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MG Midget and Sprite Technical - Anti roll bar rose jointed link

I have been pricing up making my own anti roll bar rose jointed links, before i order the parts has any one experiance of using the ones available from the usual suppliers,
cheers
Brad
Brad (Sprite IV 1380)

For ease rather than having ti fab up from scratch we used Peter May's kit on the racer.

Does whet it says on the tin although you do have to weld the rose joint tube spacers into the ARB.
Deborah Evans

Strange it wouldn't seem like a difficult job to make a stud for the rose joint that would bolt into the ARB, maybe they're just trying to save a few extra grams.
David Billington

With a rose joint you have to have a spacer tube or annular washer to hold the joint yet allow freedom of motion in the joint. On the midget ARB the mounting hole is rather large (1/2" IIRC) whereas the rose joint is (from memory) 3/8".

Thus the spacer tube has to be welded to the ARB so as to prevent movement of the rose joint relative to the ARB.
Deborah Evans

I don't see that as justification for the welding, a simple tapered stud would seem to suffice. I have designed items using rose joints in the past so can't see why this application would require welding over a threaded fitment.
David Billington

No you misunderstand me.

The 3/8" bolt that goes through the eye of the rose joint would slop around in the ARB if the spacer tube was not welded to the ARB.

The threaded part of the rose joint screws into the drop link.


Deborah Evans

I've seen the Peter May pic which you seem to have linked to or posted a copy of, it's not a good pic but I get the idea as I looked at it earlier. I see that that a bolt passes through the Rose joint and possibly through the eye of the ARB but don't see that as justification for welding. The bolt could pass through the Rose joint and a spacer that would fit the larger hole in the end of the ARB so slop wouldn't be an issue.
David Billington

The cap head bolts through the eye of the rose joint and the eye of the ARB - no 'possibly' about it.

Indeed you could make up a spacer for the hole in the ARB.

Getting it right would be critical, failure to do so would mean the drop link / ARB interface would not work correctly which would result in all sorts of odd handling issues, especially when body roll starts then the ARB suddenly 'comes in'.

Far easier to weld the spacer to the ARB and, at a stroke, you have abrogated the potential problems.

A couple of spot welds as opposed to the time taken on a lathe to accurately machine a spacer.

In my mind it's a bit of a 'no brainer' really.
Deborah Evans

I bought a kit from one of the "usual suppliers" but found both rose joints were right handed. This meant that adjustment required undoing the bolts.
Make up one with left and right threaded joints so adjustment can be made simply by turning the joining tube.
Mike Allen

Is the Peter May one LH & RH threaded?
I am going to look at a spacer as per Davids suggestion as i've only recently had the anti roll bar powder coated.
If anyones got a better picture of there set up it would help,
cheers
Brad
Brad (Sprite IV 1380)

Couldn't i just shoulder a bolt & thread both ends 5/16"?
Brad (Sprite IV 1380)

Brad,
the P/M kit is all r/h thread, which I was a little dissapointed with, the weld on nuts Deborah is describing (for both the ARB and the mounting plates) act as additional spacers to put the whole set up in line. I will be changing mine to a L/H thresd once a suitable joint has been found. Will post pic's later.

Best Regards,

Howie.

ps Brad you have mail.
Howard Wright

Howard,
joints are easy enough to find, try McGill motorsports, i used theirs on my Mumford link.
I should have thought about this earlier & measured up as i'm now in India & machining is dirt cheap from one of the local sweat shops.
Brad (Sprite IV 1380)

Can't see it's a good idea to weld to a tempered bar...... all that heat must do something adverse, even just a short flash from a mig.
D le Versha

Well it would certainly melt my power coating.
Brad (Sprite IV 1380)

D le Versha,

Seeing as the ARB is likely a medium carbon steel or higher I would expect more problems, like weld cracking, created by a short MIG weld than something like TIG or MMA. MIG is a low heat input process and more likely to lead to an embrittled weld due to the carbon levels than the others.

Regarding welding on the eye of the ARB I wouldn't see that as a problem as it's fairly low stressed compared to the main torsion section.
David Billington

Anyone fancy getting the calipers out & measuring the roll bar eye diamter & the stand off required as my cars several thousand miles away.
Then i'll go see the local Indian machinist whose got some very old & well used solid british machines all with open belt drives, no safety guards & not an emergency stop switch in the place.
cheers
Brad
Brad (Sprite IV 1380)

Brad

Rose joints are very nice and all that... but what's your motivation in a road car? Do you have poly bushes on an uprated bar etc? What are you trying to improve?

A
Anthony Cutler

Ant,
i have all those bits, i just like modifying & it stops my brain from rotting away too much when i'm bored.
Brad (Sprite IV 1380)

Before this thread dissapears, is there anyone out there kind enough to take a few measurements.
cheers
Brad
Brad (Sprite IV 1380)

BTW, some setups like these use RH UNF at one end and RH UNC at the other for fine adjustments.

