S-Works Tarmac SL 6 (DISC) OSBB Dimensions for new BB

Discuss light weight issues concerning road bikes & parts.
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ergott
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by ergott

Calnago wrote:
Thu Aug 02, 2018 3:26 am
@Ergott... the whole “OSBB” thing is a clusterf#%¥ of nomenclature. The Crux you are working on has the “old” OSBB with the narrower BB shell (61mm I believe). I worked on one of these some time ago. I used a Praxis BB but also had to use two 3.5mm spacers on either side of the shell to essentially widen it to the standard 68mm shell. All worked out fine. The narrower BB shell was a disaster as Specialized tried to differentiate themselves from Cannondale. A narrow shell with loads grinding away on the outer edges did not play well with longevity. Anyway, they’ve moved from that but I think they still use the “OSBB” term. Currently I don’t think they have any “narrow” OSBB shells in the lineup.
I understand all that, but the published timelines people refer to are wrong. The Crux I'm working on here is the current model.
https://www.specialized.com/us/en/s-wor ... 487-129101

The Tarmacs I've worked on are 2016 SL5. Both are stated as BB30 by BB literature everywhere. That's why I asked if anyone has actually measured the SL6.

The bearing to bearing measurement for the bikes I refer to is 63.5mm, not 61mm. This, just like when I build wheels, is why I measure stuff. So much misinformation online.
Last edited by ergott on Thu Aug 02, 2018 2:50 pm, edited 1 time in total.

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ergott
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by ergott

.... duplicate

by Weenie


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ergott
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by ergott

Okay, one hypothesis I need help with. When you are talking about a 68mm shell, where is that measurement to? I installed this crank with the same amount of spacers and BB30, but I'm 100% positive the bearing to bearing measurement is 63.5mm. Is there some other way? I do notice that the shell is a bit wider and the bearings a a little recessed.

Siok
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Joined: Wed May 23, 2018 5:20 am

by Siok

Confusing indeed... just built my SWTarmac Disc for DuraAce 9100 Crankset... didn’t want To waste the ceramic bearings so I inserted Enduro Bearings 24mm adaptors for Shimano and so far it’s working wonderfully. Good luck.

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