Quote:
Originally Posted by CargoBoatTails
This is a really annoying argument that defies the laws of physics. Rather than make my own independent claims I'll use an elementary example of a currently mass produced econobox that comes in different trims, ie the Ford Fiesta HB manual. If you get the 205/40/17s the epa rates it at 26/35mpg, if you get the 195/50/16s the epa rates it at 28/36. Now go argue with the epa that the bigger tire should have gotten better mpg and stop telling naive people bigger tires get them better mpg, ridiculous.
And anyone involved in racing knows you need to make less pit stops with a lighter tire.
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It's unclear what you are saying defies the laws of physics.
I don't think anyone was objecting to the idea that a lighter tire is better for RR - all other things being equal. But rarely are all other things equal.
In your example, the overall weight of the tire and wheel assembly changes mostly because of the wheel. I tried to see if I could find a tire that comes in both a 195/60R15 and a 205/40R17, and Tire Rack doesn't list any.
But if I do a survey of published tire weights, both those sizes are in the same range - and perhaps the 17" is a bit lighter, which would contradict your theory. But it really is hard to tell because there is very little commonality.
But I am basing my statement on this chart:
http://www.barrystiretech.com/smithersrrcsizemed.jpg
This is about as close to an apples to apples comparison as you will find.
And just like race tires come in different levels of grip - albeit with corresponding levels of wear, Street tires come in different levels of RR with corresponding levels of of wear and traction. These are tradeoffs and weight isn't the big factor here.
Don't get me wrong, less mass in a tire is beneficial, but there are other factors that are more dominant.