haapanen@watdcsu.UUCP (Tom Haapanen [DCS]) (11/07/84)
< Nami nami nami nami ... > The following are excerpts from VW & Porsche magazine, copyright (c) 1981, 1984 by Argus Publishing Corporation. The [comments] are mine. _____ VW & Porsche, June 1981: Front-Wheel Drive Wheel & Tire Combinations "Many of us have been led to believe that wider tires will make a big performance change. As you can see, that's not completely true. Tires with stiffer sidewall construction will improve cornering, and many of today's high performance radials offer tread patterns that are almost as good on wet surfaces as dry. But regardless of how good the tire is, it needs a rim to match. Think of a high-performance tire on a narrow rim as a Grand Prox driver put into a poor automobile." ... "When a new tire is needed, the best compromise is to choose the 205/60-13 size. A bigger tire on a 13x6 inch wheel won't deliver any better performance on the road -- or on the slalom circuit -- and it's actually detrimental in the rain. The only advantage 215 and 225 sizes have is appearance." _____ VW & Porsche, February 1984: Supertire Shoot-Out [This test compares the Goodyear NCT, Pirelli P7, BFGoodrich Comp T/A, and the Yokohama A-008. All tires were tested on a Porsche 944 equipped with sway bars (28 mm front, 22 mm back) as well as aftermarket coil springs. Tires were in the size 205/55VR16, with the tread shave to half depth to eilinate new-tire squirm.] [The following summarizes the comments made by test drivers subsequent to two five-pass rounds around a SCCA-approved SOLO-2 course] Goodyear NCT: - Quick transient response - Better-than-average projected tread life - Hard compound limits adhesiveness, resulting in less than average traction in accelaration, braking and lateral movement - Performance does not improve as tire gets hotter Pirelli P7: - Quick response to steering inputs - Puts power to ground excellently, totally controllable - Poor tread life due to soft compound tread - Tends towards high-speed oversteer Yokohama A-008: - Good traction during acceleration - Extremely stable high speeds - Great braking traction - Gives great confidence and control - Quite hard riding, small bumps noticeable - Requires more steering effort than the other tires - Input response time not as good as the P7 - Soft tread compound gives short tire life BFGoodrich Comp T/A: - Good traction during acceleration - Good lateral adhesiveness - Outstanding in low-speed corners - Less prone to trailing-throttle oversteer than others - Understeers more than the A-008 - Not totally comfortable in high-speed corners - Not as responsive to steering inputs as the P7 [The following are the best times posted by each tire over the slalom course, and over a 103-foot skidpad. The Dunlops are stock, size 205/60-15, and are not shaved.] Tire Slalom Skidpad Goodyear NCT 31.428 11.809 Pirelli P7 30.668 11.592 Yokohama A-008 30.344 11.570 BFGoodrich Comp T/A 30.515 11.862 Dunlop SP D5 n/a 11.971 [The following are excerpted from the conclusions...] The 11.570 seconds run with the A-008s equates to a lateral G-force reading of 0.9488, while the P7's fastest run is 0.9451 G. The fastest NCT time of 11.809 translates to 0.9107 G, and the poorly performing Comp T/As end up with 0.9035 G for their 11.862 second pass. In our opinion, hands-down winner is the Yokohama A-008, with second place gong to the Pirelli P7; third place gets captured by the BFGoodrich Comp T/A, witht the venerable Goodyear NCT finishing fourth. _____ So draw your conclusions, gentlemen! I have the address of Argus Publishing, if anyone wants to get back issues and/or reprints... Tom Haapanen University of Waterloo (519) 744-2468 allegra \ clyde \ \ decvax ---- watmath --- watdcsu --- haapanen ihnp4 / / linus / The opinions herein are not those of my employers, of the University of Waterloo, and probably not of anybody else either.