Axle Questions

[Capebuild]

Hello.... couple of (novice) questions in planning for the axle. (planning on getting either a Dexter #9 or a Flexiride of some variety)

What does it mean to "derate" the axle? I'm not knowledgable with that, tried looking it up but didn't really find an answer. (I've seen the spec where someone orders a "2000# axle but derates it to 1400#s). What does that mean?

The "start angle"..... does one determine that by how far off the ground they want the trailer to ride, is that the purpose of specifying a certain start angle?

Thank you, appreciate your help.

John

 

[halfdome Danny]

http://www.tnttt.com/viewtopic.php?t=7214#p84878
Here it is in a nutshell.
Danny

 

[Shadow Catcher]

I am in the process of replacing our 12 year old Dexter axle because of a case of DA (dragging tail) as it sagged. Derating the axle has to happen at the manufacturer. Based in my experience you might want to reconsider. I am sure there are calculations to tell you what you will end up in height talk with the manufacturer. OR, we are replacing our Dexter with a Flexride https://www.theuniversalgroup.com/mwdownloads/download/link/id/53/ which can be adjusted/changed.

 

[scowan]

I requested my Flexiride 2000 pound axle to be derated to 1400 pound when I ordered it to give a better ride.The unique thing about a flexiride is being able to
adjust the splined shaft for the height you want.When I ordered mine the 2000 pound had no brake option.You had to go with 3500 pound to get brakes.

 

[Tony Latham]

I've seen the spec where someone orders a "2000# axle but derates it to 1400#s). What does that mean?

It means the axle is made for a 1400 pound trailer, not a 2000 pounder. I think Dexter shortens the rubber torsion pieces to do this.

None of the steel pieces change.

Tony

 

[Capebuild]

Thanks all for the follow ups. very helpful. Danny, that was a great post with lots of info.

I think I understand the purpose of specifying a certain start angle (having to do with the distance between the road and the chassis).
As far as the derating issue.... if you order a 2000# axle and "derate" it, to say 1400#s, I'm assuming you expect your total trailer weight to be
1400#s. What if your weight winds up being over 1400? And is the purpose of derating it so you have a smoother ride (where a 2000# for a 1400# payload
would give a "stiffer" ride, not enough give in the axle to absorb the bumps.....do I have that correct?

Thanks again. Sorry for all the questions, just want to make sure I understand all this.

 

[halfdome Danny]

It's very important to get the ride height right, as I well know.
My second teardrop was drawing a lot of positive comments from the low rider guys.
Dexter told me it was ok to weld a spacer of my frame material to bring it up, worked great but a lot of extra work.
In that old post I follow the recommendations made by Grant.
Danny

 

[Kampereen]

And is the purpose of derating it so you have a smoother ride (where a 2000# for a 1400# payload
would give a "stiffer" ride, not enough give in the axle to absorb the bumps

I hope someone will comment on this because I have a question along the same line! I am building light tent campers using the Flexiride 550 lb. axle stubs. They are hard to find in stock sometimes, so I have been looking at what's available. The higher rated 935 lb. are in stock.

The empty sprung weight of the camper is around 175 lbs. So I am wondering if that is too light for a 935 lb.-rated axles. When loaded, I'm figuring ride quality wouldn't be as much of an issue, but would the ride be too stiff/bouncy for the empty camper?

 

[Shadow Catcher]

We replace our 2400# Dexter with a 3500# Flexride and I am not seeing a noticeable difference in ride.

 

[aggie79-HILO]

I can't recall the exact Dexter terminology, but keep in mind that the start angle is the angle of the torsion arm unloaded. Once the axle is carrying the static weight of the trailer, the torsion arm rotates upward, lowering the trailer. The remaining torsion arm rotation is the suspension travel.

I ordered my Dexter axle de-rated to match the trailer weight. It worked fine for about 7-8 years and then there was some sag. I would suggest giving yourself a 300-400# "cushion on the derating. Theoretically, you should include the weight of your camping supplies and furnishings too; however, these are approximately equal to the weight of wheels and tires which the suspension doesn't have to support. (They are un-sprung weight.)

Lastly - and this one is controversial - for the lifetime of our teardrop, I kept tire pressures around 25 psi rather than the 35-40 psi range per the sidewall. The lower tire pressure will drastically improve the trailer ride performance. The tires we used were not trailer tires. They were automotive tires. I wasn't worried about excess sidewall flexing because the tires were carrying about 700-800# each on the teardrop compared with the 1,000-1,500 they would be carrying on the average passenger vehicle, plus they did not experience any where near the stress as front tires on a vehicle incur during turning movements.

 

[Kampereen]

Tom thanks for that feedback. I got a set of the 935 lb axle stubs to try because the lighter ones aren't available right now and won't be for a few months. I figured that was a good enough excuse to try something new.