Wtf?

[USAFG8GT]

Ok. So I came to the conclusion that I'm going to get Breyton Race GTSs. I figured, hey the 19s are $20 cheaper a piece than the 20s. Tires are obviously cheaper for 19 inch rims. WRONG! The 20 inch rims might be $80 more overall, but the tires I want are $190 lower overall. WTF? Is it because there is less material used to make the 20s as opposed to the 19s? I don't get it. Oh and they make the All Season tires I want when I end up getting stationed in Germany. They don't make them in 19s.

[SRG963]

More 20 inch tires are sold than 19's. Supply and demand :)

[WheelWorx Auto Studio]

Exactly! Economy of scale. 19" is an odd size.
Generally 18", 20" and 22"
Price a set of 21" tyres...we sold a customer a set of 22" aftermarket wheels and Pirelli tyres to replace his factory original 21" Porsche tyres.
The entire 22" package was cheaper than the 21" tyres alone!