Rose Jointed Wishbones

[feb 47]

What advantage do these offer as compared to the OE items?

Edited June 25, 2006 by feb

[base-1 17]

Strength (in theory), adjustability.

[kman1600 0]

Hi,

 

I assume from what Ive read that most of those who have gone with the rose jointed arrangement are primarily interested in added strength and ease of adjustment. Im working on a light weight Sprint and Hillclimb project and my primary interest is removing the flex out of the system and therefore Im more interested in rose jointing the inner bushes. Can anyone shed some light on how this is normally done, before I go away and reinvent the wheel so to speak?

 

Thanks

 

Tim

[SPGTi 2]

Cheaper - yes - Weaker - no

By cutting out the middle man and buying direct from the manufacturer you save a lot of money. Does'nt take a genius to work that one out. The rose joints I bought are exactly the same as supplied by WMMS and AB - same size, same colour, same plastic bag, even the same part number but miles cheaper.

Do a search on the internet and see how many companies make or stock the Rose Joint that has the part No. RBJ79MG - not a lot. If you do find them then you will have found yourself the rose joint that PTS used, and if they were good enough for Colin McRae, Richard Burns, Jonny Milner etc they're good enough for me.

 

 

Sorry for dragging this up again but a couple of questions

 

RBJ79MG is sold by Autosport Bearings at £152.75 a pair inc VAT. This is a 16mm bore with 20mm threaded bar. I presume you use a 16mm pin straight through the rose joint into the hub.

You say that this is what WMMS sell, exactly the same part no. Why are top hats supplied with the pin ? I always presumed these fitted into the rose joint and stepped the size down ? So if you need a 16mm pin for the hub side then surely the bore of the rose joint is bigger than 16mm ? I would have thought that this would mean that the rj used would be more likely a RBJ83MG (20mm bore and 23mm threaded bar and rated a lot stronger) which cost £200.05 a pair inc VAT ? I have no idea whether this is true or not but would be interested to find out !

 

Steve

[205wrc 16]

Sorry for dragging this up again but a couple of questions

 

RBJ79MG is sold by Autosport Bearings at £152.75 a pair inc VAT. This is a 16mm bore with 20mm threaded bar. I presume you use a 16mm pin straight through the rose joint into the hub.

You say that this is what WMMS sell, exactly the same part no. Why are top hats supplied with the pin ? I always presumed these fitted into the rose joint and stepped the size down ? So if you need a 16mm pin for the hub side then surely the bore of the rose joint is bigger than 16mm ? I would have thought that this would mean that the rj used would be more likely a RBJ83MG (20mm bore and 23mm threaded bar and rated a lot stronger) which cost £200.05 a pair inc VAT ? I have no idea whether this is true or not but would be interested to find out !

 

Steve

 

You're right, Autosport do sell them, and they are the same ones as WMMS, AB, Skip Brown, Demon Tweeks (to order) etc, and are priced at around £80 each.

To answer your question about the top hats:-

The top hat spacers are fitted, one above and one below the rose joint in order to allow the rosejoint to pivot, otherwise you will have your hub to close to the arm only giving you about 0.5 to 1 degree movement. By fitting the top hat spacers, you increase the distance between the hub and the rosejoint, thus giving you about 10 to 12 degrees of movement.

In order to fit these arms, first you need to remove the drive shaft as the pin is fitted from above - thats why the pin has a shoulder on it. Then you slide the top hat under the hub, then the rose joint (thats fitted to the arm) then the bottom top hat and then the 16mm locking nut. If you need to adjust the camber you simply remove the bottom locknut, bottom top hat and slide the arm down over the pin - turn your rosejoint and re-assemble.....easy!

If you go and use a bigger rose joint, the problem you will have is in the arm itself. Because the arm has to be machined out to accept the threaded tube for the rose joint thread, any bigger than an M20 thread, and the walls of your arms become weak, because most of the strength that you need if front to back and not up and down, so you really need as much "meat" left in the arm as possible (remember that a 25mm tube will only leave you with about 4mm of material left in the arm either side of the tube)

I have a better pic of the arm fitted to the car but this is the only one I've got on my pc at the moment.

 

Edited July 7, 2006 by 205wrc

[SPGTi 2]

Thanks for the reply. Just trying to understand how everything works !!.

 

cheers

 

Steve

[205wrc 16]

Right.........I managed to get rid of some unwanted photos off my digi camera and took these photos to try and explain things better.

 

Ignore the hub - its one I found in the scrap pile and bolted the arm to in order to take the photos.

The first one shows how the "top hap" spacer system works. As you can see, they sit ON the rose joint and not IN it.

 

 

 

This one shows the kind of movement you can expect from having the top hats in place. If they were sitting in the rose joint the hub and the arm would barely move apart.

 

 

 

Just a few closeups of the Rose joint, pin, top hats and lock nuts. Note that the pin has a shoulder on the top which means that its fitted from above, and that it has a small "notch" where the hub bolt fits in order to increase strength - I haven't had one of these break yet!!!

 

 

 

As I explained earlier, you need as much "meat" left in the arm as possible in order to weld the insert in to hold the rose joint, and that you couldn't really go above an M20 thread. This pic shows you roughly how much you have left when you use a 25mm insert drilled out to M20. There's only about 4mm of the original arm left either side that insert - just enough to weld to.

 

 

 

One brand new arm supplied as a kit.

 

 

A brand new pair ready to be sold - pm me if anybody is interested !

