steering and suspension Rear Toe- How Much Is Okay?

[M3M3]

they still race them..and they are quick.  there are several Pintos running in the SCCA race group i run my E30 race car in.... 

[bento]

Bento, both 2 and 3 sound like you might have too much front toe- in.

And the rear toe WILL contribute to this, too.

Are you sure everything's tight in the front end? It takes only a tiny bit of play

in the box or the center link joint to make a very good system lose it's touch.

And having said that, the 2002 CAN feel as tight and responsive as a well- designed

steering rack system. And as it wears out, it can degrade to the point where your

Gramma's 1972 Ford LTD feels pretty sporty...

t

All bushings are new (ball joints, tie rods, center link, control arms, radius rod, strut bearings). I'll recheck torque though.

I'm not really confident in the precison of the toe plates, nor in the accuracy of the user, so if too much toe could be the cause of 2 and 3, that's probably the lead candidate. It makes a lot of sense, actually. Thinking it through, lots of front toe would probably fight steering wheel input until the inside wheel turns past straight ahead, then it would lighten up and turn in. That's exactly what I'm feeling.

BAM! I just learned something. Thanks!

If checking torque and rechecking toe doesn't resolve what I'm feeling, I'll give the steering box another look and regardless, I'll seek out a competent shop to do an alignment.

Edited November 1, 2014 by bento

[TobyB]

Yup, you got it.  Within the limits of tire wear starting

to skyrocket, front toe is a useful tool for determining

how quickly the car responds to the steering wheel.

 

I'll freely admit to setting most of my cars to zero front toe,

driving them, and then toe-ing in a quarter- turn at a time

until they're not too darty for my taste.  I hate that dead feeling

of too much toe on an otherwise responsive car...

 

In fact, the race car got toed OUT at first, until I resolved a couple of

other issues, just to make it turn quicker.

 

Oh- one other thing that caused me problems:

when you adjust the steering box 'backlash' nut, make sure the

box is in the exact center of its travel.  Then, with the nose up, make sure

you're not getting just a touch too tight.  Because that's not a very good feeling

either, and especially if the box isn't exactly centered, can dull the steering feel

too...  (oh, then center the box, too, so it's at dead center

when the car is going straight ahead- it's pretty important to do

 

t

Edited November 1, 2014 by TobyB

[M3M3]

+1 to all Toby said.  

[bento]

Thanks guys. Starting with zero toe and adding a tiny bit until I get the feel and handling I want sounds like a great approach.

[bento]

Bento, both 2 and 3 sound like you might have too much front toe- in.

And the rear toe WILL contribute to this, too.

 

Are you sure everything's tight in the front end?  It takes only a tiny bit of play

in the box or the center link joint to make a very good system lose it's touch.

 

t

Good diagnosis Toby. I set front toe to around 1/16" in. Concern #2 (wandering) is much improved to the point that I think I'm just noticing the crowning of the road, and #3 (wind up) is gone. I didn't touch the steering box preload and don't plan to. Steering feels much better at low speed and great on the highway.

Back to the original topic, I was able to get rear toe to around 3/32" total toe in on the first try today. I have a bit more adjustment to play with, so 1/16" total shouldn't be a problem. I'll give it another go tomorrow. I'm only messing with the inner eccentric, so I still get some camber correction from the outer eccentric.

Thanks everyone!

[TobyB]

If you have 3/32" total rear toe, you're fine.  Are you measuring with plates?  Or at the tire OD?

And what's your rear camber look like?

 

And if there's ANY free play in the wheel at straight- ahead, it's worth the dance to try tightening the box a touch.

Something I never did, and wish I had, was to mark the original location before I started adjusting.

 

t

[bento]

If you have 3/32" total rear toe, you're fine.  Are you measuring with plates?  Or at the tire OD?

And what's your rear camber look like?

 

And if there's ANY free play in the wheel at straight- ahead, it's worth the dance to try tightening the box a touch.

Something I never did, and wish I had, was to mark the original location before I started adjusting.

 

t

3/32" is with plates. If that's good; awesome, I'll leave it alone and chalk it up to beginner's luck.

I'll plumb bob the rear wheels in the next couple days. It's been in the back of my mind that I might've gone past zero but I haven't measured yet. They look vertical from the rear of the car, rather than the fairly significant negative camber that existed prior, but I know I need to verify.

The steering box still feels good to me but I need to drive it more. There are marks punched into it showing the current setting so I have a reference if need be.

[bento]

Oh, and I realize a degree or two of negative camber is a good thing.

[bento]

I couldn't sit around this morning wondering about where I landed on camber. Got creative with a section of angle steel just long enough to sit on the rim and a 12" bubble level.

Without ballast in the driver's seat, I'm calculating 2 degrees negative camber on the driver side and 2.5 degrees on the passenger side. Looks like that's the high side of factory specs (1.5-2.5 degrees) from what I can find.

Garage floor is just off level and is contributing to the higher number on the passenger side. I'll flip the car around later and recheck to confirm but I think I'm set.

Thanks again.