im looking at building a 2018 f150 3.5L ecoboost with 10 speed transmission, I will be running a 35x12.5 tire on this truck with 6 inch lift. I want the 3.73 gear but undoubtly ford will not let you have the heavy payload option with a lariat 502A option. I don't know why u cant have the luxury of all the bells and whistles and not get the heavy payload option :/.

My question is what would my towing capacity be considered to be like if I have the 3.5 L ecoboost with the new 10 speed transmission on 35's if I go with the 3.55 gears?

 

What cab style, bed length, and drive type (2wd or 4wd)? Will you be ordering the max tow and/or HD payload option?

Note that the lift and bigger tires will reduce the tow capacity from factory specs. Also, without HD Payload, you will run out of payload/GVWR before you reach max trailer weight.

 

it will be a crew cab 6.5 ft bed and 4x4....they don't over the heavy duty payload option with the 502A package option so I will have the max trailer tow option. I know the 35s will reduce the towing capacity but I'm curious to know how it will do towing with the new 10 speed and what will my tow capacity be lowered down to?

 

https://www.fleet.ford.com/resources...e_r2_Nov27.pdf

The official towing capacity in that configuration is 10700# standard, 13000# with max trailer tow and 20" wheels. You will definitely run out of payload before you get that heavy. 5th wheel max is 10300# with or without max tow and 20".

It will be less with a lift, aftermarket wheels, aftermarket tires. How much less, I don't know. It's not an Ecoboost or transmission issue, it's a truck chassis issue.

 

so other then the wheel and chassie ur saying evenon the 3.55 gears the ecoboost still has the power to pull 10k pounds or close to it even with 35x12.5 tires with out an issue ?

 

It should *PULL* 10k easily. Here's a 2017 with 3.55's and a 10 speed pulling the Ike Gauntlet at the speed limit towing 9k:

http://www.tfltruck.com/2017/02/2017...-150-10-speed/

Wasn't even close to the floor, 3k rpm most of the way up.

 

If you really want to find out what your truck will do you should calculate the real ratio with the larger tires. That would give you something to work with.

 

Effective gear ratio is not much of a concern with the Ecoboost and 10 speed in tow/haul mode once you get it rolling.

 

The Max tow gets all the max payload springs in it. The only thing missing is the ugly 18" max payload wheels and the door sticker that says 7650. You'll still have the front rating of 3650 and rear of 4000 but the sticker will only have a combined 7050 gross. 6.5' bed crew cab 4x4 with 20" wheels, 3.55 and ecoboost gets 13000 towing