trailer axel position

[gmc ronnie]

i'm building a utility trailer and bought a 3500 lbs. axel at tractor supply, it has the spring mounting plates already welded to the axel . do you put the axel below the springs or on top of the springs ???? thanks

 

[Chances R]

Normally your axle will be above the spring. On a tilt bed trailer we placed the axle 1" behind bed center point. With a tail gate ramp we placed the axle 6" behind bed center point.

 

[Anonymous-0]

Here is a typical Dexter axle but you should consult your axle manufacturer. Some axles are bowed up at the center to allow some positive caster and tracking stability. Mounting those types upside down would not be good.
Dexter axle mounting

 

[Don L C]

ronnie ---

You can put the springs over or under the axel...
Put the axel 60% back from the front oo the bed.....

 

[Don L C]

ronnie ---

I just re-read your post......it depends on the style of the welded on spring mounts....

You can cut them off and put them under or over.....Don

 

[keh]

Ronnie,

Those axles are designed to have the springs mounted under the axle. If you mount them above the axle, the trailer will be too high. Like the other post said, there is a bow in the axle which lets the trailer depress more under load without getting the wheels out of line.
Agree with Don about having 60% of the length of the trailer in front of the axle so as to always have weight on the hitch of the truck. I recently built a 5 x 10 cattle trailer and I put the axle closer to the back than that to allow for cattle shifting to the back. works fine. I also used a drop center axle (3500 pounds also)

You didn't mention what size you are building. IMO 5 x 12 is the absolute top length for a single axle trailer with a 3500 pound axle, and I feel better with 5 x 10.

If you are making a trailer with no sides or removable sides, 3 inch channel or something similar is best. It is reccommended that a piece of pipe be used as a crossmember halfway between the axle and the rear of the trailer to reduce the tendency of the frame to twist on uneven ground. If you are going to have permanent sides and front, much lighter material can be used due to the truss effect of the sides and front. Anyway, the first rule making a trailer is to use material you have on hand, preferrably free.

KEH

 

[gmc ronnie]

the trailer size is 6x10. i have the bow in the axel , so i will put it up and the springs will be underneith . the frame is built out of 4" channel with a set a plans i had already . thanks .

 

[keh]

Sounds like you have everything under control. I bought commercial springs and spring shackles for mine also.

KEH

 

[gmc ronnie]

if any body is looking for great deals on trailer parts , check out trailerpart.com it's a great site

 

[T_Bone]

Hi ronnie,

The only consideration to mount the axle above or below is deck/coupler hieght. As long as you keep the axle camber pointed in the correct direction it makes no difference as to strength of mounting. There both a solid connection.

The industry uses CG for axle placement that works out to be 66% of overall trailer length from the pin(ball) to axle(s) center.

A longer pin to axle distance greatly improves towing stability but at the same time adds pin weight. If your TV can handle extra pin weight then I like the longest distance I can use. This will also improve the ease of backing up.

My grandmother built a 4x6 trailer back in 1919 as they needed to move and grandpa wasn't feeling well. I still have that trailer but boy is it a bare to back up as it's just too short and wants to wander something terrible while backing. I use it for trash storage and even that use is a PITA. My Dad rebuilt it in the 60's but he just wasted his time. I think I'll send it too the scrap yard this year.

T_Bone

 

[Anonymous-0]

Meant to say CAMBER not CASTOR. Old age and CRS I guess.