BB30A83 Custom Bottom Bracket Designed and Manufactured – Cannondale Topstone

| |
Cannondale BB30A83 Shimano Bottom Bracket

A Hambini viewer recently enquired about a bottom bracket for his Cannondale TopStone Gravel bike. This bike uses a BB30A83 bottom bracket. A design which is highly unusual, extremely rare and unique to Cannondale.

From the frame centerline, the driveside and non drive side apertures have an asymmetrical offset – hence the “A” in BB30A83. There is not much room to work with on the non drive side. Additionally, the user requested a necked design to give him clearance for his internal cables.

The final design is shown below

Following customer demand, this bottom bracket has become a production item. It is available here

Similar Posts

COMMENTS! Please leave a reply to add to the discussion! NO NEED TO REGISTER!


  1. Wow, Very impressive. I just had to engineer a water tight seal! Please can you confirm the BB is for a 30mm spindle ? And price?

    1. It’s not possible to make any bearing water tight. You can make it water resistant but submersion will result in ingress. This bottom bracket was for a Shimano crank.

  2. Interesting. I’d like to fit a Campagnolo Ekar crankset to the Cannondale Topstone – I wonder if something similar to this might be a solution?

    1. It’s not straightforward fitting a campag crankset into that frame. The bearing arrangement is fixed floating, so the interference is actually on the shaft. It can be done but it isn’t easy.

    2. Hi Oshsan, I myself have the same wish. Put the Ekar Group on mijn Topstone 5 Carbon, did you already made it and did you use tis BB? I’m very querius. Best Regards Janko

  3. Hi there. Is this for the Cannondale Topstone Carbon? I was in a similar predicament last year. I wanted to fit a Shimano GRX crankset to my Topstone Carbon, but was struggling to find any tried and tested solutions. The information available was quite vague and contrasting.

    I ended up taking a punt and using the “WheelsMFG BBright/BB30a/PF30a” adapter set. This did indeed work, and just required some small adjustments to the front derailleur positioning.

    I still currently have the GRX crankset on my bike, and 1500 miles later there doesn’t appear to be any issues.

    Can you think of any long term problems of using those WheelsMFG adapters? I would have liked to purchase one of your bottom brackets, but only came across this website *after* the cranks were already on.


    1. It was used for a Topstone Carbon to Shimano. I imagine the only issue with any of the true adaptor types ie the fit in ones is a tolerance stack up and loss of stiffness.

      1. Thanks for the reply. Will the BB30A83 bottom bracket ever be available again and if so, would I need to add my name to the waiting list?

      2. Thanks for the reply. Will the BB30A83 bottom bracket ever be available again to purchase? If it will, then I will add myself to the waiting list. Cheers.