The camber adjustment on the front of a Fiero is accomplished by rotating the upper ball joints from front to the back. The ball joint is offset between the mounting bolts so you have your choice of two positions. For the best handling, you want the position that gives the most negative camber. Usually this isn't much, so you'll need to move the holes to get more. I don't recommend more then one degree of negative camber for street use.
For more caster, move the spacers between the upper control arm and the frame bracket, positioning the upper arm as far back in the car as possible. You only need one degree of positive caster to have good handling and you can usually obtain this by moving the spacers on the Fiero.
As for toe-in, it should be 1/16-inch at the front to provide good control and stability under braking. Rear toe-in is set by turning the rear tie rods. It's important to have between 1/16-inch and 1/8-inch toe-in at each rear wheel. Measure each rear wheel in relation to the rocker panels when determining rear toe-in. If you measure one wheel versus the other, you can end up with the proper toe-in, but the car will probably dog-track.
For setting rear camber, move the shock strut slotted hole where it connects to the rear upright. For street driving, you want at least one degree of negative camber; for racing, you need about two degrees.
I'm rebuilding my Fiero from the ground up, and I apparently took apart my suspension without keeping track of what spacers when where. I bought all new Fiero Store components, including the new upper control arm bolt with spacers and washers.
I'm trying to put the car back together, and I have no idea what kind of caster / camber I need / want?
My upper ball joint is adjustable since it has the slotted holes, and I've got a plethora of washers and the new control arm bolt. I also have the original bolt with the original washers still on it.
WHAT kind of caster do I want, and how do I set it? How do I know what "degree" I want if the thing is on jack stands?
I'm going to get it aligned anyway, but figured I'd rather try to set it myself as best as I can.
In the text above by Herb Adams... he talks about wanting negative camber, but then says for good handling you want positive camber. I'm really confused...
Positive caster is the alignment spec that makes your wheel return to the forward position after turning a corner. It also makes the car less twitchy at highway speeds. The stock acceptable amount of caster is +3* to +7*. The stock washers measure 3mm and 9mm thick. Depending on which one you put where, you'll get either one more degree or one less degree of caster than what is already built in. But you're not stuck with just swapping the stock washers around. You can change the actual caster to whatever you want by using thicker or thinner washers instead of the stock ones, as long as the total thickness always measures 12mm.
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09:12 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Positive caster is the alignment spec that makes your wheel return to the forward position after turning a corner. It also makes the car less twitchy at highway speeds. The stock acceptable amount of caster is +3* to +7*. The stock washers measure 3mm and 9mm thick. Depending on which one you put where, you'll get either one more degree or one less degree of caster than what is already built in. But you're not stuck with just swapping the stock washers around. You can change the actual caster to whatever you want by using thicker or thinner washers instead of the stock ones, as long as the total thickness always measures 12mm.
Thanks Boozleberry, this does actually REALLY help (the explaination more than the picture). One quick question though...
What DO I want? Do I want to adjust it? I have all the stock bushings and I can put them back on the new bolt. Do I want more caster or less caster?
Now that I think about it, the stock washers were both the same, ie 6mm thick, it was only the "service replacement" parts that were 3mm and 9mm to give alignment techs a bit more adjustability. The book calls for +5* plus or minus 2* so that means the factory was aiming for 5*. Probably a good compromise between the steering feeling too heavy (too much caster) but still retaining good high speed stability.
The problem is that you can't really tell what your caster is going to be until you install the washers, lower the car, and have the alignment shop test it. It's not easy to measure caster at home. So to be safe, I'd just reuse the two 6mm washers and go for your alignment. Don't bother trying to assess the handling before you get the alignment done because it won't feel the same once it's aligned. Once it's done, if the car feels too hard to turn the wheel at slow speeds, but then whips out of your hand when you let go the wheel as you're straightening up, then get the tech to put thicker washers in the front and thinner ones in the rear position. If on the other hand the steering feels skittish at highway speeds then get them to do the opposite. Chances are though that the 6mm washers are going to feel just right.
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10:07 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Now that I think about it, the stock washers were both the same, ie 6mm thick, it was only the "service replacement" parts that were 3mm and 9mm to give alignment techs a bit more adjustability. The book calls for +5* plus or minus 2* so that means the factory was aiming for 5*. Probably a good compromise between the steering feeling too heavy (too much caster) but still retaining good high speed stability.
The problem is that you can't really tell what your caster is going to be until you install the washers, lower the car, and have the alignment shop test it. It's not easy to measure caster at home. So to be safe, I'd just reuse the two 6mm washers and go for your alignment. Don't bother trying to assess the handling before you get the alignment done because it won't feel the same once it's aligned. Once it's done, if the car feels too hard to turn the wheel at slow speeds, but then whips out of your hand when you let go the wheel as you're straightening up, then get the tech to put thicker washers in the front and thinner ones in the rear position. If on the other hand the steering feels skittish at highway speeds then get them to do the opposite. Chances are though that the 6mm washers are going to feel just right.
