Rose Jointed Wishbones

[pug_ham 244 3 Cars]

PTS rose joints are M20 thread with a 16mm hole which makes them a bit of an odd bod bearing and cost in the region of £90 each + VAT (part number is RBJ79MG).

Is that the same size as the rj's fitted to the compbrake wishbones?

 

as you will see below, there is very little room for a vertial bolt, and it would need modifying

 

 

You're missing the horisontal bolt through the hub in that pic but it fits just the same as you've got in that picture.

 

Graham.

[Cameron 16]

Ah yeah, I remember.. I was going to use 4130 originally I think.

I'll keep going, they're on the back burner for now while I get my car back in one piece.

[Rippthrough 98]

Ah yeah, I remember.. I was going to use 4130 originally I think.

I'll keep going, they're on the back burner for now while I get my car back in one piece.

 

Your project for the week is to figure out how I've managed to use a smaller rose joint at the rear than your arms and it still be stronger

[SurGie 54]

Hi,

 

 

So where can you buy these of the shelf so to speak, if thats possible

and are they any good for fast road use?

 

Iv tried them sites but they seem to be bit gobledegoop and SB has just a use less page ?????

[meggy6620 0]

if the bolt in the picture fits vertical then they 100% wont fit,

 

as mine (compbrake) fit vertical and use a std pinch bolt horizontal

 

they those above would need to be horiztonal, else they wont fit

 

as you will see below, there is very little room for a vertial bolt, and it would need modifying

 

 

Hi in your pic your bolt is at an angle? i thort that when you fit the verticl bolt/pin you have to mod the hub and grind a flat seat for the bolt/pin to sit true vertical. haw much room is there between the shaft uj and the head fo the pin and dose it catch at all?

 

cheers.

[EdCherry 34 1 Cars]

Hi in your pic your bolt is at an angle? i thort that when you fit the verticl bolt/pin you have to mod the hub and grind a flat seat for the bolt/pin to sit true vertical. haw much room is there between the shaft uj and the head fo the pin and dose it catch at all?

 

cheers.

 

Cant see why you'd have to grind the hub, you'd use top hats so it sits flat against the hub bottom anyway. Personally wouldn't have adjusted it on that rose joint to get the camber as you can see it will quiet likely run out of movement easily, id have adjusted the joints in the subframe end, although this will be harder to setup as you are dialing in castor at the same time.

[205wrc 16]

Is that the same size as the rj's fitted to the compbrake wishbones?

 

Graham.

 

 

No. That's why they are much cheaper than PTS spec arms. They use an M16 x 16mm rose joint which isn't that strong really. Personally, I would'nt use those joints.

The M20 x 16mm rose joint is quite difficult to come by that's why they charge silly prices for them. Can't even see them listed on the rotaprecission website.

Demon Tweeks can get them, AB Motorsport and Skip Brown stock them but they are about £100 each + V.A.T now.

 

If you need M20 x 16mm rose joints, let me know, as I have a friend who has a bearing company making them for him to order. Could possibly make it a group buy if you can get enough people interested.

[EdCherry 34 1 Cars]

They use an M16 x 16mm rose joint which isn't that strong really. Personally, I would'nt use those joints.

 

M16 Rose joints will be plenty strong enough for certain applications, jumps, large bumps and humps you find in certain rallies possibly not after repeated amounts of abuse, but then again a rose joint is a consumable as is a balljoint or bush. There is a fraction of this forum that are in these type of events, but most are track day go'ers and a couple of smooth tarmac competitors where these joints are plenty strong enough.

[205wrc 16]

M16 Rose joints will be plenty strong enough for certain applications, jumps, large bumps and humps you find in certain rallies possibly not after repeated amounts of abuse, but then again a rose joint is a consumable as is a balljoint or bush. There is a fraction of this forum that are in these type of events, but most are track day go'ers and a couple of smooth tarmac competitors where these joints are plenty strong enough.

 

 

What you're saying might be true, but I've also seen the M20 thread snap.......and that was on smooth tarmac (can't get much smoother than Epynt).

[EdCherry 34 1 Cars]

What you're saying might be true, but I've also seen the M20 thread snap.......and that was on smooth tarmac (can't get much smoother than Epynt).

 

Any kerbs or barriers to kiss at Epynt? I know at combe there isnt much of a kerb but if you go to somewhere like thruxton you can bend something if your a bit to viscious!

[205wrc 16]

Any kerbs or barriers to kiss at Epynt? I know at combe there isnt much of a kerb but if you go to somewhere like thruxton you can bend something if your a bit to viscious!

 

 

Plenty of kerbs, jumps, brows, barriers, ditches, culverts..........you name it, Epynt's got it. But it's hard to be beaten on the quality of the roads - not a pot hole in sight. There's an event up there next sunday. Pop up and have a look.

Edited May 24, 2009 by 205wrc

[Rippthrough 98]

The thread snaps because all the daft buggers are using the rose joint the wrong bloody way around, it's only got 1/5th of it's maximum strength the way the use them.

 

Set 'o planks!

[Rippthrough 98]

id have adjusted the joints in the subframe end, although this will be harder to setup as you are dialing in castor at the same time.

 

 

I don't think the castor is adjustable with the compbrake arms, they're solid, so if you adjust for castor the linear distance between the joints would increase and they wouldn't bolt into the subframe properly...

 

Besides, if the joint was any stronger at the balljoint end, the arm itself would start to tweak where the kink in it is anyway.

Edited May 25, 2009 by Rippthrough

[Cameron 16]

Your project for the week is to figure out how I've managed to use a smaller rose joint at the rear than your arms and it still be stronger

 

Aha, well from having a little play last night it turns out that I may well be able to use a 12mm rose joint for both inboard mounts, and a 16mm for the bottom ball joint.

I had based the early tests on the non-heavy duty RJs, the heavy duty ones are far stronger!

[casnell 0]

No. That's why they are much cheaper than PTS spec arms. They use an M16 x 16mm rose joint which isn't that strong really. Personally, I would'nt use those joints.

The M20 x 16mm rose joint is quite difficult to come by that's why they charge silly prices for them. Can't even see them listed on the rotaprecission website.

Demon Tweeks can get them, AB Motorsport and Skip Brown stock them but they are about £100 each + V.A.T now.

 

If you need M20 x 16mm rose joints, let me know, as I have a friend who has a bearing company making them for him to order. Could possibly make it a group buy if you can get enough people interested.

I'd like some M20 PTS ones please!

[Rippthrough 98]

Aha, well from having a little play last night it turns out that I may well be able to use a 12mm rose joint for both inboard mounts, and a 16mm for the bottom ball joint.

I had based the early tests on the non-heavy duty RJs, the heavy duty ones are far stronger!

 

Yep, don't forget to model the stress riser at the end of the thread on the shank though, especially as you are appling loads perpendicular to it

[Cameron 16]

Yeah I'll be reducing the local mesh size around the highly stressed areas once they have been identified, it takes aaaaages to calculate though so the initial FEA has all been done with a global mesh that is a bit coarser.

[Rippthrough 98]

That's why we've got 2 quad-core machines at work

[Cameron 16]

 

Mine is just a 2-core Macbook running windows on a partitioned hard drive, so it takes a little while.

[fast_eddie 0]

Any update on the 309 arms from your mate yet Welshpug?

[Rippthrough 98]

The ones I know of have ben made with a slat towarsds fastroad rather than pure race/rally use

 

They're more than strong enough for rally use, someone's spent all day throwing it sideways on rubble roads, balljoint gives out before the wishbones do