I have been using Rose joints as the pivot for a sidecar swingarm, see photo



They are 16mm in size

One joint has snapped  through the threaded part and both of the spherical bearings have got some movement due to wear. Not sure whether the break was due to movement in the spherical bearing because of wear or whether it was not big/strong enough or a combination of both.

Initially I thought I would increase the size and quality of the joints but this is not possible unless I rebuild the whole system. These joints have been on the bike for about 10 years
I think in future I will check for wear annually and maybe swap them out regularly.
Now here is the question:
If I was to get the same size but better quality rose joints, say racing or aviation spec would it give me a stronger and more durable product ???

It depends if your originals were made of Chinese cheese. If they weren't, I'd settle for an annual check as surviving ten years under the stress of a heavy sidecar is good going.

As for 'aviation spec'... my favourite story there concerns the Lockheed C-130 (Hercules). For a 20mm hydraulic copper washer bolted to the undercarriage, Lockheed-Martin certified it as 'aviation spec' and charged the  US govt. U$198 per washer. Someone did some materials testing and found that said U$198 washer could be had for 0.80 cents at the nearest autoshop.

Dai wrote:It depends if your originals were made of Chinese cheese. If they weren't, I'd settle for an annual check as surviving ten years under the stress of a heavy sidecar is good going.

As for 'aviation spec'... my favourite story there concerns the Lockheed C-130 (Hercules). For a 20mm hydraulic copper washer bolted to the undercarriage, Lockheed-Martin certified it as 'aviation spec' and charged the  US govt. U$198 per washer. Someone did some materials testing and found that said U$198 washer could be had for 0.80 cents at the nearest autoshop.

Would you fly in an airplane that was assembled with hardware from a local hardware store?

There are valid reasons why said washer would cost $198.

In that particular case, Lockheed-Martin admitted they were taking the piss gilding the lily. The price of the washer dropped to (IIRC) somewhere around $1.00 a unit.

And when you get into "aviation spec" there are different standards for different applications.  

Some examples are NAS, AN, MS which are American standards.  Different tensile strengths, alloys, etc.  A lot of components are "lifed" or replaced on condition depending on the application.  Is the item subject to extreme temperatures (hot/cold) or just holding something in place which may also be subject to violent movement such as military aircraft hydraulic powered flight controls?  Some items are made for one specific job and nothing else.  What is the torque on the item?  

As for your rose joints it depends on the application.  Like all bearings, are you carrying axial or rotary loads or a combination of both?  Looks like there a grease nipple fitted, so do you give them a squirt occasionally?  

The aviation industry has always been expensive and I would expect the racing industry to be the same.  The bottom line is if something fails on your vehicle then generally you will come to a stop and walk away.  In aviation if something fails then there is a good chance you will die.  

Perhaps the engineers on this site would like to put us to sleep with their knowledge.

Follow this for total confusion
https://www.google.com/search?client=firefox-b-d&q=metric+heim+joints&sa=X&ved=2ahUKEwjR44Hn0o7oAhWG7HMBHZg7AD4Q1QIoBHoECAwQBQ&biw=1599&bih=926