bb86 to bb30 for hollowgram conversion ...

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

Rumor had it Starnut was working on a project to put a hollowgram crank (bb30) on a bb86 bottom bracket shell some how ...

Starnut seems to be tough to get ahold of these days so I would see if anyone had any clue if there was any progress :)

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by daj

To me that seems pretty stupid. Even if you would manage to put a 30mm axle into a pressfit bb86 bracket, the bearings would be really small, giving you high friction and/or low durability.

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by TheRedMantra

I started a long thread on this in the mtb section: viewtopic.php?f=1&t=85614

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by JensW

TheRedMantra wrote:I started a long thread on this in the mtb section: viewtopic.php?f=1&t=85614" onclick=";return false;

but it´s a little bit different on road then on mtb. on mtb cannondale use a axle that is longer and have spacers and a lip that is about 1 cm from the splines on the axle. on road, the axle is much shorter and no spacers and so on, so on road the chain line would be much higher then it should be

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by WileEcoyote

Reviving this thread for a question. My wife has a Cannondale SiSL crankset on her Caad9. She is considering a new frame. We have a good relationship with a local dealer that sells Giant. The TCR has a BB86/92 shell. I saw that Rotor makes BB86 to BB30 pressfit cups. So that solves that. Now, obviously the shell width is different. The Caad9 is 68mm, which uses the 104mm spindle. The BB86 is 86.5mm. Could I just use the Cannondale 122mm spindle and be good to go?

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by thisisatest

This has been asked a million times, but ill answer it again.
No, you can't.
Even if you could find a 122mm spindle, it would put each arm 9mm outboard from where they are supposed to be. It will also move the chainrings out that distance. Road chainline is 43.5mm, this would move it to 52.5mm, wider than any conventional MOUNTAIN bike, and make for impossible shifting. The front derailleur would never sweep that far, anyway. To top it all off, current SiSL MTB spindles are 132mm, another 10mm wider. You would also have to get the lip machined off.
While the stance width might be a non-issue (who knows, you could benefit from it), the chainline issue is a deal breaker.

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by WileEcoyote

Thanks. I keep forgetting the Cannondale chainrings have a different offset.

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