Low Profile Stabilization Jacks

When I looked into this for my 179 I found that FR and Lippert set the axle rating lower than the max Lippert has established for that style axle because of how it is mounted and the strength of the frame at that point. IOW Lipperts number is for the best possible mounting configuration, the axles get derated from there. The part number is a specific build for FR and stamped with a rating Lippert and FR gave it for that specific trailer configuration. I expect your find the same applies for your axle.

Adding risers does reduce the overall axle load capacity even if you use the same mounting points. This is because it adds additional frame stress. When you hit a pot hole the axle is rotated rearward and upward. That puts a torque (moment) on the trailer frame at the mounting points. The longer the arm over which that force is applied the higher the moments are on the frame, so a lift kit increases them. That might or might not cause a problem in your case but it is a legitimate reason for FR to disallow a warranty claim if it happens.

For that reason anyone adding a lift kit without FRs approval does so at their own risk, and needs to understand that there is risk due to increased frame stress in doing so. I hope you weren't suggesting removing the lift kit if you have a problem and then failing to inform FR when making a warranty claim.

All the torque (moment) from hitting a curb or pothole ultimately has to go somewhere and that is the frame. That moment is much higher than the brake loading. The weak link isn't the bolts it's the frame itself. The frame is as light as FR can get by with and there has been at least one frame bending failure at that point reported on the forum.

The best way to lift the trailer is to weld or bolt (with a coupe of gusset plates)k a tube section under the existing frame. That should be at least a couple feet long as that will move the forces outward from the axle attach point thereby increasing the moment arm, putting less stress on the frame in order for it to be able to resist the same moment.

Jato, unless you plan to change the kind of roads your towing on I'd say you don't need to change what you have currently. If you were going to bend your frame you would probably already have done so. Also, as you point out, the 177 is a light trailer. The reported frame bending was in a heavier rpod. Roughly speaking, I got a little under 2x as the safety factor for a 179 loaded to gross weight of about 3800 lbs so with a 2900 lb 177 that would be round 2.6 safety factor, should be enough if you don't make it a habit of hitting curbs and pot holes.

I didn't do the frame reinforcement mod in my trailer b4 I sold it. If you do a search back a few years I did a rough analysis of the bending moments for the 179 and came up with a length and placement for a 4x2 inch tube "doubler" under the existing 4x2 tube frame. That would replace the riser kit. IIRC the doubler tubes needed to extend farther to the rear than to the front of the axle attach point. The moment falls off more quickly toward the front than to the rear. The double tubes could simply be welded under the existing tubes. Since the welds would be at the mid point if the doubled axle they would be at the neutral axis so wouldn't get much stress and wouldn't need to be continuously welded. I think welding would be the preferred approach.

Or gusset plates about 8 inches wide could be added to the sides to connect the two tubes. TEK screws could be used to attach the plates to the sides if the tubes.

To drop the axle I would jack the frame behind the axle attachment but as close to it as I could. Place a block between the jack and frame to spread the load.