Even or Odd

I am having a hard time deciding if I should ride my road bike to work everyday or my mountian bike which is much older. I do know if i don't figure out what is causing my mountain bike flat tires, I wont be riding it much more. I road the mountian bike today to work and i did not like the pressure level in the tires. Stan in the club told me hold off a little on the pressure. So I have by 5 pounds and it just does not ride the same. The chain on both bikes should be replaced according to Stans recomendation. He has a tool the meassures the wear on the chain and my road bike is far beyond needing replace. So does even or odd mean anyting different in the choice made?