[CurtiSS 69]

Hello,

Has anyone corrected their bump steer after performing the Gulstrand modification? I would like to correct mine and I was thinking of using the Baer Tracker tie rod ends. Has anyone done this? If so where is a good starting point as far as initial spacing? Is there a better way of doing this? Heating the steering arms and bending them is a little scary.

Thanks

CurtiSS 69

[davidpozzi]

Baer and Guldstrand sell kits. Guldstrand probably has a ballpark figure to move them, it depends on how much positive caster you use. If you have tubular upper arms which allow +5 deg caster, then you may not need to fix anything, the extra caster moves the steering arm down.

You really need to measure your car, not guess off someone elses car.

[67ptcamaro]

I hear about this bump steer and theoricly now it but dont know how to check it. How do you guys check to find out how much correction needed?

[ORENCH]

Originally Posted by 67ptcamaro

I hear about this bump steer and theoricly now it but dont know how to check it. How do you guys check to find out how much correction needed?

WOW, I spent a few hours reading some of the info stored, by using a search the other day. I tell you, there's lot of info about that, there are some home made tools you can build, different techniques, like measuring without springs, one side vs. the other, etc. etc.

[davidpozzi]

The easiest way is to measure your toe-in by placing a 2X4 or straight edge against each tire, then measurig across front and rear. The spread of the tape measures should equal the tire height, - a 26" tire should have a 26" spread of the two tapes. Elevate the 2X4's as high as possible to avoid the tire bulge, but not so high as to have the tapes interfere with the underside of the car.

After you are set up to measure toe, open the hood and begin stacking weight on the radiator support. Place some blankets or cardboard there and add weight evenly on both sides, as the car goes down, read toe in at 1", 2." and 3" of dive.

Usually you will see toe-out in dive.
This will make the car tend to steer out of a turn as it rolls, the driver will have to make a correction to steering after the car takes a set in the turn to point it back toward the apex.
Toe out will also cause the car to dart left and right on hard braking.

You can record toe by raising the car too. Excessive toe-in when raised will reduce top speeds in the quarter mile.
David

[CurtiSS 69]

I just bought the Baer Tracker Kit and I will set it up the method you recommend (it seems a lot more pleasant than removing the springs and shocks). I was just hoping that someone would comment on a starting point.

Thanks

CurtiSS 69

[baz67]

The problem is that every car is different. In general .5" outer tie rod drop on a stock alignment is what is suggested. With the Guldstrand mod it would be slightly less do to the added caster. I would start around .25 and see how it is.

[davidpozzi]

Here is a little info I saved from a previous post, you can see the bumpsteer varies with different steering arms and idler arms. It also varies with caster angle, so I can't stress enough that you need to measure your car to see what you have. Some factory combos aren't too bad, some are terrible. The specs below are for one wheel, so across the car numbers would be twice as "bad".

 MAXIMUM TOE CHANGE IN INCHES
TEST 1 - Long idler/short pitman:
Passenger -  Driver       Passenger -  Driver
 31/2" susp. travel         2" susp. travel
  0.075      0.150          0.050      0.085

TEST 2  -  Long idler/long pitman:
   0.160    0.235          0.100      0.135

TEST 3  -  Short idler/long pitman:
   0.165    0.225          0.100      0.140

TEST 4  -  Short idler/short pitman:
   0.125    0.140          0.090      0.090

The sidebar says the best combination is the long idler arm and the short pitman, with the short pitman being the best regardless of which idler arm is used.  It also states that bumpsteer of more than 0.125" over 3" of suspension travel is considered excessive, and that the early Camaro exceeds this amount.

Hope this helps...
------------------
Joe
Original thread: http://www.camaros.net/forums/showthread.php?t=30316