Tire Pressure on highway trip.

Climbitnow · Aug 3, 2011

I’m taking my 2010 RAV4, V6, 4WD Limited on a 3,000+ highway mile trip to Colorado soon. Cargo includes: skinny runt me, two fellow hikers, both 200 pounders, and a lot of hiking stuff (backpacks, boots, groceries, laptops, suitcases full of clothes for 12+ nights, etc.). This will be the most the RAV has been loaded so far (7,500 mi on the odometer).

The recommended tire pressure for the 225 65R17, Bridgestone Dueler H/T 687s is 32 psi. I have always run them at 34 psi since new. Tires have been rotated once to date.

The ‘Tire and Loading’ placard on the door frame says the ‘Combined load of passengers and cargo should never exceed 825 lbs.’ The placard does not mention any change in tire pressure, from 32psi, for any change in loading. I would estimate our total load for this trip at about 650 lbs. (650/825 = 79% of max load). The tire sidewall information says, “Max load: 1,819 lbs @ 44 psi”.

The Bridgestone Tire Maintenance, Safety and Warranty Manual only says to follow the manufacturer’s recommendation for tire pressure. (lawyer talk).

Considering the load I will be carrying, would it be advantageous, to get the best mpg possible, to increase the tire pressure for this trip? Air temperature on the trip out and back will be in the mid 80s at least, and for almost two weeks at our destination the daily highs will only be in the low to mid 70s.

Thanks for any advice.

Tom

Dr. Dyno · Aug 3, 2011

I'd run 40 psi cold for a good compromise of mileage and ride quality. I'd inflate with nitrogen if possible. You can find it in Indiana, race car country.
Don't put any of your gear on the roof, it'll kill mileage. Run 70 mph max even tho you may hit speeds limits of 75 out west. My brother-in-law who was driving back to AK from CT, a 6000 mile trip, had his mileage drop from 28 to 17 going thru Montana at 75mph with some extra cargo he picked up on the roof rack. The V6 ran so effortlessly he didn't notice until the next fillup. After that he slowed down, stuffed the gear into the car and got the mileage back.

Climbitnow · Aug 3, 2011

Dr. Dyno said:
I'd run 40 psi cold for a good compromise of mileage and ride quality. I'd inflate with nitrogen if possible. You can find it in Indiana, race car country.
Don't put any of your gear on the roof, it'll kill mileage. Run 70 mph max even tho you may hit speeds limits of 75 out west. My brother-in-law who was driving back to AK from CT, a 6000 mile trip, had his mileage drop from 28 to 17 going thru Montana at 75mph with some extra cargo he picked up on the roof rack. The V6 ran so effortlessly he didn't notice until the next fillup. After that he slowed down, stuffed the gear into the car and got the mileage back.

Sounds good. I removed the roof rack crossbars a couple of months ago, wind noise dropped appreciably. Almost all of the speed limits will be 70mph so that is where I will set the cruise control. When it gets mountainous, west of Denver, I will kill the cruise and deftly manage the big grades by speeding up somewhat going down and letting the speed drain off going up.

Thanks,
Tom

Dr. Dyno · Aug 3, 2011

Good, sounds like you've got it deftly covered.
One interesting note. On a trip from CT to Nashville in my Accord my wife got two mpg better than I did at the same (or very close) speed on similar roads, mainly I-81 in VA. The only difference was I always use Cruise Control, she never does. I finally figured out how she did it. On Cruise Control I pull out early when approaching a Semi so I don't get caught behind it and have to go off & back on cruise. She's a very patient driver and didn't care if she got caught behind a truck, often following them for some distance. And there are a ton of trucks on I-81. Drafting them and slowing down while she did gave her two mpg better than my passing them immediately.

kpadget · Aug 3, 2011

One thing to note: when you get to CO, your tire pressures will be at least 2 psi higher than what you fill them to in OH. I have the same tires on my RAV and just completed round trips from Denver to Vegas and Denver to Omaha; I ran 35 psi on both trips. I touched 28 mpg a couple of times, but mostly high 23 to high 25 mpg. I drive posted +5 mph, so in UT there is a place posted for 80 mph (a test the sign says). Most of the driving was at 75 mph - 80 mph as I want to get to where I am going! So, given my speeds the mileage is respectable.

I have found that if one can keep the speeds below 70 mph, one will see higher mileage. I use the cruise control extensively but have found that my foot actually does a better job for higher mileage. Go figure. But I don't slow down behind big rigs!

For some reason I get some of my best mileage in the mountains here - going uphill. This baby likes to run at 4000 rpms! The Grand Junction to Denver leg was slightly over 28 mpg.

