I recently changed out the front and rear springs with performance springs from IAP and replaced the 23 year old struts with KYB GR-2s. That whole process went fairly well and I am satisfied with the results.
So today I take Flash in for the mother of all wheel alignments and after going to 4 different alignment places, I finally found one that could sort of spell B-E-R-T-O-N-E and had the alignment data in their computer. You suspension gurus probably can anticipate the results; I have too much negative camber on the front and back wheels. After reading the forum, I now know why since I lowered the car which changed the suspension geometry.
The guy at the alignment shop recommended camber bolts. Further reading on the forum indicates that changing the camber at the bottom of the strut is bad because it adversely effects the toe (which is also way off). The caster is dead on.
So the method that seems preferred to add positive camber is to slot the top strut mounting holes. That doesn't seem to hard to do.
My camber measurements are -2.2 degrees for the front and - 3.2 degrees in the back. I plan to set the camber a bit negative for improved cornering (-1 and -1.45 respectively).
So as I understand it, I need to slot the top strut mounting holes towards the fenders. Now here is the $64,000 question. How far back do I need to slot the holes to achieve a 1 and 2 degree change to the positive? I do not want to remove any more material than is necessary and I really don't want to have to go through several alignment checks ($$$) until I get it right. I am looking for recommendations from people you have successfully performed this surgery and the patient recovered without complications.
In advance, thanks for the advice.
1986 X1/9 FI - aka "Flash"
1980 X1/9 FI (wrecked badly from an encounter with a pickup truck)
1979 X1/9 (fell apart - now a parts car)
I wouldn't bother trying to take any camber off. Depending on your spring rates I would imagine that the roll resistance front and rear hasn't really changed all that much (from my recollection the IAP only afford a 15 per cent rate increase at the wheel). Plus, if this has resulted in a lowering of the vehicle, then you stand to have slightly more body roll than you did previously anyway (counter-intuitive, I know, but fact). By the camber figures that have been dialed up, it doesn't sound like it's much lower than standard anyway (I bet if you measure from wheel rim -- assuming 13" -- to guard vertically you get 140 - 150mm front and rear).
Thing is that Xs tend -- unless they're wearing significantly increased roll resistance -- to roll outside the geometry anyway when punted hard. -2.2 on the front isn't excessive in my book (I'm running closer to -4) and neither really is the -3.2 at the rear (mine's at about -3.8).
Anyway . . . should you decide to proceed I would not suggest slotting the towers. Better to fit eccentric mounts. Camber pins at the lower strut mount are OK (I have them fitted to the front of mine) . . . you just have to re-allign the toe again to get it right is all.
I had precisely the same thoughts as Tim this week.
September 4 2008, 6:55 PM
I too am tired of visibly "bow-legged" negative camber on the rear. But, speaking personally, and even though I have some knowledge of suspension geometry, all the threads assume everyone knows what the heck the options are and how you do them.
So, just what are camber pins? What do they look like? Where do you get them? What are the wedges that people talk about for the upper mounts? All I ever see discussed in any detail are slotted upper mounting holes or racer weld-on slotted plates. Speak to us, please.
Sorry for the intense questions, but sometimes the discussions here seem a bit terse. Assume that some of us know nothing.
I ran precisely that suspension system on my '81 X, with the exception that I cut the front springs by about 1/2 to 3/4 coil for a bit more lowering. Never touched the camber, just left it the way it was. The trick is to keep your toe-in right on the money at all times. I drove many thousands of miles with no untoward wear. Tires I ran were Yokohama A-509, Goodrich Comp TA, Yoko AVS Intermediate, Sumitomo HTR200, and some Michelin XVS in there somewhere.
Slotting is not a good way to go as there is no way to control what can happen. You will no longer have positive, specific location of the strut to the suspension hub, which if a fastener were to come loose would allow the hub to slip unrestrained back and forth. If you want to do some metal surgery I would look strongly at adding an upper eccentric bolt.
Check out the image in this post, I believe Damonfg made the eccentrics in the following post.:
Respectfully, let me offer some contrary ideas, though I know this has been discussed at length here (and on Mirafiori) before.
You can control what happens with slotting, you just have to take your time and do it well. I have done the slotting of the three upper mounting holes and they held fine (on a 128) but this weakens an already marginal strut tower top. They are prone to cracking on 128s and earlier X1/9s, from the bolt holes to the center holem so I prefer not to do it this way anymore.
I wanted more adjustment so I slotted the upper of the two bottom (strut to spindle) mounting holes with excellent results. I did the math/geometry to determine how much to slot in order to achieve the desired camber change. In my case, on a 128, I was going for more negative camber so I slotted the upper hole toward the strut tube. When the alignment was to the specifications I wanted, I welded close fitting washers to the strut ears so that the adjustment would not move. Actually, the first time I merely tacked them in 3 places and the tacks broke. It did not cause the car to go wildly out of control, only I noticed it not handling quite right at some point. Anyway, after welding all the way around the setting held, and continues to hold years later.
The eccentrics shown in Bob's post are a great idea (much better IMO than the "crash bolts" usually offered up). However, I don't see how they would maintain their setting if the bolt came loose. They would be less prone to moving due to a lot more friction in the installation but they don't seem to eliminate the possibility of movement.
I would also like to point out (since Tim mentioned toe in his post) it doesn't matter where you adjust the camber, be it at the top of the strut or at the bottom, you are changing your spindle inclination and the steering arm is going with it so you are going to have a change in toe. In fact, if you move the upper strut mount you are actually changing the kingpin inclination so you change scrub radius, camber gain, and toe, however marginal. Definitely realign the car regardless of which way you go.
P.S. Tim - Hi, from Charlotte. I just moved from CA ~2 months ago.
The basic difference between the two is:
With a slot you are relying on clamping pressure of the bolt onto a washer onto a the hub. If the bolt loosens or is not properly torqued the strut mount will tend to slide on the knuckle.
With an eccentric, the bolt does need to be properly torqued but the way forces are transferred from the knuckle to the bolt to the eccentric and then to the edges of the hole in the mount to the strut means that the eccentric would have to rotate in the hole in order to change the camber.
Welding a washer in the correct position for your desired camber is a good solution, but is not adjustable which is sort of the point. Especially if you want to induce more negative camber for an autocross or track day and then return it to a road setting.
As for slotting the upper mounting holes, personally, I don't care to do surgery like that with out really trying to fix the whole problem which is to gain control of the strut upper location and be adjustable.
1969 850 Sport Coupe
1970 124 Sport Coupe
1985 Bertone X 1/9
Re: The difference between eccentrics and slotting
September 5 2008, 4:40 PM
Yep. Question is, what kind of load is required to rotate the cams if the bolt were to come loose. Either way, I agree it's still a more secure method, compared to just slotting.
The welded washer certainly is adjustable (that IS the point), it's just not continuously adjustable. It allows you to adjust outside the stock range but one adjustment only. If you want to try incremental changes, yep, you're kind of stuck unless you do some solid tacks and grind them off each time. It all goes back to budget and resources - most of which, Fiat guys have none! Heh! I'll probably give the eccentrics a try next time around. But if your garage shop (or driveway) is limited to a round file and flux-core welder, don't hesitate to slot and weld on some washers I don't know many racers who drive to the track or autocross and start adjusting camber & toe, then readjust it to a road setting before taking off for the day. Same with coil-overs and ride height. Getting race wheels/tires mounted and aired up and is usually enough work.
One question on the eccentrics - how much material is left around the hole after drilling it out? If the bolt came loose I certainly wouldn't want to tear out the hole.
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