Axle Placement

03-21-2008, 05:32 PM

I have read this many times in the TM Forums over the years.

"TrailManor provides uniquely easy towing per pound due to the very low wind drag and the very stable ride resulting from axle placement."

I stole that statement from another thread.

Somewhere along the line it was decided that the tongue weight should be between 10% and 15% of the trailer weight. A higher tongue weight usually providing more stability. Axle placement changes tongue weight. Looking at the TM specs, all models have tongue weights between 10% and 15%. Other manufacturers have trailers with tongue weights between 10% and 15%. How does the Trailmanor axle placement make it more stable than an ordinary trailer?

I am not looking for an argument, I just want to understand the statement.

countrygirl · 03-21-2008, 06:03 PM

I "think" that the location of the axle prevents the dreaded sway that some rv's are prone to have. So if you loaded your TM properly and did not put too much weight behind the axle you should not have sway. This would also require you to have a proper tow vehicle rated to pull the TM of your choice.

**Bill** · 03-21-2008, 07:53 PM

This is my impression only ...

If you look at a TM in comparison to other trailers, the axle is pretty far back. What this means is that most of the stuff you put in the TM will be forward of the axle, rather than balanced fore and aft of the axle. This in turn means that the loaded TM will have a higher tongue weight ratio than other trailers. I believe that most weigh-in's reported on this board (and there aren't many) put the tongue weight at 14-15% of total weight. With other trailers, more symmetrically loaded, you start with 10-11%, and you end up with 10-11%.

Why is this? Many (most?) tow vehicles can't handle more than 700-800 pounds of tongue weight, maybe 1000 max for a big vehicle. The trailer manufacturer has to make sure that his loaded tongue weight doesn't exceed this number, and he also has to ensure that it falls within the 10-15% window. With a heavier trailer, the tongue weight has to fall at the lighter end of the percent scale. In other words, an 8000 pound travel trailer will probably have about 10% (800 pounds) tongue weight. A 4000 pound TM will likely be closer to 14-15% (560-600 pounds) of tongue weight. The latter is way more stable.

Did that make any sense? Hope so. Again, this is my impression. I have no magic knowledge.

Bill

03-21-2008, 08:12 PM

Thanks Bill,

With all the posts about the Magical Placement of the TM axles, no one has ever explained it before. Very simple. I don't know why I didn't see it myself. A lighter trailer can have a greater percentage of weight on the tongue. Your explanation should be on the TM website.

**Bill** · 03-21-2008, 08:25 PM

Quote:

Originally Posted by AstroBruce

A lighter trailer can have a greater percentage of weight on the tongue.

Well - - - yeah! There it is. A dozen words to explain what I rambled on for two paragraphs about. I need to hire you as an editor and proofreader. Thanks!

Bill

countrygirl · 03-21-2008, 08:26 PM

Whoops wrong again. Thanks Bill for clarifing it.

03-21-2008, 08:48 PM

This would apply to any "lighter" trailer, not just a TM. No magic.

**Bill** · 03-21-2008, 09:17 PM

Quote:

Originally Posted by countrygirl

Whoops wrong again. Thanks Bill for clarifing it.

Country Girl -

No no no, you are exactly right! Somehow I didn't make myself clear. Loading in front of the axle, to produce the desired tongue weight and tongue weight percentage, is the important thing. By putting the axle further back, TM makes it easy to load properly, so that the loaded weight is properly distributed to the tongue. And Bruce's summary, that a lighter trailer can have a heavier percent tongue weight is right on target.

I guess I'm a little thick tonight. I apologize if it didn't come out that way.

Bill

countrygirl · 03-21-2008, 10:12 PM

The way you explained it was a whole lot clearer to me...

03-21-2008, 10:36 PM

Also consider this.

Imagine if the TM was very light and most of the weight was in the front. This would make the tongue too heavy. So what if you moved the axle forward so that there was 3 feet in front of the axle and 17 feet behind the axle.

Even if this was balanced it would be prone to sway. The tail would be wagging the dog.

To maximize stability, place the axle at the rear. But now the tongue weight is too high.