Carl Fausett

I agree. I have never found toe to be that critical that a tape measure wasn't good enough. The difference between an 1/8 and a 1/16 seems negligible to us.

BTW: test your tape measures - hook them on to the same thing and go out about 72 inches. You will be surprised how far they can be off! Once you find two that match, mark them and only use them for alignments...

With camber I do find a more particular measurement is worth it. We can measure to the 1./8th of a degree with ours. See pics below. That's the rear - set to about 2.0 deg neg camber. On my car with our wheels and tires, produces a pretty even tire temp across the face of the rear tire.

Of course, its arguable whether that is right. There is a stream of information that says you DO want higher temps on the outer edge... its a bit of a barstool argument...

Finally, when you get a Camber setting you enjoy - pin it there. The torque of the rear camber eccentrics will not hold camber against racing slicks and high side loads without some help. I can show pics of how we pin our camber setting if you want.

KenRudd

As an update, I have alignment scheduled with what I consider to be the best shop in the area for this.
Reading the above on DIY Camber and Toe: Although I certainly could measure it, and will probably do so just to keep track of it, actually setting it falls into one of the very few buckets that I am happy to let somebody else do.

And regarding pinning the rear camber, I will do that if I see it shifting ( see self measurement above), but my current DE type driving and tires may not be pushing it hard enough to cause the shift.

mark kibort

carl, im running 335 rear slicks both DOTs and type Rs with no issues (for 15 years) with having to "pin" anything in the rear. in fact, usually "pinning " the rear end ends up with the car being a lot more loose.

as far as temps go, you usually will get hotter on the inside 1/3rd of the tire, no question. a lot depends on the track and how hard you push the car.
generally, a 5 to 10 degree per 1/3rd is what you usually see on the track.

yes, you can measure 1/8 to a 1/6th of an inch. the difference between 0 toe and a half of degree of toe can be the difference between wearing the inside edge faster and and not. generally, it doesnt take more than 1/8" to make a difference. remember, when we trig this out on the tire... toe-wise, thats near .5 degrees each 1/8 inch, so its substantial, AND very easy to check with a bubble level and a ruler for camber! OR, with a magic marker on the ground with a straight edge. before i go to the alignment shop, i check and usually match the pro values within a few %. the only thing i cant do is caster and the rear changes. (better to make sure the rear done on the machine to make sure everything is running straight)

mark kibort

the variance number divided by the width of the rim... INV TAN. real tough stuff.
trig is not that hard and the marks are very accurate because they are drawn against a surface. use spray paint if you want, the edge is the exact position. there is no variance and its VERY repeatable.
on an 18" spread front to rear, you can see major differences from side to side.

try it before you knock it. you obviously have no idea, or you wouldn't suggest you can be off by a "line" or so. again, Ive matched it to the hunter machine and its almost dead on.

and this is about camber and tire wear..... one way to assure you get the best performance and tire wear is by measuring, and this technique is very easy and can give you a pretty good indication of what is going on.

Carl Fausett

There you go. Just keep you eye on it - maybe this: take a tape measure and measure from side of sidewall to inner lip of rear fender. Write it down for both sides.

After an event or two... check again. If the numbers have changed, you may have lost camber. Then have it checked. No change, then there's no problem!

I too ran DOT tires for a long time and never had enough side loading to over-power the Camber eccentric. When I went to race slicks, that when it happened.

mark kibort

again, that's never happened on cars running slicks we run at the track pulling a lot more Gs than you are at the track. could it be some grease or something under your eccentrics?? maybe not tight enough. again, ive run 320 rear slicks for years , camber is still at 2 degrees and hasnt moved since i originally set it at 2 degrees back in 2001. 200 race days! you probably had a bad eccentric bushing on that upper control arm. that thing is pretty robust. i don't think anyone has had an issue with that. also, this is different than "pinning" the 928 rear end which is really more about the toe compliance and movement

mark kibort

again, that's never happened on cars running slicks we run at the track pulling a lot more Gs than you are at the track. could it be some grease or something under your eccentrics?? maybe not tight enough. again, ive run 320 rear slicks for years , camber is still at 2 degrees and hasnt moved since i originally set it at 2 degrees back in 2001. 200 race days! you probably had a bad eccentric bushing on that upper control arm. that thing is pretty robust. i don't think anyone has had an issue with that. also, this is different than "pinning" the 928 rear end which is really more about the toe compliance and movement.

