I have hopes of one day swapping out my stock tires and wheels for something a little nicer, particularly 35" tires. I plan to level, but don't have the headroom to go any higher...that's besides the point.

The point of this is I have a good friend of mine that has pointed out that my 3.55 gears probably will kill my fuel economy and cause more strain on the drivetrain. I do trust and value this persons knowledge and experience, so I'm looking for some suggestions.

1st, does anyone have 35's and the 3.55 gears? What kind of drop off did you have in economy? Does it downshift a lot? I believe it would be a concern.

2nd, since I can't lift it, I'm thinking maybe I should stick to the 33's, but maybe a bit meatier tire. Is it going to look too awkward with those on after it's leveled? The last thing I want is a truck with puny looking tires.

3rd solution is to change out the gear to a better ratio. If you think that's the best idea (which honestly, I agree) feel free to contribute to the fund

 

I have 3.55 gears on my 2010 1500 Laramie 35" Goodyear Wrangler MT/R with Kevlar. They are heavy. It does not down shift anymore than stock, however I did get a drop in mileage.

First off my truck never got very close to 20 mpg when I bought it. I was lucky to get 17 or 18. I then put a flowmaster 40 series and a free flow Y-pipe. I could feel the power diference, but gas mileage actually went down to about 15 mpg. Now with my new tires I get 13.5 mpg when I drive easy. but usually 13 or less.

I dodn't feel like 35" thires are a problem, but I would rather have the 3.92.

 

Hey Robert after installing the 35 s did you get the computer recalibrated for shifting or is it still set for the stock tires?
Rob

 

It really depends on what you're using the truck for. If it's a mall crawler, outside of the mileage drop you'd be fine. If you plan on hauling or towing anything you probably won't like 35's... you're effectively eliminating first gear, and imagine how hard it would be to get a loaded truck moving in second gear.

 

No I did not get the computer recalibrated. I did not know that there was an option to do that.,

I do plan to by a SC tuner soon, My tires are actually around 34.5". (285 65 20 R) the dealership tried to calibrate my speedo, after I got a ticket but they said they couldn't it was set it to the largest size tire their system would do.

 

i have 37" on my laramie with a 6" lift with the 3.55 and i have just altered the exhaust, installed a cold air intake and diablo tuner. I run premium and get around 17-18 mpg hwy in the summer. around 15-16 mpg in the winter. It still shifts great and i can still pull anything i hook the truck up to!

 

I have 35" tires with 3.55 and a 6" lift, towed my 26' camper halfway through canada last summer. It's doable i never had much problems, the only time it was annoying is when i had a strong headwind, then it would downshift a lil more than normal, but going up hill floored i always gain speed, if it's a really big hill i can keep a certain speed but it wont slow down, so its still pulls really good considering the weight of the camper. But as soon as i find a shop im possibly switching to 4.10 if they have them for the front diff, if not im going full out with the 4.56. But i'm getting a superchip tuner and hopefully it can help some of the downshifting.

You won't notice that much difference cruising around, but if your racing off the line its like a boat. If you wan't them tires to turn right off the line then go 4.56

 

I have the 3.55 with 35s , before getting my bullydog gt tuner and recal speedo plus the added tune I couldnt stand the truck, it was always shifting, with tuner its better but if I had the $$$$ rite now I would be rolling with the atleast 4.10s but more than likely 4.56s

 

Why am I only getting 12.5- 14.5 mpg? I use premium gas, 35 inch tires, flowmaster exhaust, replaced the Y pipe for better flow, drop in K&N fair filter. something must be wrong? any suggestions?

 

i really dont know robert. maybe the programmer could have something to do with it? i dont drive that slow either. usually 120-140 km/hr. have you ever noticed your RPM's at certain speeds? i sit around 2000 at about 130. oh and i dont use cruise either..i lose like 3 mpg or so if i have cruise control on