Wheel fitment and wheel basics!

[Radim]

http://www.willtheyfit.com/

Gives you an idea of how your new wheels and tires will look over stock.

 

http://tyrestretch.com/

Pictures of stretched tires on different sized wheel.

 

 

How to measure a wheel width correctly... Bead to Bead.

Wheel Below is 5" Wide bead to bead which means it's.... drum roll...... FIVE INCHES WIDE!

 

 

 

 

 

 

 

How to measure Backspacking/Offset Correctly... Place a flat object that fits ontop of the wheel straight across and measure from the backpad (Where it mounts to the hub) to the nearest part of whatever you used.

 

 

 

 

 

 

 

Backspace to Offset conversion

 

 

 

 

 

How to properly torque your lug nuts

 

 

 

 

 

And finally how to measure lug pattern... use inches or mm and convert either or to what you want.

 

 

 

Three basic types of lug nuts, FIY you CANNOT Interchange lugnuts between seats... unless you want your wheels to fall off.

 

[Radiant-Designer]

Any Idea what the original wheel offset is? I am not sure what the 620's backspacing is for stock tires.

[Radiant-Designer]

Ok, so my trying to figure out my backspacing for my 7" wide 15" diameter wheel has 3" to the inside of where it mounts....

 

I'm guessing its about -25

 

Any clue what the standard wheel backspacing is? I'm hoping to find wheels that may have these work on my 620, hope without spacers too.

[Radiant-Designer]

.... Unless its 21... Lol I think that's what's written on the inside of the wheel. Guess u should have looked harder, still need to find a stock wheel to compare to.

[Dime Dave]

Offset is the distance the hub surface is from the centerline of the wheel. Positive offset wheels have the hub face outboard of the centerline of the wheel; with negative offset, the hub face is inboard of the wheel centerline.

 

A reasonably close offset can be calculated if you have measured the backspace. Here is how you calculate offset knowing the backspacing. (this was the method used in the table above)

 

Formula = (Rim width + 1") divided by 2; take that number and subtract it from the measured backspace in inches and the results is your offset in inches. Multiply it by 25.4 and you have the offset in millimeters.

 

Example using your wheel.

Rim width is 7", Back Space is 3"

 

(7" +1")/2 = 4"; B/S = 3"-4"= -1"; -1"*25.4 = negative 25.4mm offset

 

The above is an approximation based on most wheels having an out to out width 1" wider that their stated bead to bead width. To accurately figure the offset you need to measure the wheel out to out and use that dimension instead of the (Rim width + 1") in the formula above.

 

A VTO 15x7 wheel measures 7.92" out to out not 8" as estimated. This throws the calculated offset off by 1mm (.039"), generally not enough to create a problem.

[Radiant-Designer]

I think the 21 is more likely the correct one, when I measured I measured the the back of where the hub meets the wheel, the part where the lugs go through is very thick so if i measured to the front of that (what faces out) then it should be about 21.

 

Guess I am going to have to find a stock rim and measure the backspace on that one to compare. I jsut dont want to buy tires to realize they rub or just wont fit.

[Rhapakatui]

I have a few different sets of rims at this point. All but one are second hand and did not come with lug nuts. I was wondering if there is an easy way to measure the wheel to be sure and match it with the correct lug nuts. Thought maybe the wheel gurus would have some advice for those of us who are less savvy to the intricacies of lug bolt threads and lug seats of varying degrees.

[Tristin]

Lug threads are based on vehicle and not on rim... Most rims will accomodate any studs and the difference is only in thread pitch...not stud size.

[Alex Datsun]

Um might be a funny question but isnt this stickied?

[Rhapakatui]

What about various lug nut types? Aren't there differences in the seats of say, a stock steel wheel and an aftermarket alloy wheel? Or, are they all pretty much a 60 degree bevel on the lug seat?

 

Would one be able to safely change between various style rims using the same lug nuts? I know mags use a different style lug nut, but are the rest standardized?

[Tristin]

Ive seen various degree lugs before but would say that any would work if the rims took acorn style lugs. The big difference between lug style would be shank, acorn (not sure what the official term is), and flat... Just look at your lugnut seating area and you should be able to tell which you require.

[q-tip]

Dont get the acorn style mixed up with a taper style. The acorn style is rounded on the mating surface and the tapers are a straight face on an angle

[Lee R]

There will still be new daily threads of "will these wheels fit?" :)