So I've seen some discussion where most people are theorizing that the range/efficiency should be minimally impacted by tire rolling resistance - I just wanted to provide a quick counter-example.
I've recently changed the wheels/tires on my leaf from stock to a set of advanti denaro b2 black 18x8 wheels and kumho ecsta spt 215/40/r18 tires.
The wheels are 19.4 lbs (compared to stock at 21lbs per the measurements taken in this forum), and the tires are 23 lbs (compared to stock @ 19lbs per the ecopia web site)
I have two routes I can take to work - a hilly 4-lane 40mph road with lots of stop lights or a relatively flat interstate. Before, I would get about 4.3 mpk pretty much every time (as indicated on the dash) on the hills and either 4.1-4.2 on the interstate. Driving exactly the same, with the tires changed, both numbers dropped quite noticeably. In no way does it threaten to be a range limitation issue, but I was still disappointed with how much of an impact it was.
So that's 2.5 lbs each over stock, but of course the existing weight is moved more to the outside of the tire. Prevailing theory would be that the weight would be the strongest contributing factor to any change in range.
But here's the thing that leads me to believe otherwise - The hills dropped from 4.3 to 4.0 or 3.9 - so a little under 10% loss of range.
The interstate dropped from 4.1-4.2 to 3.7, a more significant loss in range.
To me, it seems like loss of range due to rolling weight would not increase at a higher speed (and might even be more noticeable on the hills) - a increase in efficiency losses at higher speed to me seems much more consistent with resistance-based losses. Or am I thinking about that wrong?
Anyway, from a purely aesthetic perspective, the wheels look amazing on this car, and the tires ... well, don't. I stuck close to the factory overall tire diameter to avoid speedometer reprogramming, but now that I'm looking at old pictures and the current setup, I can see that the outside tire diameter is really just not a good fit for these wheel wells; it needs another inch? or maybe two? Having a larger diameter wheel (and therefore a smaller sidewall) actually highlighted this.
On top of that, 215 width is simply not a good match for these wheels; there's a visible 'retraction' of the tire as it comes off the rim, which makes the tire look 'too small' to an even greater extent.
So, I'll drive these 'til they wear out (paid for now
), but next go round I'm going to just deal with a speedometer change and get a larger diameter, get LRR tires, and get them a tiny bit wider so they don't 'suck in' from the rim lip.
In fact, I just noticed ecopia 422 is available in a 225/50R18 - Just enough additional width to fill out the rim, and 1" larger diameter should make it look nicer in the wheel well without adding too much.
Anyway, I know a lot of people are more concerned about maximizing efficiency than I am, so I thought this would hopefully help contribute to that knowlege base.
Actually, one thing I need to confirm - I haven't confirmed the tire shop got the pressures right. If they underinflated I'd never be able to se it at this tire size, so I need to make sure I'm not skewing the results with low pressure.