can i use these for spinning classes??

These shoes are just fine for spinning. The main difference between a road and a mountain bike shoe are the stiffness. Think of road shoes as walking on solid planks, while the MTB shoes have a little bit of flex so that you can actually walk.

The most important thing is making sure you get the cleats that are compatible with the spinning bikes. If you are responsible to bring your own pedals and change them out yourself, you'll want both of these:

http://www.backcountry.com/store/CRN0010/Crank-Brothers-Candy-C-Pedals.html
http://www.backcountry.com/store/PAR0015/Park-Tool-Professional-Pedal-Wrench.html

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