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  #11  
Old 13th March 2012, 09:27 PM
Not Anumber Not Anumber is offline
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I'll second Mark B's comment. The lower wishbones on my MK Indy bent and broke when the previous owner had the knock which turned it into a Cat C loss. The great thing is there was no structural damage to the chassis as they worked just like crumple zones hence it's not an expensive process to get it back on the road.
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  #12  
Old 14th April 2012, 04:00 PM
Oscar Oscar is offline
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This is very interesting to me; I'm at the stage where I'm looking at wishbone materials.

I was under the impression (probably wrongly) that the wishbones had to be seamless? Is there any risk that the ERW would fail during normal driving/ harsh cornering?

Also, as I wouldn't mind doing track days in the distant future (when I eventually get it finished). Would the use of ERW cause problems here?
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  #13  
Old 14th April 2012, 04:22 PM
MarkB MarkB is offline
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For track use I would use 18swg but for road use I would go up to 16swg or even 14swg...all ERW.
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  #14  
Old 14th April 2012, 06:32 PM
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Talonmotorsport Talonmotorsport is offline
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I would think that CDS / Cold Drawn Seemless tube was specified to stop people using any old length of tube and not knowing what it was for the wishbones. ERW will be fine for the wishbones although I would not go any thinner than 2mm wall top and bottom,don't forget that they are only bolted to 3mm suspension brackets and half of those have 50% material coverage welded to a 1.6mm walled chassis.
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  #15  
Old 15th April 2012, 09:33 AM
robo robo is offline
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Quote:
Originally Posted by Not Anumber View Post
I'll second Mark B's comment. The lower wishbones on my MK Indy bent and broke when the previous owner had the knock which turned it into a Cat C loss. The great thing is there was no structural damage to the chassis as they worked just like crumple zones hence it's not an expensive process to get it back on the road.

I would be horrified if my wishbones broke before it ripped the chassis brackets off that piece of 1.6mm wall thickness box section. I would rather believe that the wishbones were not properly made or welded

Bob
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  #16  
Old 15th April 2012, 11:23 AM
trick-kit trick-kit is offline
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Quote:
Originally Posted by robo View Post
I would be horrified if my wishbones broke before it ripped the chassis brackets off that piece of 1.6mm wall thickness box section. I would rather believe that the wishbones were not properly made or welded

Bob
The wishbones are made to be the sacraficial part of the build, if you ever had an accident (god forbid) they are designed to give before the chassis.

Which would you rather after an accident?

1. Replace one maybe two wishbones at £80 ish

2. Strip down the entire car, replace the £700 chassis (or make repairs to the damaged part) and then rebuild the car.

TK
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  #17  
Old 15th April 2012, 11:27 AM
MarkB MarkB is offline
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Quote:
Originally Posted by robo View Post
I would be horrified if my wishbones broke before it ripped the chassis brackets off that piece of 1.6mm wall thickness box section. I would rather believe that the wishbones were not properly made or welded

Bob
Shows how much you understand cars then!!!
For exmaple: Alloys are used over steel wheels as they break so they don't damage the suspension. And wishbones as TK points out are sacrificial. Better to damage a wheel and a wishbone than wreck a whole chassis.
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  #18  
Old 15th April 2012, 11:30 AM
MarkB MarkB is offline
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If a car like a 7 is shunted the chassis is scrap and should be replaced as you can't repair it properly as it will have bent it, I have seen it first hand and been asked to repair an early Westfield but even though it only had a slight slap at the front the whole thing was out of shape. I turned the job down and the lad bought a new chassis.
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  #19  
Old 15th April 2012, 11:40 AM
robo robo is offline
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Alloy wheels are used because they are lighter and for that reason only ,there is nothing wrong with steel wheels and they are still fitted to many cars. They are not part of some sort of engineered crumple zone. As for the wishbones you may have forgotten they are triangles therefore strong. A bit of 3mm bracket welded to a 1.6mm thick box should give out long before a wishbone period! I would sooner all four wheels were still on my car in a knock over a bent chassis any day as you might be travelling at speed still. Sod the chassis.

I cant think of a single car made that allows its suspension to be ripped of in a knock , most of them just mangle up the subframe and bend things.

Scenario. I am diving down a dual carriageway and drive over a brick, I am now driving down the road with three wheels on my wagon at 70mph thinking great my chassis is still good. Bxllxcks

Totally unconvinced Bob
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Last edited by robo : 15th April 2012 at 12:12 PM.
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  #20  
Old 15th April 2012, 12:30 PM
MarkB MarkB is offline
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Quote:
Originally Posted by robo View Post
Alloy wheels are used because they are lighter and for that reason only ,there is nothing wrong with steel wheels and they are still fitted to many cars. They are not part of some sort of engineered crumple zone. As for the wishbones you may have forgotten they are triangles therefore strong. A bit of 3mm bracket welded to a 1.6mm thick box should give out long before a wishbone period! I would sooner all four wheels were still on my car in a knock over a bent chassis any day as you might be travelling at speed still. Sod the chassis.

I cant think of a single car made that allows its suspension to be ripped of in a knock , most of them just mangle up the subframe and bend things.

Scenario. I am diving down a dual carriageway and drive over a brick, I am now driving down the road with three wheels on my wagon at 70mph thinking great my chassis is still good. Bxllxcks

Totally unconvinced Bob
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