michelin has some "splaining" to do

-
R

rustycowll69

Well-Known Member
Joined
Feb 19, 2016
Messages
2,747
Reaction score
1,475
Location
Pacific northwest
just bought new Michelin to replace my goodyear RSA's. Exact same size, 225x60R16. I noticed when I got home, the new tires didn't look as wide as the old ones used to. So I measured them, and it looks like the Michelin are about 1/2 " narrower. What gives?
 
Where did you measure? Tread to tread wont be the same.

EDUtire_dimensions_section-width.png
 
yes, inside edge of tread to outside edge of tread. I haven't grabbed my calipers to check sidewall to sidewall, but I'm pretty sure it will be similar, because I could visually see the tires are less wide
 
That is the way the cookie crumbles with metric rounding.
A 225 is only a 225 when mounted on a 70% rim and inflated IIRC to 35psi ..... and it's a sidewall section spec, and is rounded to the nearest 5mm on the 5s. So 70% of 225 dictates a measuring rim of 157.5mm or 6.2 inches. which rounds to a 6" rim. The tread width is supposed to be, in your case 60% of that 225 or 5.3 inches
But here's the deal, that 225 could be as little as 220 or as much as 230 and still be rounded to 225. and that makes the tires tread vary by 60% of those 10mm or from 5.19 to 5.43, strictly by the math. This however only indicates a treadwidth variance of .24

If you install a 225 on a different width rim than the 70 percenter, then the section width changes. And if you then math the tread from the new section width then the profile maths out differently as well.

And molds are a whole different animal. Some manufacturers roll the sidewalls up early and others add some rubber on the edges. This could easily account for another .26 to equal your estimated 1/2" difference.
Of course anything over 3/8 inch can be rounded to "about 1/2 inch", soooo then there's that too,lol.

But I do understand your perturbation,lol, unh,perturbement?, unh, well you know. Not dismay, not concern, not confusion,not ......brainfart; can't think of the word.......
 
Last edited:
I measured the sidewall width and the old Goodyears were 9-1/4"wide, new Michelins 9" wide. Both sets of wheels are KelseyHayes 16"x7" steel cop car rims, so that is a constant. Interestingly, I have a set of old Michelin AquaTreds? (or equivalent), mounted on another cop car, and they have similar measurements, but "LOOK" much wider, and more aggressive because of the tread design, I guess.
 
Tire makers never have made tire sizes the same across the board. Michelin ain't gonna splain nuthin. That's how it's always been. Even with alpha numeric sizing.
 
tread measures "about" 7-1/2" on new Michelins, "about" 8" on old Goodyears. I deliberately tried not to conveniently round for effect, hahaha.
 
AJ- I've never heard "math" used as a verb.

...but now I'm gonna start using it :)
 
RustyRatRod said:
Tire makers never have made tire sizes the same across the board. Michelin ain't gonna splain nuthin. That's how it's always been. Even with alpha numeric sizing.
Click to expand...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^see above
just the diff. between manufacturers , nothing u can do about .
 
It’s not even that uncommon for a particular size of tire to have different tread and section width measurements even from one model of tire to another, even with the same manufacturer.

Manufacturer to manufacturer specs can be quite different for a particular published size.
 
I just replaced the Goodyear Wrangler SRA HT on the pickup with a new set and they look smaller. Shrinking candy bar trick that costs more every time you buy.
 
mderoy340 said:
I just replaced the Goodyear Wrangler SRA HT on the pickup with a new set and they look smaller. Shrinking candy bar trick that costs more every time you buy.
Click to expand...
hahaha
my wife bought a bunch of Colgate toothpaste, all wrapped up together in a pack of four, Costco-like. I opened one of the "family size" boxes the other day, and I broke out laughing. The tube inside was like only 60% as big as the box. So now I've got to remember how many ounces are in a normal tube, to keep from being cheated. Where does it end?
 
Last edited:
Was it a couple years a go the Fed govn't MADE China get their tire sizing chit together. (somewhat?)) Ever see a US and china farm tractor tires side by side before the gov stepped in// Blind man cold see the difference. may still be a difference. Now of all tires come from China, them their small on a set of four works!!???? All 4 the same smaller size but who really notices>> LOL such BS we endure!!????
 
Its worse in tractor tires, since some of the tires are larger the percent difference is even bigger, it all comes down to the manufacturer, the molds and tread depth.
 
You must log in or register to reply here.
-

Back
Top