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Discussion Starter #1
I have noticed that Speedparts offer a front and rear strut brace for the 9000.

I am totally ignorant about these components, so would be grateful if anyone could tell me how much difference they make on the 9000 & where they are fitted?

In terms of suspension upgrades, I already have Abbot springs/Koni's/poly bushes, so it appears that these may be one of the next upgrades if they make a worthwhile difference.
 

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theory
stops the shell flexing and so makes a stable platform for the suspension to do its work
Marke is the only one I know that has done both on bubbles ....
 

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Takes up load space by fitting between the tops of the suspension turrets- possibly ok if the seats are up --------but not too good if you want the flat load area.

Alyn
 

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The front one is relatively easy to fit... 3 bolts on each side...



The rear one is a bit different... you have to strip back the carpets, take the top mount of the rear shocks then weld the brackets in place, giving you this end result...



The bolts that hold the rear brace in place can be easily removed as they have a pin arrangement to hold them in place. Thus if you want to carry long flat loads, it's a simple job to take it out.

The front brace made the biggest overall diffrence- it stopped an awful lot of twisting and reduced rattles. I then became aware that the rear was a bit wobbly
. The rear brace has certainly helped sort that out, but the difference is not as noticeable as the front.

On a track, the front makes a big difference. I haven't had the car on a track since I fitted the rear one, but I would expect it to help.
 

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Just remember to jack the car up when fitting each respective brace so as to have the turrets in an unstressed position for fitment

Pete.
 

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Discussion Starter #7
Hmm, the rear one might cause a problem if I want to move fridges etc (could be a market for a quick relase version????), but the front one sounds like a good idea.
 

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Jez, Mark said: The bolts that hold the rear brace in place can be easily removed as they have a pin arrangement to hold them in place. Thus if you want to carry long flat loads, it's a simple job to take it out.

Anyway, you've moved house so you should not be needing to move fridges for a while
 

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I'm looking into having a rear brace made for my c900 (she's a 5-door and that big hole in the back of the car is the biggest problem with regards to torsional stiffness). As it might be a bit much asked of my local Saab shop (they're flexible and helpful when it comes to welding/fabricating stuff ) to come up with a quick-release arrangement, it will probably be permanent and something more akin to what's in an Octavia RS as OE - something like this:


__/


It would be welded at the shock mounts on each side as well as to the boot floor in the middle.

Any feedback on this?

For the front, I have put in the diagonal reinforcement plates between inner fender and rad support from the convertible. For 50-odd euro and ten minutes of work, any improvement -however small- is worth it. As there was about seven months between the last time I drove the car with and without the plates (engine rebuild) don't have back-to-back experience - but she does feel tight and solid on the road, almost spookily so for an eighteen year old bodyshell. Only groans are from the door trims and lower dash areas, mostly when the interior is still cold on the first miles (I live along an old, bumpy road).
 

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Why - should bracing always take place in a straight line between the two points?

As a layman, I would say the Skoda Ocatavia layout not only secures left and right top shock mount locations versus each other, but also in relation to the floor, which should be a good thing?

Or am I badly mistaken here?
 

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From what I can see, what your trying to acheive, is to essentially prevent the top mounts inclining towards each other?

Now the simpliest solution is a straight bar between the 2, preventing them moving.
Your deisgn will reduce this movement considerably, but will it eliminate it?
This will depend on the type/thickness of metal used, perhaps use your design, with a detachable top brace bar, should be simple enough to fabricate.
Couple of clevis pins & R clips will hold top brace nice and tight.

Best of both worlds?
 

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If you are trying to stop two points moving apart a straight brace is the most effective and lightest. In fact, if they only wanted to move apart you could use an even lighter cable, but, of course they will also want to move together as well so a solid bar is needed.

Your suggestion of a U shaped brace would achieve the same if it was stiff enough in bending, but it would need to very stiff and bulky because the relationship between force and deflection would be greatly different between bending in your U shape and direct compression in the straight strut.

The strut will make things a lot stiffer. ( In fact it has the same effect as the steel roof of a saloon in bracing the body vs. a convertible).

However a straight strut brace between the tops of the suspension will form a quadrilateral with the body sides and the floor. This will not be ideal as it can still deform into a parallelogram /diamond shape. For max stiffness you will also need a brace from the top of one strut to the bottom of the other. One will do if it's a bar, or you could make a diagonal cross with cables in tension.

When the bracing deforms as a diamond, the struts will be kept parallel at all times but they may both lean sideways or one side might be higher than the other.
 

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Discussion Starter #14
Originally posted by /john:
[qb]Jez, Mark said:  The bolts that hold the rear brace in place can be easily removed as they have a pin arrangement to hold them in place. Thus if you want to carry long flat loads, it's a simple job to take it out.

Anyway, you've moved house so you should not be needing to move fridges for a while    [/qb][/b]
Oops, missed that bit!
 

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This will not be ideal as it can still deform into a parallelogram /diamond shape[/b]
Which is where you need to hope that the cars designers made sure that the suspension turrets and lower crossmembers were made strong.

You can see how much deflection is allowed in the bodywork and chassis by driving part way off a kerb, so that one wheel is left higher than the other three, now try opening and closing the doors, they are suddenly all a lot stiffer to operate.

When cornering hard it's the same principle, although in different directions, as the inner rear wheel tries to lift the rest of the car is suffering from the same distortions that made the doors hard to open and shut.

Manufactures allow for the twisting of the chassis etc. as part of the suspension design, it's all taken into account.

When we stiffen the suspension etc. I believe the forces are increased through the chassis as there is now less movement allowed by the suspension, the strut brace will therefor help hold the front section of the chassis in it's designed position to help the suspension geometry do it's work properly.

The rear brace will not effect the geometry anywhere near as much as the stresses are mainly further forward, although 'every little helps'

Err...does all this make any sense, it's too late for me to be thinking like this

I think got it right
Skiddins
 

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Yes, Skiddins, I reckon you got it right... what you describe ties in with my real world experience.

The rear brace is definitely a compromise. I'd have like to have use the Abbott one as it is a much better design, effectively placing the bracing point several inches higher than mine (see pic below) but it is not readily removable once fitted.



Having lived with the removable brace, there's only been one occasion that I had to remove it. So I reckon that for most folk, unless you do regularly carry long flat loads, a rear brace, even like the Abbott one, probably has negligible effect on the 9000's load-lugging abilities.
 

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Sadly, as I play in a band, several times a month I have to fold the rear seats down and literaly fill her up completely.

Would fitting the front brace without changing the standard suspension make a reasonable difference?

Skiddins
 

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Originally posted by Skiddins:
Would fitting the front brace without changing the standard suspension make a reasonable difference?[/b]
Yes, but on standard suspension with standard 15" or 16" wheels, I doubt you'd notice it in practice.

Bear in mind that when I said I noticed a big improvment, I'm running 17" wheels, 25% stiffer springs, Konis, and a lot of poly bushes... or in other words I had removed an awful lot of flexibility from the suspension, so more twisting of the body would have been taking place.
 

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im gonna take my carly over to a friend of mine who owns an engineering works.he said it would be really easy to make one using my car as a pattern.much cheeper than paying the £111 ive seen on elk.will let you know how it go,s
 
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