Rear body brace

[Bodge]

Since fitting the excellent Weitec coilovers, I've been pushing the car a lot harder around the corners, and loving it! But now I'm noticing the rear seats knocking more as I turn tightly uphill, through hairpins on mountain-style roads for example. Which indicates to me that the body is twisting more. It would only do it on rare occasions before, when taking very steep uphill hairpins (when body is under maximum twist I guess).

So I'm thinking I should try and stiffen the rear body up a bit..... What do you think?

The only rear brace I've found is this one: http://www.wiechers-sport.de/index.php?option=com_content&view=article&id=20&Itemid=121

54 Euros for an ally one seems good, so I'm interested. Just wondering how they attach, as obviously the octy has no rear strut towers. Does anyone have any ideas or experience of rear braces, as it's not something I've ever fitted to a car before. I could modify the existing braces, but I'd rather get something off the shelf, and I'm not really ready for a rear cage yet!

Thanks in advance for any info/advice guys

[countryboyhaha]

Do u have a rear arb as when i fitted mine i noticed the rear was flexing a lot less.

[Bodge]

Do u have a rear arb as when i fitted mine i noticed the rear was flexing a lot less.

Nope not got one yet, but it's on the list! I really like how it handles now (I always say that!)! I'm not really feeling that much understeer, and I actually had the back hanging out a couple of times over the weekend, so I'm pretty pleased with the Weitecs.

Cheers for the tip though

[chicken_eyebrow]

Yep the RARB makes the rear a lot stiffer

Had a go in another members car we took to the Ring this weekend, it's had a Whiteline ARB for the last 2 weeks and we got a garage in Nurburg village to fit Weitecs while we were out there.

It was amazing on the hairpins between the track and the Centerparcs, the rear is very firm but I think the front is now feeling the strain more and the knackered old front ARB might need replacing

[Oet]

Bodge,

the braces i have seen for golfs and octavias mount inner rear arch to inner rear arch if that makes sens and they were welded in. I think with a bit of inginuity you could make something to bolt above the 2 eisting rear braces at a 90deg angle to the boot floor.

Dude you NEED a rear arb!!!

[iep]

In terms of preventing body shell twisting, the rarb will actually make this worse (the same twisting load is applied to the car under cornering but now the rear axle absorbs less of it so the additional stress has to go somewhere).

Obviously the body will twist very little compared to the original rear axle so fitting the rarb stiffens up the car in terms of handling but it causes additional twisting of the body shell instead.

The VRS (at least in hatchback form) comes with the nicely set up supports in the rear of the car. These are triangular so essentially prevent the wheel arches from bending towards or away from the floor of the car. Since the tringle is the strongest possible shape, these are the best way to do this.

The strut you pictured will do very little (if anything) to solve your issue since under cornering, one wheel arch will try to fold away from the floor while the other will fold towards it (obviously only by a couple of mills). Putting a strut between these won't do much to prevent that since the rectangle it forms will simple become a paralleogram under load.

Hope that makes sense.

ip

[iep]

On a related note. Does anyone know if the triangular stuts in the hatchback can be fitted to the estate (without too much modding)? The floor panel and wheel arches have the same part number for both cars so mounting points might be present in both types of car.

iep

[rsorion]

In terms of preventing body shell twisting, the rarb will actually make this worse (the same twisting load is applied to the car under cornering but now the rear axle absorbs less of it so the additional stress has to go somewhere).

Obviously the body will twist very little compared to the original rear axle so fitting the rarb stiffens up the car in terms of handling but it causes additional twisting of the body shell instead.

The VRS (at least in hatchback form) comes with the nicely set up supports in the rear of the car. These are triangular so essentially prevent the wheel arches from bending towards or away from the floor of the car. Since the tringle is the strongest possible shape, these are the best way to do this.

The strut you pictured will do very little (if anything) to solve your issue since under cornering, one wheel arch will try to fold away from the floor while the other will fold towards it (obviously only by a couple of mills). Putting a strut between these won't do much to prevent that since the rectangle it forms will simple become a paralleogram under load.

Hope that makes sense.

ip

never thought of it in that way (triangle) i have been planning a bar to go straight across and fix to the holes that are already there. My redesign my project.

[Oet]

nice technical answer Iep!!!

I cant remember if my 4x4 estate had the mountings there, however the bars have 2 bolts either end and the bolt goes into a threaded body in the bodywork, you could bypass this im sure if not present by using decent nuts and bolts and drilling a few holes in the right place

So any suggestions as to how to increase rigidity?

As i dont think im allowed a 6 point cage:mad:

[jaymd]

Andy funny you should mention this,as i have been thinking of something similar.

A company called yarrowsport did make one for the mk4 golf

VWvortex Forums: Group Buy: Mk4 Golf/Jetta Yarrowsport rear stress bar

but i'm thinking more along the lines of an adjustable one that can be taken out even.

Go and get a RARB.

[jaymd]

nice technical answer Iep!!!

I cant remember if my 4x4 estate had the mountings there, however the bars have 2 bolts either end and the bolt goes into a threaded body in the bodywork, you could bypass this im sure if not present by using decent nuts and bolts and drilling a few holes in the right place

So any suggestions as to how to increase rigidity?

As i dont think im allowed a 6 point cage:mad:

Does anyone do a roll cage for the Octavia as i may be allowed one next year.

