Rear camber adjustment tricks?

[jwfisher]

Anybody come up with a good method for getting to the rear camber bolt to do an alignment?

I've done it by reaching thru the wheel over the rotor... there's not enough room to go over or around the tire.. it's too tight from underneath...

Any tricks anybody out there has found?


-Jeff

 

[ac427cobra]

If this is for a track set-up, it's my understanding you want the maximum camber available (in the rear) that the eccentric will give you? This can be done with the wheel off.

I have not done it yet but that's what I have been told?

 

[jwfisher]

I wouldn't want to just leave it at max... I'm looking for a specific value (mine happens to be 1 neg) to match what I've got the front setup for and max is more than that.

We've got the best alignment guy in the state here... I'm wondering if there is anything we can do with his equipment to align the car with the rear wheel off - since the alignment rack moves the car up off it's tires.

 

[Cobra-R]

Here is the specs for the 00R Front
Camber -2.5 deg
Caster +4.75
Toe -0.10 deg

Rear
Camber -1.5 deg
Toe +0.10

If your car is a street car, the above would be pretty aggressive. I would probly say set it more in the range of -1 degree camber in the front and -.5 in the rear. For track use the numbers above would be a good starting point, but depending on what tires you use you might be running up to -3 degree in the front. I wouldn't go much more than the -1.5 in the rear.

The only way your going to be able to adjust camber (in the front or back) is to take the weight off the wheels. Depending on the lift, you probly could access the rear camber bolt from under the car, but it would be much much easier to remove the wheel.

On my cars once the camber is set in the rear, I mark the cam and the knuckle so if I have to take the car apart, I can put it back to where it was set before. If you track the car, have the guy set it at say -1.5, mark it, then have him put it at your street setting. Then when you go to the track, you can change it.

Brian

 

[jwfisher]

Yup, those are the specs I'm running... the issue is trying to get it more easily setup correctly in the rear. I know how to adjust it, but I am looking for some sort of trick to get around having to reach thru the wheel. I'm going to look into doing it on the rack but without the wheel...

 

[Cobra-R]

Even if you get to the cam without removing the wheel, it is going to be almost impossible to adjust without removing the weight from that wheel. If you go that far, you may as well remove the wheel.

Brian

 

[Terry Moenich]

I know exactly what you mean, I do my alignments at a Hunter training center, I asked the instructor what you do if you don't have 5 spoke wheels, he laughed and said "you take the wheel on and off!! Fords better idea" He's Chevy guy!!

 

[jwfisher]

But, if you take the wheel off, the alignment gear that was attached to the wheel will also be off the car, and the rack's computer won't be able to tell you what reading you've got...

There's got to be some trick to this...

 

[Cobra-R]

Have you talked to your alignment guy? This is nothing that he probly doesn't face many times a day. My guess is he removes the wheel.

Good Luck, Brian

 

[ac427cobra]

Brian:

I was told the max camber you could get out of the rear adjustment is about -1.3? If you really put pressure on the front side of the bolt you can sometimes squeeze a little more out of it? Has anyone done their own here yet?

I may not have time to get to the alignment rack before Mid-Ohio? But maybe this is telling me I need to make it a point to get there?



:thumbsup: :coolman: :beer:

 

[racer726]

There is an accentric, and there are slots on both sides. Just turning the accentrics will not get you max neg camber. The knuckle has to be moved in the slots manually on both fore and aft sides, to get there. Easy to get at least 1.5 degrees this way. It naturally wants to droop in the least amount of neg camber position, and there's a lot of slop left. Take it all apart and look at if, and you'll know what I'm talking about.

If you want a lot of rear camber, here's what I recommend. Max out both sides, measure, and then for the side that is more neg, loosen the eccentric nut, so there's still some torque on it, bump the assembly towards less neg camber until it's equal, and then re-torque. If you cannot access the nut, remove wheel, loosen somewhat (you have to use judgement here), reinstall wheel and equipment, and bump the wheel to get what you need.

If you want even more neg camber, lengthen the slots. Really isn't necessary.

Also, if you're running stiffer upper and or lower arm bushings, less camber is required for the same effect, as it will deflect less under load (that camber robbing deflection thing going on)

Never mind... Just bring it by my shop, hand over some cash, and I'll get you whatever negative camber setting suits you.

