[LConn]

I have a very experienced racecar chassis guy who is setting up 3702sp.

On the bump steer kit, am I missing something or is having all RH threads really dumb? I'm going to suggest we consider changing the kit. The 5/8" bolt doesn't make it easier to find heims either (apart fromtaking forever to drill for).

Second, the kit specifically states to put the tie rod heim on top of the spindle. The chassis guy says this makes bad geometry. Any comments? The guy doing the align is a fulltime race chassis engineer with 20 years doing Nissan GTP, Electromotive and others so I tend to listen.

Thanks.

Leonard

 

[Ophitoxaemia]

could you ask im about the ackermann geometry also while you are fooling with that. thanks!

very interested in what you find out.

-james

 

[thunderball]

I ran my tie rod on top of the spindle which looks ok but what happened was during hard acceleration when you laid off the throttle the front end dipped down and it got real skeery. I now run it on the bottom and it's much better. And yes it is messed up to have right hand threads on both sides but that is normal.

 

[Alain V.]

I helped someone set up the bump on a spec car about a year ago, and can't remember where the tie rods ended up.

I do remember that the best way to set it was to move the rack along with using the bump steer kit. This can be done with oval shaped bushings, but I don't know if you are allowed that in the spec series.
(the car I helped with ended up on the strret so it didn't maytter on it.)

Also you can try playing with the caster settings as it will change the "height" of the steering arm a little.

 

[Robert Duncan]

The RH threads are not a problem. The adjustment is made by turning the tie rod that comes out of the rack. You want the rod end threaded all the way in to the adapter and not moved after locking it with a jam nut. The rack tie rod turns to adjust the toe.

You should not just "put the rod end above/below the steering arm". Check bump steer and shim it to where it works right.

I ended up moving the rack up 3/8" and puting the rod ends directly on top of the spindle arm. I could have dropped the rack 1/2" and run the rod end on the bottom of the arm. Either way corrected bump steer, but it was easier for me to move the rack up.

I made up solid aluminum bushings for the rack and custom drilled the offset I needed to move the rack.

 

[LConn]

The whole point of having lh/rh threads is SO YOU DON'T HAVE TO REMOVE THE TIE ROD TO ADJUST IT. You turn the billet piece between the tire rod and the rack arm to change the length. As it is now, you have to remove the wheel, remove the tie rod, the adjust to what you hope is the right answer.

Sounds like this may not have been thought out too much. I'll talk to FFR and see what they have to say. RH threads are just totally brain dead unless I'm really off target (and for no reason).

We'll try the under spindle mount. I just feel uncomfortable not knowing why they very specifically, in bold, said on top. I hate to learn at 135mph.

Leonard

 

[GC in KC]

The inner tie rod is free to go round and round, you dont have to disconnect anything to adjust the toe, just loosen the jamnut,leave the heim joint on the spindle and crank the inner rod in or out.

 

[[email protected]]

The inner tie rod is a socket joint that will spin freely to allow you to adjust toe without unscrewing the outer joint from the spindle. This is the same way the fixed tie rod end adjusts in the Mustang.
When adjusting for bump steer we usualy end up with the tie rod on the top of the spindle (on 93 and earlier spindles) but if you run with a bunch of caster the tie rod may end up on the bottom.

 

[LConn]

Thanks for a definitive answer Jim and others. I was not aware the inner rods turn so thats makes sense now. I'm still not clear why it is done the way it is done as it still reduces total adjustability before you have to remove the other end but it makes a little better sense.

Leonard

[ November 02, 2002, 09:20 AM: Message edited by: Leonard Conn ]

 

[[email protected]]

It shouldn't reduce the adjustability, both threads can still be adjusted it will just depend on which jam nut you loosen. We will usualy adjust at the rod end because it is easier to tell how much thread is left in the sleeve.