Are some manufacturers slowly moving back to threaded BB’s?

[unterhausen]

Originally Posted by oldpotatoe

One of my gripes is to call anything 'BB' or 'axle' a 'standard'...a lot of this 'stuff, I'm glad to be away from..I don't have to

as the saying goes, the nice thing about standards is that everyone can have their own. The ever proliferating axle standard progression is really annoying. I had just bought TA dummy axles and then Boost came along and 12mm road front TA. Those $100 sets of dummy axles for each variant really start to add up. Why the road guys didn't just go with 100mm 15mm TA, I am choosing to not understand.

[m_moses]

I thought this video by Raoul Luescher about BB30/PF30 was interesting. He makes some valid points about tolerances in production environments that lead to less than ideal installations.

https://youtu.be/RFa5HBfRhnE


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[oldpotatoe]

Originally Posted by unterhausen

as the saying goes, the nice thing about standards is that everyone can have their own. The ever proliferating axle standard progression is really annoying. I had just bought TA dummy axles and then Boost came along and 12mm road front TA. Those $100 sets of dummy axles for each variant really start to add up. Why the road guys didn't just go with 100mm 15mm TA, I am choosing to not understand.

15mm vs 12mm is so heavy and un-aero, duh, and everybody knows it....

->

That’s why when I crimp my cable condoms I do it fore-aft direction, for aero ness. Geeez don you know nuthin?

[Kontact]

Originally Posted by m_moses

I thought this video by Raoul Luescher about BB30/PF30 was interesting. He makes some valid points about tolerances in production environments that lead to less than ideal installations.

https://youtu.be/RFa5HBfRhnE


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It's funny how the press fit BBs of the '80s had excellent reputations but bike companies today can't manage to make a straight how to press bearings into.

[Black Dog]

Originally Posted by Kontact

It's funny how the press fit BBs of the '80s had excellent reputations but bike companies today can't manage to make a straight how to press bearings into.

In the 80's they were machining steel (edit: I meant to say metal here) BB shells for the bearings to press into. Molding a high tolerance opening with carbon fibre is a different beast. The molds may be perfect but the thing coming out of them rarely is. Look at the rear triangle alignment of many high end CF production frames.

[Kontact]

Originally Posted by Black Dog

In the 80's they were machining steel BB shells for the bearings to press into. Molding a high tolerance opening with carbon fibre is a different beast. The molds may be perfect but the thing coming out of them rarely is. Look at the rear triangle alignment of many high end CF production frames.

Steel, aluminum and titanium. I had thought many of the issues where with aluminum Cannondales and aluminum shells in carbon. Does anyone make a carbon BB30 shell with the circlips?

[oldpotatoe]

Originally Posted by Kontact

It's funny how the press fit BBs of the '80s had excellent reputations but bike companies today can't manage to make a straight how to press bearings into.

Merlin, Klein..I guess except when you wanted to change a crank or find the merlin tool kit..They worked pretty well but were no fun to work on.

And didn't Merlin offer a freebie, convert to threaded BB shell, once upon a time?

[Mark McM]

Originally Posted by oldpotatoe

And didn't Merlin offer a freebie, convert to threaded BB shell, once upon a time?

Yes they did have a program to swap BB shells. This involved cutting out the orginal shell, and welding in a new shell (joints with the downtube, seat tube and chainstay rewelded). I know at least one person who had his frame converted. My recollection was that the service was reasonably priced (a few hundred dollars), but it definitely not free.

[Kontact]

I'm surprised they didn't just sleeve it - I recall the shell was fairly thick if they were to bore it out.

Otherwise, there's just enough material to just thread it Italian.

[Cicli]

Well, four pages and I an still glad I jave a threaded bottom bracket on everything. Even if this Roubaix is lower end.

[Mark McM]

Originally Posted by Kontact

I'm surprised they didn't just sleeve it - I recall the shell was fairly thick if they were to bore it out.

Otherwise, there's just enough material to just thread it Italian.

Merlin pressed in BBs used cartridge bearings with a 30mm OD. The OD of the shell wasn't much bigger than the 1.37" (34.8mm) ISO thread diameter, so there wasn't enough metal to ream out the BB and cut threads. On the plus side, the small original BB shell meant that the frame tubes had a little extra length, so they could be cut and mitered for the larger threaded shell.

[Kontact]

Originally Posted by Mark McM

Merlin pressed in BBs used cartridge bearings with a 30mm OD. The OD of the shell wasn't much bigger than the 1.37" (34.8mm) ISO thread diameter, so there wasn't enough metal to ream out the BB and cut threads. On the plus side, the small original BB shell meant that the frame tubes had a little extra length, so they could be cut and mitered for the larger threaded shell.

I just had a brain freeze - I was thinking Klein, not Merlin. Yeah, the Merlin's where too small AND thin walled to screw with.