New Tires KILLED my MPG Please Advise
01-14-2018, 02:25 PM
#11
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Thanks Rick. Do you think I should look into changing my Rear axel ratio? I am currently on 3.15 which is default and probably not preferred at this tire size
01-14-2018, 02:39 PM
#13
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I bet those new aftermarket wheels are a good 5-10 pounds heavier than your stock ones.
01-14-2018, 03:04 PM
#15
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01-14-2018, 03:29 PM
#17
Senior Member
Look into the rough country recalibration tool. I just did it on mine. When I put my new tires on it was reading 12-13mpg now its back to where it should be around 17.8 or so. Really i lost about 1mpg going to 285/65-20's with my 3.5 eco
There is a thread on here for the tool with a review and they are only $140ish shipped right now. I highly recommend it for a quick easy route.
You can also use forscan or a full on tune if thats more your fancy
There is a thread on here for the tool with a review and they are only $140ish shipped right now. I highly recommend it for a quick easy route.
You can also use forscan or a full on tune if thats more your fancy
01-14-2018, 03:42 PM
#18
Senior Member
You have increased both the tire's overall diameter (making your effective final drive ratio taller) and the wheel/tire assembly's total weight (requiring more torque, and therefore fuel consumption, to get them rolling from a dead stop).
Other than buying another set of wheels and tires, your have two things you might do to increase your fuel mileage:
1. Keep it under 80 MPH - your highway mileage will improve
2. Re-gear your differential(s) to a shorter ratio. Your taller tires have made your effective final drive ratio taller. Then there's the additional weight of each tire... you may have increased each tire's weight by 15 lbs! from the factory fitment...
Don't believe an engine tuner's claims of increased MPG in your situation; you need mechanical help. You also, as the others posting before me have mentioned, need to recalibrate your speedometer reading for the new tire size.
Other than buying another set of wheels and tires, your have two things you might do to increase your fuel mileage:
1. Keep it under 80 MPH - your highway mileage will improve
2. Re-gear your differential(s) to a shorter ratio. Your taller tires have made your effective final drive ratio taller. Then there's the additional weight of each tire... you may have increased each tire's weight by 15 lbs! from the factory fitment...
Don't believe an engine tuner's claims of increased MPG in your situation; you need mechanical help. You also, as the others posting before me have mentioned, need to recalibrate your speedometer reading for the new tire size.
01-14-2018, 03:43 PM
#19
Senior Member
Whoa fella! Don't you go tooting that commie stuff around here! Sensible driving! HA! Next you're going to say to drive at 55 to maximize gas mileage!
One would think that prior to doing anything, the OP should use an online calculator to figure his true current mileage. No tuner needed.
Last edited by Ricktwuhk; 01-14-2018 at 03:47 PM.
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01-14-2018, 05:26 PM
#20
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I got the 5startuning with 87 tow perf, 87 perf, and 93 perf custom tunes. Although it fixed the sluggishness, it didn't help the MPG