Should I clean the mechanical disk brake rotors on my new bike

Question

New Bike Day for me tomorrow! It's the first time I will have bought something like this. I have heard some places to leave everything alone until a problem starts, and I have also heard that you can greatly lessened the brakes squeaking if you clean the rotors before with isopropyl alcohol. Any thoughts?

Answer 1

Cleaning the brake disks as you describe won't do any harm and it is good practice. While in transport, a greasy hand could have touched the disks and that would contaminate the brake pads which can be harder to clean afterwards. Cleaning the rotors is also recommended as part of regular short interval maintenance, that is, the kind of cleaning and inspection you should do every few rides.

However, "Leave everything alone until a problem starts" depends a great deal on where are you obtaining the bike. A well reputed bicycle dealer (bike shop) should have the bike properly assembled and adjusted prior to handing it to the new owner. That include tightening all bolts to a proper torque and checking all major components are properly installed for use.

On the other extreme, you can get a bike that arrives in a box, partially assembled and needs some assembly and proper adjustment before it is safe to ride.

Somewhere in between is to buy a bike from a store that does not specialize in cycling equipment and may or may not have a good mechanic in charge of assembling the bikes prior to hand them to customers. This may lead to a situation where the bike seems to be fine to ride, but some pieces may no be in proper orientation or not properly tightened.

So, for cases 2 and 3, if you are not experienced in doing basic bike maintenance yourself, it is best to have it professionally serviced/adjusted prior to use, or at very least, take it to a experienced and trusted friend to inspect.

Disclaimer: I have never bought a new bike for myself, but a couple of very close family members have, both from well reputed stores and the bikes where of very known brands and indeed, the store handed the bikes after a thorough inspection by the shop's mechanic. Those where both cases where "leave everything alone" was the thing to do. If anything would have failed, that would be covered under warranty.

On the other hand, I have seen "Big box stores" selling bikes (or should I say bicycle shaped objects) that are poorly assembled. At the moment of the sale, they just call "some guy" from the store to check the bike and then this person struggles to "kind of" adjust and tighten screws with general use tools and what not.