I've been building up a Pipedream Sirius frame with an Octalink cartridge BB. The driveside cartridge screws in easily with fingers but the aluminium adapter (non-driveside) feels really rough going and there are a couple of points where it appears to stick; a little extra force with a wrench overcomes this and the and it carries on in. The adapter does go in straight and the threads aren't crossing (I've removed it a few times and replaced it). I've tried a couple of 68mm aluminium adapters I have lying around and they also feel a bit rough, but again go in straight without crossing threads (the Sirius has a 73mm shell and the adapter is rather longer so I guess that the roughness is magnified a bit).

A bit of copper grease smooths this up a bit but there does appear to be a bit of aluminium dust worn of the adapter. I assume that the problem is the threads on the non-driveside not being cleanly cut (but the adapter does seem to go in square, so they are complete). My main concern of course is damaging the threads in the frame but in a steel frame I'd imagine that if anything wears it'll be the aluminium or resin adapter, which doesn't worry me as much as the next time it comes out it'll be because it needs replacing.

So, do I need the threads chased or will they clear themselves up over time? I'm not keen to have them chased unless it's necessary as I assume that there are dangers in this if the bike shops a bit heavy handed. What do people think?

I wouldn't bother myself – if it goes in with only a bit of extra force it doesn't sound bad enough to chase them. Most of the new frames I have fitted BB to have been a little variable in the torque needed to screw in the BB TBH.

It doesn't need a huge amount of force to get it in, I'm just used to being able to screw them in with my fingers, and this one is beyond that. It's a bit rough but then hits a couple of sticking points but doesn't require major force. It goes in straight and comes out fine too, and there's no crossing of threads, it's just rougher/tighter than I'm used to on the non-driveside.

My concern's for the shell threads rather than the adapter's but I guess that an aluminium or resin adapter would wear first.

yeh but presumably your only doing this every year or two no? BUt your right the Alu or plastic will wear rather than the steel 🙂

It will be fine.

Thanks, that's reassuring.