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So, my Microspline freehub bearings (or one of them at least) needed replacing. I took the wheel to my LBS and he said he could put some new ones in (happy days). However, he has put some in and when I was leaving the shop the cassette fell off the wheel. He said it was fine and that once in the frame it would be OK but I have taken the cassette of my wheels more than a few times and I know that the outer drive side dust cap needs to "click" on (it also says this in the Shimano manual). It was not doing this so I told him and he took the wheel away again and came back with it sorted saying the dust seal inside the wheel was stopping it going on. Meh. 🤷♂️
I get the wheel home and decide to take the cassette off to make sure he has got all the shims back in the right place etc and sure enough the paper thin plastic one right at the back of the cassette is now missing.. FFS. I'll have to now take it back and hope he doesn't claim that I have lost it or it was never there... It most definitely was there as I saw it myself while diagnosing the bearing fault initially only yesterday.
Anywayyyyy.
So my questions are as follows...
1. The bearings that came out of the freehub were 6802 and 6803, they are the original ones as supplied in the bike from new and seem to be made of cheese - they have done approx 1000 fairly gentle miles - maybe that's normal but it seems a but low to me. I am no expert as this the first bike I have ever done any maintenance on so IHNI. So can I put better ones in next time? The freehub is from an MT500 wheel so SLX quality I suppose ( Hubs EV-WH-MT501-CL-R12-B-29-4556_MT500 Wheel Hub.pdf  ) and therefore probably not worth spending a fortune on bearings for...
2. If I wanted to change them myself in the future what tools would I need? I'm guessing some sort of bearing puller to get them out and a press to get them in? But what do I need without spending a fortune?
3. What does the paper thin shim at the back of a 12sp Shimano cassette do and is it OK without it? My guess is that it was put there for a reason so I have sort of answered my own question but if the LBS claim it wasn't there to start with or some other such nonsense, can I run it without?
Thanks in advance... 🙂
So I've answered question 3 myself - LBS managed to find the missing part and also rang Shimano to ask what it does - it is there to stop the cassette creaking against the freehub body. I notice that on my spare/new cassette the ring is stuck onto the cassette spider, presumably they've changed it because people kept losing the loose ones!!!
Anyway, I still have questions about the bearings if anyone is able to help - what are the best replacements to get for 6802 and 6803 freehub bearings and what tools would I need....?
They are easy to get out usually. Remove the caps and any locknuts and freehub. Then tap the axel and the bearing will pop out. You can press them in with a suitable sized socket.
I use Wych Bearings
Thanks @fossy - these are the bearings inside the freehub body. There are three sets of sealed bearings - 2 x 6803 and 1x 6802 , can I get them out with a socket as well do you reckon...?
The axel bearings will pop out with the axel. The freehub, you can drift them out with a screwdriver. I have 4 bearings in my Formulas, two for the hub and two for the freehub.
OEM bearings aren't always that great. Places like Wych have a variety of the same bearing.
As others say, i get mine from Wych Bearings, you want the 6802-LLB and 6803-LLB models, enduro is a good brand, the reason for the LLB is that they are the light contact ones, so better for hubs that are constantly rotating, the LLU or medium contact are better for pivots/headsets/etc, same with any MAX bearing, avoid for hubs, but good for pivots and so on.
https://www.wychbearings.co.uk/6802-LLB-Enduro.html
https://www.wychbearings.co.uk/6803-2RS-Enduro.html
The 6803s in both my Hope Pro4 microspline freehub and Newmen one also didn't last all that long, with my experience of Pro2s lasting a good 2-3x longer. I suspect the smaller bearing that Microspline necessitates is to blame.
However, once you get used to removing and fitting cartridge bearings it is a quick job and replacements are inexpensive. I use a bearing press bought off ebay/amazon and often linked to on here. It's a pleasure to use. And you should probably be in there cleaning and lubricating the freehub by then anyway.
I bought the same as above also from Wych and, rightly or wrongly, packed them with extra grease. Although I think that's a red herring in the case of the Hope which fell to bits rather than just going rough.