Cannondale Supersix Evo BB advice

Hi my sister has a 2018 Supersix Evo 2018 (as shown below).

She wants to fit a left sided 4iiii Shimano crank so she can start training with power. I’m having a nightmare trying to find out what BB is in that bike, and also what BB conversion kit I need.

It says BB30 on the frame, but online information varies: saying BB30, BB30a, and PF30a. Does anyone know if there is a conversion BB to enable it to run a standard shimano hollowtech crank?


I have the same bike and power meter, If it says bb30 on the frame go with that, Wheel Manufacturing do a conversion BB to Shimano standard which works very well, there are other from Token and Praxis but those ones I have not used.

It would appear you’re working with a pf30a, which is not identical to pf30 but adapters for shimano cranks do exist.


Mine is a 2016 Evo I know Cannondale released the BB30a some point after. Armed with the info above it might be best to let’s your local bike shop supply and fit for you, Wheels, Praxis and Token do them across all BB standards.

I don’t know what Cannondale are playing at with this. My old 2015 SS Evo had BB30 painted under the BB when it’s a PF30. It really doesn’t help does it?!

I used the GXP version of this on my '18 EVO Hi Mod. Only difference is that there’s the silver and blue spacers you put inside for GXP, it’s the same BB for both Shimano and GXP otherwise. If you have a BB30 bottom bracket in the frame now you could just use the Wheels Mfg adapters to make the Shimano crankset work in it.

Be careful here: just because it has BB30 painted on the frame does not mean it is BB30! I learned this lesson the hard way with a CAAD12 I built up recently. It had BB30 painted on the frame but was actually a BB30A. I ended up overloading the bearing because I put the wrong spacer on during the crankset install.

Best to take some measurements with a pair of calipers to find out for sure. A BB30 frame will have a 42mm ID and a 68mm width. BB30A will have a 42mm ID and a 73MM width. PF30 and PF30A have the same widths as BB30 and BB30A, respectively, but will have a slightly larger ID (46mm) to accommodate the bearing sleeves.

Here’s a helpful link: Bottom Bracket Standards Chart