Tire and wheel math

[Digital Man]

The MKS forum so far has been unable to assist me with this problem, but it was SO easy to get the info for my Marauder I thought at least someone could provide me with the equation I need to make an accurate decision.

Problem; 2011 Lincoln MKS w/factory 245/45R20 tires. Need a winter tire package but I'd like to bring the rims down to 17" or 18" because 20" winter tires are $$$$. And not a lot of variety. What size of tire should I look for to maintain a similar circumference to ensure the speedo and other components operate correctly?

Thanks!

[Comin' in Hot]

a 235/60/17 will be about 2% off according to a tire calculator and there are lots of choices for winter tires

[ctrlraven]

Go look at www.tirerack.com

Here is the main winter page for selecting size from 17" to 20"
http://www.tirerack.com/snow/WinterPackageMain.jsp?autoMake =Lincoln&autoModel=MKS+AWD&autoYear=2011&autoModClar=3.5L+V6+EcoBoost

They also have a pre-made preferred package already set up for a 17" tire/wheel combo.

[Blk Mamba]

245/60/17's are 28.574" in diameter, and your stock 245/45/20's are 28.681" in diameter, probably as close as you will get.

[Bluerauder]

The MKS forum so far has been unable to assist me with this problem, but it was SO easy to get the info for my Marauder I thought at least someone could provide me with the equation I need to make an accurate decision.

Problem; 2011 Lincoln MKS w/factory 245/45R20 tires. Need a winter tire package but I'd like to bring the rims down to 17" or 18" because 20" winter tires are $$$$. And not a lot of variety. What size of tire should I look for to maintain a similar circumference to ensure the speedo and other components operate correctly?

Thanks!

Your 245/45/20 are 28.68 inches tall (703.2 Revs per mile)

Other combos that are very close < 1.0% ... (less than 1/2 MPH at 60 MPH)

245/55/18 are 28.61 inches tall (704.9 Revs per mile) within 0.2 %
265/50/18 are 28.43 inches tall (709.3 Revs per mile) within 0.8%
265/55/17 are 28.48 inches tall (708.2 Revs per mile) within 0.7%
245/60/17 are 28.57 inches tall (705.8 Rev per mile) within 0.3%

Hope this helps .... Before you buy, have them check the height and revs for the particular tire you pick.

[Digital Man]

Thats what I am talking about! :high5:

Thank you for the info everyone!!