The stock size wheels on the V8 were 235/40-17 and 285/35-18. That is what I use on my 89SE. Many do the same on the S4 or S4s.
You can calculate the dimensions quite easily without chasing a tire site.
Lets use a 285-35-18 as an example.
The 285 part is the width, in millimeters. 1 inch = 25.4mm. So if we divide 285/25.4, the width in inches is 11.22".
The 35 part is aspect ratio, which is the height of the sidewall, in percent of the tire width. So, 11.22x.35 = 3.927", which is the height of the sidewall.
Now, for the overall diameter, we need 2 x 3.927 (for two sidewall heights) + 18" for the wheel height. 7.854" + 18" = 25.854" total tire diameter.
You can set this up in a spreadsheet in a few minutes, and then get results, or a table, in seconds.
Here are some numbers I did the other day, looking at the stock S4 rims/tires, compared to the Saturn v8 wheels/tires. The stock Saturn rear, is the 285 one. Goodyear no longer makes much of anything in 285/35/18, so I am considering going with a 275/35/18, that are still available, at a good price.
Rears
245-45-17 9.7 25.75 stock S4
275-35-18 10.9 25.6
285-35-18 11.3 25.85 stock Saturn
295-35-18 11.7 26.2
Fronts
215-40-17 8.5 23.8 stock S4
235-40-17 9.3 24.46 stock Saturn
Brian
If you had coded your own spreadsheet formulas, I would question your results, but that website is always right.I think if I'm reading this right, a 40 series on an 18" wheel is is far closer than a 35 series.
http://www.1010tires.com/Tools/Tire-Size-Calculator/245-45R17/245-40R18/245-35R18
thanks
rotflWell, it certainly does not take much time to setup two columns to calculate with the above math, copy that down the page, and compare anything you want without running around a site looking for tire sizes.
If you would like to show where the above COMPLEX math has an error, please point it out. I thought someone might like to actually understand what the tire numbers mean, and how to turn that into something you can understand and that is useful.
If you think all websites are always right, good luck with that.
Each to his own.
Brian
Thanks Brian! I've read the definition of all components of a tire size many times in the past but doing the sample calculation is great.You can calculate the dimensions quite easily without chasing a tire site. ...
Brian
No - it's not always correct - by their own admission, bharper is prudent in verifying the numbers.If you had coded your own spreadsheet formulas, I would question your results, but that website is always right.
Way cool thanks for the info!!!!!You can calculate the dimensions quite easily without chasing a tire site.
Lets use a 285-35-18 as an example.
The 285 part is the width, in millimeters. 1 inch = 25.4mm. So if we divide 285/25.4, the width in inches is 11.22".
The 35 part is aspect ratio, which is the height of the sidewall, in percent of the tire width. So, 11.22x.35 = 3.927", which is the height of the sidewall.
Now, for the overall diameter, we need 2 x 3.927 (for two sidewall heights) + 18" for the wheel height. 7.854" + 18" = 25.854" total tire diameter.
You can set this up in a spreadsheet in a few minutes, and then get results, or a table, in seconds.
Here are some numbers I did the other day, looking at the stock S4 rims/tires, compared to the Saturn v8 wheels/tires. The stock Saturn rear, is the 285 one. Goodyear no longer makes much of anything in 285/35/18, so I am considering going with a 275/35/18, that are still available, at a good price.
Rears
245-45-17 9.7 25.75 stock S4
275-35-18 10.9 25.6
285-35-18 11.3 25.85 stock Saturn
295-35-18 11.7 26.2
Fronts
215-40-17 8.5 23.8 stock S4
235-40-17 9.3 24.46 stock Saturn
Brian
Great tool thanks!Since there seems to be some interest in comparing tires, I did go ahead and put together a spreadsheet that calculates a few more columns than the above example.
I believe it is operating correctly, if you find any problems, let me know. Its not very fancy, I have not done any complex spreadsheets in decades! Geeezzz, I started with VisiCalc!
Here is a link to my personal ftp space to download it, it should work in excel 97 forward, and I expect it should work in open office.
http://bah.warpspeeds.net/tire_calculations.xls
Note there was an error with my earlier calculations, I had put 25.2mm/inch, instead of 25.4mm/inch. Duh.... The numbers were corrected, and I removed rounding yesterday on that initial post.
Hope you find it useful.
Brian