Rose joint pin info

[Richie-Van-GTi 72 2 Cars]

Does anyone have a sketch of a rose joint pin for a bottom arm?

Thinking of rose jointing some 309 arms to enable me to get a bit more width for a dimma conversion as the wheels will not be dimma wheels and I dont fancy stupid spacers giving negative offsets etc.

Just trying to find the best solution for pin design between the hub and the rose joint.

Guessing there needs to be some kind of spacer between the hub and the rose joint as well?

Edited September 11 by Richie-Van-GTi

[petert 588]

Is this what you're trying to achieve? That's a Ø16 pin which has spacers/adaptors above and below a Ø20 bearing.

[petert 588]

The Group A hub above was destroyed in a racing incident. I decided to make similar, but obviously not as rigid, from a pair of 306 hubs. You need to mill the top of the pin mounting area flat/perpendicular to the hole and remove some material for the head of pin to seat against. Hopefully these two pics illustrate the points.

[stef205 92 1 Cars]

Speak to Allan at bridge craft he makes them with a thread to insure they don't pull through where a pin head isn't possible with big CVs 

[petert 588]

My solution doesn't work with an ABS ring either. I'm planning to add traction control soon, for which I'll need the ABS ring. The sensible thing is to upgrade to the larger 406 CV's and hubs/carriers, which is a better overall solution anyway.

Edited September 12 by petert

[Tom Fenton 1,542]

The pin has to be 16mm to fit into the hub. I use a 3/4" rose joint as they are more readily available than the metric ones. You need a spacer anyway to move the joint away from the hub. So a spacer/top hat to go up to 3/4" is simple enough. There is a bit more to it but that is the basics.

[Richie-Van-GTi 72 2 Cars]

I will be using 306 hubs with the 18mm ball joint.

I was hoping someone had a sketch of the basic profile of the pin.

Why have the top on the pin and not a groove round it to use the existing clamp bolt?

[SRDT 180]

First instead of a groove around the pin it's much better to just have a notch. That way the pin cross section isn't as reduced and the notched pin has a big contact area with the clamp bolt instead of a single arc.

 

 

Looking at Peter's solution there is no play allowed along the pin axis, the clamp bolt will only be there to add rigidity and help with radial play. You can move the notch on the bolt and go up in size or grade to compensate the smaller cross section and add extra rigidity.

In fact as long as you have it on the shank I'm not even sure that the notch can create a cross section that is smaller than the one on the threaded part.

 

 

To be as rigid with a notched pin assembly you want the hole on the hub and the notch on the pin precisely aligned. For that you need to ream the hub and pin to final size while assembled and use a shoulder bolt to compensate the increased diameter. That will also allow you to have a very tight fit for the bolt without risking damaging the threads.

 

Now having done all this you will still have a weaker pin due to the notch and less material to shear before the pin can pull through compared to Peter's solution.

I even wonder if you couldn't machine the top of the pin to clear the ABS ring and still have more strength.

Edited September 13 by SRDT

[petert 588]

The Grp A pin is indeed a precision part. As you can see in the original Grp A hub, there is no side retaining bolt, as there is not split. I reamed  the 306 hubs to suit the pin OD and added a notch for the normal retaining bolt (not shown). You can only add the notch after you have it sub-assembled, as the position may differ depending how much you need to face off the top. I’ll draw it up later.

 

It would be nicer to have used 18mm hubs. I just didn’t have any.

 

You can’t run an ABS ring. It fouls on the head of the pin. 

Edited September 13 by petert

[SRDT 180]

You didn't notch the bolt instead or the pin?

[petert 588]

I notched the pin, not the clamping bolt. It’s only a small amount.

 

The Bridgecraft screw-in pins with 406 hubs is the best solution.

[SRDT 180]

The way I saw it you don't need to be as accurate when notching the bolt and if you do it wrong a new bolt is much cheaper than a machined pin.

But maybe the notch isn't a small one when done on the M10 bolt.

[petert 588]

Is this what you need? I'd make the pin from 4140, EN25 or EN26. Adjust the length of Spacer 1 to ensure arm is parallel with track rod. I've suggested a length of 90mm, but you should make it as short as possible once you have the spacers correct. Additional length makes it harder to fit the rose joint/arm.

