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Comment by _ea1k | Hacker News Reader

The lack of spare tires is correlated with the increase in tire size, IMO. My first car was a 1987 Mazda with 14" tires. It was a two seat sports car, with a tiny spare mounted vertically. They could do that since it was 14".

Modern sports cars are 18-20" and the spare tire is a big cargo compromise.

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Makes me mad that my mustang has a spot for a spare... But no actual spare

They give you a fix it kit and some good wishes

edit: I suspect it's something to do with tire size as you say, but also brakes. Can't fit a donut with what's on the hub

For > $40k I would've liked they throw in a real spare wheel/tire lol

That’s actually a good thing, because you have a place to put one if you want to buy one.

At that point it was a cost cut. They engineered for a spare but the accountants gave you a can of foam.

The engineers may have pulled the spare to hit CAFE targets, but left the spare well as a cost cut to avoid retooling costs.

I'm sure it depends on the car as to the reason. My RX-8 does not have a spare, but does have space for one. The kit would take up over half the trunk space, though!

I think it's emissions and range rankings. When you are trying to shave off every last bit of weight to get your car into a lower emissions class, the spare wheel looks like a waste. Why not leave it out, the owner can always put it back in if the really want.

In Europe, the automakers are really getting card into Emission bands by the smallest possible margins, and as this effects tax buyers do care.

For EVs it's range - buyers pay a lot of attention to the headline range figures and a spare wheel plus the tire is not going to help.

The effect of a spare on range would be so miniscule as to not matter, tbh. Well, unless it was mounted outside the car for some reason. Some of the designs for mounting them on trucks might have an impact.

I wonder if another constraint is AWD and modern stability control systems not being able to handle a difference in circumference at one corner, so space saver tires are not an option.

Doesn't excuse RWD and FWD cars not having one.

Probably just weight/cost

That's a good point. Modern spare has struggled with some of their Tesla spare tire kits because of traction control issues. Even a small difference in diameter will make the car thing one or more wheels are slipping.

I wonder if another aspect of it is an effort to minimize weight, in order to offset the weight of the battery. The Tesla model 3 long-range battery is 1060 lb. To put that in perspective, that's essentially hauling around the equivalent of almost half the curb weight of a Honda Fit just for the battery.

Not putting massive 21" wheels on everything saves a lot of weight too, while making it possible to carry the spare. The giant wheels are easier to brake, easier to get a flat tire on, cost more to replace. The tires cost more to replace as well. They are really terrible in many many ways and are driven by looks more than anything else.

The massive wheels on modern cars are so big and heavy the suspension designs have had to be redone to handle them.. they add lots of unsprung weight, which makes everything harder.

Giant wheels for performance is mostly marketing. So much so that race cars held onto smaller wheels for a very long time. F1 only recently changed to big giant wheels, and the engineering teams were not happy about it, the change was marketing driven to make the F1 cars look more like street cars.

And that was the new fancy wheel size. From 1979 to 1985 that car came with 13” wheels.

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