BB cup lost its thread, is this just normal wear or other?

I was out yesterday and it looked like my drive-side BB had come loose. Just stripped it and somehow the BB cup has lost the majority of its threads. As per the picture (one on the right) 3/4’s of it has lost just over 0.5mm diameter.

Hope Ceramic BB, nearly 4 years old and done an awful lot of k’s (probably 10,000). I guess luckily its on a Ti frame, so doesn’t seem to have affected the BB threads.

Any thoughts?

Well maintained, and stripped/cleaned often.

Have seen this a few times,Usually because it was used one loose.

I had exactly the same thing happen with my ti frame and a hope bb. It turned out the spacers were too soft and the bb cup worked lose, destroying the thread. Hope now supply a different type of spacer. I contacted hope and they repaced it for free with new spacer.

Snap!
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DSC00841[/url] by druidh_dubh[/url], on Flickr

XTR BB / Ti Frame. I noticed one day that it was rotating with the crank. The preload was still OK, so I can’t see how it could have worked loose.

Slightly loose bb,it happens.

It turned out the spacers were too soft and the bb cup worked lose, destroying the thread. Hope now supply a different type of spacer. I contacted hope and they repaced it for free with new spacer.

Interesting as I’ve replaced the spacers regularly as they were ‘squashing’… Thanks, will call them tomorrow.

The original BB consisted plastic spacer between the frame and the cup, but this was replaced by alloy spacers. I think the combination of a slight amount of play and hard titanium threads is what did it.

I’ve had no issues with the replacement.

I had a Raceface one that had done that, came in a frame, with alu spacers. Though, no idea of its history before that obviously. It left a lot of thread stuck in the frame.

The original BB consisted plastic spacer between the frame and the cup, but this was replaced by alloy spacers. I think the combination of a slight amount of play and hard titanium threads is what did it.

Agree, but based upon a friends alu Trek wrecking its BB threads, rather it was the BB cup than the frame.

trashed a hope bottom bracket because the spacers were soft and the cup could move. It didn’t do any favours to the frame either. Frame was usable but no where near perfect.

Hope bb and the same for me!

Xtr from rose bikes now… No problems and cheaper 🙂

(Steel, not ti though!)

Just spoke with Hope. Said to send them in and they’ll sort them.

Good lads.

Also I’d suggest that anyone who has their BB with the old fibre-spacers to replace them with metal ones.

didn’t realise this was so common. luckily cups are normally softer than frame (6061 cups, 7075 frame in my case, or steel, or ti), otherwise you could have trashed frame.
shimano still give plastic spacers on the cheapest ht2 bb cups too. do not use these for reasons above.

None of this hassle with Pressfit BBs, you know

*runs off, laughing*

You guys need to tighten the BB cup better on installation.

druidh – Member
The preload was still OK, so I can’t see how it could have worked loose.

You think that’s enough to stop the cup loosening?

No, but I thought that it might have been noticeably tighter when the cup loosened off.

You guys need to tighten the BB cup better on installation.

Says a man with no idea of what is going on…

The spacers that Hope originally supplied were some fibre type material, this broke up so they switched to aluminium. The damage to mine was caused due to a spacer that disintergrated..

Anyway, just been speaking with them and there was no issue with a replacement cup (and washers, enough for both my Hope BB’s) and they’re also putting in new ceramic bearings (at cost price).

Good lads.

And an all-new BB (both cups, bearings and extra spacers) turns up 🙂