Why are Wheels Measured in Inches???

[DefyInertia]

Silly question but...

Whether it be bikes or cars....American, German, or Japanese - wheels are all measured in inches! What's up with that? Why not mm or cm?

 

[FZTofer]

People That Look Like This ----> :tard: made the system up :thumbup: lol

 

[aussiejules]

Would it be because the first production car was made in the USA so it may have been the first time it held any relivance.

 

[shaggystyle]

Let's make it even more confusing.....what about tire size, which is measured in both systems?

180/55R17
(mm)/(%)R(inches)

Two different units of measure to describe the size of a tire? Crazy!


As for an answer? No clue, probably just stubborn engineers that didn't want to change.

 

[Fred]

It's because we stopped using cubits in 1300 AD.

Tires used to be all inch sizes. For instance, my BMW airhead used the following.
Front: 3.25 x 19"
Rear: 4 x 18"

Converting to the metric system is a good thing. As to why they didn't alter the rim size? I'm guessing that it just didn't make sense to call a tire a 100/90R335.6 when you could say 100/90R14

Fred

 

[Oscar54]

Cuz its Emurrica man!:thumbup:

 

[necrotimus]

Because inches rule!!! i dunno?? why do they measure horses in hands?

 

[Oscar54]

Because inches rule!!! i dunno?? why do they measure horses in hands?

Excellent point Mr. Necrotimus! Now I will ponder why beer comes in 12 OZ bottles and tastes so good after work!:iconbeer:

 

[DefyInertia]

Let's make it even more confusing.....what about tire size, which is measured in both systems?

180/55R17
(mm)/(%)R(inches)

Two different units of measure to describe the size of a tire? Crazy!

Well, not really.

The 17 makes reference to the size of the wheel the tire will fit on. They measure tires in mm but they are made to fit wheels measured in inches.

Cuz its Emurrica man!:thumbup:

I'm talking about the fact that this is the case all over the world. Anyone out there meausre wheels in something other than inches in their home country?

 

[Oscar54]

Well, I must plead ignorance about wheel measures in other countries. So if this is universal nomenclature it must be because more tires are sold in the US. And it is something the trade standards committees they have for everything these days agreed on?

So, Emmurica wins again! Yesssss!

If I remember correctly, didn't the first number for the tire width use to be in inches too. Like 5.50 X 14? Maybe when they came out with the "Radial" tire concept instead of the old "Bias" ply is when they started with the mm widths and ratio sidewall measures and listing as 225/65-15?

Just a SWAG!

 

[CrazyBiker]

metric FTW ..

 

[ozzieboy]

Oz uses the metric system for most things but rims are in inches. Dunno why this should be except that it sounds right-er that way...lol.:rockon:
Cheers
Mike

 

[steveindenmark]

Ok being a sailmaker.

Why are yachts measured in feet?

When sails are measure in square metres.

Steve

 

[necrotimus]

If the speed limit is 60 mph aren't you following the speed limit if you do 120 for 30 minutes then stop for 30 minutes?

IN YOUR FACE JUSTICE SYSTEM!! :Flip:

 

[Shafe716]

Because inches rule!!! i dunno?? why do they measure horses in hands?

Inches do rule... that's why it's called a RULER:spank::spank:

 

[grommit]

There was an attempt in the late 70s and early 80s to use millimetric rim sizes. So rather than just quote them in mm they changed the sizes. It of course failed as nobody had spares tyres when you got a puncture and people did not understand them and hate change. You can still buy them thou.

If anybody owned a MiniMetro you would have had such wheels and tyres.


Some references...


Millimetric Michelin Radial Tyres

SAAB TRX Wheels

 

[04fizzer]

You know I never thought of it... and tires are in mm... duh know why?


Hmmm.

Not all tires are measured in metric. My truck runs 31x10.5x15's.

 

[OZXJR]

Winter sure brings out the BIG questions don't it

 

[SirIsaac]

How about considering the wheel measurement to be a size (like shoe size) which is not necessarily a dimension. That way our metricated friends won't be forced to use inches. (Just try not to think about why the difference between "sizes" is 25.4 millimeters.)