I forgot to order tubes with my tire, so I am going to the shop to pick some up and get the tires mounted. The 2 shops near me however dont have the right size tubes. One doesnt have one at all near the size, and the other has a 110/90-18 tube. I am sticking 100/90-18 tire on my front rim (3.50S18 originals), and I was wondering how poor of an idea this is? The shop thinks it should be fine, but figured I'd try getting some insight from the people im not giving money to.