About to re-gear from 3.31 to 4.09/4.10. Any reason why I shouldn't?
08-08-2017, 12:18 AM
#101
Senior Member
Where did you find 3.91? All I seem to be able to find are 3.73, 4.11 and above.
08-08-2017, 12:31 AM
#102
Originally Posted by dlbb
would you be interested in the stock 4.10 for a 17 raptor? i am thinking of changing to 4.88 cause i can get matching set for front and rear.
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dlbb (08-08-2017)
08-08-2017, 12:14 PM
#103
Senior Member
Originally Posted by dlbb
would you be interested in the stock 4.10 for a 17 raptor? i am thinking of changing to 4.88 cause i can get matching set for front and rear.
The following users liked this post:
dlbb (08-08-2017)
08-08-2017, 01:09 PM
#104
https://www.summitracing.com/parts/u...4aAj8JEALw_wcB
Just Google 3.91 gearset for super 8.8 and You will have lots of options to purchase from.
08-08-2017, 04:07 PM
#106
Senior Member
I've got the 5.0 & 3.55 with stock 275/65/18 (32.1") Goodyears on my 2017 FX4. If I go to 275/70/18 (33.2") KO2, would I notice any significant difference in power, mpg, or speedo?
I previously had an '07 FX4 with the 5.4 & 3.73 and stock 275/55/20 (31.9") Pirellis. Went to 275/60/20 (33") KO2 and speedo difference was negligible (1 mph if anything) and didn't notice much power or mpg difference. About 13 mpg in the winter and 15-16 in the summer. No tune of any kind. Leveled with Rancho quicklifts.
Wanting to upgrade from the Goodyears to BFGs and Bilstein 5100s and expect some loss of mpg, but not sure how much to expect. Still under 900 miles on the truck. Currently in the 16.5-17.0 mpg range with my city type driving but understand the truck probably isn't really "broken in" yet. Just on the second tank of fuel with the 36 gal tank. I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
I previously had an '07 FX4 with the 5.4 & 3.73 and stock 275/55/20 (31.9") Pirellis. Went to 275/60/20 (33") KO2 and speedo difference was negligible (1 mph if anything) and didn't notice much power or mpg difference. About 13 mpg in the winter and 15-16 in the summer. No tune of any kind. Leveled with Rancho quicklifts.
Wanting to upgrade from the Goodyears to BFGs and Bilstein 5100s and expect some loss of mpg, but not sure how much to expect. Still under 900 miles on the truck. Currently in the 16.5-17.0 mpg range with my city type driving but understand the truck probably isn't really "broken in" yet. Just on the second tank of fuel with the 36 gal tank. I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
08-08-2017, 06:30 PM
#107
Senior Member
Speedo is off 1-2mph
Noticed a bit less power but not bad (note I have 3.73's tho)
Noticed a bit less mpg at normal driving, waaay less mpg over 65mph
08-09-2017, 12:04 AM
#108
Senior Member
I've got the 5.0 & 3.55 with stock 275/65/18 (32.1") Goodyears on my 2017 FX4. If I go to 275/70/18 (33.2") KO2, would I notice any significant difference in power, mpg, or speedo?
I previously had an '07 FX4 with the 5.4 & 3.73 and stock 275/55/20 (31.9") Pirellis. Went to 275/60/20 (33") KO2 and speedo difference was negligible (1 mph if anything) and didn't notice much power or mpg difference. About 13 mpg in the winter and 15-16 in the summer. No tune of any kind. Leveled with Rancho quicklifts.
Wanting to upgrade from the Goodyears to BFGs and Bilstein 5100s and expect some loss of mpg, but not sure how much to expect. Still under 900 miles on the truck. Currently in the 16.5-17.0 mpg range with my city type driving but understand the truck probably isn't really "broken in" yet. Just on the second tank of fuel with the 36 gal tank. I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
I previously had an '07 FX4 with the 5.4 & 3.73 and stock 275/55/20 (31.9") Pirellis. Went to 275/60/20 (33") KO2 and speedo difference was negligible (1 mph if anything) and didn't notice much power or mpg difference. About 13 mpg in the winter and 15-16 in the summer. No tune of any kind. Leveled with Rancho quicklifts.
Wanting to upgrade from the Goodyears to BFGs and Bilstein 5100s and expect some loss of mpg, but not sure how much to expect. Still under 900 miles on the truck. Currently in the 16.5-17.0 mpg range with my city type driving but understand the truck probably isn't really "broken in" yet. Just on the second tank of fuel with the 36 gal tank. I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
08-09-2017, 09:14 AM
#109
5.0 DOHC V8
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Mach1
I've got the 5.0 & 3.55 with stock 275/65/18 (32.1") Goodyears on my 2017 FX4. If I go to 275/70/18 (33.2") KO2, would I notice any significant difference in power, mpg, or speedo?
I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
I've got the 5.0 & 3.55 with stock 275/65/18 (32.1") Goodyears on my 2017 FX4. If I go to 275/70/18 (33.2") KO2, would I notice any significant difference in power, mpg, or speedo?
I don't drive a truck for the mpgs, but like all of us, want to maximize what I can.
In the tire size ranges we run on these F150s (31" to 35+"), every inch increase of tire is akin to a .125 taller gear (lower numerically).
An inch difference should not cause much trouble... I went from a 30.5" tire to a 31.6" tire with a 5.0/3.31 axle and all I did was recalibrate the speedo using a Superchips FlashCal. Still saw 22.5 MPG on a 100-mile leg, deliberately holding 70 MPH in 6th @ 1700 revs... yet when I jump on the loud pedal it almost wants to wheelie.
A tire change of more than a two inch increase in overall diameter warrants a re-think on the axle gearing.
...of course, many won't go to that detail or expense and imho are cheating themselves of their truck's potential performance.
08-09-2017, 09:22 AM
#110
5.0 DOHC V8
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Two more things:
Granted, if someone's truck is already equipped with a 3.73+ gearset, then swapping a two-inch larger tire will put them at an effective 3.55... so that's no real big deal. Or the same scenario on a 3.55-axle'd truck; that would put them at an effective 3.31-ish... and that right there! is where I draw the line. Hahaha...
Another influence affecting MPG is increased tire weight, as you've already noted. Removing a 31-lb 17" Michelin XLT highway tire then installing a 60 lb mudder is gonna numb the throttle a bit from the weight alone.
Granted, if someone's truck is already equipped with a 3.73+ gearset, then swapping a two-inch larger tire will put them at an effective 3.55... so that's no real big deal. Or the same scenario on a 3.55-axle'd truck; that would put them at an effective 3.31-ish... and that right there! is where I draw the line. Hahaha...
Another influence affecting MPG is increased tire weight, as you've already noted. Removing a 31-lb 17" Michelin XLT highway tire then installing a 60 lb mudder is gonna numb the throttle a bit from the weight alone.