cancel
Showing results for 
Search instead for 
Did you mean: 

3:31 or 3:55

Jguetch
Explorer
Explorer
Probably going to buy 2013 F150 Crew Cab 4x4 w Ecoboost. Dealership has 2 that are priced about the same, but the one with more options only has 3:31 axle ratio......Other one with less options has 3:55.

I currently pull a 2013 Zinger 28BH. Dry weight 6400ish/estimated full to be 7500lbs. Live in Northern IL and don't travel through the mountains regularly but may consider a trip down the road.

Trailer Life Towing guide lists 3:31 as having a 9200 rating and 3:55 as having 9600 pounds. Anyone see a big difference between the ratios?

Thanks
14 REPLIES 14

JIMNLIN
Explorer
Explorer
Jguetch wrote:
Anyone see a big difference between the ratios?

Either truck with a 9000+ tow rating will do the job for a 6500-7500 lb trailer. Get the one you like best.
Doing the math on tranny gear ratios vs 3.31 and 3.55 drive axle ratios shows about 200-220 rpm difference through 3rd and 4th and 5th at 60 mph. The tranny shows to be the 6R80E that doesn't have a 1:1 direct drive gear but splits on both sides. Makes the 3.31 gears similar to the old trannies and a 3.90 gears all depending on transmission gear selection.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides

Bob_Landry
Explorer
Explorer
Skip all of the above options.The EcoBoost hasn't been on the scene long enough to prove it's durability in the world of long term heavy towing and if you look around the truck forums, you'll see some grumbling about them.. Are you buying a truck for the options or for the towing capabilities? You are going to run out of payload with the 1/2 ton.You may not think so now, but take it from someone who is on their third truck, you will. You'll load more gear, want a bigger trailer, etc. Forgo the leather seats, wood trim, and whistles and bells you really aren't going to need and put that $$$ on a 3/4 ton truck that will do what you need without worry.. You can always get a Focus for a grocery getter.
2011 Keystone Outback 277RL

bimbert84
Explorer
Explorer
APT wrote:

Skip both and get one with the Max Trailer Towing package. You'll want the extra 350-450 pounds of payload for a family, some camping gear in the bed, and 900-1000 pounds of tongue weight.

Yeah, what he said.

-- Rob
2013 F-150 SCREW 4x4, 3.5L Ecoboost, 3.73, 7650# GVWR, 1826# payload
2004 Springdale 295BHL, 31'5", 7300# loaded
Hensley hitch

EcoBullet
Explorer
Explorer
mbopp wrote:
Look at the yellow payload sticker on each truck, and I think you'll see that you run out of payload before running out of tow capacity. Especially on a crew cab. Sorry, but I'd be looking for a Max tow / Max payload SCREW truck.
My SCAB works fine since it's just DW & me towing a small TT.


Bingo. A loaded F-150 with 7200 GVW won't have much of a payload. My Max Tow has 7600 lb GVW and leaves enough payload to get by, but I'm not planning on carrying much extra in the bed.

As far as differential ratio, I wouldn't worry too much about it since you plan on mostly flatland driving. The Eco should have enough torque in lower gears to meet your needs.
Me 1954, Nana 1954, Grandson 2003, Granddaughters 2005 & 2008
2014 Keystone Bullet Premier 22RBPR
2013 F-150 XLT Supercrew 4X4 Ecoboost Max Tow

goducks10
Explorer
Explorer
Check payload 1st. 4.10's won't matter if you don't have the payload capacity for the tongue weight, WD hitch, family and gear in your truck.
7400lbs equates to 9-950lbs for tongue weight. Then add 100lbs for the WD hitch. Now your at 1000lbs. If you aren't getting the Maxtow then your payload will be in the 14-1500lb range. Add up the family and whatever else goes in the truck and see how close you are. Where are you putting the BBQ, lawn chairs, firewood, etc.

skipnchar
Explorer
Explorer
Even the 3:55 is somewhat of an economy gear. With the EB it is no doubt capable of towing using an economy gear if you can justify it by your use. If the truck spends 95% of it's time driving to and from work then go with the economy gear (either one) but the higher your ratio the less fun towing will be. You'll notice the difference most in mountainous terrain.
Good luck / Skip
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer

US Govt survey shows three out of four people make up 75% of the total population

Tystevens
Explorer
Explorer
Those ratios are really pretty close together -- I'm not sure one could tell a big difference either way.

But you do want to make sure that whichever you choose has the upgraded towing goodies you will need. **disclaimer** I don't know a lot about how Fords come from the factory, or if there are options such as transmission or oil coolers that you will need to get the max tow numbers. But with GMs, the lower (numerically) gears usually mean the truck also lacks the heavy towing equipment as well.

you should make sure that the only difference between them is the axle ratio.

