Originally posted by: jagec
Originally posted by: Pacfanweb
If you want taller, you need to change the first number, the 275. So maybe a P285.
If you want it taller AND wider, then you'll need to change the first and second numbers.....So you might go to a P305 50 R20. That's two sizes taller but drops the sidewall ratio so it'll use up some of those extra millimeters in width.
However, this varies widely by tire maker. One companies' 275/55/20 is in reality very likely to be slightly different in actual size from another's.
So you might want to have a tire store just mount up a 295 or 305 (if available) of the same tire you have and see if that gets you what you're looking for.
In review: Changing the first number makes the tire taller, and maybe slightly wider, but the added height takes away from any width gain. (just like a 5'5" guy with a 38" waist is a fatass, but a 6'5" guy with the same waist isn't at all)
Changing the second number affects sidewall height, and therefore, width. If you only changed the second number, from say, a 55 to a 50, the tire would be shorter, but wider.
So to get both, you need to increase the first number, and reduce the second number...usually. Again, this varies by manufacturer.
Actually, the first number is width, the second is aspect ratio, and the third is the diameter of the wheel it fits.
For example, a 185/60R14 is almost exactly the same overall diameter (height if you will) as a 335/25R16 (hypothetical nonexistant tire), but is a good deal wider.
Try
this to compare old and new tires.
Correct, but the first number is not the "width" of the TREAD, which is what makes the tire look wider, and that's what the person wants here.
The first number is the distance from the widest part of the SIDEWALL, from side to side. That's not just the width, because the aspect ratio of the sidewall greatly affects that. The less sidewall you have, the more of that number is the tread. The more sidewall you have the less.
So what I recommended was 100% correct. Example: A 275/70/16 is a wider tire than a 275/75/16. Why? Because you made the sidewall shorter, and that 275mm had to go somewhere, so you get a wider tread.
And sometimes you have to play around with the sizes at the tire shop to get the look you want.
In Pegg's case, he wants taller AND wider. So going up one size without changing the aspect ratio isn't going to make much difference in width, because the taller tire is going to actually look either skinnier, or about the same width.
Again, assuming he uses the exact same brand/model tire. If he switches brands, he'll just have to see what they look like, but if he wants taller and wider and he's starting at a 275/55/20, he'll need to increase it to about a 305/50/20 to see a significant increase in both.
Just going up one size to the 275 will make it look taller but skinnier, so he'll need to drop the aspect ratio to get the wider look.
Going to a 285/50/20 will likely result in about the same height as the stock tires, but they would look wider.