tire pressure - what are your psi's?

I have Michelin Energy Saver Tires, 195 X 65 X 15 with over 18,000 miles on them. From when they were first installed I had all four at Costco inflated to Max Sidewall Pressure, 44 PSI of Nitrogen.

I rotate every 5,000 miles at Costco and have them check the pressure it usually looses maybe 1-3 PSI during that duration.

Tires are wearing quite well. I expect 60,000 miles.

MPG's are a lot better than factory stock Yokohamo Avid tires.

I noticed a 2-3 mpg increase. Last tank was over 57 MPG with the Avid it would have been about 54 MPGs.

Alfon

 

Dan Kroushl, organizer of the Prius Marathon Toyota.com : Hybrid Synergy View : 2005 : Fall : Prius Marathoners Top 100 mpg, did a lot of testing with tire pressure on his Gen II Prius with the stock Integrity tires. His conclusion basically was anything up to about 67-68psi increased MPG's enough to be able to measure it. Higher numbers still increased MPG's, though so small it was difficult to measure. So anything below 68psi should give you an increase of MPG's with an inverse risk to the comfort of your bottom. And tire life also increased as well.

Wayne

 

I decided to do more psi testing and I wanted to try the higher psi on different roads. I had about 1/2 tank of gas so we took a road trip down to get a famous Meersburger at the Meers - Store & Restaurant near Fort Sill, OK. (yes, it really looks like that)

I aired up to 42/41 psi. The wind was 15 - 20 mph S-SW so we had a head wind going down for the first 1/2 of the trip. We drove secondary state highways ranging from 55 - 75 mph. The temperature ranged from 92° to 98° and we used the A/C 100% of the time set to 80°.

I set trip B to zero. It showed 279 miles @ 63.8 mpg with an average speed of 47 mph. This is a lot better than what I got with the same psi on the Big Bend, TX trip. I can say these roads are a lot smoother that what I drove on the Big Bend trip.

I didn't expect the mpg to be this high with the terrain, speed, and A/C usage but I'm impressed.

I'm going to do more testing but I'm sticking with 42/41 psi or higher for now.

PS, we started with 1/2 tank and still had 2 pips left at the end after 279 miles. I love this vehicle.

 

Stock Yokohama tires - door jam says 35/33 (I think). Tire says max 44 PSI. I'm running 44 psi on the fronts and 42 PSI on the back.

 

Goodyear Fuel Max tires, 195/65-R15. 40/38 PSI.
I am not exactly thrilled with 48 MPG, but handling is acceptable. I live in the mountains.

 

36 psi nitrogen all around on the Yokohamas. Little over 3100 miles on the vehicle--average mileage so far 44.89 mpg actual.

 

40psi (Front) 38psi (Rear) on both of my 2010 Prius vehicles. I check the cold tire pressure about every two weeks.

 

I use 47/49 in both my winter and summer tires.

 

How did you decide on higher pressure in the rear? I haven't gotten around to experimenting yet so don't have an opinion on whats best, I just follow lemming like with 2 psi higher in the front at 42/40.

 

I use the recommended pressure written on the driver's door.
One question. Is there a tire pressure alarm warning? In case the pressure is too low?

 

43/43. I just purchase my Prius last Saturday. Bummed about how many hills I encounter on my daily route. I'm putting hypermiling to everyday use, and still only achieving 59mpg. I feel like all the people posting 70-90mpg must live areas without hills. Or, with more practice my numbers will increase, and hopefully before the prices rise to 3.50-4.00 a gallon. I really like this forum.

 

42/40 Been running that for a while with no problems.

 

You're kidding, right? You're bumming out while getting 59 mpg?

I've had my Prius for almost 3 weeks. Just today I (finally) checked tire pressure and then inflated to about 41 front and 40 rear. The pressure was about 29 before. I've only averaged 38 mpg on the 300 miles I've driven.

I take mostly short trips of 10 mi or less, though, and it's only started to warm up above the 40's here. And I know short trips will not net great mpg numbers.

I think you should be jumping for joy at the numbers you are achieving! At this point I'd be happy with mpg's in the 40's !

 

I have the P215/45R17 tires on my Prius, did not notice any other posts in this thread for 17's. My car is still new and I did not check the pressures until 4 days ago after having the car just over a week. The recommended pressures are 33 PSI Front, 32 PSI Rear mine were set to LF 36 PSI, LR 36 PSI, RF 37 PSI, RR 35 PSI. Max cold inflation pressure is 51 PSI for my tires. I raised all four tires to 40 PSI. I am not sure if I like it at 40 PSI it feels to stiff and transfers all of the uneven road right in to the car. I will probably drop them back down to 36 after this tank of fuel in order to see the MPG impact of the higher pressure setting.

 

36 front and rear. ave mpg for 2010=52.7

 

Right after I bought mine in Nov 2010, I upped my tire pressure to factory spec's 35f/33r from about 30 all around. After reading about the benefits of increasing them to 40f/38r, I tried that for a couple weeks. I noticed several things; Increase in mpg's was undetectable. Car doesn't track as well going down the road as I need to do more steering corrections to keep it straight. I also felt every little bump, pebble, ridge, rough roads were the worst, and I had an intermittent resonating vibration at various speeds. Because of the rougher ride, I heard more squeaks and creaks in the entire dash rather than just from the glovebox I experienced previously. Finally, there was more tire whine as speed increased. Therefore starting today, I lowered them back down to 35F/33R. Any incremental increase in mpg's is not worth the downsides I would have to put up with.

 

I tried 40/38 for a week and got the same noisy/rough results you did. Down to 37/35 right now and may go to 36/34. Feeling every single bump and texture in the road just isn't worth the 2% or whatever mpg savings.

 

I just went to 43 all around. Handling is much better, but not sure yet about MPG. Still testing to hit the "sweet spot". On my previous car, '07 Camry Hybrid, that was 42...