Bigger Tires: What Causes Drop in Gas Mileage? Height? Width? Weight?
11-03-2012, 06:55 AM
#11
Senior Member
Usually is the weight followed by the width that effect mileage loss. Height also comes into effect a bit as the further out the weight (tread) is from the center the harder is to accelerate that mass. Added tire width causes the tires to "catch" more air and also drag you down more when there is rain/snow on the road. A Lift also effects the airflow under the truck and allows more air to cause more turbulence underneath.
11-03-2012, 07:41 AM
#12
Senior Member
I went from Scorps ATR 31" to 34.1" BFG Rugged Terrian T/A's
There was 5lbs difference on each tire. - Tire Rack specs
Air preasure changed from 35psi to 40psi - BFG wrote me back told me proper air preasure. Load range changed went up 1000lbs for towing.
These handle and ride wayyyyyyyyy better then the stock Scorps ATR's
It was sluggish to begin with 2012 5.0, compared to our 2008 5.4, I added K&N 63 Series Kit, made a HUGE!!!!!!!!!! difference in throttle responce, seems to throw you back in the seat now, and have to watch the wheel spin because it changed the torque that much. Love it love it..lol....Now Im not scared to go to 35" or 325's for my BFG KM2 summer tires>
just sayin!
Grant
There was 5lbs difference on each tire. - Tire Rack specs
Air preasure changed from 35psi to 40psi - BFG wrote me back told me proper air preasure. Load range changed went up 1000lbs for towing.
These handle and ride wayyyyyyyyy better then the stock Scorps ATR's
It was sluggish to begin with 2012 5.0, compared to our 2008 5.4, I added K&N 63 Series Kit, made a HUGE!!!!!!!!!! difference in throttle responce, seems to throw you back in the seat now, and have to watch the wheel spin because it changed the torque that much. Love it love it..lol....Now Im not scared to go to 35" or 325's for my BFG KM2 summer tires>
just sayin!Grant
The following users liked this post:
scstang (01-24-2013)
11-03-2012, 12:51 PM
#13
Senior Member
After I do my 2'' AutoSpring Level I plan on running some BFG AT's that are just one size up from the stock Pirelli tires that are on it now. Might look a little silly with all the room in the wheel wells but I dont want to sacrifice MPGs too much. I also have yet to put on my 4'' Heartthrob exhaust and my AFE Stage 2 (im in the process of moving so all my tools are in storage) so I hope that'll help. Also a tuner down the road but not until my extended 75k mile warranty runs out. I ordered the 3.73 gears just for this reason however.
I did a level to my Duramax with 20'' wheels and 285/55-20 Nitto Terra Grapplers and my MPG's dropped an easy 2mpg.
I did a level to my Duramax with 20'' wheels and 285/55-20 Nitto Terra Grapplers and my MPG's dropped an easy 2mpg.
01-11-2013, 12:41 PM
#14
Instead of starting a new thread, I thought I would bump this.
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
01-11-2013, 02:09 PM
#15
Senior Member
Instead of starting a new thread, I thought I would bump this.
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
01-11-2013, 02:31 PM
#16
Senior Member
Instead of starting a new thread, I thought I would bump this.
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
I'm looking to go from stock 275-55-20 Pirellis up to 285-65-20 BF Goodrich ATs. Anyone had problems with this move, or similar move up to 34-35" tires? I don't have a lift, but have an 2012 FX4 with 3.73 gearing.
I'm mostly worried about rubbing and handling/sluggishness. Thoughts?
01-24-2013, 10:25 PM
#17
I just put 275/65r20 Terra's and the truck definitely feels sluggish now but no way going to the 275/60r20 terra that's P rated. I love the look of the 34's. but now I'm going to start looking into 4.11 gears that come in other f150's. can they be put in the rear I have now that has 3.73? And or should I put in a tuner?
01-24-2013, 10:53 PM
#18
Pretty sure you'll need a level to fit 285/65/20 on your truck. This is the tire size I plan on going with when I replace the crappy stock scorps on my truck. I will also be installing 5100s when I buy the tires, had them on my last truck (09 lariat 4x4) and loved them!!! Good luck
01-25-2013, 10:02 AM
#19
Senior Member
Not calibrating will cause the computer to calculate your MPGs lower than what they should be. Distance covered / fuel used = your MPGs. Your fuel use will go up because of reasons mentioned above (mostly mass and resistance), but the distance covered remains the same if not calibrated. Your computer calculated MPG is therefore lower than it should be. Once you calibrate, your distance covered will increase, so the MPG loss should not be as bad as previously reported.
On the note of mass: choose the lowest weight tire and wheel combination if MPG is your main concern with upgrading your tires and go with a shorter tire, or regear. Some examples... Toyo's and Nitto's are known for being heavy. The BFG AT KO's are actually mid range weight for Load E's. All of these will be heavier than any non-LT tire. The taller the tire, the further away the mass is from the axle and the more work your engine has to do. If you want tall tires and want to adjust the work load, then you will want to regear.
On the note of mass: choose the lowest weight tire and wheel combination if MPG is your main concern with upgrading your tires and go with a shorter tire, or regear. Some examples... Toyo's and Nitto's are known for being heavy. The BFG AT KO's are actually mid range weight for Load E's. All of these will be heavier than any non-LT tire. The taller the tire, the further away the mass is from the axle and the more work your engine has to do. If you want tall tires and want to adjust the work load, then you will want to regear.
Your MPG display is wrong now, and will read low because the tires are a larger diameter. How much of is it? Glad you asked. Just take the tire circumference of each tire. This can be found on the manufacturers website. And divide the larger by the smaller. Then you multiply that by your MPG display to get your real MPG.
For mine it was really easy. I end up adding about 10%. It's actually slightly less than 10%, so I round down.
Same with your odometer and your speedometer. They are both going to be off by the same amount. So adjust your driving accordingly.
Or if you can't do math in your head, you can get a dealer to reprogram your truck for the larger tire size. Then the readouts will be back to normal.