160mm vs. 180mm rotor Pro/Cons?- Mtbr.com
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  1. #1
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    160mm vs. 180mm rotor Pro/Cons?

    I'm building a rigid Monkey 29er and need advice.
    I'm 220 lbs and don't ride too aggressive but like to go FAST when I have the chance, (without going OTB's).

    What are your thoughts on rotor size and why?

    I'm mostly concerned with burning through pads, (I want to use organic 'cause I heard they're quieter), and also don't want to easily lock up every time I touch the brakes.

    I've ridden 160mm disks only a couple of times, they were XT's and too loud for my taste.
    I hope to use Avid BB-7's...any thoughts??

    Thank you Allmighty Forum!

  2. #2
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    the bigger rotors will keep heat down which will help prevent brake fade, disc warping, and since theyre cooler, should help keep the noise down after a lot of braking

    the brakes will probably still wear at the same rate, unless temperature has an effect on how quickly they wear out. but i dont think thats too big of a difference

  3. #3
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    180's cool faster and stop better. I don't think there are any downsides except they weigh a bit more and you need a different adapter of course.

    When I switched from 160 to 180 in the front, the difference wasn't as much as I thought. But it was nice to have a little extra power. Modulation was no issue, but that was with hydros. I don't have experience with BB7s.

    Since you are a heavier guy and want to use organic pads, i would definitely go with 180's.

  4. #4
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    Good advice Gents! Thanks and I hope to hear more.
    I'm leaning towards 180 up front and 160 for rear. Thanks again.

  5. #5
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    the only downsides i've noticed to bigger rotors (200's in my case... haven't tried 180s), was that they're a bit grabbier, as you'd expect from the mechanical advantage. they do cool faster due to more surface area and they don't get as hot due to more thermal mass.
    with BB7s and your weight 180s will probably serve you well.
    i like the modulation of 160s, but we don't have any extended descents around here.
    Quote Originally Posted by pvd
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  6. #6
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    I had

    BB7s and a 185 g2 rotor on a soulcycles fork. What i liked was the single finger braking with the larger rotor but like someone else mentioned it bit really hard almost overwhelming the fork on technical descents. i also had a hard time keeping the caliper centered over the rotor when everything got warm. Huge front tires and oury grips helped.

  7. #7
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    Quote Originally Posted by jrm View Post
    BB7s and a 185 g2 rotor on a soulcycles fork. What i liked was the single finger braking with the larger rotor but like someone else mentioned it bit really hard almost overwhelming the fork on technical descents. i also had a hard time keeping the caliper centered over the rotor when everything got warm. Huge front tires and oury grips helped.
    To you and Meltingfeather - I'm not a downhillbomber so 180's sound like a good fit, per your advice. My only hangup is how well do 180's stand up to dropping or laying a bike down vs. the 160's?

    Thanks again.

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    Quote Originally Posted by Badassbassangler View Post
    To you and Meltingfeather - I'm not a downhillbomber so 180's sound like a good fit, per your advice. My only hangup is how well do 180's stand up to dropping or laying a bike down vs. the 160's?

    Thanks again.
    No brake rotor stands up well to dropping on it or laying a bike down on it.

    I am through with folks laying bikes on top of mine in the bed of a pickup truck or in a van or in the back of a Scion TC, shiat gets bent or warped every time, and a major PIA rotor tuneup becomes inevitable. The other pisser is bike racks that hold your bike by the top tube, where the bikes can swing and or slide into each other and rub holes in your paint or anodized finish.

    Treat your brake rotors like you would eggs, store them at all time so that nothing else touches them or leans against them, and they will rarely get bent or warped.

  9. #9
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    Quote Originally Posted by Badassbassangler View Post
    To you and Meltingfeather - I'm not a downhillbomber so 180's sound like a good fit, per your advice. My only hangup is how well do 180's stand up to dropping or laying a bike down vs. the 160's?

    Thanks again.
    It's not really a problem it is only 10mm more sticking out the bottom & the handle bars keep them up off the ground.

    Also the XX rotors work better IMO
    I have a 6 Berth & 2 Berth Motorhomes that I rent out . They are based in Tauranga, New Zealand

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    Quote Originally Posted by RandyBoy View Post
    No brake rotor stands up well to dropping on it or laying a bike down on it.

    I am through with folks laying bikes on top of mine in the bed of a pickup truck or in a van or in the back of a Scion TC, shiat gets bent or warped every time, and a major PIA rotor tuneup becomes inevitable. The other pisser is bike racks that hold your bike by the top tube, where the bikes can swing and or slide into each other and rub holes in your paint or anodized finish.

