I took the wheel to a local bike shop, they called Mavic to see if they could service them but since the wheels are more than 5 years old, they no longer stock the rims.

So the first question, can I ride two different wheels? And if yes how different can they be? Does it matter if the front is alloy clincher and the back is carbon tubular, as an extreme example?

Second, any thoughts about buying new or used wheels? Things I should look for if buying used?

I didn't find the right solution from the internet.
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