Toe Links <BG>

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Stephen
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Post by Stephen » Mon Jun 12, 2006 7:12 pm

Rich,
Sorry about the picture quality but here is the offending item.
Image

The problem is that the bolt is under rotational sheer at both ends, as are the standard ball joints.
The eliseparts kit is like this
Image

The point Shug raised is that the inboard strengthener needs to be rivited on and is a box section I would have thought that a triangular piece of plate sloping to the cross member would have been better. Without some additional support the inboard ball joint/bolt can fail.
There are also issues with the alloy hub carriers and bolts failing on the outboard end unless the added support is used to put the bolt in double sheer. The metal hubs don't fail but the bolts/ball joints do.
If you're not living on the edge you're wasting too much space!

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Rich H
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Post by Rich H » Tue Jun 13, 2006 7:09 am

But did the toe link or the mounting bolt fail? have I got the wrong end of the stick?

From Shug's description it was the toe link itself that failed and one of the rose joints came off the link itself.

I'm just very suspisious of the fact that this extra thin web supports the end of the lower wishbone bolt. The wishbones are on double shear, but the sideloads would have to be huge to damage a M10 bolt.

No argument on the ali hub, I've seen a pic of FFS Scuffer's broken hub carrier.

Rich
1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers

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Uldis
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Post by Uldis » Tue Jun 13, 2006 7:56 am

It was the actual thread that goes into the bar that broke. Snapped clean just after the body of the ball itself. There's no rose joints here, remember.

The bolt that goes through the wishbone was Ok.

Wish Shug could take some pics, he's got the bits.

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Sanjøy
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Post by Sanjøy » Tue Jun 13, 2006 8:28 am

W213 All Terrain

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Stephen
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Post by Stephen » Tue Jun 13, 2006 9:08 am

Sorry guys,
I thought it was the ball stud that broke, as per the picture samjoy has posted the link to. I'm surprised that the thresded stud that goes into the toe link would snap as there should be only push/pull forces there.

I also note that they have gone for a cross brace as suggested by Mac, with the addition that the brace is bolted to the sub frame in the middle to transfer the forces to the subframe and prevent the forces being transferred simply to the other inner mounting.
If you're not living on the edge you're wasting too much space!

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Shug
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Post by Shug » Tue Jun 13, 2006 9:53 am

Okay, sorry, had this horrible w**k thing to do - and Elaine wanted slabs laying last night.... ffs...

Anyway - there's a couple of pics of the offending item. I figure the balljoint seized solid (this must have been pretty quick, as it wasn't noisy and I'd checked the suspension before leaving - it was jacked up and moving fine)

Image

Image
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R

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Stephen
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Post by Stephen » Tue Jun 13, 2006 10:35 am

Too many jumps rather than tyre related stress possibly.
If you're not living on the edge you're wasting too much space!

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Shug
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Post by Shug » Tue Jun 13, 2006 10:49 am

Pish. :lol:

I'm not Bo fcuking Duke you know!

Balljoint has seized. I know this, as I can't move it (with WMDs) That's maybe a heat issue, not a grip one, but it broke under load, on a bumpy, fast corner.

Think the point is that they are under specced for everything the rest of the car can do. So, they go in the bin and rose joints get put on. There's plenty of racing elise/exiges using the currently available design of uprated joints - so I'm gonna go for that just now. No doubt a better solution is possible, but it's not available just now and I'm not in the mood to be a guinea pig :wink:
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R

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Rich H
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Post by Rich H » Tue Jun 13, 2006 9:24 pm

Forgot it wasn't a proper rose joint at the end.
I'll get back in my box with a cream tea and a pastie.

IIRC one of them is prone to overheating due to the zorst, which side was it? It may prove worth while heat wrapping the nearest part of the zorst.

Anyway, you know what to do, 15 pints of liquid anasthetic (Lager) and log onto Lizparts!
You will then no doubt come away with: brand new 3 way nitrons, a set of 4 pots and (maybe) a toe link upgrade kit :D
All for the price of a slab of stella! :wink: (until the Visa bill comes in and Elaine finds out anyway... :roll:)
1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers

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Shug
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Post by Shug » Wed Jun 14, 2006 9:54 am

RICHARDHUMBLE wrote:Forgot it wasn't a proper rose joint at the end.
I'll get back in my box with a cream tea and a pastie.