Good luck!
2008 Hornet Hideout 27B
2010 Chevy Suburban 1500 LT, Z71 package, 5.3/6A/3.42
2015 Ford F150 XLT Supercrew, 2.7 Ecoboost/6A/3.55 LS

Prior TVs:
2011 Ford F150 Ecoboost 3.5
2006 Chevy Silverado 2500HD Duramax LBZ
2005 Chevy Suburban 1500 4x4 LT, 5.3/4A/4.10

4x4ord
Explorer III
Explorer III
4x4ord wrote:
I have used my F350 with the 3.55 gears for hauling trailers over 30,000 lbs fairly regularly and have absolutely no regrets. If I was only going to be towing trailers up to 15,000 lbs or so I would want the 3.31 gears. Guys with the 3.31 gears are getting better fuel mileage than what I can get with mine. To put things into perspective the Ford 6.7 in low gear with the 3.55 rear end is capable of putting more torque to the rear axle than what two 2004 Cummins 5.9's hooked in tandem would be able to do with 4.10 gears.


sorry, don't know where my head was.
2023 F350 SRW Platinum short box 4x4.
B&W Companion
2008 Citation Platinum XL 34.5

mbopp
Explorer
Explorer
Look at the yellow payload sticker on each truck, and I think you'll see that you run out of payload before running out of tow capacity. Especially on a crew cab. Sorry, but I'd be looking for a Max tow / Max payload SCREW truck.
My SCAB works fine since it's just DW & me towing a small TT.
2017 Grand Design Imagine 2650RK
2019 F250 XLT Supercab
Just DW & me......

APT
Explorer
Explorer
7500-8000 pounds loaded TT, bunk house for a family. Skip both and get one with the Max Trailer Towing package. You'll want the extra 350-450 pounds of payload for a family, some camping gear in the bed, and 900-1000 pounds of tongue weight.

That package includes 3.73 axle ratio, and is not likely to be found on every dealer lot, or one within 200 miles.

As for 3.31 vs. 3.55: I favor the shortest (numerically highest) axle ratio possible with gas trucks. The real world fuel economy difference is not measurable. The extra wheel torque is always butt dyno approved.
A & A parents of DD 2005, DS1 2007, DS2 2009
2011 Suburban 2500 6.0L 3.73 pulling 2011 Heartland North Trail 28BRS
2017 Subaru Outback 3.6R
2x 2023 Chevrolet Bolt EUV (Gray and Black Twins)

Lynnmor
Explorer
Explorer
Jguetch wrote:
Probably going to buy 2013 F150 Crew Cab 4x4 w Ecoboost. Dealership has 2 that are priced about the same, but the one with more options only has 3:31 axle ratio......Other one with less options has 3:55.

I currently pull a 2013 Zinger 28BH. Dry weight 6400ish/estimated full to be 7500lbs. Live in Northern IL and don't travel through the mountains regularly but may consider a trip down the road.

Trailer Life Towing guide lists 3:31 as having a 9200 rating and 3:55 as having 9600 pounds. Anyone see a big difference between the ratios?

Thanks


I'd go with Plan C, none of the above. Get the truck you want with the gear you want. Have the dealer order or find it for you. I would want the 3:55 or lower if possible.

4x4ord
Explorer III
Explorer III
I have used my F350 with the 3.55 gears for hauling trailers over 30,000 lbs fairly regularly and have absolutely no regrets. If I was only going to be towing trailers up to 15,000 lbs or so I would want the 3.31 gears. Guys with the 3.31 gears are getting better fuel mileage than what I can get with mine. To put things into perspective the Ford 6.7 in low gear with the 3.55 rear end is capable of putting more torque to the rear axle than what two 2004 Cummins 5.9's hooked in tandem would be able to do with 4.10 gears.
2023 F350 SRW Platinum short box 4x4.
B&W Companion
2008 Citation Platinum XL 34.5

boogie_4wheel
Explorer
Explorer
I'd get the 331 and reap the benefits of a more optioned truck with better empty fuel economy (which I'm guessing you will be using it empty a majority of the time). Drop a gear on the hills when needed.

That isn't a big jump between axle ratios, and you already see that it has a 400lb difference in towing capacity.
2005 2500 Cummins/48RE/3.73, QCLB, 4wd, BigHorn, Edge Juice w/ CTS + Turbo Timer,Transgo Shift Kit ISSPro Oil and LP pressure gauges, GDP 20/2 filters, Custom Diesel Steering Box Brace
'10 Forest River Shockwave Toy Hauler 21'
Honda EU3000I Genny

donn0128
Explorer II
Explorer II
3.31 is a grocery getter ratio. Get the 3.55 as a minimum