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> Corner Balancing a Twisted Tub ..., Adventures in Weight-Distribution Land ...
Dave-O
post Apr 23 2006, 01:33 PM
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QUOTE
Ghetto corner balance. It actually worked pretty well. Scales went up to 360+ lbs even though they were only rated for 300 lbs. $6 per scale on sale. (IMG:style_emoticons/default/wink.gif)


That looks like a good idea for a corner blance on the cheap. How do you take into account for the motion of the suspension while the car is being lowered onto the scales? Does that bar slide easily on the scales?
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SirAndy
post Apr 23 2006, 01:52 PM
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QUOTE(Aaron Cox @ Apr 23 2006, 11:41 AM) *

whats it run to straighten a tub on a cellete fixture?


your price or mine? (IMG:style_emoticons/default/biggrin.gif)

let me just say this, if i had to pay full shop hours ...
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Dr. Roger
post Apr 23 2006, 01:54 PM
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Ok, I'll be the dingleberry to ask a dumb question....

If you lowered the LF and LR suspensions exactly 1" wouldn't you have almost identical weight numbers and a more level car?

Let the critisizms begin.... LOL....


Roger
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SirAndy
post Apr 23 2006, 01:54 PM
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QUOTE(Dave-O @ Apr 23 2006, 12:33 PM) *

How do you take into account for the motion of the suspension while the car is being lowered onto the scales? Does that bar slide easily on the scales?


easy is not the word i would use but yes, we made sure everything was perfectly centered once the car sat on the scales.
we centered the bar on the scales, then centered the scales & bar under the tire, then moved the scales out/in along the bar until they both read the same.

(IMG:style_emoticons/default/smile.gif) Andy
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SirAndy
post Apr 23 2006, 02:00 PM
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QUOTE(Dr. Roger @ Apr 23 2006, 12:54 PM) *

If you lowered the LF and LR suspensions exactly 1" wouldn't you have almost identical weight numbers and a more level car?

no.

it's not that easy at all. the car doesn't behave like that. two wheels in the diagonal will always form a plane on which the car "pivots".
so, it's either LF/RR or RF/LR and the car will pivot along that diagonal.
the trick is to get the other two wheels in a position where all 4 are in a plane and there's no pivoting going on at all.
and the *really* tricky part is to find that plane on a ride-height and front/rear balance that is close to where you want it to be.

this is a *very* tedious process because once you get close to all 4 wheels in one plane, even minute changes can have a big impact.

(IMG:style_emoticons/default/smash.gif) Andy

PS: if i did what you're suggesting i *would* have a more leveled car, BUT the corner weights would be completely off!
read my first posts in this thread. that's exactly what i had when i started. car level. handled like shit. corner weights were waaaaaaay off.
remeber, the tub is bent.
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Dr. Roger
post Apr 23 2006, 02:07 PM
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i understand planes and pivots.

so, hypothetically speaking, if your 4 wheels are now in a plane, won't you still have a plane if both the wheels on the left side are lowered thesame amount?
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SirAndy
post Apr 23 2006, 02:19 PM
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QUOTE(Dr. Roger @ Apr 23 2006, 01:07 PM) *

i understand planes and pivots.

so, hypothetically speaking, if your 4 wheels are now in a plane, won't you still have a plane if both the wheels on the left side are lowered thesame amount?


yes, the *body* would be in a plane, but *not* the corner weights ...

i told you it isn't that easy ...
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SirAndy
post Apr 23 2006, 02:26 PM
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QUOTE(SirAndy @ Apr 23 2006, 01:19 PM) *

yes, the *body* would be in a plane, but *not* the corner weights ...

to quote myself ...


here is what happens if i did that, lowering both the drivers front and rear. yes, the car would look more leved, BUT what would happen weight wise is that i would now have 3 (three) wheels form a plane, DF/DR/PR and the pass. front wheel would "hang" in the air with almost NO weight on it whatsoever.

