Steering Column Extension
 

Hi the book says to use thick walled tube to extended the lower sierra steering link. I was just wondering if anyone had any sugestions for the diameter and guage tube they used. Is 3mm sufficient?
Cheers

if i remember correctly, the tube i used was 25mm diameter & 3mm walled,

andy

Thanks Andy, I meant to measure the lower link earlier and find its diameter but the sun went down. If I ever build anything again I'll wait till I have a garage, will try not to admit that to the wife.
3mm wall is what I was guessing at.
Thanks

I used 19mm 1.6mm wall - still fine 10k later. There is very little load on the column, only as strong as the tyre grip on the road.

That seems scarily thin to me, especially as it is taking a torsional load.

Sean

Personally i would say that 19mm x 1.6mm was a bit on the trust in god side of things especially when the item you are extending is around the 16mm dia solid
Ray:)

hmmm, isnt that part of the steering rod suppose to be colapsible? mine is going to(has to according to the law here in Sweden).
cheers

the collapsible part is in the upper section of the column between CP16 & the steering wheel, & also you have the coupling at the rack end & most folk have a coupling fitted just below CP16 so this all ensures that the steering column would deform in the event of a head on impact.
the extension part is purely just that "an extension".
not sure of the rules in Sweden tho :o :)

andy

What's the wall thickness of the average propshaft? From my long ago college days a thin wall tube under torsional load is not much weaker than a solid bar of the same material and outer diameter. If I recall correctly the OD is of greater importance than the wall thickness.

That said I am a firm believer in Victorian engineering and would probably use the thickest wall I could find!

Im using a bit of 25mm od 3mm wall seamless for mine
but some people use 16 guage erw for front wishbones!
so its personal choice at the end of the day
stronger is safer
even formula 1 guys get it wrong sometimes (No names I dont want to get sued) but we all know
Ray:)

Could do with some advice again, my steering column is the adjustable type and my downlink that I need to extend is the 2 piece extendable type.

Do I need the extendable part of the lower downlink? or can I just remove it and join the upper UJ and the lower rubber one?

Thanks again.

sorry you,ve lost me a little there:confused:

what i did was to buy a splined shaft from Rally Design, cut it in half & fit it into the rack end using a new "group 4 " coupling, the original rubber end shaft was then cut to remove the rubber bit then that went into the extension i made, so the triangle part(rubber coupling) is now fitted just below CP16 which makes it easy to remove the steering column without needing to remove the steering wheel section,
i have a few pics if that would help?

andy

Hi Andy sorry for confusing you, my lower downlink is like this one below not sure whos picture this is.
I was wondering if I need to include the triangular clamp piece (looks like 2 wings) just before the extension tube is welded on, and after the UJ joint on the left.



Cheers

the way thats done in the photo is precisely how i,ve done mine, the reason i did it like that was to make the column between Cp16 & the steering rack removeable without needing to remove the steering wheel or the rack itself, & also the part that clamps onto the triangulated part that is just below Cp16 has a locating pin too, so it all more or less keeps the original spec of the sierra column which must be good for the safety aspect of having a deforming steering column in the event of a frontal impact. also it helps with installing the engine as its easily removed by undoing just 2 bolts.;)

andy

I see I think I've seen a picture of yours.
What is that joint piece of the lower link used for? (directly above engine mount in photo).

Thanks again Andy.

Also if you do as in the piccy above the top joint remains a standard replaceable part which is always a good thing
if it wears out just pop on another no welding or cutting etc
Ray:)

I see now, it is a good idea to be able to remove that universal joint incase you need to replace it, and with out that second joint piece it would be permanently fixed to the rest of the down link.
Cheers.

Also if you do as in the piccy above the top joint remains a standard replaceable part which is always a good thing
if it wears out just pop on another no welding or cutting etc
Ray:)

is there a good way to make the extinsion itself collapsible?
Samy

Attachment 483
this one has a 70mm collapsible section, but i´m not sure how its made.
does anyone have any ideas?
cheers

That looks very much as if it has been made by welding 2 short sections of square ( ish ) tube onto the round shaft.

The square sections are then placed into each end of a longer section of matching profile tube.
The top of the assembly fully welded with the bottom section left with the ability to slide ( colapse ) in the event of a frontal impact.

Very similar way as the Sierra reach adjust set up in which a triangular section is used in the upper section of the column.

With a little luck that'll all make sense :) :)

seems like a good & safe way to make the extension , maybe even make the colapsible part longer. i will for sure be making mine the same way, it´ll also make it easy to take appart .
samy