3.92s and 35s

bryan28 · Jan 12, 2016

Do the 3.92s match well with the hemi/ 8 speed combo and a 4" lift with 35" a/t tires on 20" wheels? Most of my driving is highway at speeds up to 80 or so. I will tow some but not up to max tow rating.

SilverSurfer15 · Jan 13, 2016

This will get more traction in the lifted section... while I dont have this combo, my educated guess is that you will be fine. You will notice it dropping in and out of 7th more often, but I dont think it will be terrible. Although you are in TN, if its extremely hilly there you will notice it more.

xrsman · Jan 13, 2016

I've got a 5" lift and 35's with the 8 speed and 3.92's.

My truck holds 8th very well, the 3.92's barely notice the 35's. With my tuner my 0-60 really hasn't changed much from when I was on stocks. Maybe 1/10th of a second.

I don't drive 80 mph often at all so I'm not sure how they handle at those speeds, at 75 though it likes to suck the fuel back!

I tow pretty often, doesn't seem to have effected that at all. I've towed almost at max too (10,000 lbs)

Pull Ya · Jan 13, 2016

I think you will be fine. If you change gears in a 4x4 I think that the cost vs gain in your situation wouldn't be worth it.
Jay

bryan28 · Jan 13, 2016

I'm not considering swapping gears. If I get 3.92s they will be in a new truck.

Mennis · Jan 27, 2016

If you are buying new and you want a 4x4 and 20s by all means get the 3.92s. I didnt think of gearing and my rig has the 3.21. Im running 35s with a 6 inch lift. On the highway it shifts 7th 8th 7th 8th ..you get the point? I learned to shift to 7th to deactivate MDS and prevent it from goint to 8th and I get better mileage in 6th or 7th depending on speed. Once it "overshifts" she really weighs on the hemi and sucks gas.
Bottom end isnt bad thanks to the 8 speed. but highway speeds are not the best.
Im getting 3.92 soon. HindSight 20/20

6.7CumminsDrvr · Jan 28, 2016

I'm sure the addition of the 4" lift that's getting installed right now will affect my truck a bit, more gas probably but I have no issues what so ever running 35's with 3.92's. Granted, mine are a smidge narrower than a traditional "35 X 12.50" but my truck zips down the highway just fine and is still plenty of fun around town.

GP4L · Jan 29, 2016

bryan28 said:
Do the 3.92s match well with the hemi/ 8 speed combo and a 4" lift with 35" a/t tires on 20" wheels? Most of my driving is highway at speeds up to 80 or so. I will tow some but not up to max tow rating.

You'll be fine, and you'll enjoy it. MPG will suffer at 80, but that'll happen on the stock tires too.

If i did the math right... Going from 33's (stock) to 35's will be like going from 3.92 to a 3.69/3.70 (without changing the tires). So that setup will still be closer to a stock 3.92 than a stock 3.21.

Do you have an concerns about fuel economy at all? I'm guessing not, but I've known some guys that dove in head first, and ended up hating the MPG change, mostly for the guys that like to frequently cruise at speeds above 70-75mph -- like they did with their previous truck that had a much lower axle ratio.. So I figured I'd ask anyways.

3.92s and 35s

bryan28

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SilverSurfer15

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xrsman

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Pull Ya

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bryan28

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Mennis

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6.7CumminsDrvr

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GP4L

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