More bumpsteer questions

[DND]

I recall a couple threads talking about having approximately 46 or 47 mm of spacing on the tapered bolts to the joint and I think Adam says this as well in his video.

But unless I measured wrong, I can't get that much space onto the Baer kit, I think it only supports up to 31 mm of extra spacing (not counting the nut area?). Can someone comment on this with regards to the Baer kit vs. buying the Pinto tapered bolts? In Adam's video it doesn't look like 1.85 inches of space if the main spacer I can see is a 1" spacer.

Second question (or questions), I tried to measure the bump steer with a laser level on the rotor by jacking up the car and lowering onto an axle stand to unload and re-compress the spring without disconnecting it. This doesn't seem to work at all as just jacking up the car completely changes the angle of the toe even if there is no movement on the spring/shock on that side (i.e. just moving it up and down drooped in the air). I would expect it to angle a bit with the arc of the width of the car (and I do see that with the laser level also) but why is the toe moving in and out just from lifting the car an inch or two? And is there an easy way to measure without disconnecting the shock (I don't want to mess with trying to compress them again...)? If not, what is the easiest way to compress the shock to get the bolt to line up for easy removal and re-insertion?

[Hindsight]

You can't get enough spacing with the baer taper bolt and the pinto bolt doesn't have the right taper for the Subaru spindle. You need to use a big bolt (can't remember size... 5/8" or 3/4" I think, see my build thread - it should be in there, or CPlavan's thread as well), and then you need to buy extra spacer shims from Baer or a third-party. I think I got mine from a third party - just ordered a bunch of different thicknesses of the right ID/OD. I THINK I got mine at Racerpartswholesale, or pegasus, or speedway motors. Sorry, it's been a while.

The toe moves in and out when you lift the car because that is exactly what bump steer is: As the control arm moves up and down, the differing arc of the control arm and the tie rod cause toe changes. Ideally you want no toe change at all through the range of suspension movement but on the 818 that is simply not possible because the tie rods are too short in comparison to the control arms. The only way to fix that is to get some custom tie-rod extenders made. I measured it once and if I recall correctly, you'd need each tie rod to be about 2.5" longer per side. So, having said all that, when it comes to bump steer on the 818, the best you can do is adjust the tie-rod angle relative to the spindle so that the direction of toe change doesn't reverse itself on compression or droop from the neutral ride-height position. In other words, when you are at ride height, if you compress the shock all the way in, it should ONLY toe-in, or toe-out, but never start off with toe-in and then transition to toe-out (or the opposite).

There is no easy way to measure bump steer. It's a pain in the butt, yet is so worth it when you get it right. Go spend ~$150 at Summit Racing on a bump steer gauge. I suggest the digital one. I used a laser level to set cement blocks with some plywood shims on top of them until all four were perfectly level and then I set the car up on that (with the tires on the blocks and shims). Bounce the suspension a bit to settle the car. Next use the same laser level to throw a horizontal beam that intersects the very center of the wheel, which is going to be the middle of the outer CV joint stub axle. Once the laser it aligned there, put some masking tape on the fender where the line is and then mark the masking tape right on the laser line with a permanent marker. Next jack the car up near that wheel, remove the wheel, and remove the bolt for the upper shock. To your comment, you shouldn't have to compress the shock to get the bolt to align or come out easily. If you have your ride height set correctly, at full droop, there should be no pre-load. That's how it was on mine and I had both the R and the S springs and shocks at various times. Moving on, lower the car slowly until the laser beam once again lines up with your masking tape line on the fender. Now the frame of the car is back to ride-height. With the wheel still off, you now bolt the bump-steer plate to the wheel hub. Now use a second jack (a scissor jack out of the spare tire kit in your daily driver works perfectly for this) under the lower control arm and raise it up to where the CV stub axle center is aligned perfectly with your laser line. Now both the frame and suspension are at ride height. Now put the bump steer gauge against the bump steer plate and use the scissor jack to raise and lower the control arm as required to check bump steer through the range of motion. Add or remove shims as required so that the bump steer always moves in ONE direction from neutral when moving the suspension up, and the other direction from neutral when moving it down. It takes a lot of time. Once you have it done on one side, you can use the same number of shims as a starting point on the other side but you will still have to check and adjust it!

