Okay tire experts what gives here???
 

Marty (SYBORGTT) stoped by my shop yesterday to say hi and check out the progress of my car. He asked me what the size was of my Michelin Pilots I showed him that they were 345-30-19's he tells me his KDW 335-30-18's are wider than my 345's NO WAY.. So he took one of my tire home and sent me these pictures . WHAT???. You would think thats my tire on the left its not. I'm confused here, I had Mike do a deep tub for me so I could run a wider tire and the ride hieght I want. My tire looks tinny next to this 335. Anyone have an explanation. Heck if you look at the second picture thats his 285 and its not much small than my 345:faint:

Look at the actual flat part of the tread. Its close to the same width. That's what's measured. Michelin might tell you their tires generate less heat in the sidewalls.

Are his tires mounted on a wheel and aired up?

Different manufactures have different sizes for the same tire size. 265/40/17 hoosier A6's are wider than 275/40/17 Nitto NT05's that are as wide as 295/40/17 HTRZ2's. Ran into this all the time selling tires, no 2 brands are exactly alike.

No unmounted

James I understand what your saying but to me this is a bite rediculous! Almost unexceptable..

Some tire manufacturers measure the treadwith at the actual treadwidth and others measure at the sidewall even though they sell them as the same size tire.

I got a set of cheap 255 50 17 for my Impala SS to replace the BF Goodrich tires (measured at treadwidth) the cheapies were measured from sidewall and looked god awful, and tiny. Learned that lesson. I always check now.

I've run both on my car, they both fit fine on a 12" rim. Mounting will suck in that bfg.

I have 335/30/19 NT05's
 

mounted on a 12.5 rim and I am about 14.00 at the sidewall bulge each side.

That is suprising though

I'm trying new tires on the '67 and close to the same thing.

Old - 325/30-19 have a 13.0" section width with 11.6" tread
New - 305/30-19 have a 12.3" section width with 12.1" tread

Different tires from different manufacturers have different shapes (i.e. shoulders, sidewalls, etc.) and can measure up differently. Also - section width sizes are based on mounted tires on the manufacturers specified rim size - it's really hard to see whats what with them unmounted. For what it's worth on the same width rim your tire should be a quarter inch wider at the sidewall with a half inch more tread.