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Gas prices are starting to go back up. Taller tires for better fuel mileage? Can anyone advise if they have tried this on a 2500 Suburban 4x4? I wanted to see what the results might be before I tried it.
in general, taller tires = worse fuel economy as it requires more power to push a taller tire to get it rolling and keep it rolling. May consider a thinner tire/smaller contact patch or one with better rolling resistance ratings. But beware, you can reduce the contact patch and resistance but do not go to the extreme and significantly sacrifice handling, braking, bad weather capability (like snow and ice), etc. as the only 4 small points between you and the ground are your tires.
Unless you go off road and use 4wd, a less aggressive tread may not look as cool on the 4x4 but will be better on your fuel bill.
Any increase you may get will be insignificant.
Easiest way to do better is go to max inflation (harder ride), keep the vehicle empty of heavy stuff, half fuel, and keep your foot out of the engine compartment. Keep speed under 65.
The lower the RPM, the better the economy.
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F350 4x4/ Dodge 2500HD 5.9L Cummins
Leaving the Picture of the Ford cuz I miss it
Pacific 2325 cc
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If you max out your tire pressure, keep the engine tuned, avoid jack rabbit starts, stay under 65 on the hiway, and install 1 of these you will gain about .4mpg
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Maybe the biggest improvement without really spending any cash is to clean the mass air sensor. I cleaned the sensor on my Chevy PU and the increased performance was so noticeable immediately that I proceeded to clean them in my other vehicles. It's worth a shot and what the heck it's almost free. Link to subject here: http://www.rd.com/104251/article104251.html
Taller tires on a big SUV can help to a point. Alot of full size chevys come with 245/75/16s. I have a 3/4ton HD Chevy Crew cab with a cap. I run 285s and had the speedo calibrated for the change. I picked up 35 to 45 miles per tank. I run 65psi front and 75psi in back on E rated (10 ply) tires. The bigger trucks have the torque to turn them easily with out trouble as long as you dont go overboard. I also added a K&N cone filter and I have 3" true dual exhaust, which helps with power and economy in a round about way. Also 65 is not necessarily the best speed for your truck. I have 3.73 gears and at 65mph on the highway my truck spends alot of time shifting in and out of overdrive which of course sends the rpms all over the place it cruises a little under 75 at 2000 rpm in overdrive on the highway and will pretty much cruise there all day without shifting the only time it really kicks down is going up through the mountains on I77 in VA. As stated above clean your mass air sensor keep your air filter CLEAN, change your plugs and wires, check the timing on your truck, youll be surprised how much this will help. Have your brakes checked for dragging especially the Ebrake. Chevy calipers have issues with the sliders hanging up. Also check your rubber brake lines they have a tendency to swell and wont release the calipers. If I keep my foot out of the pedal (rare) I average 18 mpg on the highway.
Any increase you may get will be insignificant.
Easiest way to do better is go to max inflation (harder ride), keep the vehicle empty of heavy stuff, half fuel, and keep your foot out of the engine compartment. Keep speed under 65.
The lower the RPM, the better the economy.
Although, my truck gets better milage @ 75 then it does at 70.
and I am running larger tires.
Thank you to everyone who took the time to reply with good information. I am a big proponent of the tune-up and air filter route, heck, I even cut out my factory muffler and spliced in a flowmaster that made a big difference. I never thought about the cleaning the mass airflow sensor - good information I will give that a try. I wanted to cruise down the highway at 75mph with a 4.10 rear and wanted to explore the idea of the larger tires thinking it would lower RPM and improve mileage. I did not want to spend more money than I would save doing it if it was feasible. I think we are on the front edge of another price increase for fuels because of the weakening dollar. Its about time to get tires and I wanted to see what others had done to give me a better idea. Thanks for the great information...that is why I like this website.
Thank you to everyone who took the time to reply with good information. I am a big proponent of the tune-up and air filter route, heck, I even cut out my factory muffler and spliced in a flowmaster that made a big difference. I never thought about the cleaning the mass airflow sensor - good information I will give that a try. I wanted to cruise down the highway at 75mph with a 4.10 rear and wanted to explore the idea of the larger tires thinking it would lower RPM and improve mileage. I did not want to spend more money than I would save doing it if it was feasible. I think we are on the front edge of another price increase for fuels because of the weakening dollar. Its about time to get tires and I wanted to see what others had done to give me a better idea. Thanks for the great information...that is why I like this website.
We must have the same truck. I have the 4.13 rear end. She turns almost 3,400 at 65. I also thought about bigger tires to reduce that rear ratio. Truck wont shift to fourth till it hits 50 @ 2200RPM. I have plenty of pulling torque. Truck does not even warm up towing 11k# cross country. The other solution is expensive - a 3.13 rear axle. I really do not care about the towing mileage. I average 9 mpg towing and 11 riding around since we went to ethanol. Before that I could squeeze 17 hiwy @ 68MPH.. Since then 11 MT is it.
We must have the same truck. I have the 4.13 rear end. She turns almost 3,400 at 65. I also thought about bigger tires to reduce that rear ratio. Truck wont shift to fourth till it hits 50 @ 2200RPM. I have plenty of pulling torque. Truck does not even warm up towing 11k# cross country. The other solution is expensive - a 3.13 rear axle. I really do not care about the towing mileage. I average 9 mpg towing and 11 riding around since we went to ethanol. Before that I could squeeze 17 hiwy @ 68MPH.. Since then 11 MT is it.
Yeah you have an issue some where even with a 4.1? gear ratio you shouldnt be turning 3400 at 65. It sounds like your tranny isnt shifting right.
solarfry, you stated,
"I average 9 mpg towing and 11 riding around since we went to ethanol. Before that I could squeeze 17 hiwy @ 68MPH.. Since then 11 MT is it."
Is that a 2500 suburban 4x4 with 8100: 9mpg city and 11mpg highway on ethanol fuel? That is not towing? If so man that must hurt to fill that up.
Larger tires will give your better mpg on highway(lowers your RPM). But city driving will hurt mpg.
That is true to a point, but what you have to realize is the wasted torque that many of these trucks have to begin with. My mileage went up both in highway driving and in town. There is a definate curve in the milage chart and as long as you dont go overboard the taller tires will help in both areas. The same factors would apply to a small car with an underpowered engine if you go to small with the tires your milage will start to dropin both areas as well. The trick is to find the right mix of power to size. For a full size pickup or SUV 285/75/? tires with a 3.7 to about a 4.3 gear ratio and a larger V8 is about the right combination. The smaller V8s with the taller gears tend to favor the 245s to 265s.
Better fuel mileage
