Showing results for 
Show  only  | Search instead for 
Did you mean: 

Can Canon USM motor interchangeable?


While I was trying to fix a Canon 17-85mm IS USM lens, I found out it was a USM motor failure.


I had a couple of other lens disassembly, such as 100-400mm. My feeling was the USM

motor of them are the same. I regret that I did not measure the diameter of them and other parameters...


Do anyone know if I can recycle those USM motors from other broken USM lens? Or is there a 

compatible USM motor list that I can refer to?


Many thanks,



What I really meant was the motor ring. I understand if adding other parts then they are different.Screen Shot 2019-01-16 at 11.03.23 AM.pngs the USM motor 

There are two sizes of Ring Type USM motors.  I believe as long as you have the same size USM motor, it should work in another lens. 



Mike Sowsun

Thank you Mike for the quick response. I guess in my case, for the normal focal distance, the small size USM motor ring are all good recycle sources that I should look for.

Yes, your 17-85 has the small size USM. I think the 100-400 also uses the smaller size. I think just the big Super tele's use the larger size. 


Just make sure you avoid any Micro Motor or MM USM lenses, as they are not Ring Type USM, and are totally different.

Mike Sowsun

Thanks for the confirmation. I will buy those cheap "AS IS" USM lens from ebay to fix mine. Will update this thread.


I won't confuse with those Micro motor and other small version motor 🙂




It is best to replace the USM as a complete assembly, once it is disassembled it can be quite tricky to get the right tension when putting it back together. The wrong tension can stop it working or make it unreliable.

Thank you Ray. This is a good point. I never realized this. I did the cleaning for two of my USM motor rings, I was wondering why there was wave-shaped bushing on top of the ring. So far they are still good. Since most of the broken lens (I fixed them as my hobby) are old version- of course the broken new model goes to Canon dealer - to save money while still maintaining functionality is the key...





A quick update on the micro USM front. I still did not have the chance to the try the USM motor ring.

The micro USM motor seems to have two different versions. One with the 4 pins and one with 5 pins. 

See the picture enclosed. They are definitely not interchangeable.





Which two lenses are those AF motors from?  


The one on the right looks like the EF 50mm f/1.4 Micro Motor USM.  It is the only MM USM lens with a clutch system for Full Time Manual Focus over-ride. 

Mike Sowsun
click here to view the press release