Why is the tread depth for new tires set at 10/32″? Why can’t it be 20/32″ for example to last much longer? eli5
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If the tread blocks are taller, they tend to flex sideways known as squirm and won’t corner or brake as well as shorter the tread blocks. Competition tires usually have less tread depth.
Tire rubber has a finite life. It’s been recommended to replace tires at five years regardless of the amount of tread life remaining. Adding more tread means a lot of people will be driving on old tires with dry rot cracks and not realize it.
It’s 10/32 because that is the ratio they have found works the most economically. More tread depth would mean adding more weight to to tire or reworking the tire build entirely to accomplish it. They’ve already done about a million tests to determine the least amount of material they can use and still get a ridiculously safe product. The standards for automotive safety are pretty high these days and the specs required are extensive.
More tread depth = more squishy and move-y tires = worse handling & control.
That 10/32 is kind of the best all around compromise I guess. But many tires have more than that, such as off road truck tires (BF Goodrich K02 have 15/32). Some have less, like high performance racing tires (Michelin Sport Cup 2 have 7.5/32)
The closest thing to what you’re describing is a regroovable tire. You will usually see this on work trucks and trailers that put on a lot of mileage. When the tire is worn down enough, they put it on a machine that cuts new tread into it.
You can’t do this with the tire on your car, because the rubber isn’t thick enough.
Others have commented that deeper threads may result in more flex. But additional flex by itself isn’t necessarily a problem.
**The real issue is heat.**
Basically when tires flex, there’s internal friction that generates heat. If there’s too much flexing then the tires get hotter and hotter as we drive long distances — to the point that the rubber compound can start to melt and the tire’s structural integrity gets compromised.
Incidentally, a tire that’s low on air pressure will also flex too much and can similarly fail due to overheating. Hence maintaining the proper air pressure is very important for safety.
You guys get 10/32″? Mine are only 5/16″…
Different tyres do have different tread depths.
Many 4×4 tyres have over 1/2” tread.
Conversely some uuhp summer tyres have about 1/4”.
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