After over 40 years of the decimal/metric system why are wheels and tyres still manufactured in Imperial sizes? I know that there were/are metric sizes but these are few and are between.
franc123,
Feb 11, 3:38am
MIXING the size systems is the bizarre bit, expressing rim diameter and width in inches is one thing, but changing the tyre width to mm is plain strange, this seemed to roughly coincide with radial tyres coming out and seems to be an indirect way of distinguishing these from old full imperial crossplys, in addition to using an R in the tyre code. It smacks of an American or English attitude of "why should we change, this is how we have always done it" or maybe the tyre manufacturers simply didn't view the cost of changing machinery to accommodate metric sizes as being good use of finance, and its simply stayed that way.
poppy62,
Feb 11, 3:49am
I was thinking that USA/UK collaboration too but then as tyres have changed surely the need to replace manufacturing machinery (worn out) should have coincided with a uniform wheel/tyre industry. Also surely the Giant Michelin, Pirelli, Bridgestone, Hankook etc., companies aren't going to be swayed by the US/UK stance. Strange why this anomaly exists.
franc123,
Feb 11, 4:01am
It may have (or may still be) a compulsory thing in the States to express tyre sizes in that fashion, remember they have all sorts of weird regulations and standards about all aspects of vehicle design laid out by DOT. Brit and Euro manufacturers trying to sell cars there got caught out several times with headlight types and configurations, emission rules and even things like pedestrian impact safety and how high bumpers could be off the ground. You couldn't use styled headlights with bulbs for example, they had to be dual sealed beams, you would have seen US market Benz W116's and Volvo 200's so equipped, Citroen couldn't use the steered headlights on the DS etc etc.
supernova2,
Feb 11, 4:04am
Don't forget some Renaults are on true metric rims and didn't Jag go that way as well at one stage. There are bound to be others on metric rims. However I do agree = why? It not like all cars are still on 155R13s any more, so surely as new models came out it wouldn't have been hard to switch to total metric.
morrisman1,
Feb 11, 4:14am
Almost as bad as aviation.
distance in Nautical Miles, speed in knots cloud height in feet, visibility in metres pressure in millibars, altitude in feet Runways measured in metres Fill up with litres, but fuel gauge reads gallons Time based off UTC, not local time
Makes tyres seem simple.
poppy62,
Feb 11, 4:20am
Am I right in saying that the UK use the metric system and it's only the US that still run via Imperial. Strange that, the US use a Decimal currency. Franc you're right about the US only using sealed beam H/lights and most of the Euros had to adapt to the single/twin 5" & 7" rounds or the rectangular twin units (ala Volvo & VW etc.,) What makes things awkward is the fact that even the stud spacings are all over the place with fractions of mm (114.3mm) etc., and then others including OZ using imperial. Maybe China may give it all a good shake up as they're used to sticjing 2 fingers up at the US.
franc123,
Feb 11, 4:23am
It was pretty much confined to French cars, Michelin and Citroen were effectively the same company and pushed it the hardest. If Ze Germans had followed things might have been different, but they didn't.
poppy62,
Feb 11, 4:24am
Yes Peugeot/Citroen and Audi, BMW also used metric wheels/tyres. Thought the especially arrogant (arguably) French would have stuck with the Metric system.
poppy62,
Feb 11, 4:26am
Ze Germans did use metrics in the 80s/90s Audi BMW. had a few cars come through the yard on them.
franc123,
Feb 11, 4:30am
114.3mm stud pattern is 4.5 inches, its simply a conversion, as is 108mm (Euro Ford, Peugeot etc) which is 4.25 inches. I AFAIK the UK is still using miles and miles per hour and selling fuel in UK gallons, and selling goods by the pound so yes still by and large an imperial society.
supernova2,
Feb 11, 4:33am
The french do lots of odd things. Their bolts are not common diameter either and they also have a bolt head that most (older) metric socket sets dont have (16mm). Also 11, 13 mm are common sizes - it's as if they just converted old imperial stuff to metric.
Then to confuse issues most roller bearings are in metric sizing.
Its like the makers just woke up one day and said ah well lets do something odd and the world will follow.
franc123,
Feb 11, 4:34am
Really? Never seen any, it wasn't something they still pursue today though is it? A BMW or Opel will have a 5x120 metric stud pattern and a Benz will have a 5x112 stud pattern but use conventionally sized tyres.
franc123,
Feb 11, 4:39am
Pretty much, a hydraulic engineer chap I worked with years ago said exactly that, 11mm was roughly 7/16, 13mm was give or take 1/2, 16mm was 5/8, 19mm was 3/4, it was simply to try and align the two systems together better.
tamarillo,
Feb 11, 12:23pm
I'll blame Americans I think. Surely with all their use of small gallons, miles, etc they're to blame somehow. Usually are.
poppy62,
Feb 11, 2:30pm
Yes! I forgot that the centre of the USAinverse dictates to the rest. The UK on the other hand the UK as of 2012 only allow for imperial measures for the sale of beer, cider, milk and also use IM for road signs and distances and Gallons for whatever. As part of the EU one would think that uniformity is an important issue. Barring the US and to a lesser extent the UK the rest of the "universe has to contend with 3 different weights and measures systems. As a consequence, Hey Tam! off the cuff give me the Litres/100kms, MPG (UK) MPG (US) that your car does.
jmma,
Feb 11, 2:51pm
and everyone still say they have 6 inches Lol (o:
pge,
Feb 11, 3:03pm
I had a 1982 BMW735 (UK import), it was on 330mm rims.
The tyres were $800 each.
It was cheaper in the long-run to get local mags to suit .
gazzat22,
Feb 11, 3:04pm
When i worked for an airline, time -worldwide -was always expressed in GMT(Z) time.
tintop,
Feb 11, 4:12pm
UTC makes a whole lot of sense for an airline, but Morris metric was certainly odd ball .
poppy62,
Jun 22, 9:40am
Just some need to use it 3X to make it.
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