How Important is Tire Pressure for MPG?

Generally higher tire pressure will result in better mpg because less energy is wasted in the flexing of the tires. My dealer puts in 41 psi all around. The owners manual says 35 psi front 33 psi rear. The tire calls for 44 psi max. Some posts on this forum indicate higher than 44 psi being used. I think that ride sufers a bit at higher pressures

 

If you haven't checked them, they could be below 35/33 (sometimes dealers lower them for a softer ride, or they could slowly fall over time). But you're getting good mileage, so they're probaby still at the recommended minimum.

Ask TonyPSchaefer, he swears by higher tire pressure and he's got good numbers to back him up. But I'd say going from 35/33 to 42/40 would increase your mileage at least 5%, or about 3-4 mpg for you. That's a guess, YMMV. Dropping below 30 psi is where the you really get a mileage hit, probably lose 10% or more ( >5 mpg).

 

That sounds like something my sister would say. If you haven't checked your tire pressure, you don't know what's in there.........Don't ever
nice person-U-ME anyone does anything right, when it comes to your car, or anything else.

Increasing your tire pressure is one of the first basic steps in the quest for better fuel economy. Slowing down comes first.
For those that choose to do so, 42psi (f) and 40 psi (r) is considered to give great results, without sacrificing ride quality. I've found above that pressure the ride is little harsh with no improvement in MPG.

 

On a Touring model you can pump them to 45/45 and still get a nice smooth ride.

 

:rockon: I am now a firm beleiver in keeping the fronts at 40 and the rear at 38. I have had my Prius since 3/27/08 and this past weekend I checked the pressure of all 4 tires and they were closer to 32 psi all around. Not even close to the 35 psi per factory spec's. Had been averaging a best 48 mpg.
Me and the wife took a 80 mile round trip from Plano TX to Denton TX to Camping World. Immediately once up on Hwy 380 W bound started seeing 50+ and at the 1/2 way mark 55.2. The wind was stiff yesterday coming directly toward us. Speed on average btw 55 and 60 mph. And if you all are familiar with N. Texas there are hill's on 380. So "YES" I am checking tire pressures at least monthly from here on out.:rockon:

 

I'm running 50 48 on stock tires. The ride is great. The mileage is great. I'm happy.

 

Do note that the max pressure given on the sidewalls of the OEM tires is 44 PSI. Higher pressure may increase the chances of a blowout.

 

I have observed a 2-3 mpg increase in fuel economy by going to 42/40 psi.

 

That's for the Base and Standard models 15" tires, the Touring has different 16" tires.

 

I run about 60 psi all around. I have been doing it for two years. It adds about 4-5 mpg. FYI - low air pressure is more dangerous than high pressure.

 

Do you know what the max pressure is for the 16" tires ?

 

rpiereck,

Yes, the Touring has 16-inch tires, but Richard Schumacher is correct in that the side wall of the 16" Touring tire states "44 PSIG Max".

priusuk2008,

Please see above. Max pressure for the Touring 16-inch tires is 44 PSIG.

 

Thanks for the info rwhoyle

 

I have the Touring and my side wall clearly reads "51 PSI Max." I will take a picture of it when I get a chance if you want. I didn't want to bump my tires up past the maximum, but when I saw 51 PSI max, I immediately put my Prius to 51 front and 49 rear. I'm thinking about bumping it higher since I do not think the ride is bumpier at all.

 

Yep, mine says 51 psi max too.

 

Top 6 factors that affect MPG in order

1) Learning to accelerate at the efficient range of the engine
2) To get the car into stage 4 where the engine shuts off immediately after lifting the foot of the pedal
3) Tire pressure
4) Route length and selection
5) Avoiding rush hour
6) Avoid using heating or cooling for city driving

I am at 49.5 since Jan 13th (~5000 miles)

 

I just attended a new owner's event at my dealership. The service manager stressed the importance of correct tire pressure and of a clean engine air filter, in attainment of the best mileage.
Add proper driving techniques, low traffic roads and a stiff tail wind downhill and you have some pretty good numbers.


ZC1