Run 37's without re-gearing? Good? Bad? meh?

[eurotrashb5]

Considering a 6" lift... With that, Im interested in how important it is to re-gear to 4.10s if I run a 37 with it. Truck is stock with 3.73s, I don't tow much, just a small camper and a car occasionally, nothing more than 5000-6000 pounds. If i run the 37's without going to 4.10s will that wreck the tranny, or just make the truck a total dog when I'm towing? Kind of a rookie question I know, never ran a lift/tires this big on anything before and of course im doing homework on my own but Im looking for your input...

[99Powerstroke7.3USnavy]

Well I got an 8 inch lift with 38's on it and I also got 3.73's. I have never towed anything yet so I couldnt tell you how good it is while towing but unloaded or stuff in the bed it isnt horrible. My intake, exhaust, superchip probably help with that but I dont have any issues. But I would imagine it might hurt while towing. Someone else can chip in. And I am still get approximatly 13 MPG with purely only stop and go so. Thats my experienced. If I boost launch it will still smoke the 38's on accident lol

[Super Diesel]

Without re-gearing, you'd really hurt the MPG on the setup. I've also heard that a 6" lift (which is what I have) will still rub on 37" tires (which is what I want). I don't think the transmission would be a factor, provided you have a good tow tune that tunes the transmission. I don't tow anything, but I've listened to what others have said and this is what I've taken from the majority of conversations.

Good luck!

[eurotrashb5]

Im starting to lean towards the 6" with 35x12.5s but keeping my options open. Super diesel, is that your set up with 35's on it in your sig?

[Super Diesel]

Originally Posted by eurotrashb5

Im starting to lean towards the 6" with 35x12.5s but keeping my options open. Super diesel, is that your set up with 35's on it in your sig?

Yep, sure is. 35s look a tad small on my truck to be honest... but I've just recently started hearing that 37s rub on a 6" lift. Looks like I'll have to go bigger on the lift to fit 37s without rubbing and/or trimming - which I'm not gonna do. So, I'll stick with 35s for now.

[Snake]

Honestly, its not worth the money to go from 3.73's to 4.10's. Very little difference, and most people will go up to 4.30's for that reason. If you end up with 35's instead of 37's, then definitely keep the 3.73's.

[Super Diesel]

Originally Posted by Snake

Honestly, its not worth the money to go from 3.73's to 4.10's. Very little difference, and most people will go up to 4.30's for that reason. If you end up with 35's instead of 37's, then definitely keep the 3.73's.

This is a little off topic, not meaning to derail - but just curious - what would be the outcome of having 4.10 or 4.30 gears with 35" tires?

[Snake]

Basically you'd have a lot of get up and go, but you'd be turning a lot of rpms at highway speeds.

[eurotrashb5]

Yeah, i do kind of like the small goofy look if the tires are poked out a bit. weird i know. but yeah 4.10s with 35's wouldnt be much fun except leaving stop lights. Would result in pretty poor gas mileage on the highway. Dont feel like spending the money to regear if I'd be best off to go with 4.30s.

[Snake]

I know I'm comparing apples to oranges, but my 6.0 came with 3.73's and the tires were 34" in diameter from the factory. Aftermarket 35's with rims are a little heavier and wider and you'd notice a difference in performance going to 4.10's, but the cost of re-gearing doesn't really make this a good decision IMO. When I went to 8" of lift and 37's, I drove on the 3.73's for a couple of months until my TruTrac showed up. I went to 4.30's and the truck is turning slightly higher rpm's at highway speeds, but I would absolutely recommend re-gearing if going 37's or bigger. Not only to try to get back to the engine rpm's "sweet spot," but to offset the additional weight of the tires, rims, and lift kit (and the decreased aerodynamics of a lifted truck).