View Full Version : Steering column geometry??

17-06-07, 10:36 PM
Does anyone know what kind of bends you can get away with with UJs in the steering column.
Basically I have a corsa power steering column pointing more or less in the right direction at the top. Then a linkage with a UJ at each end. Then the shaft of the rack.
There can be an offset (ie. a little bit of Z shape in the system) as a way of avoiding a front impact driving the column into the driver.
The question is, is there a maximum angle recommended? Or is there any benefit in getting the column as straight as possible?
So if that makes any sense I'd appreciate any thoughts!

17-06-07, 10:51 PM
The main thing is to demonstrate that the setup will prevent the column moving more than 127mm in the event of a frontal impact at 30mph.

This is usually achieved by having sufficient angle within the UJ's so that no/minimal linear force is applied to the column itself.
(I seem to remember somewhere in my research that 15 deg minimum rings a bell but as I cannot find where I got it from then don't quote it!!)
Also the incorporation of a collapsible/sliding and/or crushable section is advised.
Exactly how you prove this is ok is the question?

If it mimics the arrangement in a type approved vehicle or in the examiners view will pass then you should be OK!!!
Have a nose at a few tin tops and check the angles etc..

Maximum angle is probably dictated by the actual operating angle of the UJ in question. There will only be a certain throw on it, after which it will bind/lock/rub etc.

Not exactly helpful sorry, and I do not proport to be a steering specialist, just someone who hopes he has got his right!!!!

18-06-07, 08:43 AM
Good points but it's not really the SVA issues it's more the optimisation of what I've got.
I'm trying to decide if I should bash the manifold in a little and move a brake pipe for first possible path (most direct), or go around the pipe and so have to shorten the linkage and increase the angle of the bends. I think the UJs are fine in operation. Just trying to find out if it is worth aiming for the most direct route.
The Corsa column is collapsible so no problem there.
Thanks for the suggestions, watch this space!

18-06-07, 10:55 AM
As a pure 'opinion only' response,
Unless you feel you are getting near to the point where the UJs start to bind because of the ecute angle, say over 30deg, then I would allow them to do what they are designed for and leave your lovely headers to do what they were designed for :D


18-06-07, 05:28 PM
Cheers Robyn but just this morning I decided on the straightest route. Luckily or unluckily my headers are old mild ones, second hand from Thunder road which did not fit very well anyway and so may even get replaced when the exhaust is made. Or if I can find that bendy stuff and some lagging.......
It is beginning to get crowded in the engine bay but progress is being made!

18-06-07, 05:32 PM
Progress is Good :wink:

Purple AK
18-06-07, 05:45 PM
I seem to recall reading somewhere that Steering Column U/J's (along with Propshaft U/J's and C/V Joints) should be used at an angle. If they are used "straight" they wear much quicker as they are using the same bearing surface all the time.

19-06-07, 11:38 AM
Yup I heard that from a different source too.
Good news is it is all in and for the first time the steering wheel (albeit from a Corsa) turns the wheels :D :D It all fits and the corsa column has an excellent feel to it, which is good news cos if the power steering feels wrong I can switch it off and just use it for parking.
Thanks God for power grinders, hammerite and welders. :P