Originally Posted by
La Brea Bike
Secondly, yeah, there are numerous Shimano cranksets that are made as a unit. The individual chainrings are not replaceable. The option here is to get any other crankset with the same gear ratios. Upgraded ones will have the ability to change the chainrings. There is no shortage that I have encountered recently with getting any chain rings. Shimano welded cranksets are hit or miss. On an Allez though?
Don't think that was the case here, provided the original crankset hasn't been replaced before. This review (
https://www.bikeradar.com/reviews/bi...z-2019-review/ ) says that even the lowest-priced 2019 Allez came with the Shimano FC-RC200. Unless I'm misreading it, Shimano documentation indicates that crankset has replaceable chainrings with 110mm BCD.
https://bike.shimano.com/en-EU/produ.../FC-RS200.html
Unless it's still being ridden on the original chain and has been ridden serious mileage (and thus has a highly worn chain), I'd be surprised if told that either chainring needs replacement - though as you observed, it's indeed possible. I have to admit when I was a less experienced and naive cyclist I ruined a crankset that way once (it was an entry-level riveted crankset, so replacing the chainwheels wasn't an option).
I also am skeptical about that "can only get a chainring with the cranks attached" claim if the crank is the FC-RS200. However, the FC-RS200 is pretty inexpensive (around $48-60 US plus S/H, available from multiple sources). So depending on the shop's labor rate and the cost of the individual chainrings, it might actually be less expensive to replace the entire crankset than both chainrings. Can't see that being the case if only one chainring is bad, though.