Possible Tire Pressure Mistake?

LeftieBiker said:

The only situation I can think of in which you'd want the pressure lower than 40psi is if the tires are only rated for 40psi or less. Tires like that are rare these days. You likely have an alignment issue or a damaged tire. 36psi is more likely to cause problems than 40. Did you try another pressure gauge?

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Not to put too fine a point on it, but we _are_ talking about Leaf's here. 40 psi for most cars is quite high, likely too high excepting special circumstances (rear tires on a vehicle towing a trailer for instance).

So no, 40 psi is not a normal tire pressure to be generally recommended for any tire rated at least that high. This is a Leaf thing. I won't speculate about other EVs.

Snargleblarg said:

I, too, have noted drifting at highway speeds (60+ mph) when the tires are over-inflated. My car seemed very "nervous" on the initial ride home and subsequent highway trips. When I eventually checked tire pressure, I saw the dealer had them inflated to 46psi!!! I dropped them to 40 and noticed smoother ride quality and less highway drift. Now I inflate them to 38 and wait until they drop to 35 before adding air.

The steering in these cars seems overly boosted with virtually no useful feedback. Is it drive by wire? Maybe the narrower tires on my S model exaggerate this? My test drives were mostly <50 mph but all the models seemed ridiculously easy to turn the steering wheel. Makes for easy parking lot maneuvers but bad highway manners.

I can understand wanting to avoid under inflation. But the push for severe over inflation (44psi) seems ill advised. Yes, you'll get better range in a back-to-back test compared to 36psi. But eventually you will wear down the center tread until you have a flat contact patch again. So the range benefit will be reduced and the safe tire tread lifespan will be reduced since you've accelerated the wear of the center tread. Plus, as noted, the slight increase in range (while it lasts) is accompanied with a reduction in highway safety due to drifting. That's not a compromise I'm willing to make. With the 62kWh battery I don't have to play games to push for max range.

Do you believe the engineers and marketing folks at Nissan threw away "free range" by specifying the tire inflation too low? These are the same folks that removed the Mountain Mode feature (charge termination at 80% SOC) just because the EPA factored it into their range rating for the early Leaves. Nissan is perfectly willing to compromise the car for a bit of range. So there's got to be powerful reasons they're sticking to 36psi. This is no different for any car, EV or ICE. You can cheat the tire inflation upwards for better mileage, but there are drawbacks.

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This.

The pressure recommendation made by the manufacturer weighs many factors, with safety being the prime driver - definitely a bad idea to run lower than their recommendation. Running higher within the bounds of the tires' max inflation pressure is open to discretion, but there are practical limits as you suggest above.

The pressure recommendation made by the manufacturer weighs many factors, with safety being the prime driver - definitely a bad idea to run lower than their recommendation.

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I'm sorry, but I don't believe that safety is the primary driver here. If that were the case then 38psi would be recommended, not a pressure that is safe only if maintained carefully. And it's common for people wanting better fuel economy to run tire pressures at or near 40psi. So, no, this isn't just a "Leaf thing."

I think it's more of an early-adopter / enthusiast thing. Most of the knowledge and culture of this forum is born of the original 24kWh Leaf and its very limited range. EPA rated 75 miles from 2011 to 2013 (due to EPA averaging the 100% capacity and the 80% capacity) and then rated 84 miles for later models. Most folks buying those cars were not your normal car owners. They were willing to take on the unique challenges of a short range EV. And I expect there was tons of desire and even need to push the limits of the car's range.

Brand new, what was the useable single charge highway range of a 24kWh Leaf in the cold of winter? 60ish miles for a round trip? And after several years of degradation? Maybe 50 miles? That's 25 miles one way if you use the whole charge. You betcha, folks chose to over inflate the tires!

The 62kWh and even the 40kWh batteries are game changers. With 258% and 167%, respectively, of the original capacity, they transform the Leaf to a mainstream option that does not require mental gymnastics to figure out if you can go to the mall on the way home from work. Where the 1st Gen Leaf is a fun challenge for the enthusiast, the 2nd generation Leaf is boringly easy to use around town. If you crave the challenge you can still plan out a long road trip with DCFC points and fallback charging options.