Thanks Boozle, the steering effort isn't a huge factor for me. I'm wondering if I wouldn't want to improve positive castor.
Can I take the 6mm washer in the front, and stick it behind the bolt in the back, effectively pushing the control arm 6mm closer to the rear of the car? Would that be ok?
Like I said, stability is MUCH more important to me than steering effort, I can more than handle the steering effort... even in a parking lot. Thanks!!! I really appreciate your responses...
That may be too much. Find some stainless steel flat washers that total 12mms stacked and use them in place of the factory ones. Doing so will give you the ability to make much finer adjustments. This is what used to come in the caster kit from MOOG when they were still in production along with new bushings and through bolt.
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10:17 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
I bought this from the Fiero Store a couple years back:
What I did was this:
2 in the front 6 in the rear
That is of course, the bushing shield on one end, then the control arm bushing, then 2 washers, then the center mount, then 6 washers, then the control arm bushing, then the bushing shield and then the nut.
I'm going to do the same thing on the other side.
Like I said, I'm not really concerned with steering stiffness... the more stiff on the road, the better. I can always just muscle the wheel.. and if it gets to be too crazy, then I'll just back off a washer. I might still since I haven't put the spring in yet.
Just wanted to know if what I did there WILL improve steering stability on the highway and improve handling (at the expense of stiffer steering).
I don't think I would place all 12mm of washers in the rear either. That'll probably give you something up to +8* which might make you wish you hadn't once you start driving around in a parking lot. You should trust that the engineers knew what they were doing when they decided the caster would be best at five degrees. My '86 is set there and is more than enough to make my car feel stable.
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10:31 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
I don't think I would place all 12mm of washers in the rear either. That'll probably give you something up to +8* which might make you wish you hadn't once you start driving around in a parking lot. You should trust that the engineers knew what they were doing when they decided the caster would be best at five degrees. My '86 is set there and is more than enough to make my car feel stable.
What I ended up doing (not tightened down but just in there loose right now) is put 2 washers in the front, and 6 in the rear. It came out to 3mm in the front, and 9mm in the rear. I figured that based on what would be the acceptable amount for the adjustment kit that would otherwise be the aftermarket replacement?
I don't think I would place all 12mm of washers in the rear either. That'll probably give you something up to +8* which might make you wish you hadn't once you start driving around in a parking lot. You should trust that the engineers knew what they were doing when they decided the caster would be best at five degrees. My '86 is set there and is more than enough to make my car feel stable.
When I rebuilt my suspension (Held Motorsports kit), I set my front Caster to 9*. It was a pain to steer in the parking lots, even with the Butterfly steering wheel. At higher speeds, it was great. I then adjusted it to just under 7* and have had a much better time at low speeds and the higher speed stability did not change enough to notice. This is with 16 x 7 wheels and 225 tires. I found out there is such a thing as too much. -7* turned out to be where I like it for my setup, which puts it in the factory range.
Yep. With that configuration, you should expect that your caster will be around +6* to +7* when you get it measured at the alignment shop.
Awesome!! Thanks guys, I learned a lot in this thread.
I'm looking forward to getting this thing done. This was my first car. I've had it since I was 17, which was 15 years ago... I haven't actually driven it in almost 5 years... unless you count the time I drove it from the side of the house into the garage where it's been for 4 years or something...
Sorry. Yes, I meant just under 7* to the positive.
-Dave
This was a great thread... now I just need to figure out how to set camber.
Some of the posts I read in the searches said that CASTER is also adjusted by the upper control arm ball-joint. It said aftermarket ones could be adjusted. I don't really see how that's possible since the aftermarket ones have a side to side adjustability (side to side of car), and not a forward / aft (front to back of car).
Seems to me that I could adjust CAMBER with the ball joint.
Just put it together enough to get to an alignment shop. Since you didnt keep track of anything, your not going to get anything even reasonably close to fine tune it yourself. Take all your shims with you in a ziplock bag to the shop. Make sure they return what they dont use. You will def need a 4 wheel alignment. 2 wheel isnt going to do a whole lot of good since everythings been off.
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11:35 AM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Just put it together enough to get to an alignment shop. Since you didnt keep track of anything, your not going to get anything even reasonably close to fine tune it yourself. Take all your shims with you in a ziplock bag to the shop. Make sure they return what they dont use. You will def need a 4 wheel alignment. 2 wheel isnt going to do a whole lot of good since everythings been off.
Well, I mean... this isn't a TransAm... there's very little adjustment that's done to the front of the Fiero. I have all of the stuff, and I still have the drivers side assembled. I'm going to get the camber and toe-in adjusted... but the caster seems to be a pretty static no-nonsense adjustment now that I know how it works.
Check with alignment shop before you go. There are two shops close to my house.....one will not "waste their time" on shimming the upper A arm bolt. The other house is very familiar with Fieros and will do all it takes to get it just right. So call and ask questions about how much work they are willing to do. I would also replace the uppers with Rodney Dickman adjustable balls joints....more choices in fine tuning. Jim
PS...the shop with Fiero experience just did an 86GT for me and spent a huge amount of time....maybe 1.6 or so hours, but they charged me for much less time. Great guys!
