dmorris

I've had my 85 for about 2 years and it has always been twitchy when hitting bumps and over uneven roads. I recently had a good alignment done and it helped some. All of the components were given a big thumbs up. My alignment guy would have let me know so I could replace the components prior to doing any work.
I am now using the car as a daily driver. I had to "give" my daughter my other car. I really am looking for the answer on this handling issue. I've been looking at the camber brace and have used the search to see if this helps. It looks like most say it does.

Simply put, will a camber brace improve this handling issue?

randy814u

Doesn't on my 85. It is alot better then it used to be, but not to my satisfaction.

MBDiagMan

Thanks for the full description of your situation and what has already been done and checked. Most posters are not complete with such information.

If everything suspension related is INDEED tight as your shop is telling you, then it is hard to know what your problem is, but whatever it is, I don't think a camber brace will correct it. That is not to say that a camber brace is not a helpful addition.

If this were not a car with a rack and pinion, the first thing I would check would be an idler arm. Since that does not apply, I would want to make sure that all joints in the REAR suspension are tight. Also don't overlook checking the C Beam bolts for tightness.

I assume that your alignment was a four wheel alignment, if not, I would find a GOOD alignment guy with lots of experience and with four wheel alignment equipment. There are still guys out there who do alignment with rudimentary equipment. If they really know what they're doing they can do great work with minimal equipment, but in this case you will HAVE to have your work done with four wheel alignment equipment.

Don't be wooed by a fancy alignment system. Shops can pay $30,000 and up for good equipment, but the job will be no better than the person doing the work.

Good luck,

c4cruiser

Wide tires contribute to "wandering" especially if the road surface is not smooth or has ruts worn in from heavy traffic volumes. Both my 87 and my 92 suffered from this problem especially on roads where the surface had heavy wear. Tires on one side would find a rut and want to stay there unless I turned the steering wheel and that usually caused the car to move to the other rut.

We have sections of Interstate around here that are worn and others are relatively new or repaved. You can immediatel tell the difference when going to new pavement, the car smooths out and tracks perfectly straight with hardly any steering input.

GM went to a narrower front tire to help resolve some of this. You could have the alignment changed to help but you may experience some tire wear. Maintaining the correct tire pressure helps too.

bogus

add some more caster.

On the pre-88s, the trick is to swap the upper control arm spacer thingys (professional, eh?). move the rearward spacer forward and visa-versa.

This increases the caster to post-87 levels and inproves stability; unfortunetly, at the expense of steering response, but who cares.

96_LT4_FE1

If everything else is good, my guess would be tires. I'm a pretty firm believer that wider front tires wander more, and stiffer tires can too.

My 96 was straight as an arrow with the BFG KDWS 255/55R17's(I think I got the size right) on 8.5's, my Firestone SZ-50 275/40R17's on 9.5's will catch road grooves and bumps much easier, but they are extremely responsive.

I'm pretty sure that is the reason the lower level suspension gets a smaller front rim and tire, to help the car require less steering input.
JMHO, »keith

Slalom4me

Yes, it will improve it and reduce the tendency
to change direction over bumps. (The R-D Cross-Bar
and Cross-Frame are other products that help towards
reducing chassis flex in C4s.) But it is not a magic
cure-all.

As others already said, you want to make certain
that you have a good foundation to build on first.

Starting with the alignment, ask what values were
used and whether a printout is still available. Toe
settings can affect a car's tendency to dart. Compare
your settings to the OEM ones and to others available
from vendors like 'Vette Products & Brakes' and
'Guldstrand Motorsports'. Perhaps members with
the early cars will offer their insights on settings that
work for them.

How many miles on the car and what kind of
maintenance history does it have? Shocks, ball joints,
tie rod ends, control arm bushings, wheel bearings,
the rack and ect all play a role in stability and are
consumables that need replacement periodically.

Do you still have the OEM wheels (16 x 8.5 w/
P255/50VR-16 tires per Corvette Action Center) or
have these been replaced with aftermarket ones? How
old are the tires and was there a problem before the
alignment that might have created abnormal wear?

