IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Here's an easy way to tell if your 40s steel is a 4" or 4-1/2".

If you lay a straight edge across the centre of the wheel and up against the outer rim, On the 4" wheel the end will sit just outside the rim. On the 4-1/2" wheel the end will sit just inside the edge of the rim.

4" wheel:


https://www.fordbarn.com/forum/attac...1&d=1748698051

4-1/2" wheel:
https://www.fordbarn.com/forum/attac...2&d=1748698051

A handy little tip especially when the tyres are still on!
Mart.

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Thanks

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Leave it to Mart to come up with easy shortcuts. Good find!

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

I just carry a small tape measure on my key ring. Mart's idea is good but not all wheels have the same back spacing.

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Now we just need a " magic" eye ball to see through the tires to inspect the beads while at the bone yard!

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Thanks my friend

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

Mart, I like the way you figure things out. Your next assignment is to make a small, portable gauge to tell if a swapmeet crank is 3 3/4" or 4" stroke. I've found exceptions to the clean out hole sizing ID.

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

I measure across the large counter weight.

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

It seems like any 16" rim would measure the same distance. That makes it look like there are two different diameter rims. I wouldn't want to put a 16" tire on a 15-inch rim.

Re: IDing 40s steels. 4" or 4-1/2" wide? Easy how to.
 

You're missing the point.

I'm not measuring any diameters. I'm showing the relative alignments of the rims against the centres. The 4-1/2" wheel is 1/2" wider, so sticks out 1/4" more than the 4". You can see the difference using a straight edge.