Here in the US there is a company called Power Grid who make an alternative link.
http://www.powergridinc.com/
Many custom configurations available. Works well on my Midget, but I have a 3/4" Winners Circle ARB on it.
David "linkin" Lieb
David Lieb

"Before this thread disappears, is there anyone out there kind enough to take a few measurements."

Brad,

The drop link is 1 3/4" long.

The rose joints and fixings are 5/16" UNF.

With a drop link it doesn't actually matter if you use two right hand thread rose joints or two left hand thread rose joints, or even one of each.

Unlike (say) a rose jointed steering arm where you need to be able to alter the arm length (to set the toe) which requires one RH rose joint and one LH rose joint, with a drop link once you have set it up on the bench, there is no requirement to alter its effective length so you don't require opposite thread rose joints.
Deborah Evans

Thanks Debs
So the ARB eye is 1/2" & the Rose joints are 5/16", i will need to shoulder a bolt with a 1/2" step for inside the ARB eye & say 3/4" for the main centre section with two 5/16" ends.
How long would the centre section need to be? & is the wishbone mount the same story?

cheers
Brad
Brad (Sprite IV 1380)

Actually, if you are corner-weighting the car for racing, link adjustability can be more than convenient.
David "adjustable links" Lieb
David Lieb

David,
i've never done corner weights, how do you do it on a Sprite?
Brad (Sprite IV 1380)

I corner weight ours by shimming the spring pans at the front and the axle locating plates at the rear.

Corner weighting should be done with the ARB disconnected anyway.

If there is then an issue with drop link length it can be easily adjusted with the drop links undone from the A arms.

Of course, on my Ginetta G15 racer corner weighting is a doddle because I have coil overs all round. :)

Brad,

Just to make things clearer (Note: The set up is as on my G15 hence the bolts are longer than on a Midget, but otherwise it is the same set up and the measurements are corrected for a Midget):


Deborah Evans

Thanks Deborah,
thats perfect, i'll draw it up & see what the local sweatshop can fabricate.
If you shim the spring pan, then that adjusts the body height, so you could end up with a tilted looking car, i think? Depends on how many pies you've had i guess.

Just out of interest what is the weight distribution on a midget? can't be much at the rear.
Brad (Sprite IV 1380)

I can't see it getting much easier than this

http://www.britishv8.org/Articles/Hoyle-IRS-Anti-Sway.htm

any reason not to go the same route?
Brad (Sprite IV 1380)

Brad,

My comment would be that someone detailing modifying suspension components should learn to do a better job of the welding.
David Billington

I was refering to the anti roll bar linkage; i don't think theres much root penetration on his lower bracket though.
Brad (Sprite IV 1380)

Brad,

I was aware you were asking about the ARB links, no reason not to do it that way. It gives a short link and if that is sufficient it's a way to go. Like the PM link mentioned earlier, you have to remove the fastener from one end to adjust the length. A LH and RH threaded assembly would be nice but once set its not likely to need adjusting again.

Regarding the welding, probably poor penetration, and poorly executed welds can produce stress raisers and lead to cracking. In that case not a big deal if the bracket drops off but could be fun if a crack were to propagate into the wishbone.
David Billington

David,
if the brackets going to fall of then it'll be when its loaded up, probably mid corner, it could turn into a very big thing indeed then.
Brad (Sprite IV 1380)

It is perfectly feasible to use a male rose joint and a female rose joint to make a drop link as in that photo', however it will limit the drop link length and it is essential to ensure that enough thread is engaged between the rod ends.

Unfortunately in that photo' the muppet has used hex headed bolts - this is a major no no you should use a socket cap headed bolt.

If you MUST use a hex head then you need to make up a spacer tube to locate on the rose joint. If you don't then the hex will not allow the joint to swing properly and will limit its travel. This will result in the rose joint being incorrectly loaded leading to accelerated wear and possibly premature failure.

Brad I can't remember off hand the weight distribution of our Midget. Overall she's around 590 Kg and I intend to have her down to the class minimum of 580 Kg with some mods to the front brakes and hubs (Willwood calipers and alloy hubs as opposed to Princess calipers with stock hubs). What is interesting is that the GRP rear end on the car weighs less than a single steel rear wing!

That welding is APPALLING! I would never use anything other than TIG for suspension components.

Shimming the spring pans could end up with a tilted car that's the whole point of corner weighting (although the shims I use are of a thickness so that you wouldn't notice with the naked eye). The cars were effectively tilted when they came out of the factory (because they were hand built on rather sloppy jigs) and corner weighting rectifies this.

Imagine a 4 legged stool with one leg shorter than the rest - it will rock. Cars are exactly the same and if rock is present then the suspension can't do its job properly. By corner weighting you (ideally) make all 4 'legs' the same length, or at least the same across an axle - this prevents the rock. Unfortunately it is easier said than done since altering the weight at one corner will have an effect at the diagonally opposite corner so you end up going round in circles adjusting things till you get the best set up. Doing a car can take me a whole day.
Deborah Evans

Surely the inner part of the spherical bearing (Rose joint) is locked to the bolt so using a hexagon bolt has no relevance. The bearing surface is on the outside of the inner race I don't understand the problem you are trying to describe Debs?
Robert (Bob) Midget Turbo

Hi Brad

I'd go with rh/lh thread, with a shorter hexagonal rod and use the socket cap headed bolts and you could adjust it as much as you want wihtin reason with a spanner.

