@Landshark, thanks for the reply. I've never watched the EDM mode at higher speeds. I was under the assumption that it would drop out at less than 85 mph, I would have guessed more like 70. You are right that it would increase the speed at which it would engage by 4%, but I'd think the range at which it is in effect would go up 4%, so you should gain more on the high end than on the low end, but as you say torque may trump speed in it's operation, and if so, I am not sure anything would change in when it engages.
You could also be right about the tire life. I was thinking that for two of the same tires (Michelin Energy Saver A/S, for example) the larger tire would start with the same composition and tread depth as the smaller tire and should run longer if less revolutions per mile. Tire manufacturers may take this into account and slightly decrease the starting tread depth of larger tires. Regardless 4% isn't a lot of extra life, only 1,000 miles or so for the life I get from most tires.
I agree that MPG is painful to even talk about with a PHEV. I probably burn more gas than you do, about 1/3 of my driving is gas. I do keep up with gasoline purchased for the car, mostly to back into EV miles, and just assume gasoline mpg at 40. It's still kind of nice on trips to see what the computer mpg looks like.
As to the last one, I don't plan on selling this vehicle until it drops (either wrecked or dies), I doubt the mileage will impact the sale value much. I've got a 2002 Tahoe that I bought new in 2002 and has had 2% larger diameter tires on it since the first set of tires. On that vehicle, it helps with mpg (since it helps engine rpm to cruise at slightly lower value on the highway). I've got nearly 230k miles on it now, which means the odometer is off by about 4,000 miles. I doubt anyone would care if I told them when I traded it in.
I have been known to curb rash my wheels. The slightly taller tire might help with this. It is a pain to sand them down and repaint the damaged areas when I do this. Yes, it would be better if I was just a more careful driver and alert driver (guilty as charged).
It did also dawn on me that this would add 4% to the top end of the car, but I doubt any of us hit 100 mph on a regular basis, so 104 mph isn't much of a perk.
I have already purchased the next set of tires for the car (235/45/18) and they are in the garage, so its doubtful I will move to the larger size, but I was curious what others would think. Again, I haven't researched to make sure that the loss of 1/2 inch of clearance inside the wheelwell isn't a problem (seems most internet tire recommendations are to increase no more than 3%, this is at 3.8%). It'd suck for it to bottom out on a bump and make contact damaging something (tire or car). Thanks again for your reply.
