[MeisterS4]

Greetings,

Quick wheel size question. Currently I'm running 17x9 all the way around on my 94 S4. Fronts 17" with 40 series tire and rear with 45 series tire.

Need new wheels here soon and was going to run 17" fronts and 18" rears. Offsets don't matter as I've been using spacer/adaptors. Just wondering if anyone is running the two different diameters f/r?

I dont see a problem if I reduce the rear from 45 to 40 series side profile I should be essentially the same over diameter.

Thanks

 

[Vulcan Grey]

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.

 

[lotusespritse]

Series means nothing alone. It's all about the final diameter and width measurements. Use one of those tire size calculator websites to get exact measurements with a percentage comparison to stock. General rule is if you are within 2% of stock diameter, you are good.


Sent from AutoGuide.com App

 

[MeisterS4]

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

 

[bharper]

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 9.65 25.68 stock S4
275-35-18 10.83 25.58
285-35-18 11.22 25.85 stock Saturn
295-35-18 11.61 26.13

Fronts

215-40-17 8.46 23.77 stock S4
235-40-17 9.25 24.40 stock Saturn

numbers updated 7/15

Brian

 

[lotusespritse]

Seriously? You think it's easier to code your own spreadsheet than go to a website that is designed to easily calc an compare tire sizes?

rotfl

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

 

[lotusespritse]

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

If you had coded your own spreadsheet formulas, I would question your results, but that website is always right.

 

[bharper]

Well, 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

 

[QuadCam]

i wonder lotus changed the front tire diameter so much on the V8s Esprits.

 

[lotusespritse]

Well, 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

rotfl

 

[davidwh918]

You can calculate the dimensions quite easily without chasing a tire site. ...

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.

 

[sleekgt]

If you had coded your own spreadsheet formulas, I would question your results, but that website is always right.

No - it's not always correct - by their own admission, bharper is prudent in verifying the numbers.

To assume "that website is always correct" is risky at best, especially if you're buying expensive custom wheels based on that information:

"Waiver of Liability:

All visitors using this tire plus size calculator agree to verify the displayed calculation results for accuracy. 1010Tires will not assume any liability resulting from damage, accident, injury or death to person(s) or property resulting from the use of the measurement result values provided from this calculator. User/Technician assumes All Risks when applying values from this calculator and release 1010tires from any liability claim."

 

[EspritNOOB]

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

Way cool thanks for the info!!!!!

 

[bharper]

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

 

[Vulcan Grey]

Not to rain on the parade... I also usually calculate the tire size as Brian did, or I use the 1010tires calculator. However... The manufacturers different tires, of the same size and aspect ratio, often end up having different diameters!

Many manufacturers list their diameters, and some even list the diameter mounted on different widths of wheels IIRC. In case you really need to know.

 

[EspritNOOB]

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

Great tool thanks!

 

[bharper]

Undoubtedly you are quite correct VG, the real world can be quite different than the theoretical. At least the calculations should be close to what the manufacturers 'claim' them to be.

Brian

 

[MeisterS4]

Put them on a week or so ago, working well. Voxx Maglia 17x8 F 18x9.5 rear. I htink they look pretty close to the newer V8 wheel and for $1400 total not too bad.

Last pic was previous ASA 5 spoke wheels

Thanks

 

[bharper]

Scott those look incredible!

I have more than that $ in my saturns....

Sure a lot better value than dumping 3-4k in nova's.

Are they single piece, or 3 piece, I see bolts.

Good pick!

Brian

 

[sleekgt]

I was looking at those wheels as a cost-effective Nova wheel substitute. Not a big fan of the simulated bolts or the relatively heavy weight (but the Novas are similar weight even though they are forged (?)).

But given the 3-4X cost differential AND the fact they look much better in the 'on car' pictures, it's a great alternative.

Are your wheel centers chrome or hyper-silver?
What tire sizes did you end up running?

I know the lip is mirror-polished. They come in 5x108 bolt patterns so that helps in the front; less so for us -20mm Citroen 5x108 88 Esprits (adapter required).