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SUVs Honda Pilot Honda Pilot Real World MPG
981 messages, Last post on Oct 23, 2009 at 12:54 PM
You are in the Honda Pilot Forum. Your Hosts are steve_ & tidester
bought 09 pilot ex 4wd end of sept getting around 16.5 mpg city,20 21highway all the sudden dropped to13mpg overall took to dealer ran codes told me nothing was wrong could be due to the additives added to gas in winter NEVER herd of that also said same problem with mini van I thoght VCM is supposed t give better gas mileage
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Replying to: dschnit (Jan 18, 2009 5:16 am)  Joking aside, winter fuel does typically cause a drop in fuel economy due to the additives in it; the dealer isn't yanking your chain. VCM does help fuel mileage, and I suspect yours would be worse without it. Where do you live? Do you warm up your car in the morning before driving it during the winter? |
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I have a 2004 Pilot and I was getting 23-24 on the highway. My mileage suddenly dropped to under 20 on the highway. The only known change was that I put on a set of Wrangler MS tires. I had the dealer put the vehicle on the computer and they said there was no problem. Has anyone experienced a similar problem? I can't believe that it is just the tires.
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Replying to: peteinny (Jan 22, 2009 12:22 pm)  Serously. If you just had them installed, tire-stores are notorius under-inflators. Cushy/quiet ride for you, faster wearing tires for them. Win/win!
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Replying to: peteinny (Jan 22, 2009 12:22 pm) Larger tires roll a little farther with each rotation. The speedometer/odometer is reading rotations. At indicated 70mph you might be actually moving 73 or so. (Just using that as a number). There is more wind resistance. Also the "Effective" gear ratio for the axle has been changed by the larger tires and the engine under a heavier load while pushing the car through 74 mph air while the speedometer is only seeing 70 mph. If the tires are wider, there will be more friction and resistance as the tires contact the road. If they have a more aggressive tread, there is more wind resistance to their turning. If they are heavier, there is more weight for the engine to get and keep turning as well as more weight added to the vehicle. And yes, check the tire pressure. Each item is not much by itself, but can really add up. Especially if you tend to drive at 70+ on the road. When you calculate your MPG by dividing gallons used into miles driven for a tank of gas, keep in mind that (with larger diameter tires) you actually traveled farther than the odometer showed, so your mileage is a bit better than your calculations will show. FWIW my Scangage says I get several mpg less at 70 than at 60 mph. I believe the largest culprit there is the wind resistance on the front of the 03 Pilot. Basically wind resistance is the speed squared times the frontal area of the front of the vehicle. As the frontal area remains ( unless roof top carries and stuff are added) constant let's call that "A". At 60 mph the formula would look like 60X60XA or 3600 X A. At 70 mph it would be 4900 X A. So 70 mph creates 36% more wind resistance than 60 mph. That doesn't correlate to 36% less mileage, because wind resistance is just one of the things that figure into the mix. Without getting into efficiency of the engine at various RPM, blah, blah,,,,,, In a nut shell, yes, the type and size of a tire can create a noticeable difference in mileage. Kip
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Replying to: kipk (Jan 23, 2009 6:22 am) Just to be clear, friction does not depend on width. Wider tires are made of softer compounds which have a higher coefficient of friction. It's the difference in composition that matters and not the width per se. tidester, host SUVs and Smart Shopper
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Replying to: joemama33 (Jan 22, 2009 1:54 pm) Thanks |
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To add to what tidester said: Tread pattern matters too. The more aggressive the tread, the more rolling resistance. Off-road tires like the Wrangler will cause a drop in fuel economy vs a street or M/S tire. Lastly, when inflating the tires use the the sidewall data, NOT the plate on the car. That plate is only valid for the OEM tires that come on the car. Inflate while tires are cold, too. I inflate to 90% of the maximum rated PSI to obtain the best economy and tire wear balance. 95-98% if I'm pulling a trailer or have a big cargo load.
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Replying to: joemama33 (Jan 24, 2009 3:17 pm) Over-inflating your tires will reduce their contact patch with the road and that's not safe. And they are more easily damaged if you hit a pothole. And they will make your ride noisier. Tire Rack |
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Replying to: tidester (Jan 23, 2009 11:03 am) It was/is my understanding that a wider tire creates more friction even though it has the same tread design and tread composition of the narrower one. Thus the reason that a "road" bicycle tire is built so that it is only "running" on the very narrow center tread. Actually the tires on our two mountain bikes are also designed to run on the narrow center "Band" or tread when on hard surfaces. On rough or soft surfaces the aggressive tread can contact the ground. From personal experience I know that a bicycle with 30# air pressure requires much more energy to peddle than one with say 50#. And a car with higher tire pressure will get better mileage than one that is at under inflated or even correct pressures. Suggesting less energy required from the engine for higher inflated tires. Lower pressure allows more of the tire to contact the road . At least it sure seems that way to me.  As you say, an over inflated tire can be dangerous. Main reason being that it will be ballooned so that the center of the tread is taking more of the vehicle weight than the outer tread and there is less contact on the road, for emergency. Mileage may increase, but premature wear of the center treads may also. Most tires wear out on the outer treads first, because folks don't check the pressure often enough, and run the tires under inflated. This will also result in poorer fuel mileage. Works for me! Kip
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