[Mitch Wright]

DND here is some more info if interested. And as Hindsight mentioned adjusting the bumpsteer is well worth the effort.
http://www.longacreracing.com/techni...aspx?item=8162

[idf]

You can't get enough spacing with the baer taper bolt and the pinto bolt doesn't have the right taper for the Subaru spindle. You need to use a big bolt (can't remember size... 5/8" or 3/4" I think, see my build thread - it should be in there, or CPlavan's thread as well), and then you need to buy extra spacer shims from Baer or a third-party. I think I got mine from a third party - just ordered a bunch of different thicknesses of the right ID/OD. I THINK I got mine at Racerpartswholesale, or pegasus, or speedway motors. Sorry, it's been a while.

The toe moves in and out when you lift the car because that is exactly what bump steer is: As the control arm moves up and down, the differing arc of the control arm and the tie rod cause toe changes. Ideally you want no toe change at all through the range of suspension movement but on the 818 that is simply not possible because the tie rods are too short in comparison to the control arms. The only way to fix that is to get some custom tie-rod extenders made. I measured it once and if I recall correctly, you'd need each tie rod to be about 2.5" longer per side. So, having said all that, when it comes to bump steer on the 818, the best you can do is adjust the tie-rod angle relative to the spindle so that the direction of toe change doesn't reverse itself on compression or droop from the neutral ride-height position. In other words, when you are at ride height, if you compress the shock all the way in, it should ONLY toe-in, or toe-out, but never start off with toe-in and then transition to toe-out (or the opposite).

There is no easy way to measure bump steer. It's a pain in the butt, yet is so worth it when you get it right. Go spend ~$150 at Summit Racing on a bump steer gauge. I suggest the digital one. I used a laser level to set cement blocks with some plywood shims on top of them until all four were perfectly level and then I set the car up on that (with the tires on the blocks and shims). Bounce the suspension a bit to settle the car. Next use the same laser level to throw a horizontal beam that intersects the very center of the wheel, which is going to be the middle of the outer CV joint stub axle. Once the laser it aligned there, put some masking tape on the fender where the line is and then mark the masking tape right on the laser line with a permanent marker. Next jack the car up near that wheel, remove the wheel, and remove the bolt for the upper shock. To your comment, you shouldn't have to compress the shock to get the bolt to align or come out easily. If you have your ride height set correctly, at full droop, there should be no pre-load. That's how it was on mine and I had both the R and the S springs and shocks at various times. Moving on, lower the car slowly until the laser beam once again lines up with your masking tape line on the fender. Now the frame of the car is back to ride-height. With the wheel still off, you now bolt the bump-steer plate to the wheel hub. Now use a second jack (a scissor jack out of the spare tire kit in your daily driver works perfectly for this) under the lower control arm and raise it up to where the CV stub axle center is aligned perfectly with your laser line. Now both the frame and suspension are at ride height. Now put the bump steer gauge against the bump steer plate and use the scissor jack to raise and lower the control arm as required to check bump steer through the range of motion. Add or remove shims as required so that the bump steer always moves in ONE direction from neutral when moving the suspension up, and the other direction from neutral when moving it down. It takes a lot of time. Once you have it done on one side, you can use the same number of shims as a starting point on the other side but you will still have to check and adjust it!

I was also unable to get enough shims in with the Baer bolt so instead had the Pinto bolt machined to the correct taper. The approach suggested by Hindsight also works. Agree with all of his write up especially that it is a PIA but well worth the effort.

[bow2091]

You can also buy the correct tapper for the pinto bolt . that's what i did, the spindle drills real easy for the correct tapper . I picked the tapper up for about 15.00 on Ebay