Optical Illusion?

[dkl]

I've just noticed this weird optical illusion today. Ever since I've got these 285/45R19 Kumho Ecsta STXKL12, something always looked "off" about it. They have always looked to be on the "skinny" side. But not until today, did I realized how "skinny" they looked parked next to my M Coupe, which only have 255/40R18 Bridgestone Potenza S-04 Pole Position on it. To prove to myself that I haven't got the wrong tire on the X, I broke out a ruler. Sure enough, the Kumho on the X5 measured around 11 inches across while the Bridgestone on the coupe measured about 10 inches. Anyone wants to give a shot at explaining this optical illusion?

[four.8is]

Tread pattern.they look rather narrow compared to the ones on the coupe..

[romeokc10]

I don't think they look skinny, on the other hand I'm definitely not digging those mud flaps...lol!

[powers1]

Easy to explain!M Coupe looks wider because of the lower profile tyre.
Less tyre wall makes tyre look fatter

[motordavid]

+1...
Tread pattern, lower profile tire on M, and the M is slightly closer to cam in the photo, and not exactly squared/head on in the side by side comparo, imo.
GL, mD

[pezho405]

The tread pattern gives this look, and i hate it, i like to buy tires with a more flatter tread at the edjes.

Your edjes are much more curved that some other tires.

M roadtser tread looks closer to 90 deg

[dkl]

All good explanations...thanks

Originally Posted by romeokc10

I don't think they look skinny, on the other hand I'm definitely not digging those mud flaps...lol!

I'm not digging those mud flaps either...but it keeps the rear end clean and clear of rock chips

Originally Posted by powers1

Easy to explain!M Coupe looks wider because of the lower profile tyre.
Less tyre wall makes tyre look fatter

I would think the opposite as the higher profile makes the tire bulges out more and therefore should look fatter?

In any case, my previous Pirelli Scorpion Assimetrico Zero on the X5 definitely did not look this skinny (wished I had taken a similar picture prior to swapping them out).

Originally Posted by motordavid

+1...
Tread pattern, lower profile tire on M, and the M is slightly closer to cam in the photo, and not exactly squared/head on in the side by side comparo, imo.
GL, mD

Good catch. So...just for you, I backed up the X another 3 inches to take this picture

Here's one with both cars lined up (both wheels are lined up, but the X5's tire is actually closer to the cam due to the larger tire diameter).

[TiAgX5]

Section width (285), is not contact patch width. Tires with identical section width can vary over 1" in contact patch width. Tire Rack provides the specs.

[dkl]

Originally Posted by TiAgX5

Section width (285), is not contact patch width. Tires with identical section width can vary over 1" in contact patch width. Tire Rack provides the specs.

Very True. But according to TireRack, the Kumho should have a tread width of approximately 1.5" wider than the Bridgestone.

[four.8is]

This kind of pattern makes even a skinny tire look wide
Conti vmax summer tires