Spring over axle conversion

[nb422]

Hi everyone, i was wondering if anyone has done a spring over axle conversion and if so how they did it?
My father did one to his Trailer truck and it gained alot of height but blew its left rear shock because of the different angles.
I'm just curious as it is something i haven't seen any of around.

I noticed it did gain a couple inches lift and much better rear articulation

P1090227.JPG

[geeves]

If its going to be road legal have a good word with your chosen certifier before you start. Non factory soa is nearly impossible to certify. (you may wish to delete the word nearly from the last sentence)
It gives about 6 inches of lift which you cant match in the front without monster work

[nb422]

Yeah his is just a trailer truck. Not meaning to ask an obvious question but what actually makes it so hard to cert?

[geeves]

Axle tramp is the big one. Its very hard to control on soa as the pivot point is so far from the centre of torque. Its the main reason that the front springs on a solid axle hilux are so flat and heavy in the centre. New rules coming in next year will also kill a lift of that size forever as well unless you are a 4wd club member and they have issued the paperwork for you to get an authority card.
This authority card is going to be a nightmare but the only alternative on the table was a total ban on large lifts.

[nb422]

I see, sounds like it will be very close to a total ban on a lift anyway if you need an authority card.. my mu might just have to stay at stock height as i doubt i will afford a body or suspension lift plus cert whilst on my learners..

[geeves]

If your new to 4wding my advise is always dont do any mods on your truck till you know your into 4wding seriously. Any money you spend on mods will see about a 30% return if you sell your truck ie spend 1000 get 300 back. A standard Mu is a good vehicle to learn in. It might not be the most capable vehicle out there but its very forgiving if you get it wrong and quite cheap to run.
Only variation to that is tyres. Mud tyres do make all the difference

[nb422]

Thanks that is good to know. I am saving for steel rims and buckshots once it gets it's warrant, but my injector pump may be leaking so theres a big bill in itself for a warrant come january

[isuzurob]

get the 764 bighorns much better than buckshots, pump leaks are easy to fix if you know your way around a tool box seals are around $50

[nb422]

Oh ok thank you very much, will have a look closer at it when i next have it. What is the biggest tyre size you could fit on stock lift, I can fit 32x10.5 simexes with no rubbing so would i be able to fit 32's of Bighorns? Thanks

[isuzurob]

all depends on rims and offset, should fit 32inch bighorns

[nb422]

Went for cert today, all i have to do in relation to the spring over is remount my shocks below the diff, too horizontal.. easy. Needs handbrake cables too but that is due to chucking a 94 mu diff in for the bigger brakes and handbrake. Will post measurements soon

[nb422]

Measurementsfrom centre of hub to bottom of guard. Truck has 50mm body lift so subtract that. Torsions cranked. Spring over axle rear, 700mm rear. 660mm front.

[geeves]

First thought was it isnt that much but a tape measure on the bighorn said otherwise. The bighorn with lwb springs in the back and no body lift measured 500 flat so thats 150 more in the springs and another 50 in the body. With 32s on a Mu it will just go in my garage If it had the higher roof of the bighorn it would hit. Anything much bigger than 33s and it would have to park outside