Looks like you are right. Good call. I guess the sides are stiffer and don't let the bag expand as much. My mistake. Bags went from 23 PSI to 27 PSI after loading the trailer.

 

OK, check this...my father-in-law just got air bags on his '01 F-150. He doesn't know what brand they are (he's not much of a car guy...just went to the trailer place and said "sell me some air bags") but already had them on. I went by to check them out and wanted to share how they mount...cause it's not what I imagined....No photo's so hope you can visualize this...

They mount (clamp) on the top of the leaf spring and the top bracket mounts to the frame directly above. The top bracket is bolted to the outboard side of the frame so therefore it's directly above the leaf spring. BUT, the bottom of the air bag clamps to the top of the leaf spring like I said, but it is not centered over the axle. It clamps around the spring itself foward of the axle!! It just plain looked wierd, and looked like it had the potential to put some unusual forces/angles on the spring when aired/loaded up. Seems to me you'd want it centered right over the axle.

I've seen photo's here recently in another thread where a guy has airbags on a '07 and they are right over the axle.

So what do you guys with pre '04 trucks have??

 

Years 1997 through 2003 in both AirLift and Firestone the air bag is off-set and not directly over the axle.

There are a few reasons for this.

1st and most importantly these years had a very weak frame directly above the axle...and it is also the reason that bed mounted hitches are not recommended in these years. Yeah, I know people do it but after inspecting a '97-'03 and compare it to other years you will see why you shouldn't.

2nd there isn't much room for installation as the shock is mounted too close to the spring to get the air bag in place.

 

Does it cause any problems or is there even really any downside to having it mounted here as opposed to directly over the axle??

 

With the lesser weight that we deal with in the F150 compared to a 1-ton I wouldn't worry about the air bag placement. Being a little off center certainly isn't going to hurt anything.....unless you are trying to load your 1/2`ton like a 1-ton.

 

OK, not being argumentative here, just some thoughts...because I would guess the manufacturers thought this through before deciding on placing the bags where they do...

If the frame is known to be weak directly above the axle, doesn't seem to me like a mounting point 4-6 inches foward of that is going to make much difference?? Seems like the load on the mounting point would have more stress on it or be at an awkward angle in that foward mounting position as compared to a relatively natural movement direction when placed directly above the axle.

Also, looking at my truck I can't see how the shock would get in the way??