Optimal Tire pressure Prius 2010

Tires are Michelin Energy Saver Tires, 195 x 65 x 15, with over 22,000 miles on them. All four tires are inflated to Max Sidewall Pressure of 44 PSI (nitrogen/Costco).

Looks like they will be good for another 40,000 miles and are wearing beautifully.

We have expierence an increase of 2-3 MPG over the original Yokohama Avid tires.

These tires do roll better than any other tire I have owned and I have been driving since 1966.

alfon

 

Really, "a lot different", I think I am at least average at detecting differences in how my car drives and I can tell no difference whatever. I have tried a variety of pressures on both of my Prius and I can tell when I increase the pressure by 10 pounds over the recommended for fuel mileage. But 1 or 2 pounds difference front or back, there is no way I can tell. I'm not saying you can't tell, but I sure can't.

Measured my tread depth this morning, this thread started me thinking about it, and after 30K miles on my 215/45-17 Toyos I have between 4 and 6 32nds left on all 4 tires. Wear seems fairly even across the tread. I have been using between 45 and 50 pounds in these tires since I got the car and the edges still wear a little more than the center due to cornering forces. I don't think with modern tires we will see the classic "to much air wears them out in the center of the tread" these tires are steel belted and much to strong under the tread for that kind of wear pattern.

I have rotated my tires once at 10K miles and I was going to do it again today but after looking at wear and tread depth I see no reason to do so. I think with a properly aligned car it makes more sense to rotate tires as needed to even out wear from front to back, not to rotate them at some predetermined number of miles. Of course if you enjoy rotating tires or giving the dealer money to do so have at it.

 

I would not exceed the max pressure on the tire side wall. My Yokohama tires say max is 44.

 

Yes I kind of agree with that even thought I think they would take a lot more. My Toyos are 51 pounds for maximum load tires so I don't mind going to 48 or 50 lbs, I am running them at 45 psi cold now and the mileage is doing OK.

 

when are tires considered cold? How many hours idle?

 

I check them in the morning after they have set overnight. But I think "cold" means ambient temperature, not sitting in the hot sun or anything. I have noticed that pressures in the cool morning will increase by several pounds by afternoon, a 30 to 40 degree difference here this time of year.

 

+1. Being in the shade is important, if the sun has been shining on one side of your parked car, that side will read higher.

Rule of thumb is that your tire pressure will go up 1 psi for every 10 deg F temperature increase. That refers to the temperature of the air in the tire which is why the sun shining on the tire throws it off.

 

I not sure if it is true with the Prius, but with the Buick LaCrosse I traded in the tire pressure on it would go up about 4-6 psi when on the road. I kept them at 32 and driving on the road it would go to 36-38 psi.

 

Today I shopped online for a good tire pressure gauge. The Accutire/Michelin gauges appear to be manufactured by Measurement Ltd, and its website (measurement-ltd.com) displays the product line with downloadable "brochures". I could not there locate a digital gauge with a bleeder valve.

I nearly selected the $20 Accu-Gage EZ Air Tire Gauge (ghmeiser.com Model #EZ02) that lets you fill and bleed air with the dial gauge connected. Google "Tire Gauge with Filler Chuck".

But I discovered and ordered for $15 (normally $25) on sears.com a "Craftsman" digital gauge with a bleeder valve. (Sears Item# 02823020000) I'm convinced from the similarity of design and graphics in the downloadable manual that the gauge is manufactured for Sears by Measurement Ltd, the maker of the Accutire/Michelin gauges. It's also on kmart.com. No shipping charge if you order online and pick it up at your local Sears or Kmart. Here are links:
Sears: Online department store featuring appliances, tools, fitness equipment and more
Clothing, Toys, Electronics, Jewelry, Jaclyn Smith - Kmart.com

 

Just a heads-up, check your temporary spare tire pressure. Our $1500 dealer prep got us a temp spare with 40psi, should be 60psi. And it tends to lose air quicker, due to small size and high volume.

 

Don't forget the pressure pump that uses 110 volt power. They have a guage on them that is inaccurate but I mark the spot on the dial for correct pressure.

 

To the OP, are you sure you don't have nitrogen in your tires? If so, it won't do you much good buying a pump (but a gauge is still handy). I think many (most/all?) 2010s come with nitrogen??????

 

No. Maybe some dealers swap out the caps & maybe some deflate the tires & refill.

 

The car manufacturers don't buy into that nonsense, although they do use a gas mix that is 78% nitrogen.

 

Lol! I believe nearly every car ever made has that mix!

 

78% nitrogen. Yep, I even breathe that stuff! Imagine!!

 

All 2010's come with at least 78% nitrogen, and using a hand pump or air compressor (at home or at a service station) will also add 78% nitrogen. So if you're topping off a tire that's 100% nitrogen (assuming they can really do that) but 10% low, that means you'll be adding 7.8% new nitrogen and 2.2% other, so now your tire will be 97.8% nitrogen.

If you'd rather drive around with low tires, you can do that, but I guarantee your mileage will be better with 97.8% nitrogen than with tires 10% too low.


On a separate note, Mythbusters recently had an episode where they tested the effects of tire pressure on mileage, here's the video:
MythBusters: Tire Pressure Test : Video : Discovery Channel
Unfortunately, they don't have the results in this video !!?!
I recall they drove at 10 psi, 60 psi, and I think 30, 35, and 40 psi (35 was the manufacturer's recommendation). They showed maybe 6% improvement from from 35 to 40, but from 40 to 60 only another 1% or something. I can't find the results anywhere.
Since the Prius normally gets about 50mpg, 6% = 3mpg, 7% = 3.5mpg. I think people here would protest those results (if I remembered it correctly). Maybe there's already a thread on this.

 

Just the ones made on this planet.

 

Just a plug for Chevron in Canada, at least in BC lower mainland: they are one place you can still get free air.