Am I correct in saying that adding a 7mm spacer to wheels with a positive offset of 62 makes the new equivalent offset 55 MM ? While this seems counterintuitive to me, adding a number to make a number smaller, everything I've read on the subject of wheel offset tells me my math is correct. Can someone confirm this for me ?

 

found this to be a little fun/help/interesting

http://www.1010tires.com/WheelOffsetCalculator.asp

disclaimer: unsure of accuracy

 

no. adding a 7 mm spacer to a +62 makes the offset +69.

you're pushing the wheel away from the car via the use of the spacer. thus, making the offset more positive.

 

Nope. Adding the spacer makes the offset more negative. The new offset will be +55.

 

CORRECT. Offset is the distance from the face of the hub to the centerline of the rim, which is towards the center of the car (look at how much of your wheel rims is inside the hub face). Therefore, a spacer pushes the whole wheel, and therefore the centerline of the rim, out further, thereby decreasing the offset from the (fixed) hub face.

 

the less the number the greater the wheel sticks out. So a 62mm offset wheel with a 7mm spacer will be like a 55mm offset wheel for our cars.

 

+55 offset

 

You might want to take a look at the thread below.

We have been going around in circles with the same issue.

It makes no sense to me that when one adds distance from the hub it's a "negative" direction but that's what the wizards are saying.

From some of what I have found a distance towrds the centerline of the vehicle is negative; away from the center line is positive.

Go figure!

See: https://www.6speedonline.com/forums/...43-design.html

 

OK, then simply express factory offsets as negative numbers. On narrow body 997, the offsets would be -57 and -67mm front and rear. Adding spacer widths to the negative numbers gives you lower negative numbers.

 

you don't change wheel offset by adding a spacer...wheel offset is measured from the inside wheel flange to the wheel centerline not from the hub to the wheel center...adding a spacer moves the wheel center but does not change the offset...the wheel offset is a fixed measurement...adding a 7mm spacer would give you the same wheel centerline as a 14mm wider wheel with the same offset....see below

https://www.rsracing.com/tech-wheel.html#backspace

 

The lower the offset, the further OUT of the car a wheel sticks. Adding spacers lowers your offset by the the spacer thickness.

 

we are talking semantics here Damon...you haven't really changed the wheel offset you have effectively moved the wheel out giving the same appearance as a wheel with a lower offset...problem is, with a spacer you have moved the wheel centerline and may effect the handling

 

This finally makes sense!

VSE Chuck if you change the positioning of the wheel's centerline you have effectively changed the offset otherwise the offset would be a fixed amount.

 

Sorry, but adding a spacer DOES change the "effective" offset of the wheel. In the aforementioned case, adding a 7mm spacer to a +62 wheel effectively changes the offset to +55 (more NEGATIVE). I know its hard to wrap your brain around but that's how the wheel industry expresses these measurements.

 

Thank you! One minor correction, the spacer made the offset LESS NEGATIVE, not MORE.
Let's move on folks, and try to avoid the semantics. It isn't rocket science, just simple addition of negative and positive numbers. Any more of this discussion may cause me to go and shoot myself.