Spare wheel/tire, options

[jotarou1]

I had a quick question.

I currently have a 2004 CS with the Porsche Sport Techno 20" wearing Michelin 4x4 Diamaris 275/40/20. I also have the Bose sound system so I don't have a spare tire. I have a set of CS 18" Turbo wheels and I was planning on buying a some Pirelli Snow and Ice tires in either 255/55/18 or 235/60/18. My question is if I were to take a road trip I wouldn't want to be left stranded without a spare (yes I have the goop that is suppose to replace the spare and AAA and Porsche roadside assistance), but would it be possible to take the snow tire/wheel with me and use that as a spare to continue the trip until I am able to replace/fix the tire?

Per Tire Rack specs:

Michelin 4x4 Diamaris -275/40/20

Overall Diam. - 28.8"

Revs Per Mile - 724

Pirelli Scorpion Ice and Snow - 255/55/18

Overall Diam. - 29.3"

Revs Per Mile - ??

Pirelli Scorpion Ice and Snow - 235/60/18

Overall Diam. - 29.1"

Revs Per Mile - ??

Thanks for any help.

Juan

[RFM]

275/40/20 circumference= 228.7cm= 100% = 724 rev/mile

255/55/18 231.7cm= + 1.33% = 714.4 rev/mile

235/60/18 232.2cm= + 1.54% = 712.9 rev/mile

What Google can do for you.