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Thread: Anti Squat and Suspension Tech

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Old 01-03-2007, 03:47 PM   #41
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Quote:
Originally Posted by Cole82
I would think that would have a huge efect on the geometry.
True, but wouldn't it all be dependant on where the IC falls in relation to the CG, and Nuetral line?

Typically, a race car's CG is really low, so their links need to converge at a low point to achieve the results they're looking for.

Typically, a crawler's CG is higher than a really low race car's CG, though the link angles will still be relative to the IC & CG & NL to achieve the results we're looking for.

Point of convergence, relative to the IC & CG.

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Old 01-03-2007, 03:50 PM   #42
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Cole you know what this makes me think of?

A full suspension mountain bike that puts the rear lower pivot inline with the middle chainring. And when you shift into the smallest ring, it'd mechanically pull the rear tire inward, planting it into the ground. Or when you put it into the big ring, you get some squat effect bouncing.
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Old 01-03-2007, 04:18 PM   #43
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Quote:
Originally Posted by Cole82
This four link stuff kills me. I think I'll go back to a torsion truck. I still haven't seen any truck climb as well as a torsion rig.

If it was easy......there'd be girls building the rigs for us. Girls build the easy rigs
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Old 01-03-2007, 04:25 PM   #44
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I know exactly what you are talking about on the FS MTB.

I'm thinking of it as if your bottum rear link is below the center line of the axle. Asuming that is where the up ward torque of the axl is coming from. The higher above that point your link is. the more torque it is putting on the links. So you have more anti squat forrce applied to the suspensiuon the further up your links are mounted. Then you have to make them have less anti squat to get the same leverage as if it was lower on the axles.

I'll draw a picture as that was ?????????


Lets say the yellow links intersect in the same place as the black one. Won't the yellow links have more leverage on the axles making it have antisquat. If so then the 100% nuetral number mena nothing and that's what the suspension calculator bases there design around.
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Last edited by Cole82; 01-03-2007 at 04:30 PM.
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Old 01-03-2007, 04:44 PM   #45
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If the yellow and black links converged at the same points your AS would be the same (with no articulation). The roll center of the axles would be different though, so the axle would articulate along a different path.
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Old 01-03-2007, 05:34 PM   #46
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Timmy's 1.1 buggy does have plenty of seperationon the on the front bars and there is not a 5th link.The upper is above centerline of the rockwell axle as a matter of fact all the bars are above the centerline of the axle.The link setup is double triangulated front and rear and has almost no flex steer.
As far as added stress goes timmy will beat a rig harder than i have ever seen anybody in my life.Every thing on this one is built very stout.The heims are 1 1/8 joints using a 2 inch DOM tubeing for the bars,all mounting points are 1/2 plate that is gusseted in every way possible,the axles are 2 1/2 ton rockwells with chromoly shafts,the trans is a coustom th400,transfer case is a atlas with the biggest input and output shafts they offer and still breaks.The little alum.headed 383 he run year did not make enough so he put a ramjet 502 in this one.
I will get some better pics when it gets back from powder coat and the other parts get back from paint.
To date the buggy has coast timmy about 65,000 with out powder coat and they started on it about 2 months ago so i am sure ther is a few more $ to be spent.
Here is a picture of timmy beating the crap out of a friends rig i will also see if i can dig up some pics of the rig he run last year just so you can see how he will test the link mounts.
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Old 01-03-2007, 06:05 PM   #47
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Here is a link to a short vid of dan on a local trail and let me tell you timmy is way harder on a rig than dan.There is a little foul language in the vid so watch it around the kids.
http://www.fototime.com/ftweb/bin/ft...reenheight=768
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Old 01-03-2007, 10:43 PM   #48
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I did some testing with the unsymmetrical link suspension. I switched out springs so it would have such bad torque twist it lifted the one front tire.
I moved the rear suspension so it has one top link below the servo mount and one above. Doing this eliminated the torque twist. I mean Zero flat as can be.
In theroy you should be able to run a softer spring and still not get torque twist.
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Old 01-04-2007, 08:57 PM   #49
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Quote:
Originally Posted by Cole82
I did some testing with the unsymmetrical link suspension. I switched out springs so it would have such bad torque twist it lifted the one front tire.
I moved the rear suspension so it has one top link below the servo mount and one above. Doing this eliminated the torque twist. I mean Zero flat as can be.
In theroy you should be able to run a softer spring and still not get torque twist.
So,with that set up exactly but with it back symetrical(both upper links on the same plain)you had a ton of torque twist. Put the uppers on a different plain and the torque twist went away?......completely?

