wheel measurements

[capri_fandango]

is it possible for someone to get the distance from the back of the rim up to the back of where the wheel bolts to the hub?

[Cappn Tripps]

what wheel? thats the backspacing, BTW..

[capri_fandango]

on a tenhole

i don't think backspacing is what im talking about because i though backspacing was 22mm

I want the distance from the lip of the wheel that is towards the car to the back of the bolt holes

[madmike8]

I think it's backspacing... isn't the 22mm measurement the offset? Then again.. I could have it backwards...

[capri_fandango]

maybe thats it...

whats the backspacing then?
I'm looking to design some rims and need some measurements

[Cappn Tripps]

I think it's 5.5in. ... off hand ...

BTW, offset is how far the mounting surface is moved from the center of the wheel.. so a 22mm offset might be right.. that would be from the center of the wheel..

[capri_fandango]

thanks for the help guys

if someone ahs a for sure on the backspacing that would be great!

[PNY XPRS]

from the Wheel offset FAQ at the Corral.com forums.
http://www.corral.net/forums/showthread.php?s=724a36924ef3a508a76db82b292d7666&threadid=230709


http://www.discounttiredirect.com/images/wheel.offset.gif
The offset of a wheel is what locates the tire and wheel assembly in relation to the suspension. More specifically, it is the measured distance between the hub mounting surface and the center line of the rim. Below is an explanation of the various types of offsets which are pictured in the above graphic.

Positive Offset
A positive offset occurs when the hub mounting surface is on the street side (the side you see) of the center line of the rim. Most factory rims will have this type of offset.

Zero Offset
When the hub mounting surface is centered within the rim, it is known as a zero offset.

Negative Offset
If the hub mounting surface is on the brake side of the center line of the rim, it is considered a negative offset or "deep dish".

[telco]

If you know your offset and the rim width you can calculate the backspacing. Just convert the offset to inches, measure the rim (if you don't know the width) divide this by 2 and add the offset if it's positive.

[capri_fandango]

thanks

so then if i go with a wider wheel then the offset has to change so that the backspacing is the same, right?

like if the 10 holes are a 7" wide wheel(?) and a backspacing of 5.5 then a 8" wide rim will still need to have a 5.5" backspacing but a different offset?

[madmike8]

I'm kinda curious... What width rim do you want to use?

At one time I had bought some el-cheapo wooden Yard sticks, and used them to make a slide rule that attached to the wheel hub... I used it to measure the wheel well clearances for making a rim choices...

I don't think I can describe it well enough... but if you want I maybe able to draw it... Heck I might make another and just take a pic..

Basically you get a piece of wood and make it attach to the wheel hub.. I think I used an old universal wheel spacer as a template... Then cut up one yard stick to make spacers for the other yard sticks to slide thru...
Use one yard stick to measure wheel/tire radius and one to measure width... I think the best one I made used 1 Yard stick glued along another Yard stick in a T beam style to stiffen it... I used that to measure the radius... I then made up the width slide that attached to the end of it... I cut the width one down to where I could measure either 8" forward or back by sliding it... By doing that way I could spin it over to see if it contacted anything... It's also good for checking clearances with the fronts turned to full lock...

[capri_fandango]

i looking to make a 8" rim but ive got no reference because my car just has steelies

[telco]

I'm looking in the "Mustang Performance Handbook 2" and it says that you can mount a 255 tire with a max diameter 24.5 on a 8" rim with a 3/4" negative offset on the front. This translated to a 4.75" backspacing (which is the measurement from the outside lip of the rim to the axle mounting face). This book has allot of info about tires, supension, brakes and ust about anyting you want to know for road, cone or drag racing. Well worth the price.

[capri_fandango]

thanks for the help

much appreciated