rose v johnny joints

[serious3]

lads i'm looking at a custom 3/4 link set up on our new build and was wondering about the difference between rose and johnny joints, how do you size them? grp4 fabrications show up to 5/8" rose for rally cars but devon show 2.5" johnny joints! is it the pin size or outside dia? anyone using them instead of bushes at the axle end, as i figure that you could get some more flex that end?

[minimog]

rose joints/hiem joints are mesured by the size of the thread and by the size of the hole
johny joints/flex joints are usually measured by the overall width of the unit(the bit where the bolt goes through) and will give you the bolt size seperate and the shank thead size the good thing about these joints is they have a poly spacer around it so has a cushening efect so arnt as harsh on a road going car

if using rose joints i tend to get the next larger size and use reducing misenlignmet spacers this will give you more space for the joint to twist (allow more articulation)
also buy the best you can afford if using on suspension or steering components (you will find theres very little in cost between the two by the time you have got every thing needed)