Tire Size Issues

For the record, a Q rated tire is rated at 160km/h max speed.
That’s my point. Why don’t they just print that on the sidewall?

yep I got your point. and you are right, I would not take the time to research it. what s wrong with keeping it simple?

I think the idea of indicating the width (in mm), the rim diameter (in inches) and the ratio between the two…is among the stupider ways of measuring anything. It’s like making one side of a football field yards, and the other rods, or something.

Tire sizing has been an evolutionary process.

Rim diameters have always been in English units - and despite numerous attempts at introducing metric rim diameters, it doesn’t appear that this will change.

The second problem is how to label a tire size so it is understandable. In the bias ply tire days, this could be accomplished with a single number - which not only gave the width of the tire, but the aspect ratio as well (embedded in the way the number was written).

Then there is the problem of changing from one sizing system to another. Eventually there will be a worldwide changeover, where all the tire standardizing organizations come to an agreement on how to do passenger car tires. I anticipate screams and moans when that happens, as a tire size will look completely different.

Oh and just a thought: Has anyone considered how nuts and bolts are sized?

Metric / English
Coarse thread/ Fine thread
Whitworth/American United
SAE grade/Mil spec

Same problem, different product.

And don’t forget the difference between screw threads and pipe threads. My tap box has lots of different sizes, some of which make no sense at all.

well, I do understand why bolts are complicated to a point. there are probably a million different applications for bolts. we could probably stand some standardizing of sizes, but the many uses justifies the differences.

tires go on rims…

I know that’s oversimplifying it, but still.

Oh and just a thought: Has anyone considered how nuts and bolts are sized?

Sizing a nut and bolt is a lot more complicated then a tire.

I understand the history…but it’s way more complicated then it has to be. There really is no reason for it except to confuse the average consumer. Which may have been the intent all along.

"The second problem is how to label a tire size so it is understandable."
LOL, interesting comment in light of the current issue under debate… {:smiley:

Whatever the evolutionary path was, it has resulted in a garbled system that mystifies the average buyer. IMHO that makes it more likely that laypeople and even teenage tire-busters will make mistakes. It does, however make it easy for less-than-scrupulous shops to put incorrect tires on if they don’t have the right ones without the buyer being aware. The buyer then drives away and writes us asking “what’s wrong with my car?”. Perhaps Mike is right. Perhaps it’s intentional.