Help w/New Tire Diameter & Viscous Coupler
04-19-2008, 12:46 PM
#1
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Thread Starter
Help w/New Tire Diameter & Viscous Coupler
Post copied from 993 Turbo forum:
I'm thinking of trying these very new Dunlop Z1 Star Specs for track/street use. They come pretty highly rated according to Tire Rack tests and at about $750 with rebate, they're almost 1/2 the price of the PS2s and PS Cups. I'm planning to do at least 3 or 4 DE events this summer and I just want a grippy tire that I can beat on and not care about chunking... and at that price, I can rip through nearly 2 sets for the price of one of the Michelins.
Unfortunately, the closest the rears come in is a 275/35/18, which has a 25.6 inch overall diameter. The typical 285/30 tire I normally run (Michelins) is closer to 25.1 inches. I realize I'd be giving up a little less than 1/2 inch in surface patch by going with the 275 which is not ideal, however, My Questions: 1) will I have any fitment issues with this tire size in the rear due to the larger diameter? 2) If I were to go with this tire size, do I need to increase the diameter of the fronts to more closely match the increase in the rear due to the viscous coupler and if so, how much of a spread is acceptable between front and rear anyway? 3) I realize the larger diameter of the tires will affect the overall gearing ratio, however, is a 1/2 inch difference diameter noticeable? and lastly 4) has anyone run these tires and if so, how do you like them?
Thanks guys, your input is appreciated.
Nick
I'm thinking of trying these very new Dunlop Z1 Star Specs for track/street use. They come pretty highly rated according to Tire Rack tests and at about $750 with rebate, they're almost 1/2 the price of the PS2s and PS Cups. I'm planning to do at least 3 or 4 DE events this summer and I just want a grippy tire that I can beat on and not care about chunking... and at that price, I can rip through nearly 2 sets for the price of one of the Michelins.
Unfortunately, the closest the rears come in is a 275/35/18, which has a 25.6 inch overall diameter. The typical 285/30 tire I normally run (Michelins) is closer to 25.1 inches. I realize I'd be giving up a little less than 1/2 inch in surface patch by going with the 275 which is not ideal, however, My Questions: 1) will I have any fitment issues with this tire size in the rear due to the larger diameter? 2) If I were to go with this tire size, do I need to increase the diameter of the fronts to more closely match the increase in the rear due to the viscous coupler and if so, how much of a spread is acceptable between front and rear anyway? 3) I realize the larger diameter of the tires will affect the overall gearing ratio, however, is a 1/2 inch difference diameter noticeable? and lastly 4) has anyone run these tires and if so, how do you like them?
Thanks guys, your input is appreciated.
Nick