    Treat your brake rotors like you would eggs, store them at all time so that nothing else touches them or leans against them, and they will rarely get bent or warped.
    May be the soundest advice I've had yet! Thanks!

  11. #11
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    I'm 230lbs. and like to go downhill fast. I'm running 203/185 with sintred pad and wish for more brake power often. For me, bigger is better, at your size I'd go for at least the 180s.

    Gary
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    Quote Originally Posted by Badassbassangler View Post
    Good advice Gents! Thanks and I hope to hear more.
    I'm leaning towards 180 up front and 160 for rear. Thanks again.
    At 185# I think I am at the limit of a 160mm front rotor using BB7s on my go-to bike. It averages out pretty good between low speed modulation and high speed stopping. If I was any heavier I'd def. go with a 180 up front. btw - I am NOT using the Avid Roundagon and I didn't like the Cleansweep. I have a heavy Aztec rotor and I like it. The rear 160 still uses the Roundagon.
    My other bike has a 185 Roundagon up front and it runs pretty nicely.

    -F

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    Go 140 ftw

  14. #14
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    Never had an issue

    Quote Originally Posted by Badassbassangler View Post
    To you and Meltingfeather - I'm not a downhillbomber so 180's sound like a good fit, per your advice. My only hangup is how well do 180's stand up to dropping or laying a bike down vs. the 160's?

    Thanks again.
    using a larger diameter rotor on this bike or others. Enjoy

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    Quote Originally Posted by All_talk View Post
    I'm 230lbs. and like to go downhill fast. I'm running 203/185 with sintred pad and wish for more brake power often. For me, bigger is better, at your size I'd go for at least the 180s.

    Gary
    Same situation here, if you are big and it's long and steep in mountains, go larger on the rotors and run the sintered pads.

  16. #16
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    I am about 200 pounds and I am running a 203 front and 185 rear and like the setup. My old bike had 160's front and back and I noticed a big different going to the bigger rotors. But the 2 brakes are different brands so it could be also the new brakes are just better. If your not concerned with the extra weight of the 185's then I see no reason not to do it.

    I don't know if the larger rotors use up pads faster or not. I am still on the stock pads and have no reference to compare it too.

  17. #17
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    I like the larger rotor because I don't like to have to squeeze hard on the brake levers. It's not a huge deal, but I am happier with 180mm up front.

    The downside is that trigonometry is against you. The longer radius means that a smaller bend in the rotor is enough to cause the dreaded ka-ching as you pedal. Even so, it's not like I have to retrue every day, so no real worries there either. I probably use more choice adjectives when I'm truing a 180mm rotor than when truing a 160mm rotor, but otherwise it's all good.

    None of the hills I go down are even remotely long enough for heat to be an issue, so I can't really comment on heat dissipation.

  18. #18
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    Quote Originally Posted by JonathanGennick View Post
    I like the larger rotor because I don't like to have to squeeze hard on the brake levers. It's not a huge deal, but I am happier with 180mm up front.
    I think that's basically the bottom line on a larger rotor: less hand force needed.

    The downside is that trigonometry is against you. The longer radius means that a smaller bend in the rotor is enough to cause the dreaded ka-ching as you pedal. Even so, it's not like I have to retrue every day, so no real worries there either. I probably use more choice adjectives when I'm truing a 180mm rotor than when truing a 160mm rotor, but otherwise it's all good.

    None of the hills I go down are even remotely long enough for heat to be an issue, so I can't really comment on heat dissipation.
    I've never had to straighten a rotor, but it seems like it wouldn't be to easy, since they have to be VERY straight. How do yours get bent, and how do you straighten them?

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    Quote Originally Posted by smilinsteve View Post
    I've never had to straighten a rotor, but it seems like it wouldn't be to easy, since they have to be VERY straight. How do yours get bent, and how do you straighten them?
    I have a small, five-inch-long adjustable wrench. I clamp the disc in between the jaws, and bend as needed. I use the brake pads as my reference point. Spin the wheel. Listen or feel for rub. Bend as needed.

    Sometimes it all goes so dead-easy that I'm on top of the world and feeling like I'm ready to open up a bike shop and be the Chief Wrench.

    Other times, I want to rip my hair out. LOL!

    With mechanical brakes I sometimes cheat and just open up the gap between the pads. If I'm in a hurry and want to get out riding, I'll sometimes do that.

