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An Engineer's Ultimate Guide To 3.21 VS 3.92 Axle Ratio

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HSKR R/T

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I get that but the average is the average, that mileage over time is still 65-66mph. Going faster would decrease it.

My last Dallas to Houston trip

View attachment 121504

The average speed for that time over distance is 73 mph
And a steady cruise speed will net better average MPG than changing speeds up/down. So just because his "average" speed was 65mph, doesn't mean it would net better MPG averages. If anything it would be worse as constantly changing speeds reduces gas mileage
 

TNRamGuy

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My average speed (other than when i was stopped in construction) over my last 1500 mile trip was 80mph in the mountains and averaged 21.5 🤌
So, your saying that you have had no fun in the last 19 hours of your truck? No tire chirping, no 'wot', no f'in with guys in a Prius?
Ok, you do you, 3.92 rules!
 

IvoryHemi

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I get that but the average is the average, that mileage over time is still 65-66mph. Going faster would decrease it.

My last Dallas to Houston trip

View attachment 121504

The average speed for that time over distance is 73 mph

Yes but mtbiker’s average was 59mph makes for an almost identical comparison between 4x4 trucks
 

ferraiolo1

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So, your saying that you have had no fun in the last 19 hours of your truck? No tire chirping, no 'wot', no f'in with guys in a Prius?
Ok, you do you, 3.92 rules!
who said i didnt do any of that? that trip was when i learned there was a speed limiter around 100. And ive posted a few burnout and WOT vids on here :)
 

BowDown

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And a steady cruise speed will net better average MPG than changing speeds up/down. So just because his "average" speed was 65mph, doesn't mean it would net better MPG averages. If anything it would be worse as constantly changing speeds reduces gas mileage

He went 623 miles, you don't think it settled into a good average cruise speed? Or better, you think it varied up and down for 623 miles? Come-on man. You may also want to look up the meaning of "average speed". My speed was averaged too, you don't think mine went up and down, driving through Dallas and Houston no less? Lol
 

BowDown

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Yes but mtbiker’s average was 59mph makes for an almost identical comparison between 4x4 trucks

Agree there however he did say he was loaded on part of that trip
Still impressed by these trucks though, this was loaded with a 2300lb uhaul trailer and 3300lbs of landscaping stone

2000x1500.jpeg.81dd37669373410f94cec0f8ec2657bf (2).jpg

More than satisfied with the ability to tow
 
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m.hamner

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With the cost of freaking fuel right now I miss the additional 5+ MPG I was getting with 3.21 gears overall. That being said the 3.92's in my current truck are far less sensitive to driving style and towing than the 3.21's. For a daily driver (40K miles/yr) I'd take back my 3.21's in a heartbeat
You know, I must be a real idiot or I must be halfway intelligent, because it's only one of the two here! I have a limited 4x4 Hemi eTorque with ramboxes and pretty much all options ticked being built, but after much much much much debate and back and forth, the *ONE* thing I did not get was the 3.92 gears. I plan to leave it on the stock size tires, I don't plan to offload or tow except for very very very occasionally, and when I do, it will be around 6klbs tops. I do a lot of highway miles where I'm going 75-85mph and just figured the 3.21 sits better at that highway speed. I drove my buddy's 2022 limited and he's got the exact same configuration I've got but with the 3.92 and I barely touch the accelerator and those wheels spin (he's got the anti-slip differential too). Don't need all that. I want torque but not at the cost of traction all the time. So, I figured where I could use the gear difference is in the top end to use MDS more and to take advantage of a slightly lower RPM. Figured if I have the truck 10 years, with 2-3mpg difference between the gear ratios at highway speed and filling up the 33g tank with 115-120 worth of gas once a week, I'll have saved closed to 8 grand in fuel costs.

Didn't go diesel as those things like to have a bit of load on them a bit more regularly, and I just can't give that engine what it needs to stay healthy long term.
 
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