Originally Posted by STL 314
I was just quoted $930 for a set of Cooper CS4 Touring's mounted & balanced. I think they were 235/55 rather than the 235/40 of the PS3's. I'm tire stupid ... does this matter? Anybody have any opinions on Cooper? I'm gonna check out those Potenza's and Michelin Pilot Sport AS Plus' too. Oh ya, looking into the Continental ExtremeContact DWS's too.
The tire manufacturers will usually post the specifications as far as outer diameter, tread width, wheel width needed etc. for the different tire sizes. I posted a link to the stock 235/40x18" tire's specs above
. You can get the same specs at www.tirerack.com
for all the tires they sell. A tire store will often try to sell you an "acceptable tire size" based on what they have in stock at their stores or warehouse but I'd stick fairly close to the stock Focus dimensions/sizes myself. For example that 235/55x18 Cooper tire's outside diameter is 28.4 inches
and the stock 18 inch tire's is 25.4" so it's way too tall for the Focus.