[Gschuld]

It’s funny that I have been researching old trailer designs with expandable sections. Thx, and I’ve seen that one before. Also a modern Hi Lo type design was considered.

Aerohead: excellent points.

“9- You're appetite for fuel savings vs construction-difficulty-coefficient ( PITA) will decide your course”. Ha, I like that.

Yes, I managed 32.5mpg average at 65mph with ACC (adaptive cruise control) on at the closest setting the car would allow(estimated 75ft) to the big box semi in front. This was in modestly changing elevations (100ft swings maybe over gradual grades) on the GSP in NJ for maybe a 10-15 minute stretch.

I haven’t pulled trailers much with the Jeep since I got it last year. I’ve got a v10 Excursion(flack jacket on��) that I use for work for the heavy stuff. But I did pull my 24ft open deck dual axle trailer(2 3500lb electric drum brake torsion axles, 6ft wide frame, 1700lbs empty weight) with a long 300 lb load on it that was somewhat draggy but not higher than the Jeep, that I got 17.xx mpg over a 30 minute period doing 75mph with ACC on in no traffic.

I intend to run a few tests soon with other trailers. Specifically with the dual axle 7x14 enclosed cargo trailer. I’m very curious to see how that goes.

My trip back to NJ from Michigan (not pulling a trailer) once again had the Jeep calculated mpg figures match very well with my hand calculated miles/gas used.

I am really impressed with this Jeep Grand Cherokee SRT. Perhaps I’m just so used to my V10 excursion being such a heavy wallowing gas gulping beast on the highway. But after 12 hours on the road in that SRT, I arrive feeling relaxed and not tired at all.

That brings me to another factor in my custom trailer interest. Vintage motorcycle road racing 12-42 hours drive away(42 hours is NJ to Laguna Seca California at 70mph average for 3000 miles one way) has risks involved. Though everyone wants to stay safe and trackside safety precautions and medical services are commendable, people do crash. Sometimes it is a few scrapes, bruises, sprains. Sometimes it’s more than that. Sometimes it’s enough that the injured rider isn’t realistically able to drive himself home.

I’d be going with at times a friend, at times with my wife, and occasionally alone if it can’t be avoided. FWIW, I do have several people from my area that race too that I could have them drive my stuff home in an emergency if I’m driving alone and I get hurt(rare case)

My wife isn’t a fan of pulling trailers on the highway. Her previous experience with it was in the Excursion with the 24ft Haulmark trailer at 6000lbs or so(Excursion rated for towing 11,000lbs) Some bigger cross winds and some close passes on two lane roads by a semi had the trailer swaying enough that she was not at all comfortable with it(yes, with proper loading/hitch weight/load leveler/sway control system)

I’ve done my share of pulling that setup. And though I’m used to it and find it safe and controllable, I will admit that driving such a rig required far more concentrated effort and was far more mentally taxing than driving without the trailer. 12 hours at 65-70mph and I was spent. Throw in a windy day, or tons of rain and I was miserable. That late 1990s architecture is archaic compared to newer big trucks I’ve pulled with FWIW.

A great benefit of an efficiently sized and shaped trailer matched to the SRT should not only benefit from better mpg, but also be far less taxing on the driver on long stints. I’ve done 15 plus hour drives pulling my empty 24ft open deck trailer and it was night and day easier. I had to keep reminding myself it was even back there.

I’d like to have a setup that can logistically accomplish the mission (deliver the bikes and equipment, etc) and hardly be noticeable behind me. If I can do that, I’d feel far more confident that my wife or friend would have little issue driving it. And planning on 75-78mph average where allowed, it makes a difference I’m sure.

There are a few more logistical factors that are influencing my designs, but I’m not including them in an effort to not muddy the waters.

And yes:

5200lbs for Jeep (with 7200lb towing package and a Radarc progressive brake controller)
2700lbs(projected) for loaded trailer with single axle and electric brakes
350 lbs for my passenger and myself. I’m a big tall Danish guy.
8250lbs all up. Could be a little less, maybe 8500lbs or so at the outside.

George