Advice on Chainring upgrade

seast Posts: 4
edited September 2018 in Workshop

I've seen a few posts on this subject or close to it but the issues raised by some people weren't really answered and I don't want to fork out for new kit that doesn't fit.

I have a 2019 Cannondale Synapse Di2 which is lovely except it has FSA rings on the otherwise nice SI crank which I find shift poorly and also have quite a bit of flex in them.

The bike has an odd size of spider (120 BCD and 90 BCD rings on a four arm).

My choices for upgrade are:

1. Cannondale 8 arm spidering 50/34;
2. Cannondale 5-arm 110 BCD spider, Praxis Works Buzz Road rings 50/34;
3. New BB to convert to Ultegra crank.


1. I've read excellent reviews on the Cannondale 10 arm spidering bot nothing on the 8. The 10 is too expensive. Does anyone have experience of the 8 arm? I am assuming compatibility will not be an issue.
2. I've read a lot of rave posts on the Praxis BUT I've read at least two posts by Cannondale owners saying they were (and this is where it gets confusing) too close together/too far apart!? and one saying they "did not fit". Has anyone any experience running these rings on my set up or close to it?
3. Converting to Shimano would be nice but expensive and a longer term project overall. To get going now I'd need to get adaptors to start with and a then upgrade the BB to a nice ceramic later on - I have an Ultegra crank I can use (6800) but would need to upgrade to 8000 later to get this to match lots of money spent. Has anyone used the adaptors with the standard BB? I also wonder if this undermines the whole point of the BB30a??

Essentially its between 1&2 at the moment but 3 is there as I could easily pop in the adaptors and fir my Ultegra 6800 crank....


  • seast
    seast Posts: 4
    No-one has any info?
  • imposter2.0
    imposter2.0 Posts: 12,028
    ok, I'll start. How are you defining 'poor shifting' (in comparison to what?) and how are you establishing that the chainrings 'flex'? Assuming you mean lateral flex, that's very unusual for chainrings..
  • Thanks for the reply. Sorry it's taken a while to get back to you, I didn't get a notification and I only came back on to post that I solved the issue.

    In comparison to my other bike, full Ultegra Di2.

    Flex wise I meant excessive contact with the front mech under pressure (it is correctly adjusted).

    I've ended up with a Token Ninja bottom bracket, 50 quid and superb with my no-longer spare Ultegra crank. Shifting is now spot on.