Engine/Transmission (1998.5 - 2002) Bigger tires=more mph?

[Motofreak]

As everyone has noticed fuel is thru the roof. I have been thinking about a 5" lift to run 35' tires. Has anyone done this and if so how did it affect your mileage. I dont plan on a real aggressive tread pattern. Common sense tells me with the lower rpms I should benefit. I currently run 265/16s and get about 15-16 mph with 50% city 50% highway.

Thanks.

 

[CumminsAholic]

I gained (about 10%) when I went to the 295's , but I also have 4:10 gears. I think if I remember from past posts, you won't gain or won't gain as much if you have 3:55's.

Corey

 

[RBallard]

I used to run 315 75 16 All Terrain. Highway trips I almost always averaged 24 mpg. Now that I have the original 265 75 16 tires on it I get around 20 mpg. When my current tires wear out, I plan to step back up to 285 or 295. The reason I stepped down was the clutch slipped 5th and 6th and I thought the smaller tires would help eliminate the slip. Boy was I wrong. I have 2" blocks upfront and ran factory wheels. I had rubbing (lower control arms) making tight turns.



Something else I miss about the larger tires is that cruising 70 mph, the RPMS were well below the drone thresh hold. With the smaller tires I am right at it.

 

[RBallard]

I used to run 315 75 16 All Terrain. Highway trips I almost always averaged 24 mpg. Now that I have the original 265 75 16 tires on it I get around 20 mpg. When my current tires wear out, I plan to step back up to 285 or 295. The reason I stepped down was the clutch slipped 5th and 6th and I thought the smaller tires would help eliminate the slip. Boy was I wrong. I have 2" blocks upfront and ran factory wheels. I had rubbing (lower control arms) making tight turns.



Something else I miss about the larger tires is that cruising 70 mph, the RPMS were well below the drone thresh hold. With the smaller tires I am right at it.

 

[DirtyDodge]

The MPG should go down, there is more mass turning requiring more energy. You will get more miles per revolution, but I would think less mpg. I run 285's and the best I have ever gotten on a trip is a little over 19mpg hand calculated. I dropped close to 1 mpg going from the stock 265s to AT 285s. my 2 cents.

Derek

 

[RBallard]

Mine are hand calcs as well. I used to average 18-19 prior to the EZ and 275's.

 

[AGibson]

Bigger tires

Hey Guys,

When I have purchased tires for my truck (98. 5- 24 valve) in the past I was told not to go bigger than 265's. I now have 305,000 miles and need to purchase tires again. This will be my 7th set of tires. With bigger tires I was told that they will rub against the tie rods. How big (width and Height) can I go without rubbing issues?

Thanks!

Alan

 

[ASTAR]

Re: Bigger tires

It depends on the wheel offset.

Originally posted by AGibson

Hey Guys,

When I have purchased tires for my truck (98. 5- 24 valve) in the past I was told not to go bigger than 265's. I now have 305,000 miles and need to purchase tires again. This will be my 7th set of tires. With bigger tires I was told that they will rub against the tie rods. How big (width and Height) can I go without rubbing issues?

Thanks!

Alan

 

[AGibson]

wheel offset

With the standard offset and same wheels that came with the truck, what size tires can I go up to? How do you change the offset and is there a standard for offset?

Thanks!

Alan

 

[Hohn]

Originally posted by Motofreak

As everyone has noticed fuel is thru the roof. I have been thinking about a 5" lift to run 35' tires. Has anyone done this and if so how did it affect your mileage. I dont plan on a real aggressive tread pattern. Common sense tells me with the lower rpms I should benefit. I currently run 265/16s and get about 15-16 mph with 50% city 50% highway.

Thanks.

Actually, I think the opposite will happen. Once you account for the mathematical change from the diameter, your mileage will only be hurt.



Bigger tires give you MORE rolling resistance AND more aero drag. The lift required to run the big tires would KILL your mileage.



If you want best mileage, switch to a 235/85 or 255/85 with a hwy tread pattern.



BTW-- lower rpm doesn't necessarily mean better mpg, especially on diesels.



If you want to lower RPM for metter MPG, then there's only one PROVEN way to get better mpg-- SLOW DOWN!!!!



Justin

 

[mmclaughlin]

AGibson -



I run a 285-75-16 M/T tire that never rubbs on my 2001 2500. Some shops refused to sell me the tires because you can't get the 285 M/T's in a load E tire. I ended up getting Bridgestone M/T's and I've loved them since I put them on. As for fuel milage, I get about the same, maybe a little worse then what I got before, but I accounted that to the aggessive tread pattern. I've got about 10k miles on them right now, and the wear seems pretty good. I don't notice any difference in the wear between all the tires, so I haven't had them rotated yet. I got 56k on the original tires (and they still had some tread left when I took them off) without rotating the tires once. I figured if everything is true and wearing evenly, why change it? The M/T's are also way more fun off-road, and you can't beat the look. Sure, there's a bit more noise, but that's part of the fun of driving around in a CTD!

 

[FFL8N]

I have the skyjacker 4 1/2" lift and run 315/75/16 mud terrains. I lost about 1 mile to the gallon on the highway. I turn about 2000 rpm at 80. I also have the 3. 54 rear end. If you are looking for an increase in mileage, don't do the lift. That is where the big hurt comes from. Higher = more air resistance. I really notice it the faster I go!



David:--)

 

[ASTAR]

Actually, I have noticed that I don't have a big hurt for mileage even with the amount of lift and the size of tire that I have. I do run a LOW RPM on the freeway (1600@78mph) and I think that the low rpm improves the mileage while the larger mass of the truck and tires cuts it back down. In the end, I think it almost evens out. No, I don't get quite the same mileage as stock but it's close. Oo. Oo.

 

[Motofreak]

Thanks for all the input, sounds like I may lose mileage but gain a cooler looking truck. Will probably still lift since I need the extra clearance as I haul my Toy Hauler out on the sand when we camp. Just have to pay extra I guess.

Thanks again,,,

 

[Beast2B]

I run 4. 5" lift with 37" tires, I gained +/- 2mpg with 3. 55 gears. I think a lot of it has to do with how you drive the truck. With more rotating mass, you have the POTENTIAL for worse mpg, but with the tons of torque and increased diameter you also have the POTENTIAL for better mpg... . take THAT for what it's worth (not much, but the combo worked for me)