Right now im running (in the rear) a 275/30/19 (rims are 9.5)

Theoretically

my sidewall hieght would be 275mm X 0.30 = 82.5mm


now if i switch to a not so wide tire, 255/35/19

sidewall height wll be 255mm X .35 = 89.25mm


so the total diameter of the wheel is bigger on the 255 tire by 13.5mm.

BUT
then how come it looks like the tire is thinner on a 255 than a 275 in real life? Is it because of the stretch (255 will be more stretched than the 275 on a 9.5??) and therefore will give the illusion than the tire is thinner?

Ive seen pics of a 255 tire on my rims and it looks alot thinner than my 275 tire (exact same rims and tire brand, just diff sizes.)

 

Also is there any advantages/disadvantages in durability and comfort from running a 275mm tire than a 255? or vice versa? which is better

I know the wider the tire the better the ground contact and therefore the grip, but with these sizes isnt marginal?


I got Michelin PS2, and the sidewall is quite thick, which is kinda ugly haha
Im considerign the swtich from:

245/35/19mm (8.5inch wide rim)
275/30/19mm (9.5 )
to
225/35/19mm
255/35/19mm

but from the all the tire calculators it seems like ill be makin my tires beefier (none of them ask for rim width though, so hence my OP)

 

That measurement is if the sidewall was straightened out. If you stretch it over a wider wheel, some of the larger sidewall height gets lost in the now stretched width. I'd stick with what you have

 

Why?

funny enough i got my current tire sizes recommendation from CL members

My rim manufacturer recommends the sizes im considering changin to. (255/35/19)

I also just received some spacers (will b at +30 offsets), so will rub on current setup

 

any one?????