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Camber questions

Posted by MarkHille 
MarkHille
Mark Hille
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Camber questions
July 15, 2016 08:30AM
This may have already been answered on hear but I couldn't find it.

Why is it that in the Ford Motorsports manuals for the:

Escort rs 2000
Sierra 4x4 group N
Escort wrc
Escort Gpa

all call out positive camber of 2-3 degrees? The only place they call out negative camber is for the Sierra 4x4 group A of -2 - -3 degrees. I thought changing the positive camber found on the Merkurs to negative camber was supposed to be life altering. Any input?
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NoCoast
Grant Hughes
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Re: Camber questions
July 15, 2016 10:10AM
They were too lazy to print the negative sign? Typo.

With modern gravel tires you don't need that much camber anymore. I find around 1.5 degree to be pretty awesome.



Grant Hughes
http://rally.build
Denver, CO
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MarkHille
Mark Hille
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Re: Camber questions
July 15, 2016 11:23AM
Quote
NoCoast
They were too lazy to print the negative sign? Typo.

I was thinking maybe they meant negative camber but in the Sierra 4x4 manual the group A and the group N are in the same chart and one has "-2*" for group A and the next column over "2*" for group N.

Is that 1.5 positive or negative?
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john vanlandingham
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Re: Camber questions
July 15, 2016 12:58PM
Quote
MarkHille
Quote
NoCoast
They were too lazy to print the negative sign? Typo.

I was thinking maybe they meant negative camber but in the Sierra 4x4 manual the group A and the group N are in the same chart and one has "-2*" for group A and the next column over "2*" for group N.

Is that 1.5 positive or negative?

Neg..They made---and I have some----bottom tubes with the pokey-in part offset to do more neg..
But it should be stressed thats neg at the static right height using these longer overall length
struts..


Quote

Escort rs 2000
Sierra 4x4 group N
Escort wrc
Escort Gpa

all call out positive camber of 2-3 degrees?

No they mean neg, probably just sloppy copying..



John Vanlandingham
Sleezattle, WA, USA

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Robert Culbertson
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Re: Camber questions
July 15, 2016 01:47PM
On Dave's xratty, we found that zero camber or slightly positive(at ride height) gave the best grip and tire wear.
The stock xratty rear suspension has crazy negative camber gain and toe out as it goes into bump. So as the suspension compresses, you loose grip and the rear starts to get loose as the tires point is different directions. E30s have a similar issue as well.



Edited 1 time(s). Last edit at 07/15/2016 01:57PM by Robert Culbertson.
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john vanlandingham
John Vanlandingham
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Re: Camber questions
July 15, 2016 03:30PM
Quote
Robert Culbertson
On Dave's xratty, we found that zero camber or slightly positive(at ride height) gave the best grip and tire wear.
The stock xratty rear suspension has crazy negative camber gain and toe out as it goes into bump. So as the suspension compresses, you loose grip and the rear starts to get loose as the tires point is different directions. E30s have a similar issue as well.

Except even on the E30 the camber gain and toe IN gain is actually minimal when stroking the suspension full stroke...

It is endlessly repeated it as "crazy" camber gain and the hilarious thing is that a huge portion of the guys making these way over the top claims are Otter=exers who spring their cars to the point their suspension barely moves, --just like the idiot Xratty otter-exerz---(for example recommending for street use springs over twice the rate Ford used on a WRC TARMAC car...this on a stock car with no stitch welding, no integrated cage, no systematic strengthening...OH yeah I am going to listen to a cunt like those morons and repeat their shit... You can, because you live in a different world than I do, but don't be surprised if I dispute your bullshit.)

The real world thing is ALL suspension goes in arcs, the question becomes what is the AVERAGE position of the suspension, and average movement and in the real world, is the change noticable, and significant and worth spending time worrying or money fixing it...( ie "did somebody or lots of somebodys go waaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyy faster than me with this set up??? How did they do it if this kid says its "waaaaay crazy" whatever?"winking smiley

Way more important things to blabber about than bringing this pooor innocent forum down to the level of auto-cross washer wimmin type gossip.



John Vanlandingham
Sleezattle, WA, USA

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CALL +1 206 431-9696
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Robert Culbertson
Robert Culbertson
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Re: Camber questions
July 15, 2016 04:56PM
I definitely should not have used the term "stock" when talking about the xratty geometry, my mistake there.
I should have mentioned that the custom beam on that car had all sorts of alignment issues (as did the one that Gobright installed on another xratty). With the adjusters maxed out, there was a minimum of -2deg camber and at least a 0.5deg toe out per side.