The '85 had smaller dia/width wheels & taller profile
tires than later cars. So if yours are still stock in
dimension and in good shape then you are ahead of
the curve compared to what folks with 275/40x17
and larger on the front deal with. If you have after
-market wheels with different offset or adapters,
this could be contributing to the problem. Increasing
the track width has a decided effect on handling -
this is used as a tuning aid by racers.

If they aren't worn abnormally, I'll go out on a limb
and say old tires wouldn't contribute materially to
skittishness. They could have poor ride and less
traction but still get you down the road in a
straight line. My car came with Gatorbacks - lots
of tread and even tread wear but they had cracks
in the grooves. Car drove all right but man, it rode
rough - adding new Goodyear GS-C's (now obsolete,
GS-D3s replace them) made the car feel like I'd
replaced the suspension.

.

96_LT4_FE1

Are you sure you don't just want one of these? :







J/K »keith

bogus

wow. 70s bling.

Davemc1963-87conv

Welcome to the world of the C4.
Now before I start, I will state I love my vette and don't wish to ever sell it in the foreseable future. I have owned it for over 10 years now.
However, the 'darting around' when say negotiating a turn over an uneven road surface is a condition that most (if not all) C4's seem to suffer from, with the earliest (stiff) cars I believe suffering the most.
Stiff springs and dampers might be the hot ticket for pulling near 1G on a smooth racetrack, but are not too helpful in the real world of pot holes and uneven road surfaces.
If you do a search, you will find this topic comes up many, many times.
Solutions, I'm not sure if there is a fix for all, other than a redesign of spring rates, roll bar diameters and damper settings!
I'm sure if some one was to perform a thorough investigation and research into this, there would be may interested members on this Forum. But what is good to one person is poor to another.
Some drivers enjoy having their kidneys pounded and fillings rattled in their weekend warrior. A weak kneed half hearted effort for them just wouldn't cut it.
On the other hand for someone performing a daily commute over poorly maintained roads, with maybe the capability to handle a bit of spirited driving find the same set up tiresome and unpleasurable.
GM tried to some degree to resolve this with the different suspension packages available STD, Z52, Z51 etc. etc. But I feel none of these hits the nail on the head for may owners, especially as 'we' all too often fall in love with a car, buy it and find it has a suspension set up we maybe might not have selected ourselves given the new car option sheet.
Some say the C6 has it about right?? Maybe in about 10 years when I can afford one I will tell all.
Where do we go? I think you have made a good start with the alignment, next thouroughly check out all the suspension bushes and steering components, replace as required. Don't discount the rear bushes either. Some have reported good things about polyurothane bushes, which will outlast a rubber bush, but may decrease comfort somewhat. Maybe a worthwhile trade off!
As has already been stated, a change to the Front caster settings may help. I can't answer this one, as I have yet to try this, but I believe the last C4's had more caster and they were obviously the best (newest) of the line.
Maybe Dampers is something to consider next. There are some double adjustable setups now on the market, which would enable you to probably find a combination just right for everyones individual driving style, however, these run nearly as much as you can pick up a well used C4 for and probably arn't for most of us.
Edelbrocks have been said to help, although they carry a premium price and also carry a corvette tax as well, Konis, KYB's, Bilsteins, all have their supporters. I have heard of a report that Tokico shocks give a good ride, however they are a dual piston shock, that is thought of as being inferior in design to a single piston type. They are reputedly a high quality manufacturer, so maybe this should be borne in mind before disregarded them. Then there are the Monroes, Gabriels etc of this world, that many shun due to their 'low cost' but these may provide what some want.
Coilover conversions are said by some to help, although others say the suspension (shock tower integrity) is compromised by their fitment and shouldn't be fitted without a proper revision of the structure. Most users don't appear to suffer any ill effects...yet.
The old school used to use high spring rates and stiff shocks, but newer designs seem to use multirate softish springs, heavier anti-roll bars and a shock that isn't harsh. What that is for a C4 I don't have the answers. I'm sure someone will have done some evaluations and maybe share some info. But you have to pick out the bits of posts you like or want for your ride.
Personally I would like my 87 to ride like a BMW M3 or an M5. I don't think that is wrong and I'm sure it could given the right combination of parts, I believe it has the capability, I don't have the finances to try parts out and I just don't know what parts I should use
There must be some people that do, but at the moment they aint tellin.
If you find out, let us in on it. Its probably the best kept secret for a C4.

