MK 2005 dual cab Torsion bar standard diameter?

[LanaB]

Hi all,
Does anyone know what diameter is standard?
I am looking at uprating my torsion bars. Looking at what is available, several quote "26mm diameter / 30% stronger". As far as I know, mine have never been changed, BUT, they measure 26.5mm (with vernier calipers).

[old Jack]

Diameter of Torsion bars is measured at the plain un-splined area, diameter, spline count at both ends, length, what grade steel they are made out of and what heat treatment process they have been through all determine if the bar will fit and how it will perform. So it is possible to have a stronger torsion bar which is a smaller diameter due to material and heat treatment. Most torsion bars are marked inner and outer if they have the same spline counts and also marked left and right hand.

Torsion bars are progressive rate so the spring rate increases as they twist more with additional load. Most factory torsion bars are fine except if they been overloaded with steel winch bar, 2nd battery and winch and run with worn out shockers. If the splines are worn then replace them but chances are the torsion bars will only need indexed a few splines and the shockers replaced (if they are worn) to get the ride height you desire unless you have a lot of extra weight up front. You should aim for 2/3's compression travel and 1/3 extension travel as a maximum when increasing static ride height.

If you go too heavy on torsion bars then you can reduce wheel travel which is not desirable off-road. If you go too light on the torsion bars then you will bottom and top out the suspension travel easily and regularly and overwork your shockers.

cheers, OJ.

[LanaB]

Thanks for your reply OJ, I am the point now where I think / know that I need to upgrade. I already have dual batteries, underbody armour etc, but will be putting a steel bar and winch on in the next few weeks. So getting before I do that stuff