Cyclami 18t offset pulley wheel for expanded cassette range

[jonathanf2]

https://www.aliexpress.us/item/3256810576987349.html

A few weeks ago on a whim I ordered a Cyclami 18t offset pulley wheel. When I bought mine, it was about $20usd, but prices seem to have been fluctuating. I'd shop around or wait for a sale. Even though it wasn't advertised, other offset pulley wheels such as those from Tripeak and Sugino do suggest expanded cassette range while maintaining accurate shifting.

I installed it on my LTwoo eR9 road bike and it's successfully running a 50-34t/11-36t drivetrain with smooth shifting. I'm using an 11t Ultegra upper narrow/wide pulley wheel and the 18t Cyclami lower offset pulley wheel. The offset 18t pulley wheel takes the slack on a slightly longer while used the stock cage. Shifting with the 18t pulley wheel stays normal.

My only concern is that it uses ceramic bearings and I don't find them ideal especially in gritty conditions. I took mine apart and measured the bearing inside the casing. It appears to be a 6709 55mm*45mm*6mm bearing size.

I found some regular steel bearings on AliEx that match the size:
https://www.aliexpress.us/item/2255800723290638.html

I'll see how long the ceramic bearings will last before attempting to replace it with a steel bearing counterpart. Anyways, I like this pulley wheel since it does offer cassette range flexibility and can most likely be applied to a variety of rear derailleurs that might not otherwise be compatible with large ratio cassettes. 

* I've added photos. Though the picture of my drivetrain is still with a 10-33t cassette. 

[carbonMad]

How does an offset bottom pulley extend cassette range? When I read the title I though it was going to be used as the upper pulley to make more clearance for larger cogs

[jonathanf2]

How does an offset bottom pulley extend cassette range? When I read the title I though it was going to be used as the upper pulley to make more clearance for larger cogs

It takes up the longer chain slack without having to adjust the cage-to-cog distance affecting shift performance. The advantage of the offset pulley wheel is that it should work with a variety of RDs without the need of an OSPW.

I did try it with a 10-36t and it worked fine with decent shifting, but I went back to my 10-33t because I prefer tighter cog gearing.