So using the search function, it seems that you can replace an English BB with a BB-30 although it may not be reccommended. I have a Cannondale System Six that I am thinking of upgrading to BB-30 when i wear out my current setup. Someone said that Cannondale says to not do it for their carbon frames, but for their aluminum frames it's ok. Does anyone know if this is true? They also said most shops will do it anyway... Thoughts, criticisms, or concerns?

this is like trying to insert your fist into your mouth.

I.E. you need to destroy one or the other to make it fit.

Well, no, you can't "convert" to BB-30 from English. However, I think you probably have a BB30 frame it sounds like, with an adapter installed to allow you to use English. If you remove this adapter, it will be ready for a BB30 crankset.

The problem is that the adapter is glued and pressed in. Some manufacturers don't have a problem with you removing it, some do.

I have heard that Cannondale doesn't like you doing it with their carbon frames, and I think it voids your warranty.

It's up to you if it's worth the risk. Get a good shop to do it though if you decide to try it.

Zipp Vuma

https://www.zipp.com/cranks/detail.php?ID=70

Is thhat true? I thought it was just pressed in.

Regardless, someone that knows the adapters and related engineering stuff said that in general you don't want to be swapping the adapter in/out of AL frames. Choose one or the other. The reason is that the aluminum in the BB area will stretch a bit with repeated pressing of the adapter.

With carbon I don't know, we were talking AL at the time.

Based on my talks with this guy (a good friend and engineer for a bike company based in Bethel, CT ), I skipped buying just the SystemSix frame and swapping my non-BB30 group onto it - instead I bought a complete SystemSix bike with a BB30 BB/crank (through a shop through eBay, not through my friend).

hope this helps,
cdr

I think sometimes they're just pressed in, sometimes they're glued as well. Don't remember where I read that though, I might have made it up.

If properly installed, the adapter on the Cannondale is glued in with Locktite. Didn't know there was a green locktite but that is what is used. Not sure about aluminum frames but the adapter can't be removed from a carbon frame without the risk of damaging the frame. I just bought a Cannondale yesterday with an Ultegra crank so this is what the bike shop told me.

Well, hang on... what's the point of a BB30 frame if you can't install a BB30 crankset in the future? It can be done, right?

it almost seems line one is better off getting the BB30 and then using the FSA sleve, no? I think that one is removable with special tools...

It's specifically meant to hold bearing sleeves and races.

I don't think that there is an adapter. My frame has an English BB. So what I am asking is if there is a way to replace that BB. I know that there are adapters that you can run BB30 but that defeats the purpose.

If your frame is an English BB, you can't put a BB30 in there, there isn't room.

^^^ Yup. What a BB30 is is a way to use bigger bearings and put them inside the BB shell. Imagine taking outboard bearings and shoving them inside the frame so that they're flush with the bottom bracket shell.

And then using a bigger spindle, instead of cups inside. The 30, in BB30, is the spindle diameter, 30mm. The Zipp crankset that someone linked above uses a 30 mm spindle, but instead of pressing the bearings inside the shell, they use outboard bearings. I would imagine you get most of the stiffness of a BB30, but not the lighter weight or better Q-factor.

So that is a no then. I thought that their might be a way to drill out the hole to fit the BB30.

you can do it my friend has it on his cannondale capo. it uses custom cups and a cannondale mtb spindle turned down. the q factor gets bigger like mtb but it works, so you can use hollowgram crank

Hmm... Is this like what he did?
https://veloptimal.com/forum/viewtopi...r=asc&start=90

my french sucks, but very much the same with red ano cups and he turns spindle on lathe and presses on a sleeve

You could technically cut out the BB shell and weld in a new BB30 shell. But I probably wouldn't do that to an aluminum frame.

Merlin did this on their press-fit bb shells -> 68mm shell conversions

https://forums.roadbikereview.com/sho...65&postcount=3