Setting Toe

Without serious modifications, my 91 Civic (among other
Honda models) permits only one alignment angle to be
adjusted: Toe.

Has anyone here set the toe themselves? If so, what tools
did you use or devise? Was your effort successful as
indicated by tire wear and steering feel?

I have googled and there are some reports on this, but they
are a bit vague. Also, I see tools like the toe gage plates
advertised at http://www.quickcar.net/chassis/ch_tp.html and
Ebay Motors. Is it a big deal to find my own very flat
plates, apply them to the tire sides, devise a way to take
measurements, etc.? I am sure tempted to do so.

On rear toe --
Having just replaced the trailing arm bushings in my 91
Civic, I know there are little "compensator arms" attaching
to the front of the trailing arm. At one end, the
compensator arm is bolted to the car. The bolt, when
loosened, can move in a slot so that some adjustment is
possible. Hash marks are etched prominently into the body of
the car at this point to facilitate adjustment. The factory
service manual describes this under "Rear Toe
Inspection/Adjustment." See for example
http://media.honda.co.uk/car/owner/media/manuals/CRXManual/62SH200/12-5.pdf

The other end of the compensator arm is free-floating. That
is, it rides on air. It seems a rather flimsy arrangement
for adjusting toe with any precision. The design seems to
explain the following three comments:

"... usually only the front suspension [wheel alignment] is
adjustable." Chilton's 1984-1995 Honda Civic/CRX/del Sol
manual, page 8-12

"A unique feature of [the 1984-1995 models'] suspension
system is the compensator arm. This component allows a
certain amount of side-to-side movement of the trailing arm.
This helps to maintain a better toe angle of the wheel
throughout the suspension travel." Chiltons, page 8-16

"The [new at the time 1993 Integra] trailing arm's front end
is located by a short transverse compensating arm which
cancels unwanted toe changes."
http://dwolsten.tripod.com/articles/sep93b.html

ISTM the free end of that compensator arm will move in a
radius around its other (adjusting bolted) end. So it moves
in and out somewhat, changing toe according to driving
conditions and wear on the car. As a result of all this
commentary, I get the feeling that rear toe need not be
sweated too much. Thoughts?

 

I've done several by looking at the wear pattern. Initially I've tried to
get close with a measuring tape, but all the stuff in the way makes that
hopeless.

If you find a fairly straight stretch of road and put masking tape (duct
tape if the masking tape won't hold) from sidewall to sidewall on the front
tires, you can drive a mile or so and check the wear. Excessive toe-in shows
up as wear on the outer edges while toe-out appears as wear on the inner
edges. I start with half turn adjustments on each tie rod; your intuition
should do just fine for the finer adjustments.

It goes without saying the differential tie rod adjustment affects how your
steering wheel sits, so the iterative process often ends with adjusting the
centering after you get the wear dialed in. Within an hour you should have a
really fine result.

Mike

 

I've done several by looking at the wear pattern. Initially I've tried to
get close with a measuring tape, but all the stuff in the way makes that
hopeless.

If you find a fairly straight stretch of road and put masking tape (duct
tape if the masking tape won't hold) from sidewall to sidewall on the front
tires, you can drive a mile or so and check the wear. Excessive toe-in shows
up as wear on the outer edges while toe-out appears as wear on the inner
edges. I start with half turn adjustments on each tie rod; your intuition
should do just fine for the finer adjustments.

It goes without saying the differential tie rod adjustment affects how your
steering wheel sits, so the iterative process often ends with adjusting the
centering after you get the wear dialed in. Within an hour you should have a
really fine result.

Mike

 

[snip]

If you've had the rear trailing arms replaced, then you need to have the
rear toe adjusted. The best way to do this is to have a professional
alignment done. Just pay the $50-60 or whatever and get a 4 wheel
alignment done. I've done many alignments using computerized laser sensors
which are mounted to the wheels. A small amount of adjustment at the rears
typically makes a large difference. I believe that a professional 4 wheel
alignment will be the best thing you can do to maximize the longevity of
your tires (including of course regularly checking the air pressure and
rotating them periodically so that they get even wear).

Eric

 

[snip]

If you've had the rear trailing arms replaced, then you need to have the
rear toe adjusted. The best way to do this is to have a professional
alignment done. Just pay the $50-60 or whatever and get a 4 wheel
alignment done. I've done many alignments using computerized laser sensors
which are mounted to the wheels. A small amount of adjustment at the rears
typically makes a large difference. I believe that a professional 4 wheel
alignment will be the best thing you can do to maximize the longevity of
your tires (including of course regularly checking the air pressure and
rotating them periodically so that they get even wear).

Eric

 

You can't do it yourself with any precision.

The job is properly done this way:
1) Adjust REAR *total* toe FIRST. This gives you your "thrust center line",
upon which the FRONT toe depends.
2) After rear toe is adjusted, front toe is adjusted using the steering
outer tie-rod ends so that two things occur:
a) *Total* front toe is within spec, and
b) front-end toe on either side of the thrust center line is equal.