Les

PS Thanks again for the info
l snowdon

Robert,

The hex bolt head is only an issue if the assembly articulates enough that the outer housing comes into contact with the bolt head in the normal articulation case and prevents full movement. A SHCS has a smaller diameter so is less of a problem but the same issue can arise and so in some circumstances a conical spacer is used to move the fastener away from the clamping face on the inner ball part, the spacer tapering down from the fastener head diameter to the clamping face diameter on the ball. In that circumstance a similar taper spacer would be used on the other side also to provide full articulation potential.
David Billington

Les, Debs, Dave,
i'll have another look at this today after the morning madness is over, i don't really want to use mis-alignment washers, so Cap head bolts would be the way to go, also using 1/2" rose joints throughout seems a bit chunky for the application.

McGill do some turnbuckle rods so maybe i could rework one of them to fit, i had LH UNF taps so no problems there.

Lastly recorner weights, where i grew up, there was a father & son who were rather weight challenged shall we say, the son drove a cavilier, when he got behind the drivers seat the OS front suspension almost bottomed out, to compensate, his father used to sit in the NS rear seat.
Brad (Sprite IV 1380)

Hows this for a spacer using 5/16" rose joints, a step at one end for the ARB eye & a cone at the other for the spherical joint to move.
Any comments please before i get them made?



Brad (Sprite IV 1380)

That would work.
Deborah Evans

Brad,

That's what I would do and a thick washer on the other side to clamp the ARB eye.
David Billington

Nice!
l snowdon

Being fabricated.


Brad (Sprite IV 1380)

Lot's of H&S there (He He)
Howard Wright

Made & delivered in less than a day.


Brad (Sprite IV 1380)

They look very, very good!
l snowdon

I think you would be wasting your time with rod ends, balljoints would be far simpler and cheaper. I work for Illston and Robson, and they would gladly help you out for a lot less than you would pay for the rose joint bits.
Neil
www.illstonandrobson.com
Neil Williams

Neil,
it's progressed so far now, i'm just doing it for the engineering exercise. If it doesn't work out for a road car then i'll either sell them or save them for my next project...
Brad (Sprite IV 1380)

It will all end in tears!!!!

Random comment mode 'on'
Shaun

There seem to be plenty of people running this modification on road and track successfully.
l snowdon

Hi Shaun,

you still trying to find a 5/8" UNF x8" bolt :-)) theres one in my neck if you want it.
Brad (Sprite IV 1380)

Hey Brad, Just trying to find time to work on the Midget, good news though it flew through the last MOT!!!!!!
Shaun

Shaun,
that was 7 years ago, it's been on bricks ever since then.
Brad (Sprite IV 1380)

Just an update the anti roll bar eye diameter is actually 7/16" not 1/2", Ivan my new pet machinist has just turned mine down while i made the cafe.
Brad (Sprite IV 1380)

Brad,
How did this all work out? Have you fitted these and have you got any photos?
Neil
Neil (K series)

Silky smooth..


Brad 1380

Hi Brad,
A few questions:
1. I have seen some rose joints on ebay. Quite cheap. £3-£5 each. Can you confirm the size you used?
2. What tube did you use and presumably you had a thread put inside?
3. What thread size did you use and were the rose joints handed?
4. How did you fit the ARB to the rose joint?
5. What fitting did you use to attach the top rose joint to the bracket on the wishbone pan? The brackets look like the originals.
6. Are the dimensions the same as the image attached?
7. Anything else I should ask!!!
Neil
Cheeky in Tenby


Neil (K series)

Niel,
1. i used McGill motorsports, 5/16 unf L&R handed joints.
2. McGill do a unf turnbuckle, i chopped it to size & tapped to suit.
3. 5/16unf Left & Right.
4. The adapters are a snug fit inside the ARB eye.
5. 5/16" Cap heads.
6. No as below.
7. Use thick washers on the wishbone brackets.

i would like to make the wishbone / ARB bracket in Ali if you have one to hand to measure up for me.

cheers
Brad


Brad 1380

I rose jointed my ARB and after a year or 2 the ball joints are toast, Not happy! :(
Robert (Bob) Midget Turbo

Hi Bob. Did you make your own too?
Neil
Neil (K series)

Yep didn't see it as being too difficult
Maybe that was the problem?

I put a bolt through the ARB and the original pan bracket that captured the 2 spherical joints and slightly clamped the inner joint so that the movement was between the inner and outer of the spherical joint.
Robert (Bob) Midget Turbo

Rose joints are not happy on the road as there is just too much grit/dirt - you can get rubber boots to protect them but they won't last indefinitely...
James B

This thread was discussed between 24/05/2009 and 18/10/2010

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