ive been waiting for my car for a week now, 07 extreme, and im looking at the stock tire sizes 275 35 20 in front and 40 in rear, but 35 series would or should be wider and lower which i dont see a problem with it being lower but isnt the tire wider in the front then the rear.

Are the rear wheels on the '07's also 275's? (I thought they were 285's)If so, then you are correct in the wheel will be lower and have better clearance, but will NOT be wider. I have no idea why Saleen went with 40 series tires in rear as this just limits your clearance and tire options without re-calibrating the speedo. I think 19"s are a better choice for the '05+ Stangs and afford many more options for tires and rim widths, but is just my opinion and Steve disagreed with me :)

Jazzer

275 front and 275 rear from what i have been seeing , my car isnt here yet so im not sure what my extreme has on it the saleen web site shows the same thing 35 front and 40 in rear makes no sense 35 should be wider.

The number 35 in the 275/35/20 is the % of thehight vs. section width. The tire is 35% as tall as it is wide. So if you had a 10" wide sectionwidth (NOT rim width) and you had a series 50 tire, your tirewould have a 5" profile hight.

So if you have a 275/35/20" tire than the 275/40/20" tire will be EXACTLY the same width for the same make/model of tire. If you measure the hight of tire, the front will be a little lower.

***HERE*** (http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=46) are some helpful descriptions

Jazzer measuring up

i hear you jazzer but when i checked to see how wide they were i found that the 35 was 10.9 and the 40 were 10.8 i know we are splitting hairs hear but this is the only application i know of that uses a larger series in the front.

That is because the rear wheels are 10" wide and fronts are 9" wide. I agree with you that larger series in back (I think you may have mis-spoke) is a bit unusual. I am running 275/35/18"s in front on 9" wheels and 295/30/18"s in rear on 10.5" wheel.One can see that the overall diameter of fronts is a bit LARGER than the rear. When I install 315/30/18"s on back probably later this year, the profiles will probably be very nearly the same size but the rear tires will be about 3/4" wider than they are now. Even though the series will be LARGER in front, the backs are soo much wider that the 30% hight of rear will probably be the same as the 35% fronts.

If you ever go with aftermarket wheels, again, I recommend 19"s or maybe even 18" and you can get alot morewheel/tire widthunder the well (I dig fat meats :))

The Jaz

The only thing I can think of is that the 40's on the back have a slightly taller sidewall that may help launching. It would have more sidewall to compress or load on launch. This would improve traction and 0-60 times etc.

I will switch them out once they are done to a different size.

ORIGINAL: Jonsey

The only thing I can think of is that the 40's on the back have a slightly taller sidewall that may help launching. It would have more sidewall to compress or load on launch. This would improve traction and 0-60 times etc.

I will switch them out once they are done to a different size.


I agree, that makes the most sense [sm=signs007.gif]

I would still rather have an 11"x18" rim running 335/25's and get better contact patch and look incredible in the process :). Remember, with the wider wheel, you will get atallerside-walland will still help the launching as well.

There...... best of BOTH worlds [8D]

Jazzer a compromisin'

well in any case i understand the 08 extreme uses a different size now, does anyone know what those sizes are? and can we use them as well or are they going to a different offset on the wheels.

believe its a 305/35-20. pirelli makes it for 530 something a tire. also goodyear f1's come in that sizeand michelin is going to be making a PS2 in that size. It will probably be more than 500 a tire as well.

ORIGINAL: Jazzer The Cat

Are the rear wheels on the '07's also 275's? (I thought they were 285's) If so, then you are correct in the wheel will be lower and have better clearance, but will NOT be wider. I have no idea why Saleen went with 40 series tires in rear as this just limits your clearance and tire options without re-calibrating the speedo.



305-35 is almost exact same height as 275-40, so no recal needed if you do that.

ORIGINAL: sftdyna

i hear you jazzer but when i checked to see how wide they were i found that the 35 was 10.9 and the 40 were 10.8 i know we are splitting hairs hear but this is the only application i know of that uses a larger series in the front.


The fronts aren't larger in any way. They're shorter and narrower (as mounted on a Saleen). The section width measurements you're quoting at are only valid if the wheels are 9.5" wide. The measured section width of a tire mounted on a narrower rim will be narrower, and on a wider rim it will be wider. The Saleens that had 9" wide wheels all the way around came with 275-35 tires all the way around. The 40 series rears were only used if the rear wheels were 10" wide.

Good to know a 305/35/20 will fit in the rear.