Irregular bleeding

Q: I am now 41 years old and for the pass 3 or 4 years I have been getting haidh for more than 10days. It first starts off with a brown discharge and after a a day or two I start to bleed for 7 days and thereafter I have the brown discharge again for the next few days. This whole discharge and bleeding goes on for more than 10 to 12 days. Do I start counting my days from the day of discharge or the day I start bleeding and must I go back to following what my past habit was 7 to 8 days a few years ago or do I have a ghusul after 10 days?

Rubbing impurity on the ground

Q: I ride scooters and bikes to school. I rolled over non-halal foods/sandwich packages with leftover foods several times when riding on the streets. I live in the U.S. and the sandwiches are subway wraps with wet food oil and sauce and certainly not halal. Hence, the bike tire becomes impure. When I ride it in rainy days, the water splashes from the tire onto my shoes and pants. Since the bike tire is impure the water splash is impure. I have to go back home and wash them every time I pray and it severely impacts my life. However, I heard that walking or rubbing impurity against the ground makes the impure shoe pure. Does this ruling apply to a bike/scooter tires? If so then the bike tire can be regarded as pure as it rubs against the ground so many times?