Thrust center line (rear axle forwards):
_
|
|--------
|
-


Front wheels pointed towards the thrust center line. Their angles must
intersect the thrust line at the same point:

_ \
|
|---------
|
- /

The shop will often not adjust BOTH compensator arms, but only one. It's
not necessary to do both, so long as the thrust center line is such that
the front end can be made to conform to it within its range of adjustment.
The thrust line does NOT have to parallel the car body's front-to-back
centerline.

If you've guessed that the car may not travel down the road perfectly
straight, but may "crab" or "dog walk" a little to one side, you're right.
And it does not matter if this happens. Some cars (certain domestics come
to mind) only have a single rear adjustment on ONE side.

 

You can't do it yourself with any precision.

The job is properly done this way:
1) Adjust REAR *total* toe FIRST. This gives you your "thrust center line",
upon which the FRONT toe depends.
2) After rear toe is adjusted, front toe is adjusted using the steering
outer tie-rod ends so that two things occur:
a) *Total* front toe is within spec, and
b) front-end toe on either side of the thrust center line is equal.


Thrust center line (rear axle forwards):
_
|
|--------
|
-


Front wheels pointed towards the thrust center line. Their angles must
intersect the thrust line at the same point:

_ \
|
|---------
|
- /

The shop will often not adjust BOTH compensator arms, but only one. It's
not necessary to do both, so long as the thrust center line is such that
the front end can be made to conform to it within its range of adjustment.
The thrust line does NOT have to parallel the car body's front-to-back
centerline.

If you've guessed that the car may not travel down the road perfectly
straight, but may "crab" or "dog walk" a little to one side, you're right.
And it does not matter if this happens. Some cars (certain domestics come
to mind) only have a single rear adjustment on ONE side.

 

what he said. because of the 4-wheel alignment necessary on this
vehicle, and the difficulty of setting the thrust angle iteratively, pay
to have it done elle. but because also of the, er, "patchy" quality of
some alignment shops, make sure you take it to a place that guarantees
their work. then you can keep taking it back until they get it right.
and eric's not fooling - the rears are uber-sensitive.

 

what he said. because of the 4-wheel alignment necessary on this
vehicle, and the difficulty of setting the thrust angle iteratively, pay
to have it done elle. but because also of the, er, "patchy" quality of
some alignment shops, make sure you take it to a place that guarantees
their work. then you can keep taking it back until they get it right.
and eric's not fooling - the rears are uber-sensitive.

 

To clarify: If you have to rotate the steering wheel and hold it there to
make the car track straight, this is an issue quite separate from the "dog
walking". "Dog walking" by itself does not cause steering pull.

 

To clarify: If you have to rotate the steering wheel and hold it there to
make the car track straight, this is an issue quite separate from the "dog
walking". "Dog walking" by itself does not cause steering pull.

 

"dog walking" is also why you may have to adjust the toe /both/ sides of
the rear, not just one. the angle each side of the center line has to
be identical with their bisector passing exactly through the center line
of the vehicle.

 

"dog walking" is also why you may have to adjust the toe /both/ sides of
the rear, not just one. the angle each side of the center line has to
be identical with their bisector passing exactly through the center line
of the vehicle.

 

I personally replaced the trailing arm bushings on Monday.

But I gather your advice does not change.

Knowing this helps a lot, Eric. I value your opinion.

 

I personally replaced the trailing arm bushings on Monday.

But I gather your advice does not change.

Knowing this helps a lot, Eric. I value your opinion.

 

Okay, thanks for the elaboration.

I googled before I posted and did indeed notice discussion
of certain Fords, for one, having the adjustment on only one
rear side.

My dealer IIRC wants $89 for the job but I think I'll shop
around a bit.

The car has no pull or any odd steering. The tie rod ends
(originals) appear quite secure. The inner tire wear on the
front pass side may have been due to worn bushings and a
darn near totally corroded stabilizer link on that side. All
have been replaced. Very smooth ride now (and I think it's
more than the placebo effect; I'm feeling that cornering on
rails thing), but I know after all this work an alignment
(the first ever) is a very good idea.

 

Okay, thanks for the elaboration.

I googled before I posted and did indeed notice discussion
of certain Fords, for one, having the adjustment on only one
rear side.

My dealer IIRC wants $89 for the job but I think I'll shop
around a bit.

The car has no pull or any odd steering. The tie rod ends
(originals) appear quite secure. The inner tire wear on the
front pass side may have been due to worn bushings and a
darn near totally corroded stabilizer link on that side. All
have been replaced. Very smooth ride now (and I think it's
more than the placebo effect; I'm feeling that cornering on
rails thing), but I know after all this work an alignment
(the first ever) is a very good idea.

 

I think I'll give this a try just to see what it turns up. I
wish I'd done it before all my suspension renovation work so
I could compare. Thanks Michael!

Understood. Thanks again!

 

I think I'll give this a try just to see what it turns up. I
wish I'd done it before all my suspension renovation work so
I could compare. Thanks Michael!

Understood. Thanks again!

 

I'm just a little bit curious. Exactly which bushings are you referring to,
the ones labeled as part #12 in this diagram http://tinyurl.com/fwt4y or the
large one in the middle of the rear trailing arm through which bolt #26 goes
to help mount the trailing arm to the car?

Eric