Best Tire pressure for prius

Do you mean MPG ?

 

I was running 45psi in the stock Integrities on my 2006. Since you have different tires I suggest the max sidewall pressure. In theory, the higher the better but eventually you won't notice an increase.

 

From the standpoint of tire wear, running very near the Max air pressure seem to minimize uneven wear, Toyota's recommended tire pressure wears as an under inflated tire, Toyota appears to be biased toward ride comfort in the Gen II. In theory minimum wear should result in maximum traction, but I am not sure anyone has proved that in the specific case of the Gen II Prius.

 

I run 40 PSI front and 38 PSI rear in Nokian WR tires. Using the max. pressure on the sidewall is not recommended by tire experts (it's 50-55 PSI in my tires). It gives you max. load capacity but can make the tires more susceptible to damage from road irregularities.
Higher pressures work better in snow because the tire "self cleans" better (ejects snow from the tread). It can also work better in rain because the sipes may be held a little more open. It usually results in longer tread life as "squirm" is minimized.
On the downside, you will have a rougher ride.
Modern tires don't "balloon" like older tires used to. Hence you don't get excess wear in the centre of the tread with higher pressures. Unless you get extreme.
You'll find a wide range of pressures being used by owners, from the listing on the door-jamb placard (drivers door) to the max pressure on the sidewall. The most common is 42 PSI front and 40 rear (keep the 2 PSI difference whatever you use due to the weight difference front to rear). In the extreme, one lady we read about here had 90 PSI in the tires (until one exploded and blew off the fender).

 

I have a "new to me" 2009 Touring in Driftwood Pearl and 36.5K miles. She appears to have nearly new Bridgestone Potenza G019 Grid tires. What is the pressure I should be running them at to get the best mpgs? (I currently have them at 39 front/37 back.)

Thank you~~

 

cold, 42 front, 40 rear

 

A couple of facts.

The higher the pressure the better the mileage although it's not wise to go over the pressure on the tire's sidewall.

The further you go above the factory recommended pressure, the smaller the gain for each additional psi.

A widely shared opinion here is that someplace around 38-40 psi front and 2 psi less in the rear is a good compromise so you are already there.

 

Thanks for that. Needed the good laugh it gave me. I'm sure she thought it wasn't funny, but 90 PSI? My goodness.

Any reports on the relative impact on mpg of different pressure choices?

 

I use 42 front, 40 rear in my Prius Gen 2. I also want to add the matter of a fact, that the higher pressure, the biggest damages your suspension may get (Shock absorbers, joints, rubber bonds and stabilizers). So if you have a very nasty road surface in the most of the time, I'd recommend do not go above 42/40. Personally.

 

welcome, and thank you for the good advice!

 

I've been thinking along those lines. I mean, higher pressures reduce the tire's ability to deflect, so the springs and shocks get more exercise.

 

Agree, I tried 44/42, 42/40 in my 2010 Prius. This pressure may be good for highways, not for the side roads here in North East. Now I'm back to 36/34 and I'm really enjoying smooth ride, noticed only a small to non-existent drop in MPGs (1-2 miles per gallon).

 

I've gone 42 on all four, and I've been happy with the results.

 

I agree with the recommendation above (post #13) and run about 37f/35r, moderately above the factory recommended 35/33. I've read many threads on tire pressure and tried higher pressures but found the ride suffered and the mpg difference was negligible.

I think it's notable that even when going for maximum fuel efficiency in the 2016 Prius Eco model the engineers chose "special Dunlop Enasave 01 A/S 195/65-15 tires that have even less rolling resistance than the standard tires and are inflated to 39/36 psi front/rear rather than 36/35 psi" (source: Better—But Still Not Fun—to Drive ). It's reasonable to assume that Toyota's specification is the result of significant scrutiny and testing, well beyond what any of us can do. I'm not saying you can't eke out a bit less rolling resistance with higher pressure, just that now we have an official spec where ride, handling, etc. were likely optimized with a heavy weighting on mpg (at least for that tire on that model). It's also interesting that the front/rear difference is 3 psi on the Eco model vs 1 psi on the standard 15" tires.

 

Bumped upped to the max setting on the stock tires recently to 40/38, over the dealers setting at 35/33, and noticed an immediate 5-10% jump in MPGs; the Prius can seemingly glide forever now with minimal effort, it's pretty incredible... I'd be extremely worried about going any higher than that though, I live in Texas with wild temperature swings...

 

42 front - 40 rear. Rotate, "balance" and alignment check (adjustment as required) every 5,000 miles. After +110,000 miles best compromise for stability, tire wear and mpg. YMMV.

 

fro, do you cross rotate?

 

Negative, although I grew up learning to 5-way cross rotate with the spare back when "most" everyone had full size same wheel spares, hub caps and non-directional tires. Now with space saver spares and directional tires I just do same-side front to back. Guilty as charged!

 

Our OEM tires are non directional, but I still just rotate front to back, because it says in Owners Manual. Still it's a new one for me: Honda always recommended to cross-rotate.

One plus: all your curb rash tends to be on one side.