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My new knuckle setup on my FD!

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Old Jan 25, 2013 | 06:55 PM
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My new knuckle setup on my FD!

redesigned some knuckles and i love the out come!!!

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Old Jan 25, 2013 | 07:20 PM
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fds are awesome with like 48degrees of angle. whats this at? I bet thats going to blow minds.

Also those tires are awesome in the rear.
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Old Jan 25, 2013 | 11:21 PM
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That's about 75-80 degreas
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Old Jan 25, 2013 | 11:35 PM
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hows your inner clearance on the LCA?
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Old Jan 26, 2013 | 12:28 AM
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I fixes the problem where the caliper hits the lca with my knuckles And my wheels hit the frame or they would turn more!!
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Old Jan 26, 2013 | 11:50 AM
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your calipers on?
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Old Jan 26, 2013 | 12:12 PM
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Lol yes they are on! That picture is fully bolted up and only one inch higher than ride height!
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Old Jan 26, 2013 | 01:18 PM
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im still waiting to see if any one makes a LCA that allows for more angle/clearance
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Old Jan 26, 2013 | 09:37 PM
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Measure it up! Looks good
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Old Jan 26, 2013 | 09:45 PM
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Well with my knuckles you don't need aftermarket lcas! And if you want more angle you need to modify the knuckles any how so why even bother with them?
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Old Jan 27, 2013 | 08:56 AM
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From: gloucester
im planning to make new lca's soon.
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Old Jan 27, 2013 | 09:08 AM
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Thats some mad angle! What did you do to them to clear the lca?
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Old Feb 5, 2013 | 08:10 AM
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From: GA
I fixed the roll center by dropping down the lower balljoint on the knuckle by one inch and shortened the tie rod pickup and turned it in!
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Old Feb 5, 2013 | 03:33 PM
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I'd really like to see the actual knuckle if you have a pic of them..
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Old Feb 10, 2013 | 11:18 PM
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more pics please!
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Old Feb 11, 2013 | 05:17 PM
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It's really very cool!!!!
More pics please!!!)))
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Old Mar 11, 2013 | 11:15 AM
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From: Quartz Hill
updates? knuckle pics?
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Old Mar 14, 2013 | 09:51 AM
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soon guys! i have been overly busy down at Pettit Racing rebuilding the 20b!
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Old Mar 14, 2013 | 11:00 AM
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Well here is my secret!
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Old Mar 14, 2013 | 05:14 PM
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Originally Posted by campo
Well here is my secret!
How do you think the strength compares to stock? It is hard to see the material thickness in the photo with the paint on. Looks like chopped and turned... Did you V groove and fill with weld?
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Old Mar 14, 2013 | 06:48 PM
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yes its v-grooved! i have an old buz box welder that will melt 5 inch thick steal so i know they wont break. the steal plate i used for the drop and bracing is quarter inch.
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Old Mar 15, 2013 | 07:05 AM
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Did you get a funky/intense camber curve, since your upper and lower arms are further angled apart than they were before? Or do you not really care about that kind of stuff?
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Old Mar 15, 2013 | 10:33 AM
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You aren't going to leave that huge spacer/bolt in single shear on the tie rod end... right?

Melt 5 inch thick steel? Not with 220V and house current. And not that you would ever need to. I'll take your word that your welder has enough juice for a multipass on 1" cast steel/iron penetrating .25" at a time though.
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Old Mar 15, 2013 | 11:31 AM
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From: GA
Originally Posted by mikerbike
Did you get a funky/intense camber curve, since your upper and lower arms are further angled apart than they were before? Or do you not really care about that kind of stuff?
the straight line driving has intense neg camber but at full lock the tires have full contact leading wheel and trailing wheel like i wanted.

Originally Posted by RogueFab
You aren't going to leave that huge spacer/bolt in single shear on the tie rod end... right?

Melt 5 inch thick steel? Not with 220V and house current. And not that you would ever need to. I'll take your word that your welder has enough juice for a multipass on 1" cast steel/iron penetrating .25" at a time though.
No im not gonna leave them like that, even though they are all grade 10. it was just a mockup i made but im going to drill out the knuckles and put in copper bushings so there is no taper and then i just replace the copper bushing over time when they wear down.

and it wont melt 5" on a quick pass but its a 50+ year old welder and i can melt these knuckles to a pile of scrap if i wanted. its intense. i can take a video of it when i get back from vacation if you'd like
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Old Mar 16, 2013 | 10:26 AM
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Originally Posted by campo
the straight line driving has intense neg camber but at full lock the tires have full contact leading wheel and trailing wheel like i wanted.



No im not gonna leave them like that, even though they are all grade 10. it was just a mockup i made but im going to drill out the knuckles and put in copper bushings so there is no taper and then i just replace the copper bushing over time when they wear down.

and it wont melt 5" on a quick pass but its a 50+ year old welder and i can melt these knuckles to a pile of scrap if i wanted. its intense. i can take a video of it when i get back from vacation if you'd like
My concern isn't the hardware, it is the Z distance from the knuckle casting to the point where the heim is mounted. Your stress in that pin is much more significant from bending load than from shear, and your bending load is proportional to the moment arm length (Z/vertical dist). Furthermore, your linear steering force required is inversely proportional to the Y/forward distance from your knuckle pivot axis to the tie rod hole. Without taking measurements, it looks like you cut about 1/3 of steering moment arm off, and tripled the Z distance. With those numbers, you will have more than 450% of the load in that pin that an OEM setup has. If you want to see a free body diagram or more engineering analysis, let me know.

One other drawback will be deflection in that long bolt (or any other long hardware you use). With the long moment arm and high loading, you will see some serious movement at the heim before the tire moves (which will of course be worse with the engine installed and when the car stopped).

You did an amazing job cranking a ton of steering travel out of that setup, and I am only posting this so that I can alert you of what in my opinion is a safety issue. I am glad you are innovating, and I would love to see this thing drifted at steering lock with this setup! Just don't want to see it break and harm anyone

Thanks for considering this. If you want to take some measurements I can measure my OEM stuff and do a more detailed analysis for you. I'm a mechanical engineer with a background from industry that includes FEA and other structural analysis, and my business is designing metalworking tools with Rogue Fabricaion.
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