What determines the size of the break rotors? Combined weight of bike and rider+type of riding? Does the frame of the bike have anything to do with determining sizes?
determining brake rotor
- Thread starter MeMTbiker39
- Start date
basically everything you mention determines rotor size...
The size/shape of the rear triangle will determine how big you can go in the back and not hit the stays. In the front, it depends on the fork/axle type. If it's a QR type hub, you probably shouldn't go larger than 185mm -- if it's a thru axle, then you can go larger. Check with your fork manufacturer to be sure.
Then you want to size for rider/bike weight + type of riding. For example, when I was 200lbs on a 30lb bike for aggressive trail riding, I found that 185/185 was a good size to easily stop me - smaller would work, but on a long run 160 would struggle a bit.
So - first, determine what the max size is your bike can accomodate. Then determine what size you want for your weight and riding style. Remember, larger rotors adds weight, so you want to keep that in mind too (i.e. just because 205mm rotors fit doesn't mean you should use them).
The size/shape of the rear triangle will determine how big you can go in the back and not hit the stays. In the front, it depends on the fork/axle type. If it's a QR type hub, you probably shouldn't go larger than 185mm -- if it's a thru axle, then you can go larger. Check with your fork manufacturer to be sure.
Then you want to size for rider/bike weight + type of riding. For example, when I was 200lbs on a 30lb bike for aggressive trail riding, I found that 185/185 was a good size to easily stop me - smaller would work, but on a long run 160 would struggle a bit.
So - first, determine what the max size is your bike can accomodate. Then determine what size you want for your weight and riding style. Remember, larger rotors adds weight, so you want to keep that in mind too (i.e. just because 205mm rotors fit doesn't mean you should use them).
I find that length of downhills and amount of braking (basically how much heat you'll generate) determine necessary rotor size. When cool, even 6" rotors have plenty of power but they fade quickly with heavy use. 7" seems to handle heat much better and 8" is the way to go for heavy braking on sustained, steep runs.
Oh, tires also come into play. Low knob XC tires lock up too easily with 7" rotors.
Oh, tires also come into play. Low knob XC tires lock up too easily with 7" rotors.
All good info thanks