Old fasioned cars, like Ford’s Model T, had very narrow tires. This went on for quite some time; photographs of trucks in the 20s and 30’s show tires not much wider than a bicycle or motorcycle on rather big trucks (for the era).
Did it really takes decades of trial and error to find out that if you make tires wider, they offer more traction and allow a vehicle to support more weight? If you look at tractor trailers, with legions of ‘duallies’, its obvious that more and wider tires allow you to get both more traction and spread out loads more.
I imagine that this would be even more critical back then when there were comparitavely few paved roads. What were they thinking?!
Old cars were much lighter than new cars. I can’t quote you the reasons and exact time frame, but I know that the change in average vehicle weight was one of the factors named in the Silver Bridge collapse.
Tradition may have played a part, but
I would suspect technology and cost.
I don’t believe the tire manufacturers knew how to make a wide tire that would preform well at a price that would sell/compete.
Tires seem (to me) to get wider with a lower side wall as the years progress.
I remember seeing tires some time back that looked to be 12" to 15" wide with only a 4" to 5" sidewall, and thinking- “How does that work?” They are common now.
Something else I’ve just noticed is a lot of the big trucks and trailers that always used to use dual wheels, now are using big/wide single wheels. Big 18 wheelers are becoming 10 wheelers.
Again (still?), technology and cost. That’s my wag
This threadis about historic grand prix racing cars, but it’s relevant to the OP.
Also, keep in mind that Model Ts and other cars of the period were not high performance machines. The Model T’s engine output was somewhere around 20 horsepower. A wider tire, by virtue of increased mass, would likely have diminished certain performance numbers (e.g., acceleration and braking distance).
It took a long time to work out how to make belted radial tires work. Prior to that you only had bias ply tires. A bias ply tire carcass has a round form. You can put a bit o shoulder on the tread to get more robber on the road, but this leads to heating if overdone. Basically bias ply tires need an aspect ratio (middle number in modern tire designations) near 100. If you try to make tire very wide, it becomes very tall and tends to want to roll under lateral loads.
Tire technology did not allow for wide tires way back when. Also a tire with tall sidewalks is very compliant and forgiving on rough roads. Today’s low profile belted are more resistant to tread punctures, but the sidewalks are paper thin and fragile compared to an old bias tire.
Set the way back machine to say 1920 and take a set of say Pirelli PZero tires back (mounted on rims that will fit both the tire and a car back then) mount them up and go for a drive. Assuming you aren’t in downtown NY you will have 4 tires with unrepairable sidewalk damage in a few hours of driving. In addition the ride would be horrible.
Quite. It was true for horse drawn vehicles which didn’t need traction, and the same wheel technology would have been used in early cars. All of the technology that had applied to wheels up to that point had to change in order to end up with modern wide tires, but the first mass produced cars would have still used the old technology.
The first major technology for road paving, macadam, was designed for four-inch wide wagon wheels. The top layer of stones were hammered and chipped down to a lesser width so that tires would always be on several. The workers would literally test the size of the stones by seeing if they fit in their mouths.
Asphalt paving was beginning to be used in center cities by the time cars were developed but outlying roads were still iffy at best. It’s likely that early car builders would think in terms of wagon wheel sizes and what worked on existing roads rather than trying to develop tires for a road system that had yet to be built.
Enthusiasts who drive old Land Rovers are quite used to pulling modern 4WD trucks out of the poo. Their narrow tyres with chunky tread on the sides cut into soft ground, which gives them more traction than a wide, relatively smooth tyre which sits on top.
Another thing is that back then you carried a spare tire and tube, not a complete spare wheel. The driver was expected to be able to mount and unmount the tire by the side of the road, and that’s easiest to do with a relatively narrow tire and a nice tall sidewall.