I don't think the story is terribly different for other EVs. The short range cars encouraged hypermiling tricks, and the Tesla crowd (at least those participating on the forums) is brimming with enthusiasts that love to have some bragging rights.

I appreciate the wealth of knowledge accumulated by 1st generation Leaf owners. But I also take into account that the 1st generation Leaf was truly a pioneer for EV technology. Didn't Leaf beat the Tesla Model S to market? Amazing that Gen 1 lasted until 2017. And the only significant functional advantage I see in the Gen 2 Leaf is the massive increase in range ... which transformed the car into a viable option for me.

Brand new, what was the useable single charge highway range of a 24kWh Leaf in the cold of winter? 60ish miles for a round trip? And after several years of degradation? Maybe 50 miles? That's 25 miles one way if you use the whole charge. You betcha, folks chose to over inflate the tires!

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No high inflation pressures when dealing with snow and ice. That would have been a recipe for disaster. And if you look closely at the Gen II Leaf, you can see that the entire midsection (door skins excluded) is still the Gen I Leaf.

Snargleblarg said:

I think it's more of an early-adopter / enthusiast thing. Most of the knowledge and culture of this forum is born of the original 24kWh Leaf and its very limited range. EPA rated 75 miles from 2011 to 2013 (due to EPA averaging the 100% capacity and the 80% capacity) and then rated 84 miles for later models. Most folks buying those cars were not your normal car owners. They were willing to take on the unique challenges of a short range EV. And I expect there was tons of desire and even need to push the limits of the car's range. ...

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Yes it's informed by the early adopters, but had more to do with tire wear than hypermiling, I think. The early models shipped with a version of Bridgestone Ecopia tires that had very pliable sidewalls. Many owners had to replace tires at shockingly low mileage, and it was shoulder-wear, a classic sign of under-inflation. I had very even wear across the tread in my 2012 by running at 44 PSI. Also, better handling. On the 2015 with OEM Dunlop tires the magic number for me was 42 PSI.

Treadwear is something that takes time to develop and evaluate. Handling gives much more immediate feedback. My practice for many years with any new (or new to me) vehicle or new tires has been to drive several days, adjust pressure by 2 PSI, and repeat. I evaluate handling at each step and that's how I choose. If after some miles treadwear suggests adjustment then I'll do so but usually the handling test gets me pretty close.

And I don't always run higher pressures. On my 1991 Miata I was disturbed on the drive home because the car was wandering on the highway, and didn't feel "on rails" like my test drives. When I got home I found the tires overinflated by about 8 psi. Returning to the recommended pressure set things right. I followed up by testing adjustments as above, but the recommended pressure truly was the best for that car/tire combo.

I too notice how twitchy the steering is on my 2019 Leaf. While checking the tire pressure, I noticed that the cold pressure was ~38-39 (probably from the last dealer service when it was still really cold) so I lowered it back to 36 as I do prefer a softer ride and I noticed that the car tracks better and less twitchy. It still doesn't track as straight / stable as say a Benz sedan at high speeds but acceptable!

Now I can hold off on getting new tires until these wear out a bit more - https://www.mynissanleaf.com/viewtopic.php?t=24350

38psi is a better, and possibly safer, pressure to run on both the Gen 1.X and Gen II Leafs than 36psi. I can't tell if you just like slower steering response, or if there is another issue, like the car having tires on it that oversteer. I suggest that, if you want to run 36psi, you check it once a week, because you don't want to run much less than that.

Nubo said:

Snargleblarg said:

I think it's more of an early-adopter / enthusiast thing. Most of the knowledge and culture of this forum is born of the original 24kWh Leaf and its very limited range. EPA rated 75 miles from 2011 to 2013 (due to EPA averaging the 100% capacity and the 80% capacity) and then rated 84 miles for later models. Most folks buying those cars were not your normal car owners. They were willing to take on the unique challenges of a short range EV. And I expect there was tons of desire and even need to push the limits of the car's range. ...