IIRC one of them is prone to overheating due to the zorst, which side was it? It may prove worth while heat wrapping the nearest part of the zorst.

Anyway, you know what to do, 15 pints of liquid anasthetic (Lager) and log onto Lizparts!
You will then no doubt come away with: brand new 3 way nitrons, a set of 4 pots and (maybe) a toe link upgrade kit :D
All for the price of a slab of stella! :wink: (until the Visa bill comes in and Elaine finds out anyway... :roll:)
You know me so well..... :oops: :damnfunny
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R

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Rich H
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Post by Rich H » Wed Jun 14, 2006 10:19 am

How do you think I ended up with a Larini (And harnesses for that matter!)

Normally:

I like the look of that (Name expensive upgrade) but I really can't justify the expense at the moment.

Add lager :drink :

I really like the 'hic' look of that (Expensive item), where is my 'burp' credit card....

Morning after:
What is this e-mail? Recipt of payment for (expensive item)? Oh well...:puke
1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers

Gaz
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Post by Gaz » Wed Jun 14, 2006 11:13 am

In this case Shug I doubt if the inboard bracket would have helped you!

If you imagine the arm as being fixed inboard and rotating around the bolt of the ball joint, you can see the torque is at it highest at the bolt decreasing as you move away.
Normally there is no lateral strain as the joints on each end convert it into axial stress/strain instead.

However, if you lock or restrict the ball joint, the arm has to take some of the strain and will bend to some degree.
As the main bar is solid and of larger diameter then the ball joint spigot, it's clear the ball joint spigot will cop the most stress when the suspension is in motion.
It will not take long for it to fracture under these conditions.

The kits come with spherical bearings and dust covers to eliminate this problem.

If you hold the toe-ling in the middle and try to twist, it should rotate a few degrees quite freely (you can see the inner joint rotating around it's range of motion) though there should be no lateral or longtitudinal motion possible.

For those who do not track day, these are such cheap items and so easy to change I would tend to do them every couple of years regardless.

For those who do, the rubber covers with the kit should keep them OK for years.


:)

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Shug
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Post by Shug » Wed Jun 14, 2006 11:30 am

Gaz,

Good to see you here - sorry to hear about the misfortune that kept you from Mexi Towers :(

So, in your opinion, am I best going for one of the commercially available kits (with boots) or doing something with the new GT3 style cross brace that Lotus are now fitting as options (according to Mac)?
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R

Gaz
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Post by Gaz » Wed Jun 14, 2006 12:23 pm

Hi Shug, here thanks to Stephen's prompt :)

Just go for the kit, (or make one) :)

I will be making these components, but for track use and too expensive for what you need. anyway it is months off.

If you do arrange to make your own, the inboard bracket can be made in 2mm stainless with a stainless washer fully TIG'd onto the outside for full support. You can also close the top gap this will strengthen the bracket and also stop some crap being sprayed in from the wheels.
Use a 12.9 plated cap bolt, this will stop any flexing.

I would be inclined not to fit a cross brace on a road car.
The entire vehicle is designed to fail progressively on impact, suspension first, and then subframe, etc.
This helps protects you from fatal shock and also allows damage to be compartmentalised and hence repairable.

For road use this could mean a misjudged corner and hard kerb impact that would normally result in needing a new toe-link, wheel, wishbone, etc now becomes a distorted sub-frame.


You have to remember you cannot lose energy, only arrange to transfer it where you want it or convert it. If you substantially increase the rigidity of the suspension you just transfer the energy somewhere else.

The worse result of this was when the F1 designers didn't really look at side impacts too closely as they were not considered likely in a race environment. thus the energy from a relatively low energy side impact was sadly transferred to Aryton Senna's neck.

OK, sometimes the designer f_cks up and a component's failure point ends up too low and/or out of sync with the other supporting components, i.e. Elise rear toe- link :)

For a track car though it's ideal, might as well put one across the top as well on the roll over bar support arms just behind the engine and triangulate the rear completely.

Glad to hear you were not injured Shug; luckily the rear has an awful lot of castor.

:)

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Shug
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Post by Shug » Wed Jun 14, 2006 12:37 pm

Cool thanks. :thumbsup

Yeah - the rear wheels are like a frigging shopping trolly (as we found trying to push it backwards!)
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R

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