Spreader bar
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Melting Slicks
Joined: May 2001
Posts: 2,812
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From: Gig Harbor Wa
Spreader bar
Why are all the spreader bars adjustable? Wouldn't it be simpler and cheaper to make a solid one than one with heim joints? I think I am going to make a solid one unless someone can give me a good reason why not. Seems like all the Camaro and Mustang shock tower braces are solid. Same idea, right?
Race Director
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From: San Francisco CA
St. Jude Donor '07
I'm thinking they're seeing a lot of forces that don't act down the shaft. In a solid brace, it might buckle something, probably the frame. With heim joints, it'll take an axial load but will keep parts from breaking when flexed in another direction.
Race Director
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From: San Francisco CA
St. Jude Donor '07
Originally Posted by 70 LS1
I thought the whole point was to prevent flexing completely.
Le Mans Master
Joined: Jul 2005
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From: Austin Texas
The Corvette frame has a weakness in that the tops of the shock/spring towers creep togeather gradually over the years. This can be seen when doing a wheel alignment, and there is insufficient adjustment for camber, hence the need for off-set upper shafts. I believe the only loads distributed to the spreader bar are compression.
Instructor
Joined: Mar 2002
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From: Bonney Lake WA
Originally Posted by big_G
This can be seen when doing a wheel alignment.
Scott
Race Director
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From: Waterloo ontario Canada
Originally Posted by 70 LS1
I thought the whole point was to prevent flexing completely.
If you have a fixed bar and you want to add a 1/8th shim for alignment purposes how does the bar accomodate it.
Rod ends in 5/8th from Coleman for the bar are about $8-$10. Two of them won't break you and a bar in the 16-20 inch length is about $12.00 YOU just have to make the brackets.
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Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
This is from a post I did about 2 weeks ago
I finally got around to building a spreader bar. I had a special problem because of the 3 inch blower belt. I had to pull the rad and support to get in there for welding
I ended up making brackets from angle iron that slid over the A arm studs and didn’t have to weld on the car at all.
This is one of the brackets after powder coating.
My car is black, everything is black so things don’t show up that well.
For the cross bar I used 1 inch solid aluminum hex and turned the center down for appearance and left the hex at the ends for a wrench.
I used 5/8th rod ends, one left on the left side of the car and one right with locking nuts.
The bar is only 16 inches long. It is strickly bolt on and required no on car welding.
I finally got around to building a spreader bar. I had a special problem because of the 3 inch blower belt. I had to pull the rad and support to get in there for welding
I ended up making brackets from angle iron that slid over the A arm studs and didn’t have to weld on the car at all.
This is one of the brackets after powder coating.
My car is black, everything is black so things don’t show up that well.
For the cross bar I used 1 inch solid aluminum hex and turned the center down for appearance and left the hex at the ends for a wrench.
I used 5/8th rod ends, one left on the left side of the car and one right with locking nuts.
The bar is only 16 inches long. It is strickly bolt on and required no on car welding.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
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From: Twin Cities Minnesota
The real reason is that the spreader bars sits on the A-Arm over the A-Arm bolts. Without the heim joints how can you adjust the Camber / caster??
You NEED to be able to back it off, reshim, adjust the spreader, measure the camber and repete. Also with caster the A-Arm will not be perpendicular to the spreader, hence the Heim joits. The issue with Norvals design is since the bar is not between the A-Arm bolts he will have to tighen the A-Arm bolt between each adjustment, When the bar is between the bolts you just have to preload the spreader after each adjustment.
Now if you welded a mount to the shock tower it's work great and not need to be adjustable. but most people do't want to weld to their car.
You NEED to be able to back it off, reshim, adjust the spreader, measure the camber and repete. Also with caster the A-Arm will not be perpendicular to the spreader, hence the Heim joits. The issue with Norvals design is since the bar is not between the A-Arm bolts he will have to tighen the A-Arm bolt between each adjustment, When the bar is between the bolts you just have to preload the spreader after each adjustment.
Now if you welded a mount to the shock tower it's work great and not need to be adjustable. but most people do't want to weld to their car.
Last edited by 427V8; Oct 13, 2005 at 09:33 AM.
Team Owner
Joined: Jul 2004
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From: Redondo Beach, California
Originally Posted by big_G
The Corvette frame has a weakness in that the tops of the shock/spring towers creep togeather gradually over the years. This can be seen when doing a wheel alignment, and there is insufficient adjustment for camber, hence the need for off-set upper shafts. I believe the only loads distributed to the spreader bar are compression.
A C2 acquaintance of mine claims he had this problem. He ran out of camber adjustment and had to have a frame shop push the spring towers into their original position. He said the shop used torches to heat the frame crossmember (just below the crank damper) to make bending the frame easier.
Race Director
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From: Waterloo ontario Canada
Originally Posted by 70 LS1
So how far apart should the A-arm mounts be?
I find Coleman has all the parts in stock.
Safety Car
Joined: Oct 1999
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From: NorCal
Originally Posted by norvalwilhelm
Rod ends in 5/8th from Coleman for the bar are about $8-$10. Two of them won't break you and a bar in the 16-20 inch length is about $12.00 YOU just have to make the brackets.
Total cost was about $40.00.
Hans
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
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From: Clearwater FL
Originally Posted by 70 LS1
So how far apart should the A-arm mounts be?
Dan