Shop can't mount 37/13.50/18 to 18x12 wheel. Should i run quickly?
 

Took my new 18x12 wheels today to have my 37/13.50/18 tires mounted on them. The shop wasn't able to get them on. I know MANY people run setups similar to this as well as much more aggressive.
I almost felt like it was as if a dentist was saying he didn't have the experience to fill a cavity.
I called a different shop and they acted like it would be a piece of cake so I'm going by tomorrow morning.

Is this something they should have been able to do easily? Should I stay away from there?

No one?