Mythbusters tire pressure testing: +5 psi = 6% fuel savings

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Now past 48k miles, still liking the way the car feels with 50psi. Counter intuitively, it seems to be less harsh than at 44psi. I did get a flat though! Damn shard of metal from an accident that had just been cleared up (Not!).
I posted the quote below on this thread: http://www.mynissanleaf.com/viewtopic.php?f=27&t=4370&p=295901#p295901" onclick="window.open(this.href);return false;
Started running the Ecopia's at 40lbs then 44lbs about a month after getting the car. After 45k miles, they are wearing evenly with two having 9/32" tread and two with 8/32". Admittedly, I am driving very gently, mostly on freeways.
Now, based on the recommendation of two august members of this forum, I am running them at 50lbs. I like the way the car feels at this pressure but don't notice any change in range. It will be interesting to see how they wear. 2k miles this way, so far.
No, I do not recommend that anyone go over the the maximum pressure listed on the sidewall!
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Keep in mind air never leaks into a tire. Air is always leaking out. Therefore, if you set your pressure once a month at the gas station, when the tires are warm, you are running UNDERINFLATED all the time.

Tire pressure should be set as follows: Overfill the tire slightly. Park the car overnight. When you come out in the morning, lower the pressure to the desired cold PSI. NOW you have them set correctly.

Nate
 
It does just the opposite; it increases tire life... I think 5 pounds over is the sweet spot, however... That said, I run 44 on Michelin MXV4s...

LTLFTcomposite said:
How much does a set of Leaf tires cost, and how much does overinflating reduce their life?
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Randy said:
I run 40 psi in the LEAF, have 20,000 miles on the car, and have some good tread life left.

Just rotated tires again, and the fronts were starting to wear slightly on the outer edge before they went to the rear. I'm thinking that I should be able to get 30K miles or so on the original tires...

One thing I notice about people at work who have a LEAF and run "regular" pressure is that they get severe edge wear, especially as the tire slowly leaks over time and they don't air up...

I keep it at 40 psi...
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I should have mentioned that I've never worn out a set of tires running them at 40-42psi (set once a month or so, cold at home). I always end up replacing them because of age, or because a mechanic chews up the sealing surface.

Interesting about the Leaf tire wear. My guess is that having all the battery pack weight so low in the car encourages more 'sporty' cornering behavior, and that rolls the edges under enough to cause extra wear...
 
And that the car is under-tired for its weight and suspension... And that the stock tires are basically crap.

LeftieBiker said:
Interesting about the Leaf tire wear. My guess is that having all the battery pack weight so low in the car encourages more 'sporty' cornering behavior, and that rolls the edges under enough to cause extra wear...
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TomT said:
And that the car is under-tired for its weight... And that the stock tires are basically crap.

LeftieBiker said:
Interesting about the Leaf tire wear. My guess is that having all the battery pack weight so low in the car encourages more 'sporty' cornering behavior, and that rolls the edges under enough to cause extra wear...
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You kids don't understand "under-tired"! ;-) Back in the day, this car would have 13" tires and lead-acid batteries! And no heater!
 
TomT said:
And that the car is under-tired for its weight... And that the stock tires are basically crap.
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Your favorite BMW 328i circa 2008 comes with the exact same tire size in the base model and weighs the same as the LEAF. The BMW Active-E also ships with the exact same tire size, yet it weighs about 4,000 lbs, quite a bit more than the LEAF.

The main reason the outside shoulder of the fronts wear on the LEAF is alignment and soft suspension. Not "crap" tires. The Ecopias are just fine aside from the fact that they do wear fairly quickly, but that's par for the course for OEM tires. It's a good thing you don't have a Tesla with the high $$$ 21" tires - the rears wear out in 5-10k miles thanks to aggressive rear camber. I hear that's also a common problem on BMWs.

On my last car I had MXV4s - personally I disliked those much more compared to the Bridgestones on the car previously (tires similar to the Ecopia). Less grip, heavier, more rolling resistance.

And yeah - 40-44 psi works great on the Ecopias. Sure I get a bit of shoulder wear on the fronts thanks to a bit of aggressive cornering. But with regular rotations they still have plenty of tread at 20k miles for me and I can't blame the tires for compromises Nissan made with the suspension.
 
