PRNDL

Ok guys, this isn't the usual "what rear end gear ratio should I get, 3.37's or 4.10's?". I'm guilty of posting said question in the past, but I was never very clear as to what I wanted out of my truck. Same goes for other people that have posted the same question. However, it is a fair and great question. A gear change is expensive! Picking the perfect gear is very important.

The problem I see when people respond with answers to this question is that they give answer based on past experiences. Which is great, but most of the experience comes from vehicles that are very different from our NEW (2009+) F150's with 6 speed autos. I read examples of a car someone had with certain gears or and old F150. The issue is that most of these "old" F150's had 4 speed autos. When people say that they were perfectly happy with 3.73's in the Mustang they used to own, it bothers me because that car could have had 27 inch tires not a minimum of 30 like our trucks.

What I would like to know is what does that 3.73 or 4.10 do to our deep 4.17 geared 1st gear? Does it render it completely useless? I know 4.10 gears have worked fine for you older F150 guys, but I would like to hear from new F150 owners with 6 speed autos.

I have a 2010 XLT Screw 5.5 bed with the 5.4. I came stock with these horrible 3.15 gears. My tires are 30 inches tall, for now. When I do change them Im getting 305/50/20's (32 inches tall.)

My question is, which are better, 3.73's or 4.10's? I dont want to be disappointed with the 3.37's not making much of a change. I also do not want the 4.10's to be too deep and make my 1st gear useless. Im torn between these two ratios. Some say 3.73's are not deep enough or perfect. Some say 4.10's are perfect or too deep.

Everyone always pulls out their little gear ratio programs and say... "Hey get the 4.10's or better yet 4.56's. At 80 mph, its only like 400 rpm difference between 3.73's and 4.10. I don't care about that. Thats the highway in overdrive. There will be not much of a difference. However, Im very worried about 1st and second gear. How will 4.10's affect that?

I hope for some 6 speed F150 owners to chime in and advise. What rear end gear and tire hight do you have. What do you think about your 3.73's or 4.10's with regard to your 6 speed?

Also, I want my truck to be fast and fun. Moderate highway use. Mostly city. I haul light loads very rarely.

Thanks in advance guys

smurfs_of_war

Here is a good way to think about it. Take to potential offset larger tires will cost. Then, look to the opposing offset a gear change will give you. When you mash the two together, you should come up with a ratio as close to stock as possible. I know it's not the perfect answer, but it's an answer

fordfan77

Raptors come with 4.10 gears and 35" tires, so those work with the 6 speed.

My '09 FX4 has 3.73 gears, factory. I now have 305/65/18 tires on it, the tire circulate says that is 33.6", but the tape measure says 33". I feel like these gears are perfect for my setup. Of course I used a tuner to adjust for the tire size. On the highway I get 17-18 mpg depending on the wind, road and temperature. I've seen as much as 19-20 mpg on cool 60-70 degree mornings, with little to no wind. I never noticed a loss of acceleration with these tires, since I bought the SCT tuner when I added the tires.

Just something to think about.

And get a tuner to adjust for your tire size and the gear change.

TwinTurboFx4

Ya but also raptor has 400+hp.

smd5231

My 5.0 V8 XL came with 3.31 gears and Michelin 255/65R17 All-Season
LTX A/S 30.05" diameter, 671 revs/mile. I changed the ratio to 3.73 and the acceleration from the start became effortless (hardly touch the gas!) but the RPMs at freeway speeds seemed a bit high. So I put in allegedly bigger tires - PRODIGY 265/70R17 (Yokohama) 31.61" in diameter, 638 revs/mile. However when I used my tuner to correct the tire size, 31.5" was too big and the speedo was still wrong. I played with some chalk and measuring tape and found out the new tire was 30.239" in diameter, actually. Now the speedo is correct, and the RPM did get down a bit bringing the effective ratio to 3.55. I'm happy with this setup as the truck does 65 MPH at roughly 1800 RPM.

sllydderrr

I have stock sized 32" tires. If I didn't need the higher payload available only with Max Tow, which requires 3.73:1, I would have been happy with 3.55:1.

The six speed + 3.73:1 + 32" tire configuration makes first gear VERY short. It makes for great pulling power when towing but it also makes manual mode useless when unloaded. First winds the engine up so quickly you're in second... in a second.

This is sorta relevant since you have the same transmission gearing and are intending to go with the same size tires.

PRNDL

Awesome!! Great answers. Thank you. From what i can gather, based on the above, 3.73's seem just right for 30 to 32 inch tires. Any 4.10 owners out there?

PRNDL

That what i needed to know. 3.73 plus 32 inch tires and 1st gear seems too short.

fordfan77

The short first gear gear is one of my favorite features of my truck.

straightaxle

I would not ever worry about 1st being too low, as you rarely spend any time in first. If it was a lightweight Mustang, then yes, 1st gear can be too low, but not so much in a 6k lb truck. I have 32" tires and 3.73 and the 5.0 loves first gear. True it shifts under normal throttle about 30-40 feet out, but that doesnt matter at all, as it gets higher in the gears especially 3rd, the gearing is great, I couldnt imagine having any taller gears. Cruise on the freeway is 2k rpm at 75 mph, and there is enough gear multiplication to actually accelerate well in 6th at those speeds. Lower gears (to a point) typically get better city mpg due to ease of acceleration and reduced engine load.

Dont fear the gear!!