When cycling the suspension on an alignment table, we saw that the rear initially toes out until the axle centerline rises above the pivot of the trailing arm... then it starts to go toe in. Dave's car was sitting around 3-4 degrees of negative camber at bump. That's not very good for grip... there's a picture somewhere of a rear tire after Idaho last year with 1/4in or more of tread on the outside due to the camber of that car. There's also a good photo from Big White where the rear end has a large amount of negative camber.

After moving the inner pivot point up about 3/8in, the camber was set as close to zero as was the toe. The results: more stable, more grip, less tire wear.... Maybe we're doing something wrong... I don't know?!?!
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MarkHille
Mark Hille
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Re: Camber questions
July 15, 2016 08:43PM
I wouldn't consider mine to be even remotely stable on gravel at speed in a straight line. Could just be me. Seeing how I have to adjust the front to something I was hoping to get it in the ballpark of "the easiest to drive" setting. I appreciate all of the input and I think my original question has been answered and I'm heading in the right direction. It should get done tomorrow. Thanks guys!
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john vanlandingham
John Vanlandingham
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Re: Camber questions
July 16, 2016 12:56AM
Quote
MarkHille
I wouldn't consider mine to be even remotely stable on gravel at speed in a straight line. Could just be me. Seeing how I have to adjust the front to something I was hoping to get it in the ballpark of "the easiest to drive" setting. I appreciate all of the input and I think my original question has been answered and I'm heading in the right direction. It should get done tomorrow. Thanks guys!

Then something is up..I've drive stock street cars at 70-80 on gravel and they were nice and stable..
My little old Saab is stable to 105 mph.. 1mm toe in, 4 degrees castor, ~~ zero camber to a smidge neg..

You sure all the wheels are pointing ahead? No toe out in rear? No toe out in front?
On Xratty anti-sway bar there's a shoulder and a big washer..I always put at least one extra washer kinda cupping with the one, and this shoves the arm a wee bit forward and that gives a bit more castor...With low castor the cars are wonky.



John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.
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MarkHille
Mark Hille
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Location: The hills of CT
Join Date: 10/04/2011
Age: Settling Down
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Rally Car:
I have two crap boxes


Re: Camber questions
July 16, 2016 05:14AM
Quote
john vanlandingham
Quote
MarkHille
I wouldn't consider mine to be even remotely stable on gravel at speed in a straight line. Could just be me. Seeing how I have to adjust the front to something I was hoping to get it in the ballpark of "the easiest to drive" setting. I appreciate all of the input and I think my original question has been answered and I'm heading in the right direction. It should get done tomorrow. Thanks guys!

Then something is up..I've drive stock street cars at 70-80 on gravel and they were nice and stable..
My little old Saab is stable to 105 mph.. 1mm toe in, 4 degrees castor, ~~ zero camber to a smidge neg..

You sure all the wheels are pointing ahead? No toe out in rear? No toe out in front?
On Xratty anti-sway bar there's a shoulder and a big washer..I always put at least one extra washer kinda cupping with the one, and this shoves the arm a wee bit forward and that gives a bit more castor...With low castor the cars are wonky.

Could have been the castor or maybe a bent rear beam. I'll check today if I have time. I have the medcroft adjustable arms installed so I'll be sure to aim for 3-4 degrees castor.
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MarkHille
Mark Hille
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Location: The hills of CT
Join Date: 10/04/2011
Age: Settling Down
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Rally Car:
I have two crap boxes


Re: Camber questions
July 16, 2016 03:15PM
I don't have rally tires on it at the moment so ride height isn't perfect but it's close. Rear beam ended up having 2-3mm toe in with a hair of negative camber. The front ended up being around:
castor +3.5
Camber -.5
Toe 2-3mm in
I'll give it a go with these setting and change before the next rally as needed....if I have time.
Thanks for all the input.
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FunctionAuto
Tyler Patik
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Re: Camber questions
October 25, 2016 01:08AM
Hey john you inbox is full.

So the struts I got from you for my subaru oh-so-long ago won't allow me negative camber, much less 0* camber in the front. I don't want anything crazy but I'm sure the positive camber isn't helping my turning which in turn isn't helping my tire wear. My car is coming apart here shortly to go through for next year could I send you the front struts or just the lower portions to fix that issue and how much would it cost me? The rear seem fine albeit a little close to the tires, I have about 5mm of clearance with my good wheels/205 width tires.
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