I changed my bottom bracket bearings. Shimano cartridge bottom brackets are only about 14 USD and they make such a nice change to the ride quality, why be stingy? I guess I don't like the words "don't disassemble." Shimano BBs use non standard bearings, and can't be disassembled apparently but Chinese BBs for about 10USD use 6805-RS (37-25-7mm) bearings which can be purchased for less than 1USD each or less than 2USD for a BB refit.
I don't even have the tool to hand so I used a standard adjustable wrench to remove (and replace) the BB from the bike. The drive side is reverse threaded. Many BBs will have a "Tighten" arrow.
Changed BB Bearings by
Timothy Takemoto, on Flickr
It was not as easy as I hoped. Getting the old bearings out was easy enough, bashing, with a metal rod or hole punch, from the inner side. But pushing bearings into BB casing was not so easy at first until I realized I could use the old bearings as a plunger in my vice. Today I used bearings from a new ZTTO BB, which is a bit perverse but I wanted to try it out. I have four bearings @2.8USD on order from this shop on sale
https://www.aliexpress.com/item/4000...21ef18027pcEaG
I will change BB bearings as soon as I feel any grittiness in future.
And to be honest, I only changed the drive side bearing. The other side seems to be okay with new grease. I swapped it to the drive side. Revitalising my bottom bracket cost 70 cents.