My local bike mechanic tells me that I have worn out the teeth on the larger chain-ring of my 2016 Cannondale Synapse road bike, and that I need to get a new one; he says he can't get one through his normal channels and that I should look online for one.

Well, I looked online, and they do seem to be difficult to obtain and rather pricey as well ($180-$300), which makes me wonder: do I really need to get that exact chain ring, or are there other chain rings of the same size (50/34T) that would be cheaper and work just as well? How strict are the compatibility rules for two-gear road-bike chain rings?

FWIW the bike has the Ultegra groupset and Di2 electronic shifting, with 2 rings on the front and 11 gears on the rear cassette. Cannondale's product page for my current chainring part is here.

1 Answer 1


The other option if you're staying with 50/34 is get the Cannondale 110 direct mount road spider. I believe there's also an FSA 110 spider that's basically the same thing (the DM attachment bolt pattern and lockrings are the same). Then you can get a normal matched pair of rings, from say Shimano, FSA, or various aftermarket chainring companies.

There are good things about the SpideRing design and it is meant to be a pro-level, cost-no-object, ultimate stiffness and low weight type part. I don't think paying what it takes to buy a new one is crazy. That said, unless you have pro level power output or you're a pedal masher, it's fine to go with the spider plus a good pair of chainrings such as Shimano.

These spiders exist in both 110 5 bolt traditional and 4 bolt road asym versions. The 5 bolt generally gives you more freedom and cheaper options for rings, for now.

  • Given the price of these components ($180 for the 50/34 set of rings, or $85 for an adapter to 110 BCD), I think buying an entire new crankset might be an option, as well. There are plenty of 50/34 cranksets that are priced <50€. The only remaining question then is whether OP would be satisfied with a used crankset (this assumes the spindle dimensions are the same or at least that a replacement bottom bracket would not be too costly). The upside of, say, Shimano or FSA spiders is that the rings are easily (and cheaply!) replaceable.
    – jayded-bee
    Aug 2, 2022 at 16:07
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    @jayded-bee it's true that you could do that for a smaller total price tag. what might not be clear is these are very light and expensive cranks, they're not just random oem ones. the more expensive version of the hollowgram crank arms (i believe the version on this bike) retails for around $500US/set Aug 2, 2022 at 18:27
  • Right, thanks for pointing that out. I tend to forget my penny pinching mix-and-match approach to bike building is a bit of a rarity -- I'm here putting somebody's scrap 30€ Hollowtech crankset onto a 1980s steel frame haha
    – jayded-bee
    Aug 2, 2022 at 18:36

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