I have a 2013 F150 FX4 that i recently put 2.5 inch Rough Country leveling spacers on. I always carry quite a bit of weight in the bed. I have a packrat tool box that i keep stocked with motors and parts for HVAC work. Now with that load in the back the back sags about 1 3/4 inch. That makes it sit nose high. I thought about putting airbags on it, replacing the factory block with a 3", or add a leaf. I want to maintain a decent ride. I was wondering if i put the 3" block on will I need to replace the rear shocks? Please let me know if anyone has experience with this. Pictures would be appreciated as well. Thanks!

 

I measured my truck after installing the auto spring 2.5 inch complete level kit. After doing front end there was 1/8 inch difference between the front and the rear (rear being higher) from the wheel wells. after installing the rear 3 inch blocks there was just over 1.3 inches difference front to rear. If you are sagging 1.75 inches you will definitely need something other than just a 3 inch rear block. The add a leaf will stiffen your ride and add anywhere from 1.5 to 2 inches of additional rear lift, but according to my tire guy, the add a leaf kits have a nasty tendency to come un stacked like when crossing on a grade with a load (the example he provided was coming out of a hilly area of the woods with a load of firewood in the bed, he said the leafs came unstacked). Probably better option: remove 2.5 front and go back with 2.0 spacer and then ad 3 inch block in rear.

 

I don't want to change out the spacers in the front because I already put 305 55 20 tires on and I am afraid they would rub if I put it down any lower. I am just wondering if maybe airbags would be it the best option that way I can adjust the height. I am afraid with putting the 3 inch spacers in the back of that I would need to replace my shocks and it wouldn't give me enough lift.

 

A few options for you. If you want to swap your OE block for a 3", that would give you a little rake back. Matter of preference, but it's relatively inexpensive. Replacing the shocks with longer ones would be a good idea, but not necessarily required since you're only gaining about 1.5" of lift.

http://www.realtruck.com/readylift-o...s/66-2053.html
http://www.realtruck.com/maxtrac-sho...-2900ll-4.html

Next option is my preference for maximum versatility. Firestone Ride-Rite air bags. I have these on my truck right now and they're awesome.

http://www.realtruck.com/firestone-a...tems/2525.html

Now a simple solution giving you the benefits of airbags without having to inflate or deflate them are airless airbags called SumoSprings. They take the place of your factory bump stops.

http://www.realtruck.com/superspring...013Y212MA.html

 

with the airbags would I need to replace my shocks?

 

You can keep your factory shocks with airbags since you're not altering the limits of suspension travel.