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11:59 AM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Check with alignment shop before you go. There are two shops close to my house.....one will not "waste their time" on shimming the upper A arm bolt. The other house is very familiar with Fieros and will do all it takes to get it just right. So call and ask questions about how much work they are willing to do. I would also replace the uppers with Rodney Dickman adjustable balls joints....more choices in fine tuning. Jim
PS...the shop with Fiero experience just did an 86GT for me and spent a huge amount of time....maybe 1.6 or so hours, but they charged me for much less time. Great guys!
Thanks Bow, I just checked out Rodney's upper ball joints for the front... looks like they are the EXACT same ones I bought a while back. I bought all this stuff years ago... so it's possible I bought mine from Rodney.
Just curious, the adjustable ball joints are to adjust camber, not caster, right?
It helped my still new to alignment characteristics self greatly in better understanding suspension Geometry.
Edit to add, I recently began questioning some of my prior upgrades and re installation after some recent threads so I have been researching a bit and this was some of the best and easy to understand content I could find. It proves some of the stuff I have done was consequently correct, however it makes me want to tear back into it and play around with my suspension Geometry when I install my Eibachs soon.
[This message has been edited by katore8105 (edited 08-20-2010).]
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12:35 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
It helped my still new to alignment characteristics self greatly in better understanding suspension Geometry.
Edit to add, I recently began questioning some of my prior upgrades and re installation after some recent threads so I have been researching a bit and this was some of the best and easy to understand content I could find. It proves some of the stuff I have done was consequently correct, however it makes me want to tear back into it and play around with my suspension Geometry when I install my Eibachs soon.
Thanks Katore,
Yeah, I found that link too... I plan to use that when I set up my base camber and toe-in before I take it to an alignment shop.
I really wish there was some way to have easily removable bushings on the upper control-arm bolt. I'd love to be able to easily remove them at will and see what setting I like best. I can't wait to get this thing finished...
What I ended up doing (not tightened down but just in there loose right now) is put 2 washers in the front, and 6 in the rear. It came out to 3mm in the front, and 9mm in the rear. I figured that based on what would be the acceptable amount for the adjustment kit that would otherwise be the aftermarket replacement?
You are actually running less than stock caster now. The farther to the rear you move the upper suspension arm, the more positive caster you have. Six in front and two in the rear would give you more caster.
Good catch there rwhughes! He's right... more washers at the back means less positive caster. Sorry, I goofed in earlier posts up above. To increase positive caster you need to put the thicker washers at the front, this effectively moves the upper control arm and it's ball joint further backwards. The impact is that the imaginary line drawn between the upper and lower ball joints contacts the pavement further ahead of the tire contact patch. The further ahead that point is, the greater the caster.
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06:39 PM
Aug 21st, 2010
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Good catch there rwhughes! He's right... more washers at the back means less positive caster. Sorry, I goofed in earlier posts up above. To increase positive caster you need to put the thicker washers at the front, this effectively moves the upper control arm and it's ball joint further backwards. The impact is that the imaginary line drawn between the upper and lower ball joints contacts the pavement further ahead of the tire contact patch. The further ahead that point is, the greater the caster.
No, that's not right.
If you move more washers towards the FRONT of the control arm mounting tube, that will move the control arm CLOSER to the FRONT.
If you move more washers towards the REAR of the control arm mounting tub, that means that the armature of the tube will be FURTHER AWAY from the mounting tube (towards the back) which means that the control arm will be closer to the REAR of the car.
I appreciate the responses guys, but let me ask a quick question.
Do I want my control arm further forward, or further backwards for improved high-speed driving and handling? (obviously at the risk of harder steering effort).
More positive caster makes it harder to steer and be less responsive. The benefit of higher positive caster is improved camber when cornering, A large increase in positive caster will actually alter the suspension geometry and make the wheel more vertical when cornering.
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04:02 PM
Aug 23rd, 2010
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
Thanks Tony. I just set it back to stock... 4 washers on either side (even both sides), which is basically what the stock suspension was (using 1 thick washer on either side).
I'll fiddle with it when I get the car totally put back together. No point in worying about it now.
I'm curious are there torque specs for that bolt? I've got it pretty tight, but the control arm will still drop / slide down on it's own after a couple of seconds.
I'm curious are there torque specs for that bolt? I've got it pretty tight, but the control arm will still drop / slide down on it's own after a couple of seconds.
The service manual says to torque the nut to 66 lbft while control arm is in a horizontal position.
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03:15 PM
82-T/A [At Work] Member
Posts: 23043 From: Florida USA Registered: Aug 2002
The service manual says to torque the nut to 66 lbft while control arm is in a horizontal position.
Nice, thanks Blooze...
Actually, I just downloaded the 87 Service Manual from someone on here who was kind enough to scan it (forget who). It's going to be my new friend for the next 6 months while I fix this bad-boy up.
