Let's talk tire pressure

When I got the car, it was at 40/41 (cold). Is this too high? Recommended is 35.

The door sticker is the "correct" pressure to use. I often run mine at the maximum recommended cold pressure (as shown on the tire sidewall) when maximum range is desired or when I know I'm not doing any aggressive driving. There's a noticeable reduction in ride quality, but not enough to justify the range hit when I need the range.

Just by increasing your tire pressure from 35 to 44 psi, you will see a measureable improvement in efficiency. Note that this is NOT recommended by GM, so you do this at your own risk.

Bryce

My experience on the Volt tires, suggested running the tires at 42-45 PSI despite a GM recommendation of 38 PSI to maintain ride quality. Many Volt owners said that tire wear was actually better at 45 psi as the tires were under inflated at 38 PSI.

I'm not sure if the same applies for the Spark EV, however I tend to run my tires at 38 PSI vs. the recommended 35. When I got them from the dealer it was at 30 PSI but that was due to it sitting on the lot for 500 days.

I run them at 45 psi, and it fluctuates between 42-47

The classic approach is to keep an eye on tire wear. The tires should wear evenly from side to side. Overinflation will wear out the center sooner, under inflation would wear out the sides faster and stress the sidewalls.

I slightly overinflate my tires on all of my cars (compare to recommended my OEM) except the Sparky, this one gets the max allowed on the sidewall. Usually after pumping it to the max at the Discount Tire or any other place, it drops to 41lbs measured in the morning.
I am still to see any of my tires waring out in the center, in the past I saw plenty of the sides worn out. I suspect that manufacturer and resellers goal is to get you to buy tires more often rather than keeping you safer.

I have avid ascends on the front, stock on the back so I keep that at +2 PSI (47 front, 37 rear) in normal warm So Cal weather so that when it's cold out I don't drop below 45/35. When it's real hot they'll get to around 48-49 and 38-39

mczajka said:

When I got the car, it was at 40/41 (cold). Is this too high? Recommended is 35.

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I set mine to 37 cold. Works for me.

I hate to be a spoiler but 4x4 off road experience has taught me that high frequency shakes and jiggles are extremely bad for batteries and light bulbs. Even at the recommend 35psi the Spark rides rougher on the highway than my 4x4 did on the trail. I'm sure hoping they did a much better job stabilizing these batteries than the typical lead acid.

One other thing to remember is that an overpressurized tire is more likely to get a crack if you run over something, hit a pothole, or jump a curb. And these tires are pretty weak. I accidentally nicked my curb pulling into my driveway and it cracked the sidewall.

nozferatu said:

mczajka said:

When I got the car, it was at 40/41 (cold). Is this too high? Recommended is 35.

Click to expand...

I set mine to 37 cold. Works for me.

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I do too. And remember, too high a pressure leads to squirrely handling, faster center tread wear, and a greater likelihood of blowout. It's all about balance.

About a week ago I bumped up my pressures from 35 to 40. I have noticed no significant differences. It seems to be slightly more efficient and squeal a bit less in hard turns, but it could be placebo.