I am now the proud owner of a 2000 v10 4x4 limited excursion. She's got what I was told is a 6" lift and she's on 35's. My next riding/camping trip will be here before I get a chance to regear. I'm wondering how much I can tow with the 3:73s and 35's

 

Good looking rig!

 

Nice looking EX! How heavy is the trailer that you are looking to pull and what is the terrain you will be pulling over?

 

WELCOME to the world of XXX's ... 6000 to 7000 LB's you won't even break a sweat. Things you want to check for the long haul are: The spring rating of the lift used, the u-bolts in the rear are long enough to have a full nut or more, AND that they DID NOT use a second block on the rear axle.

 

Normally I pull a toy hauler that's about 7000 pounds loaded with a 2008 f150 5.4 with 3:55 gears. This trip I want to take a bigger toy hauler it's 8500 pounds dry. I'm going to say maybe 10k loaded. There's a few decent grades on the trip and about a 3-4 mile stretch of beach I have to drive down

 

You may also want to know that your hitch is rated @ 500/5000 LBs

 

Well that sucks but not a problem to change to a better hitch. I'd like to upgrade the hitch, get a tune and air bags very soon

 

I did a little welding on mine & pull a 20' 10-12K loaded utility trailer with it straight pull. 5-6 MPG 4.30s on 37's. The biggest issue I have is checking the speed-o to see I doing 75+ then thinking: CRAP what if I have sudden air loss in one of my tires or THAT idiot is not really going to pull out IS HE !!

 

PS: it's a hardware issue..You can use upgraded bolts to gain a few 100/1000 LB's

 

There really isn't a set answer as to how much you can pull with 3.73 and 35's, the only thing you can say for sure is that it will be more stressful on the trans with that setup whatever you pull. Using an online tire size /gear ratio calculator 4Lo.com :: Tire Size Change, New Gear Ratio Calculator and plugging in your 3.73 gears and the stock tire size of 31.5" vs your 35"s it shows your current effective ratio as being 3.36. That is pretty low for a motor that likes to rev and makes most of it's power at higher revs. I'm sure it will pull the heavy TH but at what cost to the trans?......... You might want to stick to the smaller TH until a gear change. I used to pull a 9500lb TH with my EX with 3.73s and 32" tires and it got the job done but was a little doggy and couldn't stay in OD on even tiny hills. I upgraded to 4.88s and 35"s for an effective ratio of 4.39 and it now pulls a heavier 11k load even better!


Is that what your hitch says for WD use? I think that may be for no WD, and I hope our new friend here is using a WD setup with these big toyhaulers!

Hitch availability for EXs is very limited, our hitches are unique to the EX and a Super Duty hitch will not work. At this time only Curt makes a replacement hitch for us and it has similar ratings as the later model EX's hitch which is slightly higher than yours due to upgraded attachment bolts.

 

Pulling a high profile trailer like a tall toyhauler puts a lot more load on the tow rig than a similar weight on a low utility trailer. Your 4.30 and 37"s wouldn't like a 12k TH nearly as much.
4.30s with 37"s nets an 3.66 effective ratio, a little less than a stock tire on 3.73s.

 

AGREED 100% But in my defense the afore mentioned trailer has 4' sides & the mulch peaks close to 14' above ground level .


Just curious: How would gear ratio relate to anything other than the total load no mater how it showed up ??

 

Towing performance is all about load on the motor and where that motor makes it's power. The effective gear ratio is the mathematical calculation that relates the total load (dead weight plus wind drag) to the power plant's output. The deeper the multiplication of the gear set the easier it will be for the motor to make the pull as long as that ratio puts the motor into it's "sweet spot" for ample power/torque to handle said load. This mark can be missed both high and low, too less of a ratio and the motor won't be making enough power to handle the load in typical conditions. Too much ratio will have the motor over revving beyond the point where adequate power is being made, wasting fuel.

Once the weight gets moving the air pushing against it (outside of the profile of the tow vehicle) adds additional drag which acts like a parachute. That's why a 10k flat load on an open car trailer will seem like next to nothing (and return decent MPGs) while an 11' 6" TT that is 8.5' wide and has a nearly flat front at that same 10k weight will drop MPG so much. The flat rear wall of a TT or enclosed trailer also hurts the drag as the large wake vacuum it creates is actually trying to pull the vehicle backwards into the void.

I'd love to see a picture of the 14' tall mulch load on the trailer!

 

That's comforting. I normally tow slow and with OD off so I'm thinking I may be ok. It's a 1 time thing, by the next time I tow that heavy I'll be regeared

 

I guess this weekend I'll be upgrading hardware, maybe some welding on the diff and trans temp gauge so I can keep an eye on things