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Yes it's informed by the early adopters, but had more to do with tire wear than hypermiling, I think. The early models shipped with a version of Bridgestone Ecopia tires that had very pliable sidewalls. Many owners had to replace tires at shockingly low mileage, and it was shoulder-wear, a classic sign of under-inflation. I had very even wear across the tread in my 2012 by running at 44 PSI. Also, better handling. On the 2015 with OEM Dunlop tires the magic number for me was 42 PSI.

Treadwear is something that takes time to develop and evaluate. Handling gives much more immediate feedback. My practice for many years with any new (or new to me) vehicle or new tires has been to drive several days, adjust pressure by 2 PSI, and repeat. I evaluate handling at each step and that's how I choose. If after some miles treadwear suggests adjustment then I'll do so but usually the handling test gets me pretty close.

And I don't always run higher pressures. On my 1991 Miata I was disturbed on the drive home because the car was wandering on the highway, and didn't feel "on rails" like my test drives. When I got home I found the tires overinflated by about 8 psi. Returning to the recommended pressure set things right. I followed up by testing adjustments as above, but the recommended pressure truly was the best for that car/tire combo.

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This ^^^
I was one of the early'ish adopters to have my Ec"rap"ia OEM tires wear out before 20k miles, I was shocked and not happy. But as I didn't drive my Leaf that many miles it was over a year before I noticed the sidewalls getting bald and 2 years before I just had to replace them, even though the middles still had 50%?? tread left. I even paid(the car was over 12 months old) to have the car aligned only to hear it was only a "little" off. As much as I didn't want to give Bridgestone any money for making such a crappy wearing tire(the OEM Ecopias are apparently made specifically to make a price point and tend to have much faster wear than the Ecopia II tires you purchase aftermarket) I ended up purchasing Ecopia II tires for a very good price and very low RR. With the OEMs I ran 38psi in the case of the Ecopia II's I ran max sidewall(44psi) and noted much better wear and bald sides. By 20k miles I could hardly see wear, I'm a firm believer in max pressure and have been doing this on my other vehicles all with no problems. My new Prius Tires are even 54 psi max, those I run at 52, 54 just seemed so high :lol:
Honestly, I really think Leafs with their added weight should have load range C tires which have a much stiffer sidewall, unfortunately, when I looked into them for my Leaf I was told they didn't come in the Leaf size, that was for Crossclimate 2 tires, which I think will be the only tires I purchase anymore, due to wanting better winter traction and not having to swap tires 2x/year.

(Crossclimate 2) will be the only tires I purchase anymore, due to wanting better winter traction and not having to swap tires 2x/year.

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I thought about those tires too, but decided to instead buy Nokian Hakkapeliitta R3's on steelies for winter and Ecopias on the stock alloy wheels for summer.

The Ecopias definitely suck in the rain, to the point of being dangerous, so I tend to run the Nokian's well into spring before making the swap.

Given your experience, I think I will give the CrossClimate 2's a try when my Ecopias wear out. I love the Nokian's, hoping to get at least another winter season out of those regardless of which tire I use in the summer.

LeftieBiker said:

38psi is a better, and possibly safer, pressure to run on both the Gen 1.X and Gen II Leafs than 36psi. I can't tell if you just like slower steering response, or if there is another issue, like the car having tires on it that oversteer. I suggest that, if you want to run 36psi, you check it once a week, because you don't want to run much less than that.

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Thanks! Keeping the tires at 36 and checking often for now until I can swap the Ecopia and budget Sumitomos for proper Summer tires. Hopefully those will help with steering feel

I do prefer slower response at highway speeds. the PHEV C class I had (that got me interested in EVs) before the Leaf was amazing with its active steering - very responsive at lower speeds and nicely weighted at high speeds giving it that sure footed feel. The air suspension was just icing on the cake