Shimano 105 + Shimano Tiagra? I am looking to buy a new high end performance road bike soon along with a power meter. I'm looking at possibly a Shimano 105 or Tiagra groupset. However, stages doesn't make a power meter for Tiagra crank arms. Is it possible to ride with a Tiagra right drive side crank and a Shimano 105 left side crank? I know its a silly question and it probably wont work but all in the name of saving money!
Latest 105 and Tiagra iterations at this moment are 4700 and 5800. Both have same crankset design, so I don't see why left crankarm wouldn't be compatible. I'd figure you would be more concerned about color mismatch. There's also a slight weight difference, but I doubt most riders would notice it.