Spherical Rod Ends

Started by Fylnn, October 10, 2012, 09:58:08 AM

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Fylnn

I am running higher ride height than normal on my GTV6, or at least I want to run higher ride height since it is a rally car and roads we use in Queensland are a bit rough.  One issue I am anticipating amongst many is bump steer because the standard steering arm mounts mean the arms will angle down well below horizontal.  To improve this, my thoughts would be to bore out the tapered hole for the tie rod end, and go to spherical rod ends mounted on top of the spindle arm and not below.

Next question is has anyone done this sort of thing before and where do you get the spherical bearings locally.  I can see you can get M14x1.5 from the US but prefer local supply if I can get it. 

BradGTV

I've bought them from CBC bearings, not sure if there in qld tho. I like the idea, on my car I've swapped the uprights to their opposite side, cut the steering arm off, made a new steering arm that bolts to the calipers mounts and then weld a new caliper mount where the steering arm uh is.
79 gtv sr20, 83 gtv, 83 gtv6 3.0, 75 ts x 3, 85 gtv, 76 gt, 91 164, Subey L Series, S13 silvia, Bmw e30 318i, VT SS 6spd

Fylnn

Well not quite as radical as I had in mind.  I was only looking to raise the front suspension about 50mm, turn the tie rod over onto the top side to improve the bump steer and maybe put on some extended upper ball joints from Vin but without the spacers, to move the top arm back towards horizontal.  Otherwise it will be drooping down quite badly.  As to what that does to the roll centre yet to calculate, but could be adjusted.

I am going to take it to my aligment guy on Friday and put it on his machine and raise it up and down and see just what it does.  Just need to have my options ready to discuss.  Most discussions on this forum except for Greg Wyatt's are about lowering.  So i am going to try something different. 

Duk

Fylnn, have you checked the bump steer of your car?
They do have some bump steer in standard form, but it's not too bad. What you are suggesting would cause a very big change to the bump steer characteristics of the car. The correction to fix the bump steer that the standard geometry give would be measured in millimetres and needs to down, not up by 30+mm.
If you use Vin's long shank top ball joints, the outer tie rod end needs to go down some more, but not massive amounts. When I get to doing the bump steer correction on my 75 that uses Vin's ball joints, I'll post what it is I've done (it will be based around drop links (as opposed to my first attempt of bending the arms) and uses spacers to lower the outer spherical rod end. Drop links are 4140 steel and work with the 5/8" rod ends I've got, but are designed for Mustang steering).

And finally, you won't find a spherical rod end with enough articulation if you raise the ride height by 50mm. I've got some high articulation angle rod ends and even at a slightly lowered ride height, when the suspension was at full droop, I didn't have enough articulation. And that's before correcting the bump steer (moved the rod end lower and so needing even more articulation).
The only way you could use a rod end in you proposed situation, would be to twist the steering arms so the rod ends don't bind up at full droop.

http://www.youtube.com/watch?v=LO07qmJ9zkk is the best way that I've seen to measure bump steer. It's also incredibly cheap to do.

Fylnn

yes good point on the articulation.

Duk

Quote from: Fylnn on October 10, 2012, 09:36:29 PM
yes good point on the articulation.

When you look closely at your suspension, you'll see that they are all good points  ;)

Beatle

Will the suspension TRAVEL increase significantly on the raised ride height?  If not, maybe there is scope to install/weld in some form of angled or tapered shim to the body where the tie rod attaches to realign the installed angle of the tie rod end (bush or spherical)?  Might solve one of the many geometry problems of the suggested mods.
Paul B
QLD

Past:
'79 GTV - Loyal 1st love
'76 GT - Track entry
'89 75TS - Saved
'76 Alfetta - Sacrificed
'83 GTV6 - NT bullet
'67 Duetto - Fun
'66 Super - Endearing
'92 164 - Stunning
'85 90 - Odd
'04 GT 3.2 Rosso/Tan - Glorious
'02 156 V6 Auto Rosso/Tan - Useful daily