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  1. #1
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    29er = 180mm > ?

    Those of you running 29ers are you running 180mm rotors in front? Anyone running 160mm rotors finding them to be a little underpowered regardless of brake type? Just trying to see if the upgrade is worth it.

  2. #2
    ballbuster
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    samey same

    Quote Originally Posted by D1PHAM
    Those of you running 29ers are you running 180mm rotors in front? Anyone running 160mm rotors finding them to be a little underpowered regardless of brake type? Just trying to see if the upgrade is worth it.
    Momentum is turned into heat just the same regardless of how big your wheels are. If you are heavy, ride at altitude, ride steeps, ride fast and hard, a 180mm front rotor is a good upgrade for any bike.

    I'm 200#, ride steeps, ride pretty fast and hard, ride wagon wheels... and 160mm rotors work fine for me. I hardly ever overheat anything.

  3. #3
    zeebot
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    I run 160/140 on my SS 29er. I usually only ride my mtb for the 100 mile NUE events so that means long and sometimes steep descents. I've never had an issue or thought I needed more power.

    I'm 160lb's, ride hard and fast and crazy on the downhills.

    Perhaps the brakes have something to do with it.

    Recently I've used Hope X2 pro and Juicy Ultimates. Both seem plenty powerful but I think the x2 pro are better brakes both in power and lever action.

  4. #4
    turtles make me hot
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    I weigh 250 pounds. My 29er came with 203 front and 185 rear. Works awesome. I rode a 29er with 160s front and rear and that bike didn't have anywhere near the modulation my bike has.
    In my opinion, bigger wheels should have bigger brakes... Especially when you're a clyde.
    I like turtles

  5. #5
    Just Trying to Get Better
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    I rode my 29er with 160 mm front and back this weekend for the first time...felt really underpowered. I do weight about 215 lbs and rode some fairly quick, s-curve downhills. I'm also going to upgrade to bigger rotors (probably 203 mm front and 185 mm back) or get a new braking system altogether. I currently have Juicy 5's. Does anyone know if using Juicy 5's with 203 up front and 185 in back will be a good move? Or would it be better to try to sell my Juicy 5's and buy new BB7's with the bigger rotors?

    I rode my friend's bike for a while on the trail and he has BB7's with 203 mm front and 185 mm rear. MUCH more powerful than my Juicy 5's with 160 mm. But, I'm not sure how much of that was rotor size versus the BB7's instead of Juicy 5's.

  6. #6
    turtles make me hot
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    I had to send my Juicy 7's to Avid for warranty work. While they were gone, I borrowed some Juicy 3's on my rotors. They worked great.
    I like turtles

  7. #7
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    I've run 160F/140R on my SS29er. Got some steep trails here in Colorado Springs, but it wasn't until I spent a summer riding ridiculously steep trails in Germany that I decided to up the rear to 160. Now, back in Colorado, I think that's a good deal. Could use a little more power now and then, but I think that's a function of (A) XTR brakes not being the most powerful out there, and (B) some of the out-there trails we ride in the Springs. I think for normal trail riding 160s are probably fine for most folks.

    I only weigh a buck-sixty, so for someone significantly heavier larger rotors are probably a good idea. I'd also recommend against XTR 975 for people interested in power alone. I'd personally like to try the XT's, I think the newest generation probably has a lot more power than the XTR...
    Alison Dunlap Coaching
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  8. #8
    Always Learning
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    Quote Originally Posted by D1PHAM
    Those of you running 29ers are you running 180mm rotors in front? Anyone running 160mm rotors finding them to be a little underpowered regardless of brake type? Just trying to see if the upgrade is worth it.
    I was running 185mm front and rear for several seasons on my 29"ers as that's what I ran on my 26" HT in the mountains in Austria. In retrospect, I think that was overkill for me even in the mountains to have that much power. I moved to the US and eventually swapped to 180mm front and rear last season on all my 29"ers with the Alligator serrated rotors. This year I swapped to 160mm front/140mm rear on all my 29"ers and haven't noticed any loss in braking power. I still have plenty of braking power for all my needs (using Avid mechanical calipers and Alligator serrated rotors). I weigh 180.

    If I lived in or close to the mountains again, I would use some from of larger rotors. Probably 160/160 or 180/160. It all depends on your weight, riding style and local terrain. It's not going to cost you too much to pick up a $20 rotor and $10 adapter to try a larger rotor up front.

    BB

  9. #9
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    Heat shedding should be the same with the 29" and 26" assuming weight is somewhat close.

    The 29" gives the brake less leverage so they will be less powerful.

    Even though it will take more caliper force to stop in the same distance, there's less rotor passing through the caliper for a given distance so heat buildup remains about the same.

    I rode a 29" just for the heck of it at the LBS and the 160mm brakes were pretty weak but it's a safe assumption they weren't broken in.

  10. #10
    Bicyclochondriac.
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    Quote Originally Posted by D1PHAM
    Those of you running 29ers are you running 180mm rotors in front? Anyone running 160mm rotors finding them to be a little underpowered regardless of brake type? Just trying to see if the upgrade is worth it.
    I run bb7's on all my bikes. I had a 6" front on my 26" SS HT, and when I went to a 29" SS HT I felt a little underpowered compared to the 26" bike. Not too big of a deal, and I've lived OK with it for a year or so, but I just got a 7" for the front.

    I run a 7" front on my 26" AM bike.

    I'm ~185-190 with gear.

  11. #11
    Weird Eh
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    160s front and rear on the Niner. Plenty of brake.I weigh 185 btw

  12. #12
    Chronic 1st-timer
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    Big front rotor here, even back in the days of 26" wheels.
    I run it like that cuz I'm a big fat hog, nothing to do with wheel size.
    Les grimpées, je m'en fou!

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