for those playing at home. in order to camber to change, there needs to be forces applied to the rear tire when it is compressing that exceeds the upper control arm. that lever point just cant generate those kind of forces regardless of the tire compound. you might straighen that camber out if you really side into a curb at the track (or street )

dr bob

Part of any alignment procedure is to make sure the pads the car sits on are level at least side-to-side. That's easy to check with a 6' carpenters box level, or a piece of box tubing that can hold whatever level you have. Flip the direction of the level to confirm your readings. Level front to back is less critical, and only needs to be considered in your calculated caster numbers.

Camber uses the same math as the toe. But rather than trying to measure the gap between the top of the wheel and the bubble level, use drill bits as spacers. I have some digital angle gauges that are repeatable to 0.1º, plenty good enough for setting camber. The readings are confirmed with the bubble level and drill bit.

Caster uses the digital angle gauges, calculated from angle measurements at each wheel from 15º right and left steering angle at the wheel. This is simple calculator math, no trig involved. I use plastic shopping bags sprayed inside with Pam under the front wheels to minimize friction when turning and adjusting. The car is rolled fore and aft a fw times after each adjustment to normalize any suspension load remaining, before final check and blessing.

I'm not near the car now to share pics of the procedure and the relatively simple equipment.

Carl Fausett

If you have need for a greater range of adjustment, I can offer two suggestions.

Either line your Camber Eccentric Pockets with our steel liner, here:

http://www.928motorsports.com/parts/...er_pockets.php

or you can install our newest item: Rear Camber Eccentric Bolts where we have moved the ellipse over as far as it can be moved - provides more camber range than was ever before possible. Great for racers and cars with really wide rear tires!

http://www.928motorsports.com/parts/...mber_bolts.php

dr bob

Great stuff Carl! Is there any provision in your products to better lock the camber adjustments? Maybe serations on the eccentrics?


And for folks at home afflicted with lack of adjustment in the other direction, ie: can't get the camber numbers higher (closer to zero negative camber), these adjusters might help particularly on cars that are significantly lower than spec rear ride height.

mark kibort

max camber is near 2.3 or so, even lowered . i think if anyone has had issue of it slipping, they didnt tighten them enough.. there is no where near any forces great enough to move that stuff out of adjsutment, but i do like the quality of the Carl parts. nice work!

Carl Fausett

I thought about that Bob, but for those not using or steel camber pockets, was concerned that serrations might chew up the aluminum too much.

As you know from the WSM, these camber eccentrics are supposed to be torqued to 200 Nm when set. Usually, that's enough. Note the WSM does call for some lube on these eccentrics, but IME, over-lubing can contribute to them rotating in their pockets.

Have tried several ways to pin my camber, and the best by far has been the simplest. I simply drill through the eccentric and tap for a M6 fastener. Then I just put a little loctite blue on the threads and insert it. Has been working very well for us.

The little M6 fastener in shear functions as a dog pin. That, plus the 200 Nm of torque, has been more then enough to keep my Camber adjustments static.

Carl Fausett

I love this anecdote - thanks Fred! Made me smile...

Carl Fausett

This was an excellent discussion about racing alignment. Thanks to all contributors.

Surprised no-one mentions the roll cage. Just throwing it out there. IME, cars with a roll cage will require less Camber, and cars without a roll cage (not a roll bar) will require more because of frame twist.

Just something to keep in mind if you do not have a roll cage and you are about to adopt alignment settings from Kibort or myself who do...

Carl Fausett

...and pinning the Weissach. Another place where I would be cautious when transferring alignment recommendations from car to car.

Both Kibort and I have our Weisach's pinned. So our rear alignment recommendations might be affected if you do not have your Weisach link pinned.