in the olden days

[dave]

standard tyres looked like this


but people didn't like the road noise and wanted tyres to last for 20k miles

so now a standard tyre looks like this



so its not hard to see why the country comes to a halt now when its snows a little when years ago it didn't even when it snowed for weeks

 

[Pugglt Auld Jock]

standard tyres looked like this
View attachment 188856

but people didn't like the road noise and wanted tyres to last for 20k miles

so now a standard tyre looks like this

View attachment 188858View attachment 188857

so its not hard to see why the country comes to a halt now when its snows a little when years ago it didn't even when it snowed for weeks

Very good point Dave. What I'm about to say is a bit simplistic but I hope it touches the main points.

Tread design is often "smoother" now which makes the tread more stable and quiet running and puts more rubber on the road. Long life also important but, in very basic terms, this has to be traded off against grip. So soft rubber gives good grip and short life, hard gives poor grip and long life. Casing construction plays a part but to a lesser extent. So smooth, fine tread patterns and hardish rubber gives quiet running and long life.

Section width today is also much greater than in the past so the tyre is putting more rubber on the road than "back in the day'. This is great when the road surface is dry and in good condition but when it's wet or snowy a narrower tyre will be able to bite through to the road surface and will not be so prone to aquaplaning. Just look at what rally and ice racing cars run on when it's slippy. Back in the 60's/70's Minis were running round on that 145r12 in your illustration and Cortina's on 155 or 165r13 with bigger stuff on maybe 185 section fitted to 14 or 15 inch rims. Look at today with my "cooking" Ibiza on 185r16 and my boy's 1.6 Astra on 205 section. No wonder they slide around on the slippy stuff!

Have to say I'm not a great fan of low profile tyres and wide rims for everyday runners. The short sidewall tends to give a hard ride as it can't flex much to absorb surface irregularities and the wide rims usually are well supported on the outside by the wheel centre but on the inside there is no support at all and, especially when fitted with a low profile tyre, if you hit a big pothole or obstruction in the road the outcome is often a buckled inner rim. A higher profile tyre will deflect and offer greater protection to the rim. Many years ago we lived up in the hills, in a small village to the south of Edinburgh. Lots of snow in the winter. Apart from the farmers in their 4WD's the only other vehicle which regularly made it up the steep hill when the snow fell was my Citroen Dyane. It had very skinny tyres - 135 section, lots of ground clearance and an engine with so little power we all used to cheer if it actually managed to get wheel spin! The only thing that would stop it was sheet ice.
Kind regards and stay safe
Jock