Cheers,
Dave

 

[ac427cobra]

Dave:

Thanks for the reply. I am in the process of finishing my Delrin bushing install on the rear upper and lower control arms. Are you saying I may not want -1.5 degree rear camber? Maybe more like -1?

Your input is appreciated.

:thumbsup: :coolman: :beer:

 

[racer726]

There is probably a range you want to stay in, I would estimate very roughly that it's 1.2 to 2.0 degrees with delrin and again roughly 1.4 to 2.2 degress with Cobra R bushings, at the track with R compound tires, as an example. Looking at the temperature profiles when running at the track along with car balance and driving style, there are several factors that would influence you to go with either the higher end, the lower end, or somewhere in between.

Now that's sort of mumbo jumbo I guess To clarify, when the determination is made to increase neg camber during the off-season from say 1.3 degrees to 1.6 degrees, for whatever tuning reason (lets say that one has determined that it's the right thing to do to achieve better cornering grip, better balance, drivability, traction, lap times, or whatever)... if at the same time the rear bushings are changed to a less compliant material, then that bushing change would also provide the benefits of increased negative camber relative to the soft bushings, in a dynamic cornering situation. In other words, one would not have to go to as much negative camber due to the addition of the bushings.

I would say that -1.5 degrees is an excellent decision if one were to blindly guess, even with the delrin bushings. The situation where you may want to decrease that is if the temperature profiles across the tire carcass were significantly skewed towards a hotter inside section area as determined by either observing the condition of the rubber, or by using a tire pyrometer.

1.5 is what I have on the car, and if it wasn't for the fact that the car is pretty well balanced, i would add a little more negative camber in the rear. A guide is also that if decreasing rear negative camber, the car will tend to over steer more, and decreasing front negative camber, and a car will tend to understeer more... but I'm sure that's nothing new to anybody in this forum, just something to consider with decisions regarding camber.

Stay with -1.5, and if you find that understeer is increased beyond your liking, then reduce it to perhaps -1.3... just remember that understeer increased due to the fact that rear cornering grip is increased relative to the front especially during beginning and the middle of the turn. It's sort of a steal from Peter to give to Paul ordeal, but the right changes will have a good benefit in overall track times of course. Unless the inside temps are excessive though, as I've indicated, I would tend to go with increasing the front neg camber in such a scenario. Hope that makes sense.

Dave

 

[Cobra-R]

Bruce,
One thing that Dave didn't mention, the ideal camber setting is going to vary from track to track based on the types of corners as well. You can get by with less camber at a track like Road America than a MAM or Gingerman.
With the griggs setup, I would run -2 to -2.5 (in the front of my 95) and tracks like MAM or Gingerman, I would run -3.

Brian

PS: With those Dunlops you have (I didn't let the secret out, did I????????????) You need more camber, in fact you will probly need as much camber as the car will give you.

 

[ac427cobra]

Dave:

Thanks for the explanation and the reassurance. I feel better.

Brian:

Dunlops? :shrug: What are you talking about? ;-)

My concern, even on Road America, is wear on the outside edge of the tire. Something I have been experiencing now that I can get around the track there a little better. IMHO the Carousel really tears up the outside edge of the left side tires. This is why I think I should have the rear camber negative cranked as far as I can get it?

I'm not going to be able to get my MM CC plates in before Mid-Ohio or even RA for that matter. I think that is going to be a very necessary thing?

I could use another month of Winter! Did I say that? ;-) :lol:

:thumbsup: :coolman: :beer:

 

[Andy M]

When we did my delrin bushings a few weeks ago, we set my car up with -1 degree camber in the rear and -2.5 in front as well as close to 6 degrees positive caster in front... and the car was handling VERY well at the track.

I agree though that these settings are probably a bit too agressive for a street car.

 

[jwfisher]

Jog my memory.. somewhere recently I saw a replacement for the rear upper control "ball" joint - forget the exact name (well, somebody here has to focus on work), but it's the attachment to the upright which is also used to adjust the camber. It's suppossedly weak... I was wondering if anybody else say this, has it, or thinks it might be worthwhile.

 

[racer726]

SHM has some aftermarket upper and lower ball joints or whatever they call it... or at least they did about 6 months ago when I was looking. It's really pricey though, and I haven't heard of any failures or problems with the stock pieces.

Dave