Why do trucks have two sets of thin tires compared to one set of really thick tires?
In: Engineering
So, two tires is basically a hold over of tire technology and economics. In trucking, the more you can move, the more you can make. So, there is an ever escalating drive to increase capacity. As trucks are able to pull more, trailers are able to carry more. This is all limited by regulations and technology. Diesel technology and tire technology sort of run hand in hand. So, as ‘pulling’ increases, so does ‘loading’.
There are tires called ‘super singles’ that are basically wide single tires that take the place of duals. They are commonly fitted to the rears of tractors. They are more efficient (fuel economy) than dual wheels but more expensive outright. I have not seen them on trailers and I don’t think the efficiency would follow as one is driven (traction) and one is pulled (friction). I would expect super singles to become more common on semis as the price will come down and fuel efficiency is increasingly important.
Kinda rambled there but I hope it makes sense.
For carrying heavy cargo. Each tire has a max load rating. Multiple tires can hold more weight than a single wider tire.
The side wall of a tire is what carries the weight above it. Two tires have twice as many side ways as one and can therefore carry more weight.
Would the safety aspect have anything to do with it? If you have a single blowout of a tire in tandem, the driver has time to be able to safely slow and pull over. If there is a blowout of a single tire carrying that corners full weighted load, the outcome would be more catastrophic. Eliminating the single point of failure aspect could be important.
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