Region Thanks
>Actually they are 5.5" wide wheels.
>Could they have a 120mm backspace and the 12 in there also means 12mm
>offset?
>
>Thanks
>Rob Seamon
>
>
>-----Original Message-----
>From: richard nichols <rnichol1@san.rr.com>
>To: Robert & Katherine Seamon <forestg@ionet.net>; team net
><autox@autox.team.net>
>Date: Tuesday, June 01, 1999 7:57 AM
>Subject: Re: Wheel Backspace measurement and NeOkla Region Thanks
>
>
>>>I just measured the backspace on my Ford Escort GT 15" wheels and it came
>>>out to 120mm.(There was a circled 12 stamped on the inside of the wheel
>>>which seems to back up the 12cm measurement.)
>>>That seems really high to me. Can this be right?
>>
>>
>>In my experience, that stamped number is offset, not backspacing. I
expect
>>you have 7.5" wide wheels, if you have 120mm (4.75") backspace and 12mm of
>>negative offset; or 9.5" wide wheels (unlikely on an Escort, yes?) if you
>>have 120 mm backspace and 12 mm of positive offset.
>>
>>Anyhoo, if you've measured 120mm of offset, then of course it "can be
>right"
>>:) At 4.75" backspace, you've got a dimension that's not uncommon on
>>Mustangs, for example (and is the backspace I'm currently running on my
>>SVO -- its stock backspace is 5.75").
>>
>>I ran 110mm backspace on my Pinto, using Enkeis off a 4-lug Mustang in
>16x7,
>>which wheels were stamped with an offset of 7mm (negative). Fit very
>>nicely, and handled very well (first in class at one event -- now it's
>>headed for a museum -- today, in fact).
>>
>>Hope that helps!
>>
>>Richard Nichols
>>rnichol1@san.rr.com
>>San Diego, California, USA
>>
>>86 Mustang SVO-1C: SM Class Autox
>>Team SVO -- "Bred to race, not show"
>>SVOCA Member
>>
>>1972 Ford Pinto Sedan -3J (Original Owner - Restored)
>>On display at the San Diego Automotive Museum
>>12 June 1999 through 31 January 2000
>>
>>
>>
>
>
|