this is *exactly* what we measured when we first set the car down on the scales!

i had the car leveled (same ride height on all 4 corners) but i always felt that in left hand corners, the pass. front wanted to move out on me (no grip).
when we measured the weight for the first time, the pass. front had almost no weight on it at all and the drivers rear was way heavier than any of the other corners.
basically, the car was sitting on the drivers rear corner with the drivers front and the pass rear forming a 3 corner plane and the pass front floating in the air.

but the car looked perfectly level. just handled like shit (doh!)

remember, the tub is bent ...
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Joe Bob
post Apr 23 2006, 02:34 PM
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Have you asked Yeaman what it would cost to untwist it?

BTW...you ever sell those long studs you had in yer signature?
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SirAndy
post Apr 23 2006, 02:37 PM
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QUOTE((*)(*) @ Apr 23 2006, 01:34 PM) *

Have you asked Yeaman what it would cost to untwist it?

BTW...you ever sell those long studs you had in yer signature?

yes and yes. sold the studs and scott yeaman is the only one i know with a celette bench AND experience in pulling 914s ...

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Joe Bob
post Apr 23 2006, 02:48 PM
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So what did he say it would cost to pull it out right?
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Aaron Cox
post Apr 23 2006, 02:54 PM
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QUOTE((*)(*) @ Apr 23 2006, 01:48 PM) *

So what did he say it would cost to pull it out right?



guessing 2 large
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SirAndy
post Apr 23 2006, 03:02 PM
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QUOTE((*)(*) @ Apr 23 2006, 01:48 PM) *

So what did he say it would cost to pull it out right?

aaron is in the ballpark. doing it on normal shop hours is *expensive*. besides the need for an experienced operator, it's a time consuming process and time is money ...

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Joe Bob
post Apr 23 2006, 03:57 PM
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Well as good tubs are getting more expensive. It may be worth it sometime soon.

BTW....if we ever have a WCC 07, I have a set of scales I'll bring and we can do a corner balance clinic. They are used for balancing heavy computers and I can "borrow" them pretty much any weekend.....
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Wild 6
post Apr 23 2006, 04:40 PM
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Andy,
Reset your ride heights and this time if you adjust the right front lower, adjust the left front higher. Same with the rear. All adjustments have to be made in tandem - this keeps the ride height level.
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SirAndy
post Apr 23 2006, 08:38 PM
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QUOTE(Wild 6 @ Apr 23 2006, 03:40 PM) *

this keeps the ride height level.

except .... if you have a twisted tub ...

guys, there is *NO* way to get this car Level AND Balanced at the same time ...
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J P Stein
post Apr 23 2006, 08:51 PM
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We (Britian & I) just did mine. It was damn close to start out.
We lowered the drivers rear about 3 turns on the sleeve and bingo.
It took longer to set it on level scales that it did to balance it.

Raising or lowering any corner effects the other 3 weight-wise.
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Borderline
post Apr 23 2006, 08:58 PM
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What did you do with the rear sway bar? IIRC it doesn't have adjustable links. If you just re-connected it, then you would preload the bar one way or another and that would change your corner weights. (IMG:style_emoticons/default/huh.gif)
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Trekkor
post Apr 23 2006, 09:05 PM
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Well if everybody is doing corner balances now, sign me up. (IMG:style_emoticons/default/boldblue.gif)

KT
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SirAndy
post Apr 23 2006, 09:13 PM
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QUOTE(Borderline @ Apr 23 2006, 07:58 PM) *

What did you do with the rear sway bar? IIRC it doesn't have adjustable links. If you just re-connected it, then you would preload the bar one way or another and that would change your corner weights. (IMG:style_emoticons/default/huh.gif)

good point. both swaybars were disconnected during the balance act.
i did reconnect the rear bar afterwards, i'm sure it shifts some weight around as it has to be under preload, the way the tub is bent.

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