I haul more stuff with my Fit than I should, and just installed some Firestone Coil Rite Air Helper Springs (# 4183) on my '09. These are some cylindrical bladders that go inside the rear coil springs. There's an air fitting to pressurize the bladders when needed, which stiffens the rear suspension. For normal driving, you let the air out of the bladders and the springs act normal.

These are an easy install and cost around $100. I haven't hauled anything heavy, but have inflated them and then sat on the tongue of my attached small trailer, and they definitely keep the rear springs from compressing excessively. I wouldn't use these for that kind of tongue weight when hauling (the hitch and uni-body aren't made for that), but they should help stiffen the rear for hauling reasonable loads. They do make the car even stiffer when unloaded as well - you racy guys might like that.

I really like these as a low cost, simple add-on. One thing I would recommend is that the stiff, 1/4 inch plastic airline comes out the bottom, through an existing hole in the center of the coil spring support. Those airlines will become the lowest hanging thing under the car, unless you really flex them which I believe will put too much stress on the connector at the air bag. So I obtained two elbows for the airlines so they route horizontally without the stress of a bend. Search for "Parker 165PNP" for the type of elbow I mean. This is not something you can get at Home Depot, so order ahead of time if you want to do this.

Note that the #4183 Coil Rites are listed as fitting '10-'13 Honda Fits, but they worked fine on my '09. They must just have an incomplete database.

 

air lift shocks do a better job.

 

Monroe Max Air Shocks work good too on my 2015 GK. Check my sig for the thread. Well worth the 65 bucks for the set! Some mod required but parts cost are minimal.

 

Bassguitarist - I did a lot of searching but never saw your nice thread since it's in the GK sub-forum. I did look into making some air shocks fit since there's no direct-fit part number for the Fit, but decided that the easy airbag kit would meet my needs - just jack up the rear of the car, support on jack stands (gotta be safe), remove the rear wheels for easier access, slip the airbags between the rear spring coils and then run the airlines. The longest part of my install was making the car driveable again half way through the job to get the air line elbows I mentioned. Fortunately, we use those type fittings where I work.

And with the airbags, the suspension is 100% stock when they're deflated.

 

The other day a close buddy here installed that firestone air spring on his '12 Fit along with his new tires on, he mentioned he got good discount getting them all at 4WheelOnline.com. He's very please with the stiffen suspension so I research the net and here, seems ideal one as I recently loading more than I used to on my '11 Fit sports. Great it works on your '09, where did you get the kit?

 

I bought the Coil-Rites from SD Truck Springs (Leaf Springs, Helper Springs and Suspension Parts | SD Truck Springs), but your source 4WheelOnline.com is currently a couple of dollars cheaper. Note that it took 2 or 3 weeks for delivery because they're not always in stock.

 

You are welcome! The procedure is very similar if not the same for the GE and GD frames. Not much difference with the rear axle shocks and spring config. I too have looked at the Airlift Kit too. Specifically the remote and air pump kit. Love the idea of adjusting on the fly via remote, but the cost is very expensive for the convenience. I'm very happy with the function. Difficulty is not bad either, just need to cognizant on installation procedure mods and you're good.

 

Exactly how did you get the elbow fittings? I Google "Parker 165 PNP" and get zilch, it doesn't even come up on the Parker website.

 

I think he meant 165PTC. All you need is a 90 degree elbow with a 1/4 push to connect fitting on each side.