Rear chassis rail mods.

[oz_ek]

Last time I spoke to a certifying engineer in regard to moving the rear rails inward on my ute I was told it wasn't allowed, is this still the case?

[EK283]

VSB14 are what NSW use and I believe that's what's used in Victoria as well, lots of great reading and of course will need an engineer certifier to approve it.

https://www.infrastructure.gov.au/vehic ... 011_v3.pdf

Section 4.5

Greg

[Harv]

Heavily dependent on the engineer involved, but normally yes.

NCOP Section LH Body and Chassis Section 4.5 allows wheel tubbing without certification (with a few provisos). If you move the structural sub-frames or chassis rails, the vehicle must be certified under Codes LH5 and LH6.

LH5 allows for structural modifications to extend inner mudguards (amongst other things). It mandates the dreaded beaming and torsion test, and requires all reinforcing material thickness designed to be no more than twice original section thickness and with no stress concentrations at the ends of reinforcing sections. LH6 is a little more gentle, and really only mandates an inspection before (and after) paint/trim.

The kicker is the beaming and torsion test. Few have been done, expensive, and no guarantee your mods will pass (perhaps doubtful even an original vehicle will pass some days). I thought about it (as I wanted aircraft landing wheels on the back of my wagon) but was scared off by the cost and risk of failure mid-project.

Cheers,
Harv

[gpi]

i was quoted 1800 bucks to get it done to certify the CRS chassis kit that was fitted for the 202 in my car in vic.

[Blacky]

was talking to Brodie over here the other day , he does these mods every day of the week at his shop , in WA it is doable but yes a torsional rigidity test is required , cost over here in the vicinity of $1500

[Mick]

Heavily dependent on the engineer involved, but normally yes.

NCOP Section LH Body and Chassis Section 4.5 allows wheel tubbing without certification (with a few provisos). If you move the structural sub-frames or chassis rails, the vehicle must be certified under Codes LH5 and LH6.

LH5 allows for structural modifications to extend inner mudguards (amongst other things). It mandates the dreaded beaming and torsion test, and requires all reinforcing material thickness designed to be no more than twice original section thickness and with no stress concentrations at the ends of reinforcing sections. LH6 is a little more gentle, and really only mandates an inspection before (and after) paint/trim.

The kicker is the beaming and torsion test. Few have been done, expensive, and no guarantee your mods will pass (perhaps doubtful even an original vehicle will pass some days). I thought about it (as I wanted aircraft landing wheels on the back of my wagon) but was scared off by the cost and risk of failure mid-project.

Cheers,
Harv

i have spoken to many NSW engineers re tubbing and none of them want a bar of it if it involves moving the rail, they are fine to go to the rail but not moving the rail, i've even asked can i narrow the rail nope! (and some i have spoken to are quite open to pushing boundaries) BUT there are NSW cars with obviously moved rails that are apparently engineered, i've spoken to some owners about it and they seem very coy to talk about it