I have a 2002 F150 4x4 with 4.6L and 3.31 gears. Currently running 235 70R16 tires but want to upgrade to at least 255 tires. Two questions on towing.....
1) What is the current towing capicity of my truck?
2) What would it cost to change the gears to 3.55 or something in that range?
Any help would be appreciated... dan

 

We'll need a little more info to give you a solid answer. Do you have an auto or manual transmission and are you regular or supercab? Also how much trailer do you plan to tow?

In the meantime, check out Raoul's Trailer weight chart (the stickey posted above) and a post in the Transmission section from about 3 weeks ago called Tow w/3.31 rear end and 4.6 Tranny effect. Since you are 4X4 a gear change would be $ X 2 so if you have a manual trans I don't know if would be worth the cost.

My .02

 

Dan,
You are in Kansas City? I would call Raytown Transmission for a gear change. Don't know the cost, but they are some of the best people to deal with, and know what they are doing. Also, you might consider a 3.73 gear if you are going to go through the cost of the swap.

flafonman is right, have to switch both rear and front gears, 2x the cost on a 4x4.

If you put different tires on it, remember, taller tires will raise your overall gear ratio, but bigger tires will handle the load better. Alse, look for "D" rated tires when you go to do something, they will give less under a load over "C" rated.

 

going from a 3.31 to a 3.55 wouldn't be much of a change go to a 3.73 or better.

 

flafonman, Sorry about that, it is a supercab with automatic. I checked out Sticky's chart above but didn't see my combo. I will check out the other one as well. As far as how much trailer I plan to tow, that is the question. I want to know what I can comfortably tow. Thanks.


Spaceman, What would you suggest for tires. I just want to fill up the wheel well. Used to work in Raytown so I am familiar with Raytown Transmission. Thanks

 

The largest you can go on a stock setup is 285 65 R 16, which is approximately the same size as a 32 x 12+. The tire store swore they would rub the fender but agreed to mount one and see. After realizing that they were wrong they mounted them on my buddies '98 4x4 with no problems. 265 65 R 16's aren't bad, they are approximately the same size as a 31 x 10.50. If you really want the fender well full, go with the 285's, but the 265's will still be quite a jump from the 235's. (about 1.2" wider compared to 1.9" wider).

I was thinking, probably part of the reason you have 3.31's is because of the smaller tires lowering your final driveline ratio. With the larger tires on my buddies truck, we didn't notice a power difference from the gearing difference (5.4 with 3.55's though). So, not changing the gears will make a little difference, but if your not looking at towing a large amount all the time, it may not be worth it.

If you can find the proper rating for your rig, you might want to go from there. IMHO, I wouldn't pull more than 7,000lbs with ANY f-150 and no more than 5,000lbs on a semi - regular basis. The frame/braking/suspension just wont hold up to regular pulling of these loads. If you are only going to pull loads like this once or twice a year, I wouldn't worry about gears unless you just want the seat-of-the-pants gain for daily driving. If you plan to pull a heavy boat, race car, or travel trailer on a regular basis , you might want to consider gears and/or other mods for that purpose.

 

Spaceman, Thanks for the reply. I am not sure how much wider I want the tires but I definately want some height. The guys at Ford shop told me that 1) Whatever I can stuff will work without any big loss of power 2) Anything larger than 255s will rob noticeable amounts of power. 3) The truck was designed for the tires on it and I shouldn't change them. 4) We don't sell tires so I don't know what will fit.
I'm a little ticked at them anyway since when I was looking for the truck I gave them very specific desires and the order I wanted them in. They came up with this truck and told me I could stick bigger tires on it but it met all my other requirements. I should have asked about the gearing but they actually acted like they knew what they were talking about on this particular deal.
(I had a debate on the show room floor with my salesman and another supervisor of some sort on whether my truck came with shift on the fly since it didn't have the push button. They insisted if it didn't have the push button you had to stop the truck to put it in 4wd. After I told them that if this was the case I would take a Chevy they decided to ask around. Fortunately there was an old guy there that wholesales cars for them that set them straight.)

 

Well Dan we're getting there. I don't have a 2002 Owner's Manual, so I guess it's time to crunch some numbers. Going on the data in my 98 manual you should be able to tow a max trailer of roughly 6000#. Now, if we take you from 3.31 to the suggested 3.73 you should increase you max trailer to roughly 7000# and low end oomph by about 18%. However, the addition of larger tires would then reduce your ratio to about 3.65 (depending on the size) so your overall net gain-oh forget it my head is starting to hurt .

Let's start again. If you plan to tow about 5000# on a semi-regular basis (like a boat or travel trailer) a reasonable distance leave the gears alone and buy the new tires and a transmission cooler. If you want to tow 5500# or more, get 3.73s or 4.10s (expect the mpg to suffer), a bigger trans cooler, and the larger tires are OK, but get a heavy-duty load rating.

Lastly, you never said if you have a factory tow package, which would open the door to 4-pin, 6-pin, 7-pin connectors, brake control units, loadleveling hitches etc.

Aren't you glad you asked?

 

flafonman, Thanks, you answered almost all questions. We are looking at a travel trailer some time down the road and I wanted to know what my options are. I did get the factory tow package but don't recall off the top of my head what all it included. Will have to dig out file on it. I'm starting to think my best option would be to wait another year or two and pick up my trucks big brother.

 

Good plan. I'm getting my next truck when I retire. Going to do the fifth-wheel thing. It will be a SuperDuty dualie diesel.

 

Raoul, Not sure about the dualies but definately super duty and probably diesel. I figure the diesel warming up won't bother the neighbors any more than the Harley. <G>