one axle vs. two axles on short TT (20')

[SkiMore]

I was wondering what the pros/cons were of one axle vs. two axles on a short/lite TT. I'm talking about something less than 22' and 3500 LB dry.

I guess I should also ask about wheel size too.

[ghaindle]

I have dual axels. Blew a tire on the interstate last week and was able to limp to the next exit. My travel buddies have a single axel. If this had happened to them they would have been stuck on the interstate.

[PAThwacker]

21ft nonslide hybrid: dual axle, 19ft nonslide hybrid: dual axle.

[K-9_HANDLER]

I owed a single axle trailer for years before I got my current trailer. I prefer the dual axle myself.

[colliehauler]

On small trailers that I looked at the double axle had two 13 inch tires and lite weight axles. The single axle trailer had a heavier duty axle and 15 inch tires.

If you had a blowout on the double axle you would have ruined two tires because you would have seriously over rated the 13 inch tire.

I have always thought two axles would be better then one but I think I have changed my mind in favor of a single axle small trailer.

I like the fact I can get load range C and D and in 15 inch tires.

If I look for a 17 foot trailer to explore with I think I will look at single axle for rugged ground.

[atreis]

69 Avion wrote:
A real nice positive attribute to the rubber torsion axle when using the Flexiride axle is that the torsion arm angle can be adjusted in about 30 minutes. That can come in real handy.

Makes me think some enterprising person could build a device that would do this automatically... Speed above 45? Lower the trailer for improved aerodynamics. Speed below 20? Raise it up for better clearance. 🙂

[AH64ID]

One can also add the Dexter EZ-Flex system to their spring suspension tandem axle trailer. It made a big enough difference that my wife noticed in the passenger seat of the pickup.

http://www.dexteraxle.com/e_z_flex_suspension

[69_Avion]

AH64ID wrote:
The other potential issue with torsion axles is they require weigh to work. A torsion axle that is loaded lightly has very little give and rides much worse.

When shopping cargo trailers for my dad last summer we where talking with the trailer manufacturer and they only reccommended torsion axles if the trailer was going to be loaded at least 65% of the GAWR most the time, otherwise the leafs where a better option.

You are correct. The rubber torsion axles start riding real nice when you get over 60% of the rated weight on them. That is also a factor with leaf springs on a single axle. It is the equalizer on a tandem axle, leaf spring setup that keeps that rough ride from occuring when the trailer is real light.
I forgot to mention another positive attribute for rubber torsion axles is that they are "independant". Dexter used to make some leaf spring axles that were split in the middle with a pivot point so that the trailer would have leaf springs, with an equalizer that are also independant. Those trailers handled and performed very well.

[AH64ID]

SkiMore wrote:

AH64ID wrote:


... just like someone tried earlier to state most trailers under 23' are single axle which is not true.

....

It might be true for the very light ones. Most of the ones I have looked at that were sub 3000 lb dry seemed to be single axle.

In a certain class it may be true, but as a blanket statement about sub 23' trailers I don't think it is.

[SkiMore]

AH64ID wrote:


... just like someone tried earlier to state most trailers under 23' are single axle which is not true.

....

It might be true for the very light ones. Most of the ones I have looked at that were sub 3000 lb dry seemed to be single axle.

[AH64ID]

SkiMore wrote:

AH64ID wrote:
The other potential issue with torsion axles is they require weigh to work. A torsion axle that is loaded lightly has very little give and rides much worse.

When shopping cargo trailers for my dad last summer we where talking with the trailer manufacturer and they only reccommended torsion axles if the trailer was going to be loaded at least 65% of the GAWR most the time, otherwise the leafs where a better option.

I think a TT will be over 65% load most of the time. CCC is typically less than a third of max. At least it is on the 20' ones.

It fully depends on the trailer. Some trailers have more axle than GVWR and some trailers use TW to meet GVWR. It's impossible to put a blanket rule on it... just like someone tried earlier to state most trailers under 23' are single axle which is not true.

My trailer is larger, but at GVWR counting a 15% TW the axles would only be right at 65%. That means I would have to be at GVWR all the time to get the ride benefits out of a torsion axle. (I am always well above GVWR for the trailer so may actually benefit, but the average user would not).

TT's will be higher loaded most of the time, but not always. Just something to think about when looking at axle design.

[SkiMore]

AH64ID wrote:
The other potential issue with torsion axles is they require weigh to work. A torsion axle that is loaded lightly has very little give and rides much worse.

When shopping cargo trailers for my dad last summer we where talking with the trailer manufacturer and they only reccommended torsion axles if the trailer was going to be loaded at least 65% of the GAWR most the time, otherwise the leafs where a better option.

I think a TT will be over 65% load most of the time. CCC is typically less than a third of max. At least it is on the 20' ones.

[AH64ID]

The other potential issue with torsion axles is they require weigh to work. A torsion axle that is loaded lightly has very little give and rides much worse.

When shopping cargo trailers for my dad last summer we where talking with the trailer manufacturer and they only reccommended torsion axles if the trailer was going to be loaded at least 65% of the GAWR most the time, otherwise the leafs where a better option.

[SkiMore]

I didn't know anything about rubber torsion axles until now. I thought all trailers had leaf springs. I found some pictures of and can tell them apart now.

I looked at a couple of websites for trailers and it doesn't look like they discuss what type of axle or the weight specs of the axle the trailer has. How do you get this from the web?

Thanks again for all the info.

[westend]

69 Avion wrote:

westend wrote:
If considering alike travel trailers, one having single axle and the other, a tandem set, I would choose the trailer that is built better. There is a lot unknown how a trailer will tow, regardless of axle count. Tandem axles will support more weight and for some, that is a great attribute. I have a 22' with tandem axles supporting 5K lbs. It tows like a train and stops adequately.

Even though I respect Avion69 quite a bit for his trailer building skills (and he's helped me a ton), I'd differ a bit on the ride quality of sprung axles over torsion bar for a small TT application. My current TT has two torsion axles with shocks (I've forgotten the ratings). It is the smoothest towing trailer I've owned (current count is 6). Part of that may be due to the low attitude but the torsion axles are a highway dream.

The issue isn't as much the ride as it is the stress when one rubber torsion axle has to carry most of the weight of the entire trailer when you hit a bump that is greater (or close to) the travel of the axle. When you hit a 6" speed bump and the axle only travels 5", one axle will carry the entire weight of the trailer for that bump. A leaf spring has an equalizer so you get the travel of the equalizer plus the travel of the leaf springs. If you aren't hitting large bumps, a rubber torsion tandem trailer should tow real nice and ride nice as well.
If I were picking the "ride" of an individual axle, I would pick the rubber torsion over the leaf spring. The other issue is lateral stress when cornering. It isn't real bad with tandem axles, but it can be tremendous with triple axles. Some rubber torsion axle manufacturers don't recommend their RT axles for triple axle configurations because that stress can pull the rubber swing arm right out of the axle tube.
They all have their positives and negatives. Most of the time a person doesn't get their choice when buying a trailer. Another down side of the rubber torsion axle is that the rubber is usually only good for about 25 years. Then it is time to buy a new axle because you can't replace the rubber. In many cases the TT needs a rebuild by that time anyway. A positive attribute to the rubber torsion axle is that it can be used as part of the structural integrity of the trailer frame and it is easier to install. A real nice positive attribute to the rubber torsion axle when using the Flexiride axle is that the torsion arm angle can be adjusted in about 30 minutes. That can come in real handy.

I'm always learning here, thanks.