How can I determine the width of a wheel with a tire already mounted?

[Old Mopar Guy]

I suppose I can consider the width of each side of the tire outside of the wheel, add them together and subtract that from the overall width of the tire. Then figure the back spacing and compare those two numbers to the manufacturers listing to see which numbers come close. Any thoughts? Seller has no idea. The tire btw is a MT 305 45r 18 on a Weld S77. Seller stated they came off a ‘15 HC Charger. Thanks.

 

[SilverBillet]

Most tire shops have a caliper like tool that can tell the rim width

 

[BULL]

Most wheels are stamped on the inside of the barrel with their size

 

[Stormtrooper1320]

Since you say it's an 18 inch rim, cut a 2x4 or other suitable size piece of wood to 18 inches. Lay the rim assembly flat on the ground. Lay the piece of wood across the rim. Using a tape measure or something else suitable, measure from the rim face at the center hub up to where it it intersects the wood. Flip the rim over and do the same from the other side. The you just need to add the hub thickness measurement to the other 2 measurements.

And Bob's your uncle.

Welds come with different thicknesses of center hub.

 

[Old Mopar Guy]

Thanks @Stormtrooper1320 Ill ask if the numbers are stamped inside as Bull suggested otherwise great suggestion. Thanks.

 

[SilverBillet]

We

Thanks @Stormtrooper1320 Ill ask if the numbers are stamped inside as Bull suggested otherwise great suggestion. Thanks.

The only drawback is you have to remove the tire to find the stamped numbers

 

[Jimmy N.]

We

The only drawback is you have to remove the tire to find the stamped numbers

The wheel from the vehicle, maybe, but not the tire from the wheel.

 

[Old Mopar Guy]

I remember my OEM HC wheels had that data stamped on the inside of the barrel, I don’t know about the Welds.

 

[Magnified]

So this person ran 305 on stock narrow body charger hellcat wheels, took them off and it mounted the tires on a rim of unknown width?

 

[Old Mopar Guy]

^ No, the tire/wherl assembly came off of a 15 Charger. They are selling the assembly but dont know the size of the wheel. Allegedly original owner of tires and wheels but cant find receipt.

 

[Jimmy N.]

A tape measure should be good enough for getting within 0.25".

 

[Old Mopar Guy]

@Jimmy N. yup. That should get me close enough to figure it out after determining the back space and just checking Welds website.

 

[SilverBillet]

We

The only drawback is you have to remove the tire to find the stamped numbers

The comment was regarding finding the stamped wheel size on the rim. If the rim is stamped on the inside (not the barrel part) where it usually is, you have to dismount the tire from the rim to see it.