Dolly trailer build question

[kenlms]

Hi all,

I am embarking on my first custom truck project and am building a dolly. I have knocked one up from parts of the Tamiya pole trailer and and other spare bits.

I have 2 what I think are important configuration questions:

1) where should the kingpin sit in relation to the axles? I copied the configuration from a truck kit, which has the king pin just behind the centre of the axle group, but it seem to sit tail heavy on the suspension under load.

2) Should the draw-bar be rigid mounted or pivot where it attaches to the trailer? I.e. should there be any vertical load transferred to the tow hitch?

Thank you for any advice!

Ken

[diesel950]

king pin should be in the middle of the axles
and a-frame should pivot

[kenlms]

Thank you gentlemen!

[Cossett]

Hi kenlms, the other benefits of having a pivoting draw bar on the dolly is when you have a drop deck trailer and a normal trailer and the tow hitch is at a different heights you can connect the dolly with out any hassles.....

Cheers Tracy

[Msmaddie]

You can do either. All the tandem converters I pull have a pivoting draw bar. But Pepsi has a wack of rigids.

You wanna try and set your converter up so your fifth wheel is centered between the axles. The 1:1 converters are basically just a spring ride suspension. Just like you see on a tandem on a trailer. I have pulled a couple converters where the fifth wheel is located towards the back. But I think that was due to pulling trailers that have a deep pin.

Have a look at my "brass tandem axle converter" build thread. I built on from scratch with realistic working suspension.