1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
mtn. biking 101
2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
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  1. #1
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    Rotor cleaning - rust, dust

    Hi, I have a 2011 MTB with Shimano M445 Hydraulic disk brakes. I was cleaning the bike and I noticed what looked like dirt/rust spots ( small circles) on the rotors. The braking area is clean and shiny. The braking action is fine. It's only from center to towards braking area(where the pad grips the rotor). Should I be concerned? I live in a tropical area with high humidity.

    Do I need to clean the rotor?

    thanks

  2. #2
    Total Goober
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    Not for performance, probably, but definitely for looks. I keep mine touched up with alcohol, but this article shows how you can fix yours.

    Tech Tuesday - Silence That Squeaky Disc Brake - Pinkbike
    Quote Originally Posted by Fuglio View Post
    You guys suck im all bummed now

  3. #3
    Fat-tired Roadie
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    Don't clean the friction surfaces. The effect that makes disc brakes work is negated by that, until the pads and rotors bed in again.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  4. #4
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    Thanks. The rust is not on the place where the pads come into contact with the rotor across the diameter of the rotor. It (rust spots - few mm in size) is on the area where the pads do not come into contact. Won't the rust corrode the rotor? I live in a tropical, coastal area where relative humidity is above 80%.

  5. #5
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    P.S : there is no squeaking noise or any abnormal noise during operation.

  6. #6
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    Performance wise I doubt surface rust will affect anything, but like someone said above, looks wise it is horrible. Use some rubbing alcohol to clean them and maybe some light sandpaper/wet'n'dry on the rotor.

  7. #7
    Fat-tired Roadie
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    Quote Originally Posted by sanjayc View Post
    Thanks. The rust is not on the place where the pads come into contact with the rotor across the diameter of the rotor. It (rust spots - few mm in size) is on the area where the pads do not come into contact. Won't the rust corrode the rotor? I live in a tropical, coastal area where relative humidity is above 80%.
    Rust tends to be self-limiting. Once some surface area has rusted, there's no exposed unreacted iron anymore. So, no more rust. The reason things get eaten away by rust over time is that rust is not as hard as steel, so it wears away more easily. But it takes a long time or some help from a catalyst.

    You could always get your rotors powder coated or something. Obviously the friction surface wouldn't work like that, but it wouldn't take too long to chew away the powder coat in the area where you wanted friction. I'd be inclined to do that with brake pads I wasn't planning to keep.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

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