4.88's Overlander/Tow Daily Driver
10-06-2016, 11:06 PM
#1
Senior Member
Thread Starter
4.88's Overlander/Tow Daily Driver
I currently have 4.56's paired with 35's on my 01 Supercrew 5.4. When I got my gears installed, I did so because of a "deal" on a set of used gears and a near money free install.
I've been planning on Buying a set of new 4.56's with some sort of locker but I just haphazardly throughout the idea of 4.88's since I was buying new anyway..
I Off Road this Daily Driver more often than most owners. Elk Hunting in Montana, Black Bear in Michigan, Cali/Nevada High Desert and Overlanding in Virginia. When I'm not towing, the truck is loaded up pretty good but I don't do a lot of technical climbs. I put A LOT of miles on the truck every year and I'm Ok with that.
I also tow a 5,500lb boat/trailer regularly and once I get another race car project, that'll be back there as well.
My question, I'm happy with my 4.56's as they are now but if I'm buying new gears anyway, would any of you suggest 4.88's? (I don't see myself ever going with larger tires.)
I've been planning on Buying a set of new 4.56's with some sort of locker but I just haphazardly throughout the idea of 4.88's since I was buying new anyway..
I Off Road this Daily Driver more often than most owners. Elk Hunting in Montana, Black Bear in Michigan, Cali/Nevada High Desert and Overlanding in Virginia. When I'm not towing, the truck is loaded up pretty good but I don't do a lot of technical climbs. I put A LOT of miles on the truck every year and I'm Ok with that.
I also tow a 5,500lb boat/trailer regularly and once I get another race car project, that'll be back there as well.
My question, I'm happy with my 4.56's as they are now but if I'm buying new gears anyway, would any of you suggest 4.88's? (I don't see myself ever going with larger tires.)
10-11-2016, 07:04 PM
#2
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The first question I would ask since this is your daily driver, is how much freeway driving you're doing and how your MPG is right now.
Assuming you've got the 4 speed auto with a 4th gear overdrive ratio of .70, axle ratio of 4.56, and 35" tires, you should be sitting at just under 2k RPMs at 65 mph (1992 RPM to be exact).
If you went to 4.88 gears with all else being equal, you would be sitting at 2132 RPMs at the same speed. Really not a huge difference (7% increase in RPMs) all things considered, but it is definitely something to keep in mind.
Do you have a decent figure of how much you could get it done for front and rear? If you can get another good deal on labor and will have to get the rear done anyway to install the locker, then I'd say it could be a worthy trade off of a little bit of MPG for the added torque off the line and pulling up hills -- especially since you're towing quite a bit.
This is a really helpful tool here to calculate your RPMs with different axle ratios, transmission ratios, tire size, and speed: http://www.crawlpedia.com/rpm_gear_calculator.htm
Assuming you've got the 4 speed auto with a 4th gear overdrive ratio of .70, axle ratio of 4.56, and 35" tires, you should be sitting at just under 2k RPMs at 65 mph (1992 RPM to be exact).
If you went to 4.88 gears with all else being equal, you would be sitting at 2132 RPMs at the same speed. Really not a huge difference (7% increase in RPMs) all things considered, but it is definitely something to keep in mind.
Do you have a decent figure of how much you could get it done for front and rear? If you can get another good deal on labor and will have to get the rear done anyway to install the locker, then I'd say it could be a worthy trade off of a little bit of MPG for the added torque off the line and pulling up hills -- especially since you're towing quite a bit.
This is a really helpful tool here to calculate your RPMs with different axle ratios, transmission ratios, tire size, and speed: http://www.crawlpedia.com/rpm_gear_calculator.htm