What shafts are you running? They look like miniature Revo shafts. Do they have an index spline?
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Old 01-04-2007, 09:02 PM   #50
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Quote:
Originally Posted by raptorman57
So,with that set up exactly but with it back symetrical(both upper links on the same plain)you had a ton of torque twist. Put the uppers on a different plain and the torque twist went away?......completely?

What shafts are you running? They look like miniature Revo shafts. Do they have an index spline?
exactly

They are revo shafts. They have 8 or so ridges evenly spaced apart.
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Old 01-04-2007, 09:03 PM   #51
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Cole, aren't those Jato shafts?
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Old 01-04-2007, 09:08 PM   #52
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Woops sorry you right.
I'm really tired at the moment.
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Old 01-04-2007, 09:21 PM   #53
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I was gonna say,they look awefully small to be Revo's. So,anyway you slide together they slide with ease?

Revo's will go together anyway you like. They have an index spline,can't really tell which one it is. If you don't assemble the shaft on the right index,they are harder to slide together.
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Old 01-04-2007, 09:25 PM   #54
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Man you made me get the allen wrench out to take the shaft out and see.
There is NO indexing.
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Old 01-04-2007, 09:37 PM   #55
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Cole, pretty sure there is a notch on the Jato shafts as well. Just keep the ears lined up, and they will work fine. If you clock them, you will notice they are a little tighter.
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Old 01-04-2007, 10:06 PM   #56
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Quote:
Originally Posted by Cole82
Man you made me get the allen wrench out to take the shaft out and see.
There is NO indexing.

Sorry bud,didn't mean to aggravate ya I'd like to find a shaft thats smaller than the Revo's,dang near as strong and with no index(for a dig set up )
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Old 01-05-2007, 06:18 AM   #57
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Quote:
Originally Posted by raptorman57
Sorry bud,didn't mean to aggravate ya I'd like to find a shaft thats smaller than the Revo's,dang near as strong and with no index(for a dig set up )
I think they are weaker than pede shafts. The plastic is softer, so the holes around the x pin round out fast.

Etype R is right.
Allright afdter checking it out this morning when I'm not a sleep at the wheel. It has 180deg Indexing. The yokes allways line up with each other.

Last edited by Cole82; 01-05-2007 at 06:22 AM.
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Old 01-05-2007, 04:00 PM   #58
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Quote:
Originally Posted by raptorman57
Sorry bud,didn't mean to aggravate ya I'd like to find a shaft thats smaller than the Revo's,dang near as strong and with no index(for a dig set up )
The reason for the indexing is to keep the ujoints in phase. Might not be so important at crawl speeds though.
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Old 01-05-2007, 06:29 PM   #59
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Quote:
Originally Posted by Cole82
I did some testing with the unsymmetrical link suspension. I switched out springs so it would have such bad torque twist it lifted the one front tire.
I moved the rear suspension so it has one top link below the servo mount and one above. Doing this eliminated the torque twist. I mean Zero flat as can be.
In theroy you should be able to run a softer spring and still not get torque twist.
When I put my dig in I had to increase the vertical separation of the rear chassis mounting points to clear my dig linkage. After this I noticed the right front tire lifting alot more than before.

I'm going to experiment with this asymetrical setup to see if I can fix my torque lift. Thanks for the great info guys.
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Old 01-06-2007, 03:26 PM   #60
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To show what good suspension tuning can do. Before it was tuned, this 65deg incline was inpossible. Couldn't even ramp up it. Now after several hours of theory and testing. I can both crawl up this and ramp up it nothing else on the truck has changed just link placment.
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Last edited by Cole82; 01-06-2007 at 03:34 PM.
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