Im trying to decide what to do! I want bigger tires but don't want to lose any more mileage! Will 37" be any different from my 35" tires i have now? What are gonna be the advantages and disadvantages?

 

You will lose some mileage no matter what... But the sacrifice might be worth it to you.
Scott

 

I love the look of the 37"s but I didnt want to sacrifice speed or mileage more than I had to so I went with with 35"s. You just have to decided whats more important to you and if its worth a little bit of a sacrifice

 

I would rather have better mileage i think so maybe ill just stick with the 35's

 

Dude you got a smarty so I dont think that the decrease in mileage is going to be that drastic and as far as power. Do you really need more than that Smarty is capable of. If you are concerned with Mileage your probably not going to get on it anyway.

 

My interstate mileage rose dramatically when I switched to 37"s... in town is better as well, so long as I'm easy on the throttle.

 

My mileage rose as well. I attribute it to the fact that the new tire/wheel package is lighter than the old ones, the RPM's dropped dramatically, and the smarty jr. might have something to do with it.

 

As did mine, actually. My 37" Yokohamas are lighter and narrower than the 35" Toyos I previously had mounted. They also have a slightly less aggressive tread pattern.

 

My 37" Toyo MTs are a bit wide & heavy, but I really wanted their load capacity - 17,200# !!!

(I don't do duallys)

 

My fathers truck is identical to my sig(except he has the Laramie edition) and he has a 6" lift w/ 37" Toyo m/t's.

We both see a consistent 18mpg cruising at 65mph. Not to bad once you factor in the aerodynamics of a barn yard door and tires the size of a small child.

On a side note I just want to vouch for the 48re. I know it always gets slamed for being junk but any stock tranny that can handle stacked boxes pushing around 35/37's and has lasted over 70k miles has my thumbs up.

I also noticed his truck rides alot smoother then mine, I don't know if it's because he has a long bed or the 37's absorb more shock. But I can tell you it's a noticeable difference. What's your take on that XLR8R?

 

Not sure what gear ratio your running....4.10's? Tire size increase basically gives you a taller ratio (lower number), thus decreaseing RPM's. If 410's w/35's your probably dropped to about 3.73 ratio. The taller gear is better for highway, but not so good in the city. The optimum lasting performance = 35's/4.10's, 38's/4.56's. You will likely see a slight MPG increase, but you will be adding stress on the ring & pinion, carrier, etc.. They will need to work harder to spin the increase rubber.

 

Both the long bed and the taller sidewalls contribute to a smoother ride; some lifts can also give a smoother ride if they reduce the spring rate.
The MT's lugs feel a bit squirmy in the beginning until the tread wears some - you're probably noticing that as well.

 

I figured that the mileage would decrease?

 

The larger tire diameter lowers the effective final drive ratio; since the CTD's brake specific fuel consumption "sweet spot" is ~1900 RPM, the reduced cruising RPMs increase fuel economy. Due to decreased wind resistance, actual best mileage is probably 1600RPM - but you'll be seeing a lot of taillights!