This is my boy, some 19 years ago!
He is rolling, what seemed at the time, an enormous tyre! I think it was a 285/45R19 from the rear of an early BMW X5.
Fast forward to the current day, my boy is 6 foot 1 and the rear fitment to the latest version of BMW’s X5 is 325/30R21!
Does being bigger make things any better, in my boys case it means he can reach high up things easier, but in the case of tyres? Our jury is out deliberating.
Some of the reasoning behind the size growth of tyres on some vehicles is that vehicles are getting larger.
The original X5 (to use this example again) was approximately 4.5 meters long and weighed 2 tonnes.
The current incarnation is pretty much 5 meters long and up to 2 1/2 tonnes in weight.
Quite some growth!
2000 BMW X5
2021 BMW X5
So it’s understandable that they would want to fit wider and to lower the profile of the tyre, to effectively lower the centre of gravity to help keep the goliath of a vehicle slightly more stable. But in doing so, in my opinion, they compromise the ride quality. It is after all a big SUV intended to do long distances. And, with having such low profile tyres, have created a vehicle that is not really suited to modern, pot holed roads, especially as they don’t supply a spare wheel!
We have been out to many a forlorn motorist with a damaged, massive tyre and no spare wheel!
Aesthetics seems to be the main reason for the growth of the modern tyre. Where an 18 inch wheel was seen as huge 15 years ago, 22 inch is fairly mundane today and 23 and 24 inch are getting more common.
We don’t see this trend changing any time soon, the only difference we are seeing is that some electric vehicles are coming with tall thin tyres to reduce the rolling resistance and increase mileage on a charge.
Maybe I’m old and don’t quite understand the trend but I don’t see the point as there doesn’t seem to be much benefit and too many negatives?
Whereas, my boy can see over people in a crowd and reach his beer at a packed bar!