TM Towing Problems

We took our new 2720SD out for the first time last week. I'm towing with a Jeep Grand Cherokee 4X4 with the big V8 and trailer package. We had absolutely no problems with the mountain passes, one was over 10K feet. I kept the speed at 60 MPH and below when the speed limit was 65 and 75 (on the interstate). I limited my speed because going faster led to the onset of a noticeable sway. The trailer was lightly loaded and so was the TV since we were out for a quick three day camping trip. I'm aware that it is recommended that the bulk of the weight should be concentrated in front of the trailer axle and that's where I stowed most of the things we carried inside the trailer. However, I had the dealer install a hitch on the rear of the trailer for my bike rack and I had two mountain bikes mounted there for this trip. I just occurred to me that that could be my problem.

As a greenhorn to the trailer world, I may have shot myself in the foot. I would appreciate any constructive advice on how to deal with this fine mess I may have gotten myself into. Most of what I've read on towing the TM suggests that the TM is a dream to tow with no sway.

I am overwhelmed by the large variety of anti-sway devices and weight-distributing hitches out there. They all seem to be designed for towing trailers much larger and heavier than the 2720SD. Moreover, reading through many of the posts found here, it seems like few TrailManor owners have encountered trailer sway and when they are loaded correctly they tow like there's nothing back there without the need for anti-sway devices and weight distributing hitches.

Any words of experience and wisdom would be greatly appreciated.

ColoradoAl

[Civil_War_Buff]

I added a trailer hitch receiver to the back of my TM 2720 and I notice a small amount of sway when the two bikes are loaded. I wouldn't be too concerned at this point...just take it a little easier when hauling the bikes.

[mjlaupp]

Al,
The 2720SD should tow without sway. I doubt that your bike rack biased the weight that much to the rear. The 2720SL & 2720SD models have an extra 50-70 pounds tongue weight that should offset the weight of the bike rack and bikes.
The other thing that will cause sway is low tire pressure. They must be pressurized to 50 psi. The independent suspension on the TM will allow the unit to start bouncing from tire to tire if the tire pressure is too low. This bouncing is turned into sway by the TV/TM hitch connection.
HTH
MJL

Al,

I installed a receiver on the rear of our TM 2619 so that I could quickly install/remove our tandem bike rack. I have definitely noticed some sway when the tandem is mounted. Fortunately, I still have the friction sway control that I used with our pop-up trailer. Due to the folding tongue of the 2619, I cannot mount the sway control on the right side of the hitch as I would like, so I have ordered a sway control adapter which will allow me move the control to the left side without much adaptation required.

Michael

One other thing to check is to make sure the rear tow vehicles tires are inflated to equal and correct pressures. Unequal pressures can also cause sway.

[Denny_A]

Al,

I believe that if the tongue weight is at least 10% or greater (of the trailer weight) there should be no problem. Therefore if lightly loaded, as you indicated, the trailer was likely near or under 3500 lbs. You had two bikes on a bumper hitch. Let's try a little math exercise using assumptions.

Assume: Trailer 3500 lbs; tongue weight (w/out rack) 12% of 3500 = 420 lbs.
N.B.: I had the geometry wrong in original post. Below was amended to reflect moment arms measured from axle attachment point on the frame.
Geometry: Axle-to-rear bumper = 7'3".; Axle-to-hitch = 12'9".; bike rack arm behind bumper approx 1 ft(?).
Bikes plus rack = 2@35 lb + 10 lb = 80 lbs total. (replace with actual weights).

Moment around trailer axle = 420 lbs*12.75 ft - 80 lbs*8.25 ft = (5355 - 660)lb-ft = 4695 lb-ft. (sum of moments)

Question: What is the new tongue weight?

Answer: Tongue Wt = Sum of moments / Arm = 4695 lb-ft / 12.75 ft = 368lbs.
Result: Tongue weight dropped from 12% to 10.5%.
Reason: Long moment arm to the bike rack.

The point - small increments of weight at a long moment arm have a large effect. The geometry is such that each 10 pound increment of additional weight behind the bumper removes about 6-7 lbs pound from the hitch. If the bikes and rack weighed more than in the example, and the hypothetical tongue weight were even less than I used, the final tongue weight could be closer to 9%.

Denny_A

Originally Posted by ColoradoAl

-------snip---------noticable sway----snip
The trailer was lightly loaded and so was the TV since we were out for a quick three day camping trip. I'm aware that it is
recommended that the bulk of the weight should be concentrated in front of the trailer axle and that's where I stowed most of the things we carried inside the trailer. However, I had the dealer install a hitch on the rear of the trailer for my bike rack and I had two mountain bikes mounted there for this trip. I just occurred to me that that could be my problem.