Good points, but I want to say that I like the suspension just fine set where it is. Maybe Nissan should offer a "Sport" or "GT" version of the Leaf, with the previous torque along with the new improvements, stiffer suspension, and maybe flush headlights so it gets fewer laughs from other drivers. And maybe one of those giant wings on the rear... ;-)
 
I might agree with you except for the fact that I now have more than three times the mileage on the Michelins than I did on the Ecrapias when I removed them, and they still appear essentially new, whereas the Ecrapias were showing many signs of distress already, beyond just wear. I also found the handling, braking and ride to be much better with the Michelins. And the increased robustness gives better piece of mind. All that was more than worth the roughly 3% range hit I took (and, everything being equal, new tires always have less range than old). YMMV of course...

drees said:
The main reason the outside shoulder of the fronts wear on the LEAF is alignment and soft suspension. Not "crap" tires. The Ecopias are just fine aside from the fact that they do wear fairly quickly, but that's par for the course for OEM tires.
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TomT said:
I might agree with you except for the fact that I now have more than three times the mileage on the Michelins than I did on the Ecrapias when I removed them, and they still appear essentially new, whereas the Ecrapias were showing many signs of distress already, beyond just wear. I also found the handling, braking and ride to be much better with the Michelins. And the increased robustness gives better piece of mind. All that was more than worth the roughly 3% range hit I took (and, everything being equal, new tires always have less range than old). YMMV of course...
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It's not that I don't believe you, but well, I don't believe you. Why don't you post a pic of your MXV4s with the number of miles you have on them.

On the MXV4s I had on my previous car they had the same tendency to chew up the outside shoulder with anything close to aggressive driving. And pushed hard they rolled over like a donut and shed rubber like crazy. Sure - they might do it at half the rate thanks to the higher treadwear rating, but as others have said, I wouldn't give up any hit to efficiency for slightly better grip.
 
drees said:
TomT said:
I might agree with you except for the fact that I now have more than three times the mileage on the Michelins than I did on the Ecrapias when I removed them, and they still appear essentially new, whereas the Ecrapias were showing many signs of distress already, beyond just wear. I also found the handling, braking and ride to be much better with the Michelins. And the increased robustness gives better piece of mind. All that was more than worth the roughly 3% range hit I took (and, everything being equal, new tires always have less range than old). YMMV of course...
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It's not that I don't believe you, but well, I don't believe you. Why don't you post a pic of your MXV4s with the number of miles you have on them.

On the MXV4s I had on my previous car they had the same tendency to chew up the outside shoulder with anything close to aggressive driving. And pushed hard they rolled over like a donut and shed rubber like crazy. Sure - they might do it at half the rate thanks to the higher treadwear rating, but as others have said, I wouldn't give up any hit to efficiency for slightly better grip.
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I the outside shoulder on the tire is chewed up it indicates either low tire pressure or incorrectly aligned wheel setting...
 
taztaz said:
I the outside shoulder on the tire is chewed up it indicates either low tire pressure or incorrectly aligned wheel setting...
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Not always. Most OEM alignments will result in outside shoulder wear on the front tires if you corner aggressively. I suspect the front A-arm bushings are overly squishy as well, leading to dynamic camber changes that make the wear worse (Check them out here: 2011 Nissan Leaf: Suspension Walkaround

Dialing in somewhere between -0.5 to -0.75 camber in the front would make things better and improve turn-in, too.
 
drees said:
It's not that I don't believe you, but well, I don't believe you. Why don't you post a pic of your MXV4s with the number of miles you have on them.
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Here you go:

They are currently at 33,567 miles and were installed at 7,108 miles. Note that there is virtually no uneven shoulder or tread wear... And, yes, I am an aggressive driver and do tend to corner hard. Sorry, I didn't have my tread depth gauge handy...

swtz0l.jpg
 
drees said:
Not always. Most OEM alignments will result in outside shoulder wear on the front tires if you corner aggressively. I suspect the front A-arm bushings are overly squishy as well, leading to dynamic camber changes that make the wear worse (Check them out here: 2011 Nissan Leaf: Suspension Walkaround

Dialing in somewhere between -0.5 to -0.75 camber in the front would make things better and improve turn-in, too.
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I don't grok suspension settings, but if a change from the OEM alignment would improve wear, what was the OEM alignment optimized for?

Cheers, Wayne
 
wwhitney said:
I don't grok suspension settings, but if a change from the OEM alignment would improve wear, what was the OEM alignment optimized for?

Cheers, Wayne
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It was optimized for efficiency.
 
Ingineer said:
Unless you do something sneaky, such as an eccentric cam bolt, the camber is unadjustable on the stock suspension.
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Which isn't all that sneaky, but there's also usually at least 0.5* of play in the strut mount bolts, too... You should see some of the contraptions the auto-x guys pull to get more out of a "stock" alignment.

TomT said:
They are currently at 33,567 miles and were installed at 7,108 miles. Note that there is virtually no uneven shoulder or tread wear... And, yes, I am an aggressive driver and do tend to corner hard.
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The MXV4s I had looked much worse than that after 10k miles. You should see what real aggressive driving does to them. Literally shredded half a tire off thanks to couple right-hand sweepers (yeah, I over-drove the tires a bit!)

img1554ji.jpg


That's a MXV4 with about 10k miles on it! Looks much worse than my EP422 with about 20k miles on them!
 

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