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  1. #1
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    brake rotor size

    hey all-
    I know this is kind of a dumb question, but what is the logic for running a bigger rotor on the front? Currently i have avid bb7's on my heckler, 160mm rotor in front, 185 mm in back. This seems to work well for me, it seems I use my rear brake a lot more than the front when going downhill (no, i am not skidding). But, everyone who sees my setup thinks I'm insane; apparently everyone else does it the other way. Also, do the larger rotors get better, or worse, modulation than the smaller rotors? I'm gonna switch them around back to the traditional way to see how it feels, but if anyone has any info for me that would be great. thanks. I also might switch to 185 mm fr and rear.

  2. #2
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by dwyooaj
    hey all-
    I know this is kind of a dumb question, but what is the logic for running a bigger rotor on the front? Currently i have avid bb7's on my heckler, 160mm rotor in front, 185 mm in back. This seems to work well for me, it seems I use my rear brake a lot more than the front when going downhill (no, i am not skidding). But, everyone who sees my setup thinks I'm insane; apparently everyone else does it the other way. Also, do the larger rotors get better, or worse, modulation than the smaller rotors? I'm gonna switch them around back to the traditional way to see how it feels, but if anyone has any info for me that would be great. thanks. I also might switch to 185 mm fr and rear.
    The front wheel and brake works harder and has more weight on it under braking. A larger front rotor lets me control the braking (modulate) more easily with less effort. A larger rear rotor can lock more easily as the weight shifts forward. The most effective braking is using both brakes together.

    If you swap your rotors front for back you will need new caliper mounts. They are different front and rear even for the same rotor size.
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  3. #3
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    The front brake is your most powerfull stoping power since it stops your forward motion. Having a larger front rotor increases the brake effect with better modulation & stays cooler. The smaller rear rotor takes more lever preassure to lock up so it is better at slowing the bike rather than stoping like the front brake. I use the rear alot to control speed & the front to actually stop, running a 6in rear & 8in front.
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  4. #4
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    Quote Originally Posted by dwyooaj
    hey all-
    I know this is kind of a dumb question, but what is the logic for running a bigger rotor on the front? Currently i have avid bb7's on my heckler, 160mm rotor in front, 185 mm in back. This seems to work well for me, it seems I use my rear brake a lot more than the front when going downhill (no, i am not skidding). But, everyone who sees my setup thinks I'm insane; apparently everyone else does it the other way. Also, do the larger rotors get better, or worse, modulation than the smaller rotors? I'm gonna switch them around back to the traditional way to see how it feels, but if anyone has any info for me that would be great. thanks. I also might switch to 185 mm fr and rear.
    Dude i got to say i have never seen this set up on the trail, it goes against all the fashion rules, beyond having barends on riser bars. But i have met heavy on the rear braking types that probably could benefit from your setup.

    The thing is, you can generate more stopping power with your front brakes, its just the physics of your weight transfer under braking. If you are comfortable with your current setup no reason not to stay with it but as your riding skills develop you will find the need to have most your braking power up front.

  5. #5
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    run the same front and rear,then theres no confusion.

  6. #6
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    try a 160 on the front and rear, the only part you need is a rotor, remove the adaptor you have on the rear now and mount the caliper direct

  7. #7
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by dan0
    try a 160 on the front and rear, the only part you need is a rotor, remove the adaptor you have on the rear now and mount the caliper direct
    If you are addressing your reply to the OP this is poor advise.
    Just removing the 185 rear IS mount will not let you use the caliper on the rear with a 160mm rotor--no rear post mounts. Will work on the fork only if it have post mounts. A front 160mm IS mount is different that a rear.

    For him to convert to 160mm on both ends he needs the rotor AND a 160mm rear IS mount. To put the 185mm rotor on the front and 160 rear he would need a front 185mm mount and a rear 160mm mount.
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  8. #8
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    My new XTR calipers have 160F/140R stamped right on them, and that's how I set it up. I assume the next size up would say 180F/160R. It is the IS mount.
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  9. #9
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    Quote Originally Posted by shiggy
    If you are addressing your reply to the OP this is poor advise.
    Just removing the 185 rear IS mount will not let you use the caliper on the rear with a 160mm rotor--no rear post mounts. Will work on the fork only if it have post mounts. A front 160mm IS mount is different that a rear.

    For him to convert to 160mm on both ends he needs the rotor AND a 160mm rear IS mount. To put the 185mm rotor on the front and 160 rear he would need a front 185mm mount and a rear 160mm mount.
    it wasnt "poor advise" it was wrong advise, sorry late night

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