A simple tire size question

[G20Rob3]

Okay, after years of riding stock tires and rims, I am upgrading. I've learned a little about rims and tires thanks to this wonderful forum. But, I have a really dumb question. When dealing with tire sizes, which would give a more low profile look, a 205/40R17 or a 215/45R17? I know this is probably a bonehead question, but I have a very limited knowledge of tire sizes. If anyone has a picture of those particular sizes on a G, that would be helpful in my decision process (you see, I found some great tire/wheel packages, but I'm not quite sure what the tires that come with the package are going to look like on the rim). I'd hate to get a nice set of rims shipped to my door, with FAT 4x4 tires on them. To make it easier, my G is lowered roughly 2" front/back. So, there won't be any wheel well gap. So, should I go 205/40R17 or 215/45R17??? Thanks!!!!!!

[JustinP10]

I think you will have better luck fitting the 205 tire, as the 215 may be a tad wide, and you'll really have to worry about the offset, as it'll have to be right on to fit. I had 205-45-16's on my P10 and I didn't have any rubbing or anything, i still had some room on each side (not much though), i think a 215, in my application, would have been pushing it, especially if i went up in sidewall size too, like to 205-50, or 215-45... however, i'm not sure how the p11's are for wheel well size? Your car may differ quite a bit from mine?

[b-b00gie]

Originally posted by G20Rob3
When dealing with tire sizes, which would give a more low profile look, a 205/40R17 or a 215/45R17?

Tire sizes are given in the format:

Width(MM)/Sidewall height percentage of Width/wheel size


So...

205/40/17 has a width of 205mm and 82mm profile (40% of 205)
215/45/17 has a width of 215mm and 96.75mm profile (45% of 215)


http://www.discounttiredirect.com/he...imensions.html


I have noticed that the profile never appears to be what the formula says. For example my 225/40/18 have a "90mm" profile which is about 3.5" however if you look, it does not appear to be that big. I think it has to due w/ air pressure, weight of the car and the fact that the tire rounds over on the corner.

[Cue-Ball]

Rob,

You're looking at two very different tire sizes here. Generally, you either want a wider tire with a lower profile, or a narrower (relatively) tire with a higher profile. If you go with 215/45's you're getting a tire that's wider AND taller (not a good idea with a 2" drop, IMO). I recently bought new wheels and tires for my car and got 205/40-R17 Toyo's. However; i only bought that size because it's the size that came in the "package deal". Otherwise, i would have gotten 205/45-R17's instead. Take a look at Jason's wheel page and you'll see why. 205/40's and 215/40's are smaller in diameter than the stock tires. 205/45's are almost exactly the same size, while 215/45's are larger diameter than stock. So, the tire you select will affect your gearing and speedometer/odometer error as well as the look of the car. Also, using a 45 series will look very similar but will give you just a *little* more sidewall to cushion your rim when you hit a pothole (which you will). As i said, i've got the 205/40's on my car (as do most of the people here) but if i had not been "forced" into that size by the package deal that i purchased, i'd have gotten the 205/45's instead.

BTW, just got my new wheels this morning. Haven't even mounted them yet. Hopefully i'll get them on tomorrow - at which point i'll start budgeting for springs and shocks. :-)

-Grant

[v_knot]

b-boogie,

You are correct in explaining the tire format, however, you missed the key word: "aspect ratio". The number 40 or 45, as an example above, is known as the aspect ratio. You can learn about tire dimension and its characteristics at most tire sites.

I am getting new rim/wheel this Spring. I am looking at the 215/40/18 with around 40 to 45mm offset.

[b-b00gie]

I just didnt want to get all technical... I was explaining how you figure the numbers. The link I posted from Discount Tires has pictures..


BTW with 18's on a P11 the 215/40 will be a little smaller than the stock diameter which is 24.2".

225/35/18 is a perfect match, but I went with 225/40/18's for a little added support. This was mainly because I first had 215/35/18's (rubber bands, lol) and ruined 2 wheels. I was gonna go w/ the 225/35 but figured I might as well get the added protection.

Next tires I get will be the 225/35's though.