Please help me change my bottom bracket.
 

Hey all.

I need some help please. I have a Cannondale super six Evo with a 105 group set.

The only non 105 component is the crank which is an FSA gossamer.


The bike has about 1500 miles and i like to stand up and power up the few inclines we have around.


Unfortunately after climbing over a hill i noticed a clunking with each pedal stroke. It sounds like a ball bearing falling down each time and is loud.


I put the bike on my workbench and took the chain off and confirmed it is coming from the crank area.


I removed the crank and the bearings. I almost expected there to be something inside rattling around but there wasn't.


1 bearing seems noticeably stiffer and had some black grease that seemed to have come from inside the bearing.


I would love to change to a Shimano 105 crank and understand i need an adapter but i am completely lost when looking for the right one.


I have no bottom bracket in my bike. I only have press in bearings with no c clips.

This has thrown me off as it looks different to all the write ups i see.


Can someone help me find the right parts please?

@Sabotage5.0

Sorry I completely read thru the supersix part.

disregard mine

The Supersix does not have a threaded bottom bracket. Depending on the year and model of the Supersix, it will either have a BB30 or a BB30A pressfit-- the BB30 is a 68mm shell width, the BB30A is 73mm. Wheels Manufacturing has BBs to fit a Shimano crank to either style.

BB30A Outboard ABEC-3 BB for 24mm Shimano Cranks
BB30 Outboard ABEC-3 BB for 24mm Shimano Cranks

That is correct i checked them 6806-2rs

Will A praxis 68mm bb30 ceramic be right for me?
And then which pick of the 105 or ultegra crank would be best considering i like to stand up and be aggressive on inclines?

The BB will depend on the year of your frame (for the BB shell width.)

Either of the Shimano cranks will be about the same, as they both have 24mm spindles. Be aware that you're getting into Shimano's proprietary 4-bolt chainrings, so make sure whatever crank you buy has the rings you want. It's not like old 5-110 or 5-130 where you can buy rings from a catalog of manufacturers.

Lastly, there's absolutely no need for ceramic bearings in a bottom bracket. If you want them, knock yourself out. But there is no need. I have a Shimano BBR-60 (undersized bearing cups, no less) that has split time between 3 bikes, and still works perfectly with well over 20,000 miles on it. My Rotor press-fit PF4630 got 8,000 miles before the plastic cups started to creak. The ABEC-3 steel bearings are still fine.

Thank you, all great info.
I have been trying to figure out which size bb i have. i don't see my style anywhere online. It has no proper bottom bracket or c-clips. The bearings just fit right in the frame of the bike.
I am also confused as my crank states 130mm BCD and all the cranks online have 160-175mm. I would assume i would get the same 53/39t.
I really wanted to make this an upgrade but if i won't notice much difference between the ultegra and 105 i guess it would be sensible to go 105 and have all my groupset the same.

Reading up some more, it appears that the Supersix Hi-Mod is the only model of Supersix using the BB30a, so you just have a BB30. So the Wheels MFG BB30 to Shimano will work. There are others that are direct conversions, like Kogel, but only if you feel like shelling out $175 for press-fit. The Wheels BB will run about half that, and threaded will be the best bet to prevent future creaking.

You're confusing BCD (130 bolt circle diameter) of the chainrings with crank arm length (160-175). Two totally different measurements

...I've never installed a conversion unit into a BB30 frame, but I'm not certain you need two of the tools in order to tighten the thing into the BBshell. I could be wrong. Someone who has done it should chime in soon.