zxcvbob
Rookie Author
Minnesota
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Message Posted: Apr 7, 2012 10:44:24 PM
Two years ago, I switched tire sizes on my Silverado C1500 pickup from the P255/70R16's that came on it to LT215/85R16's. The diameters are the same, and the load ratings are almost the same (the LT's can actually carry a little more.) I get about 2 more MPG in both city and highway driving, and the skinny tires handle better (even when pulling a trailer) and they have a lot more traction in the snow. The only problem is, if I take it to a shop for something, they often let the air out of the tires to match the door sticker. (I run them at 55 psi. The sticker says 30-something psi, but that's for the OEM fat tires, and the skinny tires are underinflated below about 45)
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CiVX
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Oakland
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Message Posted: Jan 27, 2012 11:57:00 AM
It depends on how you drive besides.
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dontuknowOH
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Ohio
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Message Posted: Jan 27, 2012 11:44:01 AM
I had installed 12.50x32"x15" on 10" alloy wheels in place of the stock 10.50x31"x15" oem 8.5" steel wheels/trim (both sets are traction tires).
The 4X4 vehicle had lower gear final cogs(oem trailer tow package),but the wheels alloy weight being lighter/tires heavier,slower speed read-out,results were better for my driving habits (mileage wise).
I have never checked the weight difference between the two sets of wheels,because the mileage improved slightly,ride improved,but braking suffered a bit(new rotors/drums shoe/pads etc.PB.(good but not Great still!
I'm not sorry I made the change,miss the softer brake pedelforce... results,possibly a better choice in disc pads/rear shoes, can improve it later. HABetterDay !
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jimmy544
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Boston
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Message Posted: Jan 27, 2012 10:43:01 AM
bigger diameter tires act like a lower numerical ratio gearbox. The tendency is for a little better mileage.
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rhail2
Champion Author
Kentucky
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Message Posted: Jan 27, 2012 9:10:09 AM
big tire cut gas mpg in half
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BrianJ48
Rookie Author
New York
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Message Posted: Jan 18, 2012 7:07:30 AM
I'm baffled by auto manufacturers move to larger tires. Just discovered cost of 18" snows - ouch!
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outlaw329
Champion Author
Austin
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Message Posted: Jan 13, 2012 5:52:46 PM
Yes the larger tires will cause your mileage to decrease. For years and currently have driven 4X4 Blazers and Jeeps that have been risen with larger tires. My current Jeep went from 14 to 12 mpg when larger tires were installed. The larger tires require the drivetrain to work harder unless you regear your axles. There is the added weight to deal with as well. Your vehicle is designed to get the best gas mileage with the tires they come with. Adding the larger diameter and added weight will decrease mileage.
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Gas_Buddy
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Maryland
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Message Posted: Jan 13, 2012 4:59:52 PM
Big difference? No, not a big difference but there will be a difference (for the reasons explained below).
What will make a difference between the two of you (and you haven't mentioned it) is your driving patterns, how you drive (i.e., heavier foot, etc.), and what you're carrying than one specific size larger.
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maryph1958
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Cincinnati
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Message Posted: Jan 13, 2012 4:38:03 PM
not sure
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maryph1958
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Cincinnati
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Message Posted: Jan 13, 2012 4:38:02 PM
not sure
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Bodiney
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Detroit
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Message Posted: Jan 13, 2012 10:44:13 AM
it depends on the overall diameter & the weight of the tires
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MAZmobile
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Baltimore
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Message Posted: Jan 13, 2012 8:41:53 AM
Check your tire pressure before your get a new tire size.
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MertieMan
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Lexington
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Message Posted: Jan 13, 2012 2:56:05 AM
You answered your own question in stating the tire size.
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oilpan4
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Virginia
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Message Posted: Jan 12, 2012 11:26:12 PM
In 2007 I went from P235/75R15 tires (about 29 inches tall) to goodyear 31x10.5R15 load range C tires and was fully expecting fuel milage to go down. The load range C tires weighed about 15 pound more each too.
But suprizingly fuel economy went up slightly on high way driving and seemed to stay the same in the city.
Apperantly larger tires and the lower cruising RPMs they provide have more of an effect on fuel economy than the change in ride hight and the tire weight difference.
http://ecomodder.com/forum/showthread.php/tire-size-change-need-answer-quick-20066.html
This guy over on ecomodder is switching to larger tires on his "95% highway driven" car and will have results soon.
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pilotmass
Champion Author
Boston
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Message Posted: Jan 12, 2012 7:45:38 PM
bigger tires = more weight poorer braking and lower mpg.
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GLM4205
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Toledo
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Message Posted: Jan 12, 2012 3:10:21 AM
I do'nt have.
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gasgzln
Rookie Author
Mississippi
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Message Posted: Jan 9, 2012 10:36:27 AM
Yes, a larger tire makes fuel mileage worse. A heavier oil in the engine will too.
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tattoo666TX
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Texas
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Message Posted: Jan 8, 2012 8:09:06 AM
If you change wheel/tire size you have to have the system recalibrated. Your speedometer will be wrong as well as your odometer, so anything you say your are getting for fuel mileage will be wrong also. I have a 2010 FX4 with 20 inch wheels/tires and was talking with someone that has the same truck but put 22 inch on. He said he was getting about 8-10 mpg less then before the change which would be 8-10 less then what I was getting. I asked him if he had the computer recalibrated for the larger tires and he looked at me funny. Then he went to Ford and asked, and then paid to have it done. Now his mileage is right back around what it was stock.