SPEED750

There is a lot of truth to this. Every car magazine that has tested a C4 always states "harsh ride, kidney buster, finds every bump, but give it nice smooth pavement and it pays off".
I think a lot of people buy a vette thinking it's gonna be the nicest ride ever only to find out their old caddy with wore out shocks is a lot smoother.

I have 11 inch rears and poly bushing. My car will find every rut and groove in the road. I just don't think you can have it both ways (not with a C4 anyway). If you want a car to track and handle like a race car then your gonna have to make some sacrifices.

Riks40th

Slalom4me

Uhm, I have an '89 with the FE1 package (note that
the front spring rates for the FE1 were moderately high
compared to later years.) It has a Cross-Bar, a
Camber-Brace and a Cross-Frame. Bilstein Z51 shocks
were installed this year. As mentioned earlier, the
tires are GY GS-C 275/40x17 (9-1/2 wheels) on all
corners for the street. Hoosier 305/30x18 (11"
wheels) for events. There are aftermarket swaybars,
too.

At 60k+ mi, my lower ball joints have play that is still
within tolerance but I may change them out this
winter. Some other parts fr/rr are in a similar state
- ok for routine service but perceived to be
sub-optimal for my purposes.

There, but don't tell anyone else ...

For comparison, my 540i has 235 fr/ 255 rr on 17".
The difference in stiffness between the two cars is both
an indictment of the decision to go with the targa and
a testament to the advances in chassis design.

Guys, he has a 20 yr old car. He's had it for two years.
Long enough to get the itch to dig into it a bit and
start tweaking it to suit his needs. Now that he needs
to deal with its quirks on a daily basis, he isn't so
willing to tolerate them. Let's help him figure out
what will best get him to the place he wants to be
with his C4.

.

vader86

I would do as has been suggested and add caster to the front, see if that will help.

Camber brace wouldnt fix this particular issue, help some maybe, fix no.

Trog

My car used to wander more than I liked too, talked to my alignment guy & went w/ 1/16" more toe & it was much better. Although tire wear "can" be more I have not noticed it. Now that I have coil overs, camber brace, rear DRM brace & a retrofitted convert. X brace I have ZERO wander.

VenkmanP

My camber brace makes things much worse on bumpy roads.

Shocks, alignment, condition of other suspension parts, coilovers are some of the things that can help with the bump steer.

SPEED750

Just for the record, that's the pimp ride from James Bond "Live and let die".

dmorris

Thanks for all of the input guys.

The car has 135k miles. I should have included that. The alignment was a four wheel alignment. I shouldn't have much trouble finding out what the specs were on the alignment. The wheels are the original wheels (for now) and the tires are in good shape, but are not new.

I will probably eventually bite the bullet and replace all of the components in the front and rear, but I did get a good report from my alignment shop guy. He knows what he is doing, he worked for several Nascar teams before he hurt his back. I know that alone doesn't make him an expert, but he isn't a kid that was flipping burgers last week either.

I want to get this item either fixed, or improved as much as possible. If it is a quality that all C4's suffer from, so be it. If it is not, I want mine fixed. It really is a bit unsettling when going through a curvy road with some bumps.

VenkmanP

It is something that all C4s have, with the possible exception of cars with a few grand into aftermarket suspension parts.

JrRifleCoach

Not entirely....missing the boomerang antenna



But seriously, the tires running through the traffic rut on any street or highway are the likely cause of wandering. There are a number of fixes you can try.
1. Camber brace. Not going to make a BIG difference but will help.
2. Alignment like Andy suggested.
3. Different tires. Look for a tire design that has a more rounded edge.

My 86 did exactly like your Vette is doing. Some sections of road were enough to pull the steering wheel from your hands. So after using steps 1 & 2 things were better but still not quite right.

Then the Michelins were replaced with Kumhos. What a difference!