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I have a w350 4x4 5 speed. I believe the axles are 355 gear. It seems like it could use a 6th speed on the highway. I wonder if a taller tire would help mileage? I think I have 315 70 16 on it now. Any thoughts?
taller tires improve mileage?
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If its not way heavier and wider it may. Itll drop rpms, but if its a heavy or wider tire it will also increase rolling resistance
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x2 on what turbodiesel said. You can get a 255/85/16 tire which is 34" tall and it's about as wide as a 265/75/16.
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Welcome to CF.
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Also really depends on your driving habits. Ive got a 91.5 w250 nv4500 5 speed sitting on 37" military tires on steel wheels with 3.55 gears, i'm averaging 23.1 on my fuelly app. Thats on a 60 mile round trip to work everyday with atleast 10 stop signs and lights, and running between 45 and 55 mph. But 99% of the time i drive like the oldest grandpa you can think of. Oh and the truck has just a shaved pin, fuel screw in a few turns, and a h1c with a 12cm housing. Now i don't have any mpg numbers from all stock but i sure cant complain about 23 mpg on 37's. There isn't any scientific numbers to back it up but if you ask do i think the 37's help my mileage, i'll say yes. One of these days im gonna find a set of 33's or 35's to see what the difference is.
There are so many factors involved, just like was said, rolling resistance is one. If you decide to try it make sure to use a good street tire on an aluminum wheel for the least amount of weight and rolling resistance. No super swamper boggers on steel wheels.
There are so many factors involved, just like was said, rolling resistance is one. If you decide to try it make sure to use a good street tire on an aluminum wheel for the least amount of weight and rolling resistance. No super swamper boggers on steel wheels.
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Thanks for the replies. I suppose a 10 ply tire is what we need for our trucks? I am looking for options locally now. I am seeing a few 16.5" tires like for RVs I wonder if that would be a cost effective option. I would have to swap wheels... But If I am not planning on getting into sloppy mud I dont really need aggressive tread, right? I would love to get some hummer wheels w 37s like "toyota" mentioned but I think it takes a radical spacer to make those fit right.. LOL what does a 37" do to your speedo?? Any way to make it right?
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You would need a spacer or recenter the wheels. I run them on my toyota crawler recentered to 3 1/2" backspacing but the expense of recentering is a little pricey. I've got $120 in the wheels, $120 in the centers, and $80 in having the centers cut and welded in. Plus either the pvc inserts or magnesium runflats to seat the beads. I just run 16.5x10 black wagon wheels on my dodge and thry work fine. I only run the 37's because in my area a set of 4 with 3/4 or more tread are only $200. It will throw your speedometer off some. I got lucky and mine was fixed when I bought the truck but mine also had the nv4500 conversion done.
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One thing you do have to think about is tires too tall will increase the ind resistance of the truck, decreasing mileage. You just have to find a good balance point for tire size for your truck and driving habits. Taller tires also have a greater moment of inertia. they will take more energy to get rolling but will also take more energy compared to stock tires to slow down (or change its angular speed). SORRY for the physics lesson, but its hard to not do that when you take engineering classes. If you dont off road it you can get away with some low rolling resistance tires. Also another thing you could do is re gear it and keep the tires you have now. This would also likely be cheaper than new tires, but also more time consuming. So its really just personal preference and finding the right tire size and highway rpms for what you do.
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Pump your tires up to max pressure, helps the mpg. I have a gear vendors unit (6th gear so to speak) and it helps if i am really easy on it but i usually end up driving faster. At about 115-120km/hr the motor starts to work harder (boost goes up) and you lose mileage anyways. Lack of aerodynamics of these trucks is a big fuel economy killer.
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Thanks for the feedback. Like I said, I am pretty sure I have 355 gears. How expensive/ difficult is a gear change? Have to reset gear lash and pinion to do this? Do diffs use crush washer or shims to setup?
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3.54 is low as you can go. Unless you want to swap axles and go 3.07.
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l
ol if you want mileage drive a neon! just playing go with taller tires but i have noticed 16.5 are a little more pricey than 16.
ol if you want mileage drive a neon! just playing go with taller tires but i have noticed 16.5 are a little more pricey than 16.
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Pesonally if you havn't done it before its a heck of an undertaking re gearing two axles. The first axle i did was a dana 60 and it took me a couple days to get set right, but it's till going today in a toyota rock crawler so i must have done something right. You can get used gears but still have to set them up to your axles. If you happen not to have 3.55's and want to drop to them, new gears and master install kits will run somewhere near $1,000. Then why not throw in a good locker or atleast a good limited slip so that's another atleast $400 per axle. I'm pretty sure a 60 and 70 both use shims. Again if you don't hav 3.55's it would probably be easier to just buy a set of axles with the right gears, freshen them up, and throw them under your truck.
Either way you go theres money involved but a lift, wheels, and tires would be less labor intensive but you get the look if thats what you want. But who is to say that would help your mileage? It works for me but may not work for others so take the advice with a grain of salt so to speak.
There is basiclly no need to run 16.5's unless you run military tires. I only run them because i can pick up a set of 37" military tires for $200 with 3/4 tread all day long. There is much less selection of tires and are more expensive plus a very limited selection of wheels.
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