As a greenhorn to the trailer world, I may have shot myself in the foot. I would appreciate any constructive advice on how to deal with this fine mess I may have gotten myself into. ----snip-----------
ColoradoAl

Our 2619 had the water tank located under the driver-side dinette seat, which was located in front of the axle. One way to add tongue weight is to carry water (8#/gal). The advantage of the extra tongue weight far outweighs the disadvantage that extra weight has on mpg. Our current trailer has a 50 gallon water tank under the front-mounted queen bed. It is always full when we leave home.

I don't know where the water tank is located on the 2720SD, but if it is in front of the axle, try filling it at home and experiment with your towing stability.

[RockyMtnRay]

Originally Posted by ColoradoAl

However, I had the dealer install a
hitch on the rear of the trailer for my bike rack and
I had two mountain bikes mounted there for this trip.
I just occurred to me that that could be my problem.

Greetings to a fellow resident of Colorado Springs and welcome to our online community!

Yes, as Denny-A's math quite conclusively proves, putting those two bikes on the back of the trailer is undoubtedly at least 90% of the cause of your sway problem. Certainly, the other recommendations like correct tire pressure and filling the water tank will reduce the potential for sway but the solution is to get those bikes off the rear of the trailer.

As the owner of a very similar 2720SL who's had each tire of my loaded trailer weighed, I would strongly caution you to NOT fill the water tank over half full as you're very likely to exceed the axle limitation for the street-side tire if you also have a full load of food in the fridge and a filled hot water tank. Besides which, because the water tank is just barely in front of the axle on the 2720SD (and SL), its affect on the trailer's center of gravity (and anti sway stability) is pretty minimal.

IMO, bikes (or any other weighty object) simply should never be carried on the back of the smaller TMs as their weight that far behind the axle substantially reduces the inherent sway resistance of the trailer. I also think that Dave Unruh and the gang at The Car Show (presuming that's where you bought your TM) are doing buyers a major disservice by offering to install hitches on the rear bumper so people can put bikes back there.

I am overwhelmed by the large variety of anti-sway
devices and weight-distributing hitches out there.
They all seem to be designed for towing trailers much
larger and heavier than the 2720SD. Moreover, reading
through many of the posts found here, it seems like
few TrailManor owners have encountered trailer sway
and when they are loaded correctly they tow like
there's nothing back there without the need for anti-
sway devices and weight distributing hitches.

Do NOT mask your sway problem with an anti-sway device. Folks with convential TTs have to use them because they have no alternatives. TM owners have the far better alternative of relocating weight to solve the problem. Since you have a Jeep GC that can readily carry cycles on the roof rack, I'd definitely suggest that alternative. My previous tow vehicle was a Jeep Cherokee (not the GC) and a roof rack worked very well for carrying my mountain bike. Another alternative that works very well (I use it on my current tow vehicle, a Toyota Tundra pickup) is this Swagman "towing" 3-bike carrier that I bought at Camping World in Denver. You can also get them at cycle shops here in the Springs but CW was quite a bit cheaper if you are a member of their President's Club. This rack clamps over the hitch bar of the WDH and carries the bikes over the trailer's tongue. I've had zero clearance problems with the trailer and it would work equally well on your 2720SD as you also have horizontal propane tanks.

[Civil_War_Buff]

Originally Posted by RockyMtnRay

Another alternative that works very well (I use it on my current tow vehicle, a Toyota Tundra pickup) is this Swagman "towing" 3-bike carrier that I bought at Camping World in Denver. You can also get them at cycle shops here in the Springs but CW was quite a bit cheaper if you are a member of their President's Club. This rack clamps over the hitch bar of the WDH and carries the bikes over the trailer's tongue. I've had zero clearance problems with the trailer and it would work equally well on your 2720SD as you also have horizontal propane tanks.

This is the same carrier that I use, but with my WDH I cannot use it to tow the trailer. I used to use it as designed when I had my Coleman, but couldn't see getting a new one that worked just fine (with the slight sway exception).

[fcatwo]

I've read all the above posts twice and I don't see any mention of the TM spare tire. I've toyed with the idea of carrying our tandem bike on the back of our 2619 but I plan to take the spare off the rear bumper of the TM and bolt it down inside our TV to offset the added weight of the bike. Is that solution so obvious that everyone else has already done it? I also second the advice of not getting a sway control bar. Those things just mask a problem that can be fixed on a TM. A WDH is well worth the money however.