Now I've gone and done it... broken something... 😧

[synchronicity]

Attempting to install a M640 Zee crankset to an XT MT800 BB.
The BB has gone in nice enough.

But I seemed to have cracked some little plastic sleeve on the steel axle/spindle.
A little sleeve which I didn't even know was there!

Can someone tell me, what is that? Is it part of the crankset or the BB? Where can I get another one?
It appears to be a spacer sleeve of some kind. Without it the axle just flops around inside the bearing.

WHY DOES SHIMANO MAKE PLASTIC SHITE PARTS ON LOAD BEARING SURFACES??

 

[klunkrider]

The sleeve that sits inside the bearing?

You can get them on eBay https://www.ebay.co.uk/itm/374217796430?

No idea what the quality will be like though.

I’ve had them get loose and come out, they’ll usually sit there alright if you place them back in as the cranks kind of hold them in, maybe not if it’s broken though?

As for why, to allow for poor tolerances in frames probably.

 

[novocaine]

As for why, to allow for poor tolerances in frames prprobably.

Never knew you could get them on ebay. Thats a win.

There as a shield and spacer.
As to why? Allows 2 sizes of axle woth only 1 bearing soze. Shimano doesn't make the bearings so they have to go with what is available, ll. Also there so there isn't a bearing to sale contact to corrode together and stop you ever getting the axle out.

 

[synchronicity]

So. These little blasted plastic Chinese-made BB bearing covers arrived this week. Finally!

I fit the zee crank spindle in the the XT bottom bracket, but now there is definite drag in the system.
Too much for my liking. They don't spin freely at all. Too much friction.
Without even turning that silly little "TL-FC16" plastic tool thing; without even cinching the pinch bolts up!
What could be causing that?

 

[synchronicity]

Now, attempting to rectify the situation, in order to work out where the friction is coming from, upon removing the remaining side spacer, that left hand side plastic spacer (original shimano) has broken too!
I have fitted the dodgey chinese replacements both sides, and it seems to be better (less rotational friction).
But still, I am not happy about this plastic shim bullsh¡t.
Not ideal. Why did they do it?
It's the last shimano bottom bracket I ever buy, I tell you.

 

[klunkrider]

Remote diagnosis is difficult, especially with no visual clues but this really doesn't sound right.

In my time I must have had HT2 cranks in and out of their bottom brackets thousands of times (I'm a mechanic so I'm actually not exaggerating) and I've done the forbidden disassembly a couple times in order to repack the bearings and I've never broken one of the plastic top hats never mind two!

I have had them fall out or pull out on the crank axle but not break.

The plastic is, imo, a really good idea, it's an inert material so won't seize to the axle like a metal on metal interface could/does in other brands and as previously mentioned, it does a good job of accommodating poor manufacturing tolerances.

 

[synchronicity]

It seems to be "satisfactory".
I'll just have to live with it.

 

[dan28]

theres a guy on ebay with a lathe maybe if you send him one he can machine some out of brass