4.10's

[Mr. Stroker]

Hey all, someone near me is selling a ring and pinion out of a 8.8 and he said they are factory 4.10's. First of all, did any truck with a half ton axle come factory with 4.10's? Also how do i check to see if its really 4.10's. Gears are out of the axle.

 

[Mr. Stroker]

DOAH! Never mind, he has a pic of the pinon and it says 410 rite on it.

 

[msb71]

I have heard of Factory 8.8's with 4.10's , also in the front as well. But they are very rare , and almost sure it had to been a special order thing.

 

[Mr. Stroker]

He wants 100 bucks for the rear axle 4.10 gears. Low miles, anyone want em?

 

[msb71]

If I did that I would have to get the front done too.NO $$$$ at this time.
Besides I would get a 10.25 Sterling and a TTB out of a F-250, 8 lug heaven.

 

[Mr. Stroker]

Yea for sure, no sence of doing it without front gears. Figured you can maby save some money by getting these ones.

 

[Skandocious]

Hey doofus... I've got Ford 4.10s in my rear end. DUH!!

 

[Mr. Stroker]

First of all, did any truck with a half ton axle come factory with 4.10's?

Doofus? I asked if any trucks came factory with them and yes i can read your sig..

 

[msb71]

Hey doofus... I've got Ford 4.10s in my rear end. DUH!!

Yeah , yeah , we know about your 4.10's , take a bow and a seat.

 

[Skandocious]

Doofus? I asked if any trucks came factory with them and yes i can read your sig..

Whoops, misread it. I thought you were asking if factory 4.10s for an 8.8 existed Either way, I've got them you and don't

 

[Mr. Stroker]

waa waa i got the balls to take my truck off roading!

 

[msb71]

I love taking the truck to the Dunes and the beach, what it was made for.

 

[polarbear]

It was an option, as I recall, but there were specific engine/transmission constraints to having them. On another note- you guys have a helluva lot more gas money than I do- those 4.10's aren't exactly fuel efficient if the truck is a DD.

 

[Skandocious]

It was an option, as I recall, but there were specific engine/transmission constraints to having them. On another note- you guys have a helluva lot more gas money than I do- those 4.10's aren't exactly fuel efficient if the truck is a DD.

With the 33 inch tires, I think the gear swap actually improved my gas mileage by about 0.5mpg. There is somewhat of a 'sweet spot' with tire sizes and gear ratios. See my post here:

http://www.fordtruckfanatics.com/forum/showthread.php?t=3192&p=45636

EDIT: That post actually says I went from 12-13mpg to 12.5... In actuality I really went from about 11-12 to 12.5 consistent.

 

[polarbear]

Skan, don't believe a word of it. The tires add rolling resistance, the gearing just compensates for it. Can't defeat laws of physics. I can all but guarantee you you're giving 2-3 mpg to the wheel/tire/axle ratio combo alone in stop and go driving. On the highway, it's a bit less of a difference.

 

[Skandocious]

Oh I know that my 33/4.10s are giving me worse mileage than 29.5/3.55s (stock). My argument is that with a given tire ratio larger than stock, you can actually IMPROVE your gas mileage by decreasing the gear ratio (higher numerical value) which takes load off the engine. And conversely, for a given gear ratio, you can actually improve mileage by increasing tire size and thus reducing engine RPM.

It sounds crazy but I know first hand Ernie... I used to turn 1700-1800rpms at 65mph and now I turn 2000-2100rpm at 65mph with very little difference in gas mileage if not BETTER, and a DEFINITE improvement in performance.

I don't have an math equations or scientific proof but this is what several people told me before the gear swap and the results don't lie... With stock 29.5" tires my mileage should have drastically decreased when switching from 3.55s to 4.10s, and with my 33" tires it did not.

 

[polarbear]

Oh I know that my 33/4.10s are giving me worse mileage than 29.5/3.55s (stock). My argument is that with a given tire ratio larger than stock, you can actually IMPROVE your gas mileage by decreasing the gear ratio (higher numerical value) which takes load off the engine. *1 And conversely, for a given gear ratio, you can actually improve mileage by increasing tire size and thus reducing engine RPM.

It sounds crazy but I know first hand Ernie... I used to turn 1700-1800rpms at 65mph and now I turn 2000-2100rpm at 65mph with very little difference in gas mileage if not BETTER, and a DEFINITE improvement in performance.

I don't have an math equations or scientific proof but this is what several people told me before the gear swap and the results don't lie... With stock 29.5" tires my mileage should have drastically decreased when switching from 3.55s to 4.10s, and with my 33" tires it did not. *2

1. Sure- same as changing out the 3.55 gears for 3.08's, numerically. That's only true on the highway. In stop and go driving, the larger tires still take substantially more energy to move from rest.

2. That's where speedo calibration comes into play. There are two factors you can't defeat:1) The larger tire has a larger contact patch with the pavement- which means, more rolling resistance. 2) The lift allows more air underneath the truck. That, in turn, generates more turbulence, and aerodynamic drag. When you're dealing with a 2.5 ton brick ) ), those factors are significant.

Example- on the '06 KR, we went from stock 18's to 35's on 20's with a levelling kit. Mileage dropped from 18-18.5 to 14-14.5 hwy. City mileage was never stellar, but fell into the 11-12 range (from 13-14). No matter how you slice or dice it, unless someone has figured out a way to rewrite some laws of physics, the added tires size and height is gonna cost you at the gas pump.

 

[Skandocious]

Ernie you're not understanding me brother. I completely agree with what you're saying --- from stock -> larger tires you will ALWAYS see a decrease in mileage, that much I know. But you can take back SOME of that lost fuel economy with the right gearing (not all of it... like you say, that would be defeating the laws of physics). But you can bring back SOME mileage by not lugging the engine with tall tires and numerically low gearing and also not overrevving the engine with short tires and numerically high gearing (those are both very bad combo's). There is a sweet spot to get the best mileage possible for a given set of tires, even though that possible mileage will not be as good as smaller tires. This is all I'm trying to say


Also -- when keeping constant tire size and changing gearing (like in my case) speedo calibration has no effect. The speedo on my truck takes its readings from the ABS ring (ring with teeth on it to the left of the ring gear) which has a constant diameter no matter what the gearing as (as does the ring gear). Change the gearing --- ABS ring stays the same --- speedo stays the same. Changing tire sizes? Yes of course your speedo calibration will be off and hence your fuel economy calculations, based on the odometer readings, are going to be skewed.

And for any 3rd parties out there -- we're DISCUSSING not ARGUING

Much love Ernie

 

[TheRoadVirus]

I love taking the truck to the Dunes and the beach, what it was made for.

Hell, even I used to go out in the pit with my truck and tear around in the dirt/mud. Not to mention the odd puddle.

 

[Mr. Stroker]

At 70 im doing around 1800-1900 rpms and it purrrs. Thats with 3.55's. Untill i deside to lift it, and get a small car, theres no way in hell i can live with having my truck do 2100 rpms @ 65 mph let alone at 70. So right now gears are NOT for me. Im enjoying my Mid 15 mpg on the highway. Especially with the gain im getting with the cruise control. amazing how that makes it so much better!

The truck handles AWESOME, and i repeat AWESOME off road, and i have nothing to complain about at the moment with the 3.55 gear ratio. Even the Lifted jeep guys and H3 guys had there jaws drop with the hills i was climbing. Never once upshifted going up a hill, nore got to a point where i bogged down because of not enough power. Fine by me..

If anyone wants those gears just let me know. Still seam like a hell ov a deal