Axle placement

• dexter axle

For a pull type trailer: Take the length of your frame only, NOT including the tongue. For every foot of length in the frame, make that equal 1/2". Move the center of your axle assembly 1/2" from the center of the frame back per foot of frame length. Example, a 16 foot trailer would have the axles centered at 8" from the center of the trailer frame.

For a goose neck trailer: For every foot of frame length on a goose neck frame, take and make that 3-3/4" per foot from center. Example, a 20 foot goose neck would have the center of the axle assembly, placed on the frame at 6.25 feet (6 feet, 3 inches), behind the center of the frame.

I've used this method, and know of a trailer manufacturer that uses the same method and a trade school as well.... (which is where I learned the formula) I've built a couple and the balance is great. No problems. My formula is only off by roughly 2.08% on the goose neck formula than from what T-Bone gave you as the 2/3 rule. (if my math is right.)

Stephen

Stephen

Stephen

If you were to use 3ft for a bummper pull and 7ft for a goose/5'er then I think it would be closer to industry standards for tongue length. That would put the axles center line at 10ft-11-13/16" on a 20ft deck or 17ft-11-13/16" from the pin/ball. Measure a few commerical built trailers and see where were at.

T_Bone

Stephen

T_Bone

2/3 from the center of ball to center of axle or center line of between axles

T_Bone

Yes take your overall length, and the above rule works on any number of axles on a flated, upto a tri-axle on a beaver tail with the 2/3 being the center line of the middle axle.

example;
24ft trailer tandum axle, 15.98ft from the center of ball/pin to the center inbetween the two axles.
On a flatbed that will give the correct "empty" tongue weight with loaded tongue weight adjusted with the load weight moved forward or aft to make weight. If building a fixed load trailer, like an RV, then the inside load weight would be distributed over the number of total axles.
On a tri-axle then it would be 15.98ft to the center of the middle axle.

Example;
on a 32ft flatbed tandum it would be 21.31ft from the center of ball/pin to the center inbetween the two axles.
on a tri-axle it would be 21.31ft to the center of the middle axle.

The 2/3 rule comes from the Bible so it's tried and true "rule" and can be applied to any design.

A cross is placed at 2/3 of it's length and 1/3 of it's length is also it's width of the cross.

A round tank base diameter is 1/3 of the height of the tank. Square tanks will go oval when filled, it's liquid filled balance point!

A boat beam width is 1/3 of it's length.

A building square base is 1/3 minmium of the total building height.

etc;

T_Bone

Thank you! You must be easyly impressed. LMAO

Glad I could help someone.

T_Bone