dave blissett
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| posted on 11/8/02 at 08:40 PM |
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wish bone lengths
i am buliding a locost with a siera back end
ie torque tube this will have the standard half shafts
the chasis is a mcsorley 442
what center distance should i have for the front wish bone i will be ussing the siera stub axels 
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interestedparty
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| posted on 12/8/02 at 07:39 AM |
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When I saw this one at 23 views and no replies I thought I am going to have a go at this one, but now I've read the question I am not so sure.
All I can do is say what I would do, and that is I would buy a set of wishbones from MK and get them to shorten the Sierra rack to suit.
The rack is actually the main problem here- in the straight ahead position the inner balljoints on the rack need to be in a line between the lower and
upper wishbone pivots, in order to avoid bumpsteer. The position of the wishbone pivots is defined by the width of the chassis. After that the length
of the wishbones sets the front track. The front track is often more or less the same as the rear, but doesn't need to be. If you want the front and
rear track to be the same then as long as the trackrod ends can reach the steering arms (some people including MK use extenders for this, see cover of
March 2002 Which Kit) then all is well. I would use the standard length wishbones and not worry about the track difference.
In the end it is of course your choice but the only definite thing is if you use a sierra rack in a standard width (at the front) chassis then it will
need shortening.
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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bob
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| posted on 12/8/02 at 08:34 AM |
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When i can borrow another digi-cam for a minute,i'll put some more pics of shortened rack and extenders on my photo archive.
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jbmcsorley
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| posted on 12/8/02 at 09:30 PM |
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steering rack width is an issue... but it sounds like your concern is the track width.
Measure up the sierra rear end from tire center to tire center. Imagine the front tires at the same width (assuming you want constant track width
front to rear) and figure out where the lower ball joint will sit with the front wheels mounted the uprights, etc.
The wishbone length will be from the lower bracket center to the lower ball joint center. You should be able to stretch the book design lower
wishbone accordingly. The upper wishbone is a whole different story... now you're getting into independent suspension theory and design.
I wish I could help more with the suspension points on the 442 chassis but I just haven't had time of late... and it differs for every situation.
Cheers,
-Jim M.
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James
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| posted on 13/8/02 at 10:11 AM |
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quote:
The wishbone length will be from the lower bracket center to the lower ball joint center. You should be able to stretch the book design lower
wishbone accordingly. The upper wishbone is a whole different story... now you're getting into independent suspension theory and design.
Cheers,
-Jim M.
So I take it it's not possible/wise just to extend both upper and lower wishbones by the same amount? I assumed that if you change them both then the
upper and lower balljoints will still 'point' at each other just they'll be futher away from the chassis. I was hoping to gain an inch or so each
side by this method.
Cheers,
James
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Alan B
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| posted on 13/8/02 at 12:45 PM |
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James,
Although maybe not ideal I'm sure that approach would work. The suspension behaviour would be similar, but slightly different. Could even be better
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