With my current steering column arrangement, the collapsible section of the column (a sort of ridged tube) rubs against a chassis rail, requiring a bit of a rethink.

I think the answer is a new shaft, with the collapsible section moved to the middle of the shaft where it won't contact anything, but it will be much easier to fabricate one without the collapsible section.

My understanding is that the UJ angles alone should satisfy IVA requirements (if over 10 degrees), but strictly from a safety point of view, would I be significantly safer with a collapsible section, or are UJ angles a good mechanism for protecting me?

Thoughts?

put simply ask yourself if your happy to be speared through the chest with the column.

i'd always have the collapsible option, even with my full harness and rollcage.

Of course I'm not keen on getting a spear through my chest!

I'm not saying, is it OK to cut corners here, what I'm asking is: do the UJs protect against this to the point where the collapsible section would not provide any benefit?

Personally I think that both have their merits and combined they make a much safer option.

Regardless of what the IVA man says I would want to satisfy myself that I wasn't going to get speared in a crash

is there no way some sort of bush arrangement could protect the chassis rail?

quote:

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Originally posted by rodgling
the collapsible section of the column (a sort of ridged tube) rubs against a chassis rail, requiring a bit of a rethink.

Thoughts?

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It may be possible to use the "Disengagement " method on the shaft ....... Using my phone so see IVA manual for detail sketch.

RD

If its only 'rubbing' against the chassis than surely a small welded in scallop into the chassis rail would be better?

As for the spear in the chest.... its all a little meldromatic as the steering wheel is attached to the end of column and not a pointy piece of flint.

Yes you need the collapsible sections. Uj's alone may work in certain conditions but unless you can cover all eventualities with your design then it is far better to play safe (ie angle, orientation of Uj in crash, crash forces and impact direction etc etc). You can never predict with certainty how safety critical components will behave in a crash as all crash conditions are different. Even if all the collapsible sections does is give you a margin for safety, then for that reason alone they are worth it.
Consider other possibilities too, you may have a crash where the upper steering shaft doesnt move back far enough to impact the chest, but would you want 2 broken wrists / arms?

I seem to recall that there may be other options to a collapsible lower column, like a collapsible steering wheel boss. Im no expert in what protection these can offer and if acceptable to IVA. I do recall having to fit one for SVA when i replaced the original OE steering wheel for aftermarket version on grounds that the steering system type approvat was for the complete set up from wheel to lower intermediate shaft connection to rack.


i take it you are making own chassis and may have a non-standard (ie different to what other people do) column, tubes, rack position etc. Id be looking at making a standard unmodified safe column fit the car the mod the column itself.

Hurrah, I've found a way to make it work and keep my existing column (with collapsible section). It's tight, but I think I can get enough clearance to satisfy IVA chaps.