Quote:
Originally Posted by Bnr32gtr
Please help/need input. Set up is pbm cut knuckles with pbm bent style lca. I have a street faction sheet metal sub frame. running the rack in the Farthest Position forward which I believe is about 1" further forward than factory also running the lower control arm mount At the higher pick up point. Not shore if the lower one would be better? Lca seams pretty Parallel with the ground, the tie rods Seem pretty parallel to the ground as well. My question is I just got new otr the kind that have the spacers for bump steer. Should I take more out is this to much with cut knuckles? Car is on scale stands in pic. Greatly appreciate any help/input
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Quote:
Originally Posted by Speed Junkie
The first thing to remember is that its not the control arm, per say, that should ideally be parallel with the ground, it should be the pivot points. With that being said, yours looks fine.
In regards to bump steer, this happens when the arc that the outer tie rod joints travels is a different distance than the LCA ball joint arc. This results in the wheels turning as needed to compensate (the alternative is the tie rod compressing lol). With that being said, spacing the outer tie rod end as much as you have is probably the best thing you can do to reduce bump steer. If you trace the arcs you could see that they're still not the same radius but it's better than stock. How much bump steer you get will also vary based on how much you are turning. In other words, you may have almost no bump steer going straight but get more bump steer mid corner when you hit a bump.
So, yeah align the car with a hair of front toe in. OEM spec has a hair of toe in to help band-aid the toe out bump steer in the oem suspension. And then just go out and drive it. You know you're getting toe out bump steer when the car darts around as you go over uneven surfaces and hilly roads.
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I would not use the upper hole on those crossmembers. As much as street faction likes to tout that they "engineer" their products, they do not. Motary has models of bump steer with the control arms moved up and they are much worse than stock. Spacing the tie rod end cannot fix this.
Also, with regards to alignment: Unless you're planning on driving in the wet a lot, an alignment with front toe in and low-ackerman knuckles will make the turn in quite poor, and the car will understeer. I highly recommend starting from zero and adjusting toe out as you like it. You'll find steady state handling is quite dependent on static toe settings, and I almost always end up running some kind of toe out on MacPherson suspension setups.