Uber Driver - Motor vehicle Expenses

Hello,

1. Is cost of winter tire allowable for motor vehicle Expenses?

2. On my Income Summary from Uber I have the following millage:

     a. On trip Mileage 

     b. Online Mileage

Are I going to add the two mileages together as my kilometer driven in the taxation to earn income?

3. How I my going to report GST paid to Uber on T2125?

Thank you