Parameters: A). No driving in the rain. B). Not a track day car, just road use. C). Sports suspension shocks etc. already done. D). same size tires. For performance/handling/stopping - Is it better to have an "ultra High performance" summer tire that weighs 21 lbs. or an "ultra high performance" all season tire which weighs 17 lbs.? On one hand one tire is higher performance but on the other hand 4lbs. of unsprung weight is considerable on a small low powered car. (1983 Alfa spider).
Without having more info, I'd say the lighter tire wins.
VClassics reader here is "more info" for the theoretical question....which kinda' makes it a bit less "theoretical". UHP Summer tire - BF Goodrich Sport comp2 = 21lbs. UHP ALL Season tire - General Gmax AS-03 = 17lbs. both 195x55x15, both highly rated in their categories, one is a higher performance category, the other lower performance but a lot lighter. again this is just in reference to a dry summer tire, car not used in the rain/bad weather, not tracked, just street driving, wear ratings not worried about.
We've only been able to show a minimal performance difference (if any) even with 10+ pounds of difference between two sets of wheels with identical tires.
Pick the stickier tire.
Thank you.
As an Alfa spider owner, I'll beg to differ, Tom. The less torque a car has, the more important it is to reduce rotating mass (like wheel and tire weight).
Example: I had an 03 MINI Cooper S with 17", 8 spoke "Minilite-style" wheels and run-flat tires. In magazine photos, I noticed all the SCCA guys were running the 16" R83 "5-Star" wheels. Hmmm.
Car & Driver tested a MINI convert (with 5 stars) and noted "it's the quickest MINI we've ever tested, we just can't explain why." Its the wheels. I replaced my 8 spokes with 5 stars, and replaced the heavy run flats with Yokohama radials, saving 11 pounds per corner. The MINI felt like it had gained 40 horsepower !
I would pick the lighter tires.
Stickier tire. I've never had a low torque performance car, but on the z28 I always got better performance on stickier tires.
I looked and the treadwear is 340 vs 480; so my question is what is on the car now? If you're current tires are as hard as 480, then I would go with the lighter tire. It's not the unsprung weight you'll notice it's having to turn 16lbs worth of flywheel weight as in low powered cars heavier tires have a huge flywheel effect.
When you drive the car is it on tight twisty roads with few straights or with a low speed limit? If that is the case then the grippy tires will be the way to go. If corner carving is mostly freeway on ramps then the acceleration off the corners will be aided by the lighter tires. Having road raced small bore cars and bikes it's always a balancing act between grip and acceleration.
With that said if the tires on the car are easy to get squealing with moderately. Enthusiastic cornering (like the granite compound on my Outback) go for grip.
Tom
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