[banditbarron]

In this months Performance Vw there is a golf with a fancy rear strut brace. Worth a look.

[Bodge]

Dude you NEED a rear arb!!!

I know I know!! Now I have a taste for good handling, it's where my money's going.....

[Bodge]

In terms of preventing body shell twisting, the rarb will actually make this worse (the same twisting load is applied to the car under cornering but now the rear axle absorbs less of it so the additional stress has to go somewhere).

That's what I thought, makes sense to me. Cheers for the clarification

I know what you mean about the nice triangulation that the current braces use, but I was just after something a bit stiffer maybe. Obviously the Skoda engineers had practicality limitations, but I'm not too bothered about that!

I was thinking of maybe running a tube from one of the existing upper mounts to the opposite lower corner where the arch meets the floor, then doing it the other way to form a cross, then running a tube horizontally between the tops. That shape feels nice and laterally stiff to me. Hmmmm

[Bodge]

Andy funny you should mention this,as i have been thinking of something similar.

A company called yarrowsport did make one for the mk4 golf

VWvortex Forums: Group Buy: Mk4 Golf/Jetta Yarrowsport rear stress bar

but i'm thinking more along the lines of an adjustable one that can be taken out even.

Go and get a RARB.

Oright Jay! Cheers for the link, looks like exactly what I'm after, shame they seem to have dissapeared as a company! Do you know how those ones attach?

I had the same thoughts on wanting it to be removable, just incase you really have to carry something huge one day! I might email Wiechers to ask how their ones attach (assuming all Germans speak English)!

Oh and ref a rollcage, Wiechers do those too. Download their pdf catalogue to get it in English, I just sort of guessed my way around their German only website!

I'll buy a RARB when you put the Speedlines on your car! I was looking at some Octavia WRC pictures yesterday and fell in love with those wheels again!

[jaymd]

IIRC the yarrowsport bar fixes to the seat belt anchor points.

Des (delcac) has got a couple of interesting bars welded in his car.

[Bodge]

Now this is what I'm talking about! Stops the shopping from moving about too....

[Bodge]

Another link with some flash bars on: Google Image Result for http://www.hpamotorsport.com/forums/rear-tie-bar.jpg

[David 8]

Thats out of the mk2 Oz edition isn't it.

Could it be made too fit ???

[KenONeill]

Short of an Octy WRC cage, I think anything you do to stiffen the shell will be at least partly snake oil! If you don't believe me, ask the makers of the aftermarket braces for a copy of the shell model they used in their finite element analysis program.

And the people who say that a RARB will increase shell flex are correct. As for the original problem of hearing the rear bench rattling, I suspect you'll get the same issue on a straight but bumpy road because you've fitted harder springs and dampers.

[iep]

Perhaps I shoudl have said earlier. I had this problem in my of golf vr6. I just jammed some foam beween the seats. Solved the rattlin/knocking sound a wee treat.

iep

[Bodge]

Thats out of the mk2 Oz edition isn't it.

Could it be made too fit ???

Well spotted that man!

No idea if it would fit, but plenty of options out there for the mk4 golf/bora anyway. They all seem to attach to the upper seatbelt anchor point, and some have diagonal bars down to the anchor points in the boot. They all seem to be simple bolt in affairs.

But, we have an advantage over the golf crew, because we already have 4 purpose made fixing points for a rear brace arrangement. So I might try and take advantage of these, and make something up myself.

Something like this would be rigid as hell (original photo stolen from TheOrs!):

Either add to the existing bars, by finding some more oval tube and shaping to fit then tacking them in place while still fitted to the car (full welding would be done once removed from car). Or just start from scratch and make 4 new bolt plates, and repeat the same practice again using round tube.

Or just end up fitting a straight bar between the seatbelt anchor points, if that's how the Wiechers one attaches.

It's going to be a bit of a compromise anyway, because I don't want anything to encroach into the passenger area, or too much into the boot space.

[Fat Boy Slim]

Well spotted that man!

No idea if it would fit, but plenty of options out there for the mk4 golf/bora anyway. They all seem to attach to the upper seatbelt anchor point, and some have diagonal bars down to the anchor points in the boot. They all seem to be simple bolt in affairs.

But, we have an advantage over the golf crew, because we already have 4 purpose made fixing points for a rear brace arrangement. So I might try and take advantage of these, and make something up myself.

Something like this would be rigid as hell (original photo stolen from TheOrs!):

Either add to the existing bars, by finding some more oval tube and shaping to fit then tacking them in place while still fitted to the car (full welding would be done once removed from car). Or just start from scratch and make 4 new bolt plates, and repeat the same practice again using round tube.

Or just end up fitting a straight bar between the seatbelt anchor points, if that's how the Wiechers one attaches.

It's going to be a bit of a compromise anyway, because I don't want anything to encroach into the passenger area, or too much into the boot space.

If you make your own new rear brace as in the image I would make you an offer for the stock brace bars

[jaymd]

Do i have to do everything for you.

Raceland Rear Stress Brace Upper Golf IV Mk4 R32 Blk: RR-BWSB-GIV-B Raceland USA

[rsorion]

I had the same thoughts on wanting it to be removable, just incase you really have to carry something huge one day! I might email Wiechers to ask how their ones attach (assuming all Germans speak English)!

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