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Stormy150
Rookie Author
Ottawa
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Message Posted: Jan 5, 2012 1:36:43 PM
The larger the tires the better the fuel economy.
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PaylessKY
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Kentucky
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Message Posted: Jan 5, 2012 9:35:52 AM
If you move to a different size, have you odometer re calibrated.
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13Octane
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Tucson
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Message Posted: Jan 4, 2012 3:56:16 PM
not an expert here, but, if you change the diameter of the tire, you can no longer use your odometer for distance travelled.
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Tahoe2PA
Rookie Author
Pennsylvania
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Message Posted: Dec 27, 2010 5:59:34 AM
I am not complaining about my mpg. The comfort,4x4 and towing my travel trailer is worth the lower mpg. We also have a Vue for daily driving with 30mpg. The stock tires were 265/70/16 and I have 285/75/16 on now.
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matt8sj
All-Star Author
San Jose
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Message Posted: Dec 25, 2010 11:20:49 AM
Tahoe2PA,
one size larger....
do u mean ur rim size stays the same but your tires s one size wider?
as long as your tires s the same diameter as the stock tires then it should not matter that much.
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timmyC4
Veteran Author
Twin Cities
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Message Posted: Dec 25, 2010 5:54:00 AM
Skinny and tall is good for tire Mpg. Recalculate you MPG taking factoring in the extra size.
However, if you want MPG, get rid of the TaHO.
I drive a 90 F250 FIVE SPEED Manual 4x4 Diesel for hauling. Get 22.
Everyday driver is a 90 Jetta Diesel - 35 in town.
[Edited by: timmyC4 at 12/25/2010 8:57:36 AM EST]
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dieselb100
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Massachusetts
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Message Posted: Dec 24, 2010 7:37:36 AM
@Tahoe2PA
chemist74 is correct. The odometer is calibrated based upon the recommended tire size. I did the math for one of my cars P215/65R15 and assuming I go to a P225/65R15 the circumference difference is about 1.6 inches. All things being equal (weight, drag, etc) for a distance of 15 miles that means that with P215 my odometer would read 15 miles. But with my P225 my odometer would read about .28 miles less for an actual distance of 15 miles. If my mileage before was 15MPG and assuming my engine efficiency is the same at turning my wheel one revolution then my mileage is actually slightly better by .28MPG since I will go more actual miles on a tank of gas but my computed mileage is less by .28MPG since I will drive less perceived miles on a tank of gas.
[Edited by: dieselb100 at 12/24/2010 10:39:32 AM EST]
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DasAuto92
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Montreal
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Message Posted: Dec 23, 2010 11:41:26 PM
If your tire size as stated is larger than GM recommends it will change your RPM,MPH,& mileage.I assume your tires are larger by height but the same width.If your tire is wider the more rubber on the ground(width) creates loss of mileage,because of more resistence, but better handling.Sometimes less is better as there is less resistence.And if your tires are higher & wider it will take more power to start off.You didnt state the tire size of your friend and what yours are.
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Ryan456789
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Milwaukee
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Message Posted: Dec 23, 2010 4:42:19 PM
Should not make a 3mpg difference, but a wider tire or heavier tire will bring it down a little bit, but not from 17 to 14.
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chipote
Champion Author
Washington
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Message Posted: Dec 23, 2010 11:03:36 AM
Larger tires are heavier and use more gas.
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luvmyburgi
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Ohio
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Message Posted: Dec 23, 2010 10:31:20 AM
Not sure on that one
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WEPSMAN
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South Dakota
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Message Posted: Dec 23, 2010 5:44:27 AM
Lots of factors could be involved. Generally, larger tires take more energy to get going. They way you drive makes a difference. Year makes a difference also. The newer ones tend to make a little better mileage.
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chemist74
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Cleveland
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Message Posted: Dec 23, 2010 5:36:53 AM
Your odometer is calibrated for the tire size standard on the vehicle.
If you change to a larger tire size, the odometer reading will not be accurate and will make you think you are getting a lower MPG. A different tire size will mean that you may be operating at a different RPM or in a different gear to travel the same distance at the same true speed and this could impact real MPG.
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Bus936
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Lexington
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Message Posted: Dec 23, 2010 4:39:05 AM
If you are running a different size tire than what origionally came on the vehicle you are thereby tampering with your gas milage.
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DasAuto92
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Montreal
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Message Posted: Dec 22, 2010 9:10:28 PM
After you do the tune-up check your mileage then get back to us
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Tahoe2PA
Rookie Author
Pennsylvania
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Message Posted: Dec 22, 2010 2:48:02 PM
The larger tires were just put on and were brand new when I purchased it. I know it could use a tune-up too. Maybe that will help the fuel economy.
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jes
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Pennsylvania
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Message Posted: Dec 22, 2010 2:14:02 PM
I doubt going one size larger would make that much difference....but it's possible.
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PaylessKY
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Kentucky
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Message Posted: Dec 22, 2010 1:34:40 PM
Its best to use the size that came on your vehicle.
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reenman
Sophomore Author
California
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Message Posted: Dec 22, 2010 7:54:38 AM
The Manufacturer considers all aspects of tire size (ie.) safety, performance, mpg. etc. In order to have the product obtain the best mpg. they determine the tire size. By changing that size you change the dynamics involved concerning mileage such as coefficient drag ratio
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