Last post on Apr 21, 2013 at 3:55 AM
You are in the Honda Fit
What is this discussion about?
Honda Fit, Fuel Efficiency (MPG), Hatchback
#2465 of 2554 Re: Honda Fit 2009 MPG [wtmkz]
Jul 18, 2010 (5:59 pm)
Nitrogen in Tire is a scam anyway. Our breathing air consists of >78% nitrogen ~18% oxygen and the rest are misc 'pollutants'. If the 'tire-air' is dry and free of oil, it will be just as good as garbage n2... If you really want to save gas, turn off the A/C. Your tire has a max PSI rating. Inflate it to 3 or 4 PSI below that number. The PSI call-out in your door jamb is a compromise from the manufacturer to get a smoother ride, That is why they are calling for ~32 PSI in most cases... I run my Element and CR-V at ~38 to 40 PSI improving the mpg by about 3.
#2466 of 2554 Re: Honda Fit 2009 MPG [cwalti]
Jul 19, 2010 (5:18 am)
I agree about the Nitrogen being an extra charge scam. Its claim to fame is supposed to be that the tire pressure will not fluxuate as much when the temperature changes. While it may help some, both our 09 RAV4 and 09 Ridgeline's nitrogen filled tires turned on their tire low pressure lights when the temps got down around freezing last winter. And I didn't have any Nitrogen available to add to them. So they got air!
There are two camps when talking about air pressure. Both will aggressively defend their stand.
I personally believe that inflating a tire to near the maximum on the sidewall results in the center of the tread bubbling out and bearing more of the weight of the car than the outer edges. Therefore wearing quicker in the middle. Also because less tread is on the road, the tire is less safe in wet weather and emergency maneuvers.
The tire will also ride rougher because it doesn't flex as easily. Over inflation can result in a bit better fuel mileage because less tread on the road results in less friction.
The tire pressure on the door jam reflect the tire being able to run with all the tread on the road equally across the tire. This has to do with the weight of the car and the sidewall construction. The car will ride better and handle better in emergency situations and likely last longer.
Makes sense to me that with EPA mileage ratings being so important these days, that the manufacturers would use tires inflated to the highest "Safe" pressure possible to obtain the best mileage possible.
The best way to find the absolute best pressure to meet safety and mileage considerations is to put a chalk mark across the tread and drive the car a mile or so on a straight smooth surfaced road without turning the steering wheel any more than necessary. When the pressure is correct for the car and the tire design the chalk will wear evenly across the tread.
Excessive pressure will result in the chalk in the middle wearing before the chalk on the edges. Too little pressure will result in the edges wearing off before the center.
With that said, if the vehicle becomes heavier due to load, towing, and so forth the tires will flatten more and need a bit more pressure.
Different strokes for different folks.
#2467 of 2554 Re: Honda Fit 2009 MPG [kipk]
Jul 19, 2010 (5:58 am)
I think the center-buldging is more a problem for the old bias-ply tires that the modern multi layer steel belts. These should hold contour pretty steady across a 'wide' pressure range...
#2468 of 2554 Re: Honda Fit 2009 MPG [cwalti]
Jul 19, 2010 (6:08 am)
You may be right. The best way to be sure would be to do the chalk thing.
Like I said, both camps will defend their beliefs.
#2469 of 2554 Re: My MPG before and after Idle Learn [manlok]
Jul 24, 2010 (9:10 am)
I'm doing a similar mpg test after I had the idle learn procedure performed by a local Honda dealer on my newly purchased 2006 CRV automatic. The best mpg I got was over 31, but this was on a relatively flat very good FWY a cruise control speed of 70 mph for 351 miles. The outside temp was fairly consistent 97 degrees F. More data to follow.
Jul 30, 2010 (8:11 am)
I run 40 psi and have no wear in the center of the tire. The tires actually last longer with more pressure because more pressure = less flex = less heat = longer life. The extra pressure also stiffens the sidewalls and make the tire handle better.
The only down side to more pressure (within reason) is a stiffer ride.
BTW - look in the manual of a BMW and it will recommend adding abut 8 psi for high speed autobahn travel. Would they say that if it was less safe?
Jul 31, 2010 (1:22 pm)
This is very interesting what you wrote.
I have been keeping my FIT Base Tires at the Manufacture recommended 32 plus 2 lbs=34
I may pump em up to 38 next time and see what happens.
I am always scared to exceed in fear that they will blow up under hot highway long drive conditions.
#2472 of 2554 MPG Results from my 3K Mile Summer Vacation Drive...
Jul 31, 2010 (1:51 pm)
I just got back from from my summer vacation. Drove my Base 2009 FIT 3128 miles over 10 days from Los Angeles to Portland, OR, then Seattle, WA, then to Vancouver BC, then back to Seattle, then to the Washington Coast, then down the Oregon Coast 1/2 way to Newport and then to Eugene, OR and then back to LA. I drove of course on the highways primarily, but also touring and parking around the stop and go cities, some traffic jams, stop and park for fuel, food, touring, 25 MPH zones on coast, road construction zones, etc., and approx. 5 to 6 hours of idle time looking at maps, GPS, phone, etc. (3 hours of that with AC on sleeping in the car in a rest stop). FINAL MPG over 3000 miles--per the car meter: 37.4. If I did not have the idle time, I am thinking it would have been closer to 38.
PS. No problems with the FIT or Tires at all--excellent performance the entire trip. Easy to drive, turn and park in large crowded cities.
#2473 of 2554 Re: Honda Fit 2009 MPG [wtmkz]
Aug 29, 2010 (12:28 pm)
It's amazing . I actually got 45 mpg yesterday driving on the freeway with no a/c and no passengers. Just me driving. Average speed 60 mph.
#2474 of 2554 Super unleaded vs Reg. unleaded
Aug 29, 2010 (3:45 pm)
Question. I use reg. unleaded. Has anyone used super unleaded and noticed any diference in the mpg? Thanks.