So, have fun with your trip and possible experiment a little with the pressure and driving technique/speeds. Remember, you are going to be moderately+ loaded going uphill ALL the way here once you hit KS. Happy hiking!

co_mtn_grl · Aug 3, 2011

Climbitnow, this is a bit off topic but I have to ask. You are planning on taking lots of pictures and sharing them with us, correct? :mrgreen::mrgreen::mrgreen:

It would be great to see Colorado from another person's perspective

Climbitnow · Aug 3, 2011

co_mtn_grl said:
Climbitnow, this is a bit off topic but I have to ask. You are planning on taking lots of pictures and sharing them with us, correct? :mrgreen::mrgreen::mrgreen:

It would be great to see Colorado from another person's perspective

Definitely! I love taking pictures of the mountains and my RAV4 and you will see them for sure!

This is my second hiking trip to CO but I did not have my RAV on the first trip.

I liked your pictures of some of those rough roads that you wisely avoided, I will do the same. The other car in our group is a 2005 GMC Envoy 4WD and loaded with all the options. He has a real super low gear set up for real 4 wheeling. Like last year, we won't be getting too adventurous with our SUV investments as long as our legs keep working.....

RTexasF · Aug 3, 2011

For me 40 psi in the tires makes it ride like Fred Flintstone's car........harsh and too brutal for me. I have found that 35 psi all around is a happy medium. Ride not harsh yet decent cornering ability and mileage. Using that psi and my foot (not cruise) yielded 28.9 mpg on a 150 mile jaunt. The road was mostly flat and the A/C was on all the time. Now that was with 100% gasoline. I doubt I could duplicate it with the current E-10 fuel.

Climbitnow · Aug 3, 2011

kpadget said:
One thing to note: when you get to CO, your tire pressures will be at least 2 psi higher than what you fill them to in OH. I have the same tires on my RAV and just completed round trips from Denver to Vegas and Denver to Omaha; I ran 35 psi on both trips. I touched 28 mpg a couple of times, but mostly high 23 to high 25 mpg. I drive posted +5 mph, so in UT there is a place posted for 80 mph (a test the sign says). Most of the driving was at 75 mph - 80 mph as I want to get to where I am going! So, given my speeds the mileage is respectable.

I have found that if one can keep the speeds below 70 mph, one will see higher mileage. I use the cruise control extensively but have found that my foot actually does a better job for higher mileage. Go figure. But I don't slow down behind big rigs!

For some reason I get some of my best mileage in the mountains here - going uphill. This baby likes to run at 4000 rpms! The Grand Junction to Denver leg was slightly over 28 mpg.

So, have fun with your trip and possible experiment a little with the pressure and driving technique/speeds. Remember, you are going to be moderately+ loaded going uphill ALL the way here once you hit KS. Happy hiking!

We will be staying at ski condos at about 10,000 feet above sea level. Then we drive UP to trailheads every day at 11,000 to 12,500 feet. I'm thinking 37 psi would be good compromise. I'll be tracking every gallon of gas.

It's kind of odd arriving in the mile-high city of Denver and realizing we have 4,000 more feet of climbing heading west.

Thanks for the tip.

Blogson · Aug 4, 2011

RTexasF said:
For me 40 psi in the tires makes it ride like Fred Flintstone's car........harsh and too brutal for me. I have found that 35 psi all around is a happy medium. Ride not harsh yet decent cornering ability and mileage. Using that psi and my foot (not cruise) yielded 28.9 mpg on a 150 mile jaunt. The road was mostly flat and the A/C was on all the time. Now that was with 100% gasoline. I doubt I could duplicate it with the current E-10 fuel.

Agreed on the tire pressure - 35 psi is a good compromise.

If you can get your hands onto more of that 100% gasoline can you ship a half tanker load here?? All we can get is the E-10 stuff . . . Many thanks!

rav4two · Aug 5, 2011

I normally run 37.5 PSI in the front, 36.5 PSI in the rear. For loaded high speed freeway driving, I only increase that by 1 PSI front and rear. Any higher and impact harshness becomes a problem, and handling worsens as it skips on washboard surfaces. We've traveled a few times with 1000+ pounds of passengers and stuff and haven't experienced any problems with those pressures. Tire wear is good and even (well, excepting some outside shoulder wear due to exuberant cornering) on all four tires.

cpotoso · Aug 5, 2011

Dr. Dyno said:
... I'd inflate with nitrogen if possible...

A mix of N2 (~78%) and O2 (~21%) behaves exactly the same as pure N2 as far as your car is concerned so do not bother. The ONLY time it makes a difference is if you expect that your tires could get so hot that small amounts of powdered rubber could burn (they won't if there is no O2) which is why they use N2 in high performance vehicles/airplanes/etc. I am quite sure that your RAV4 will never get the tires hot enough, LOL!

Tire Pressure on highway trip.

Climbitnow

Dr. Dyno

Climbitnow

Dr. Dyno

kpadget

co_mtn_grl

Climbitnow

RTexasF

Climbitnow

Blogson

rav4two

cpotoso

Top Contributors this Month

Recommended Communities