 

 

Aled

Edited July 10, 2006 by 205wrc

[M@tt 77]

 

I've just been reading this with interest as i have been thinking baout doing something similar to my wishbones fairly soon as Jackherer mentioned, replacing an entire wishbone for the sake of 1 balljoint pisses me off so this seems like a good long term solution.

 

i have a few questions about rosejointed wishbones though.

 

As far as i can tell from the pics above the threaded section of the rose joint just slides into a hollow tube welded onto the end of the wishbone, so as i understand it the rose joint can be pushed in and out by adjusting the nut.

http://img74.imageshack.us/img74/3641/20060710image02652dw.jpg' alt='20060710image02652dw.jpg'>

 

1) Would the threaded section of the rosejoint sitting inside of the tube part not eventually have it's threads crushed due to the stresses put on it?

 

2) As the rose joint doesn't appear to be physically attached to the wishbone ie not screwed into it, would this place additional stress on the driveshafts & track rod ends in keeping the hub held in place and therefore cause them to fail earlier because as i see it the wishbone also performs the fuction of holding the hub in place.

 

3) Would the adjusting nut not need to be nyloced? as road vibrations could cause it to move therefore altering hte rosejoints position.

 

Cheers

 

Matt

Edited January 21, 2007 by M@tt

[Guest jarrods]

 

I've just been reading this with interest as i have been thinking baout doing something similar to my wishbones fairly soon as Jackherer mentioned, replacing an entire wishbone for the sake of 1 balljoint pisses me off so this seems like a good long term solution.

 

i have a few questions about rosejointed wishbones though.

 

As far as i can tell from the pics above the threaded section of the rose joint just slides into a hollow tube welded onto the end of the wishbone, so as i understand it the rose joint can be pushed in and out by adjusting the nut.

http://img74.imageshack.us/img74/3641/20060710image02652dw.jpg' alt='20060710image02652dw.jpg'>

 

1) Would the threaded section of the rosejoint sitting inside of the tube part not eventually have it's threads crushed due to the stresses put on it?

 

2) As the rose joint doesn't appear to be physically attached to the wishbone ie not screwed into it, would this place additional stress on the driveshafts & track rod ends in keeping the hub held in place and therefore cause them to fail earlier because as i see it the wishbone also performs the fuction of holding the hub in place.

 

3) Would the adjusting nut not need to be nyloced? as road vibrations could cause it to move therefore altering hte rosejoints position.

 

Cheers

 

Matt

The rose joint is screwed into the arm. The nut is just there to lock it in position. To adjust you need to disconnect it from the strut, back off the nut and screw it in or out as desired.

 

Jarrod

[niklas 1]

1) Would the threaded section of the rosejoint sitting inside of the tube part not eventually have it's threads crushed due to the stresses put on it?

 

It happens that the threaded part between the RJ and the locknut snaps. I wouldn't use this kind of setup on a car driving on regular roads, and especially not on bad roads.

[M@tt 77]

oh right so a thread must have been cut into that tube welded onto the wishbone in the pic above in my last post?

 

That makes sense then in that case

 

205wrc out of interest what sort of price would we be looking at for all the bits excluding the fabrication of the wishbone but including suitable threaded bar that would be welded?

 

Cheers

[Rippthrough 98]

It happens that the threaded part between the RJ and the locknut snaps. I wouldn't use this kind of setup on a car driving on regular roads, and especially not on bad roads.

 

 

We get around this on the rally machines by fabricating the rod ends from T45, or occasionaly cro-moly alloys, and we also don't run the internal rose joint, we machine a socket up and press hard poly bushes in instead, as the even the big rose joints die very quickly from the shock loads when you aren't on track.

 

M@tt, do you have a spare wishbone at all?

Edited January 21, 2007 by Rippthrough

[M@tt 77]

i might have one in my old garage i'll try and remember to go have a look this week if i can

 

what you planning??

[Rippthrough 98]

i might have one in my old garage i'll try and remember to go have a look this week if i can

 

what you planning??

 

Tubular arms, threaded and poly bushed at the subframe mounts and using 306 balljoints on the end (then you can replace balljoints for 7 quid a pop if need be). Have to have a gander at a 205 wishbone first though, and finish up some of the other projects.

 

Edd can probably jig you something adjustable up there and then if I can find my spare balljoints.

Edited January 21, 2007 by Rippthrough

[niklas 1]

We get around this on the rally machines by fabricating the rod ends from T45, or occasionaly cro-moly alloys, and we also don't run the internal rose joint, we machine a socket up and press hard poly bushes in instead, as the even the big rose joints die very quickly from the shock loads when you aren't on track.

 

Nice! Is the wear of the RJ a bigger problem than it snapping?

Looking at the prices of the RJ's it's obviously annoying if it wears quickly, but snapping is plain scary

[Rippthrough 98]

Nice! Is the wear of the RJ a bigger problem than it snapping?

Looking at the prices of the RJ's it's obviously annoying if it wears quickly, but snapping is plain scary

 

Well, we were using rose joints at £120 a pop, (PTFE lined cromoly, tried non-ptfe too, but they die even faster with all the crap being chucked up) so we didn't manage to snap one but there'd be some 'clunk' in them after one lap....

 

I'd say you'd be fine on relatively smooth roads and for track use, but be aware that the joints may wear out quickly with the road salt and abuse down potholed roads, they're not that cheap to have to replace every year or less.

Edited January 23, 2007 by Rippthrough