 

 

 

Edited September 14 by petert

[Richie-Van-GTi 72 2 Cars]

42 minutes ago, petert said:

Is this what you need? I'd make the pin from 4140, EN25 or EN26. Adjust the length of Spacer 1 to ensure arm is parallel with track rod. I've suggested a length of 90mm, but you should make it as short as possible once you have the spacers correct. Additional length makes it harder to fit the rose joint/arm.

 

 

That's what I need, although, you threw a spanner in my thinking now. I had wondered about 406 hubs but wasn't sure how viable they would be.

Any idea what the strut situation is woth them regarding angle, I was going 306 to help undo a degree of the camber the extended bottom arms will introduce.

I am wanting to get wide enough to run 306 shafts and have narrower coilover springs and a modified adjustable top mount to bring the strut top out as far as possible.

The car will be purely a road car (dimma rep) so not looking to go too crazy on suspension.

[petert 588]

Look at the bruising on the casting from the side and bottom of the pin head. That thing really gets some serious loads. I'm only doing the 306 hubs as an interim measure until I've finished the 406 hubs.  I can't say what difference there is in oem camber values. A friend uses them (with the Bridgecraft pins) but has the same fully adjustable arms as mine.

 

There's a lot more time involved with the 306 hub modification, compared to the 406 hubs. If you aren't handy with the lathe you'll be paying considerably for time.

Edited September 14 by petert

[SRDT 180]

If your rose joints have rubber seals or even bronze rings it's better to design Spacer 1 and 2 so that at extreme angles they hit the joint steel body first.

It's usually only a problem during assembly and maintenance but with the whole A-arm as a lever it's very easy to damage the joint. On bronze rings a single nick can turn a free joint into a stiff one.

[Richie-Van-GTi 72 2 Cars]

4 hours ago, SRDT said:

If your rose joints have rubber seals or even bronze rings it's better to design Spacer 1 and 2 so that at extreme angles they hit the joint steel body first.

It's usually only a problem during assembly and maintenance but with the whole A-arm as a lever it's very easy to damage the joint. On bronze rings a single nick can turn a free joint into a stiff one.

Not bought the rose joints yet until I am decided exactly what I am doing 

[Richie-Van-GTi 72 2 Cars]

8 hours ago, petert said:

Look at the bruising on the casting from the side and bottom of the pin head. That thing really gets some serious loads. I'm only doing the 306 hubs as an interim measure until I've finished the 406 hubs.  I can't say what difference there is in oem camber values. A friend uses them (with the Bridgecraft pins) but has the same fully adjustable arms as mine.

 

There's a lot more time involved with the 306 hub modification, compared to the 406 hubs. If you aren't handy with the lathe you'll be paying considerably for time.

I design complex stuff for a living and have access to a 4 axis turning centre so no worries with making the part up. Looks like an M40 x 1.5 thread one end then a step for spacing between the rose joint and hub, a tolerance shaft to pass through the rose joint then a thread for a nut on the end.

Guess I need to get hold of a 406 hub to check the angle.

[Richie-Van-GTi 72 2 Cars]

Another thought, what about making an end for the wishbone that can be adjusted in and out and uses the standard 406 ball joint. Might be simpler.

[petert 588]

5 hours ago, Richie-Van-GTi said:

Another thought, what about making an end for the wishbone that can be adjusted in and out and uses the standard 406 ball joint. Might be simpler.

This is what I made for mine and my friend Adrian with 406/Bridgecraft hubs. Another friend Parry, also uses them, but with dodgy Ø16mm pins clamped in std 205 hubs.

[welshpug 1,657]

 

 

this is what satchell make for the 106, 205 arms are similar but the rear link mounting to the tca is inverted

 

 

[Spesh 31 1 Cars]

pretty sure the satchel 406 setup adds a minimum of 25mm to the track width, i assume to overcome any addition of positive camber from the differing hubs?   I've thought about 406 hubs down the line but when you add the cost of sorting the brake offset and longer driveshafts it adds up quickly

[welshpug 1,657]

i think most likely that the hubs have a taller offset from the hub flange to the strut clamp, pushing the balljoint out.

 

for the narrow (standard)  track kit they use the 307 hubs though,  very similar lower balljoint arrangement, same caliper fitment as a 205/306, but a 2 bolt clamp to the strut.