Tie Bars / Compression Struts

[Longboarder]

With the tie bars (or original ARB) disconnected you no longer have control of fore and aft positioning of the TCA and thus castor of that wheel. The TCA will take up a position of its own moving forward or back, whichever it chooses. This will vary the angle of the mounting point for the tie rod/ARB front bush. You should try to fix the TCA at it's ideal position where the castor is close to correct before you can decide where to put the mounting bracket for the tiebar rear end and decide the length of the tiebar. The rear joint of the tiebar should ideally be in alignment with the inner joint of the TCA.

 

Nigel

[cb750]

Thanks Nigel. As everything is new I thought if I let the TCA take up its natural fore and aft position the castor would be nearly correct. It looks like I will be buying a gauge earlier than I thought or is there a home method? I still think I will be forcing the original tie bar over too much on my car. Can't do anymore to this yet as I am preparing the car ready to get some welding and strengthening done once this snow clears. It's about a foot deep outside the garage!

 

Rob

[Peter Bell]

If this works I will be lucky but hopefully you can see that by using a bit of basic trig you can set it up roughly to get a good start point. The difference between dims A & B then divided by dim C will give the tan of your castor angle, try for somewhere between 3 and 5 degrees and make sure your rose bearing is not screwed fully in or out so you can adjust it either way to get some adjustment.

measure castor.pdf

[Peter Bell]

Flushed with success if you want to add a bit of auntie dive this attachment may help. Not that you get much movement anyway as the CoG is pretty low compared with a sierra.

anti dive.pdf

[Snapperpaul]

Interesting point on the anti dive

In its normal position the antiroll bar is 10mm to 15mm below the tub due to the antiroll bar mounts, when you fit the tie bars the mounting point is 5mm to 10mm higher than the tub floor

In my case I used 50mm x 25mm box for the mount and coned washers for the rose joint

[cb750]

All my welding was done (professionally) yesterday to strengthen the tub so I can now get down to the tie bar mounting. Fitted polybushes to the TCAs, can hardly twist them now! Got nice shiny stainless angle made up for reinforcing the side of the tub plus 50x25x3mm box section for the cross member. Going to refit the brake discs and wheels to check what clearance I have for the tie rod brackets, may have to fit stops on the steering rack.

 

Downloaded the pdfs (thanks Peter)

 

Rob

[Guest bumpy]

So how did it all go?

[Guest mower man]

Having run tie bars for some years [10 ish ] I found it made a vast improvement handling wise , when building the susp up just make sure that the tca is at 90 degs to the centre lineof the car and markup and fit the pick ups to give that as a base with the rose joint at approx half its shank length so adj can go both ways,idealy a caster gauge should be used but it can be done by trial and error log all adjustments and do it eaqualy my car runs at approx 7 degs and self center is fine ,steering is heavy at less than walking pace but in normal [?] driving far better than with orig a/roll bar but remember ridehieght, caster ,camber, toe in that order!!!!!