GM based its initial recommendation for my Volt's tires on the 35psi used for the Cruze, because the platform was the same. The additional 900# added by the battery and other novel powertrain components somehow totally escaped their consideration throughout the design and testing phases.
Early Volt drivers found that the recommended pressure produced a high rate of classic underinflation symptoms, including cracked and pitted sidewalls, edge wear, and frequent blowouts. Not surprisingly, increasing the pressure to 40-45 psi evened out the treadwear and reduced catastrophic events. Empirical testing by one pair of owners indicates that 49psi on the more heavily loaded front and 45 on the slightly lighter rear actually produces the most even treadwear.
GM, in response, increased the recommended pressure by about 2psi. Why so little? Community consensus is that they're unwilling to admit to having been so wrong. Look at the recent recalls, and tell me OEMs are never wrong.
Just food for thought. I'm not advocating exceeding the tire's limits, but I don't think anyone here is.
Thanks for that --- I'm really surprised at the number of hyperbolic negative responses here. In a world were virtually everyone I know consistently exceeds the speed limit by 10% (maximum "legal" speed) it is as if I committed a crime and am endangering everyone on the road by maxing out my tires on my 4,000 pound vehicle. Yeah, I'll switch it out to a much more fuel efficient car someday. And then I'll max the tires out on that car as well.
And yes 15% was my personal tested amount on that particular day. (thanks to the posters who enjoyed my click bait!) I haven't bothered to further test as that was a pretty good indicator run day.
So far one of my tires has worn more so on the inside of the tread. While you might think this is a bad thing, when I bought the truck all 4 were worn on the inside. My friend owned the truck for 10 or 11 years and always had this issue with the all wheel drive Mountaineer. So it appears that my tread wear has actually improved. Most of the sites I referenced indicated that in general tread wear is less with high inflation. That makes sense as there is less flexing of the rubber.
I have put maybe 5-6K on the truck since starting this and haven't had any handling issue or dangerous stops in that time. As I say, I always try to anticipate stops well ahead and an increase in stopping distance appears to be the primary negative mentioned on the tire sites. I have noticed, and perhaps I'm wrong, that I need or want to drive much slower on rocky bumpy roads. That is about 5% of my summer time driving.
I'm going to use one more trick and have that worn tire reversed on the rim. Please don't beat me up over that.