  20. #20
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    But why are they getting bent in the first place?

  21. #21
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    Quote Originally Posted by smilinsteve View Post
    I've never had to straighten a rotor, but it seems like it wouldn't be to easy, since they have to be VERY straight. How do yours get bent, and how do you straighten them?
    There is a special tool for that.


    I occasionally had the "ching ching" problem with flat six bolt rotors in the past. Since I've been using center lock rotors with an aluminum spider never had the problem.

    Ronnie.
    The trouble with having an open mind is that people will insist on trying to put things in it.

  22. #22
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    Quote Originally Posted by smilinsteve View Post
    But why are they getting bent in the first place?
    Most of my trouble comes when I install rotors new out of the box, or, most recently, OEM rotors that had been packed in plastic wrap. Otherwise, they don't really bend often enough for me to remember why they bend. It's not like I'm sitting here and truing my rotors every other day.

  23. #23
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    Go as big as you want, within the specs of your fork. The only thing you are adding is weight and stopping power.

    Someone said something about "brake-fade"... rotor size has nothing to do with it. Rotor material, pad material and your cable/housing (on a BB7) are what dictates fade under heavy braking. Larger rotors gain you mechanical power over your wheel. If you want to get rid of fade on a mechanical disc setup:
    1. Use good rotors... Avid XX 185's are solid.
    2. Use a really solid run of housing that will not buckle. I use ripcords, but there are better options.
    3. Use solid levers... yes levers flex and can cause fade.
    4. Do not use shifter cable. Some weight-weenies do this. It works fine, but it will stretch causing fade.

    I run BB7's with ripcords and FR5 levers and XX rotors... at 160mm, I have no issues. I have some fade, and it is all due to the cable housing. But it isn't so bad that I care.

    The only other thing I've see that could be an issue... slicing off a finger. A friend of mine had a 203 on the front of his bike. It was big and there was plenty of space to jam a few fingers in there. And he did just that... wasn't thinking and lost half a finger. ????
    - The only thing that keeps me on a bike is happiness.

  24. #24
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    Quote Originally Posted by OmaHaq View Post
    Someone said something about "brake-fade"... rotor size has nothing to do with it. Rotor material, pad material and your cable/housing (on a BB7) are what dictates fade under heavy braking.
    Brakes fade from excessive heat. Bigger rotors stay cooler.

  25. #25
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    Like others have said...

    Quote Originally Posted by Badassbassangler View Post
    I'm building a rigid Monkey 29er and need advice.
    I'm 220 lbs and don't ride too aggressive but like to go FAST when I have the chance, (without going OTB's).

    What are your thoughts on rotor size and why?

    I'm mostly concerned with burning through pads, (I want to use organic 'cause I heard they're quieter), and also don't want to easily lock up every time I touch the brakes.

    I've ridden 160mm disks only a couple of times, they were XT's and too loud for my taste.
    I hope to use Avid BB-7's...any thoughts??

    Thank you Allmighty Forum!
    .. the bigger the grabbier... as in, less modulation.

    I run 215# these days. My Titus RacerX29er trailbike has a 180mm rotor up front. I had a 160mm. I like the added stopping power when slamming down the trail, but much of my riding is tight slow speed techy stuff... like downhill switchbacks so tight that the rear wheel almost stops rolling. I'm entirely on super light feathering of the front brake to help keep my balance and roll around the switchback. My 180mm rotor makes the brake feel like its on or off with no in between, whereas the 160mm rotor has more control.

    I never really had a problem with overheating my brakes, tho. I like the extra stopping power with less hand pressure, but I was doing alright before the 'upgrade'.

    Also, I prefer semi-metallic or sintered pads (same thing). I found I could overheat organic pads at the drop of a hat. Noise isn't really an issue as long as my brakes aren't wet. Organics are less grabby feeling, but I like the bite of metallics. I don't think that 'bite' directly translates into less modulation.

    Gratuitous pic:

    <a href="https://picasaweb.google.com/lh/photo/KyQwB9D6iN_csXUWPu_gYg?feat=embedwebsite"><img src="https://lh3.googleusercontent.com/-M3yxwBB68-o/Tc8qJ-xsHlI/AAAAAAAAUAE/fDDdgbDNkmY/s800/IMG_0515.JPG" height="600" width="800" /></a>


    Quote Originally Posted by smilinsteve View Post
    Brakes fade from excessive heat. Bigger rotors stay cooler.
    Problem I find is the rotor isn't the hot spot... the pads and calipers are what get hottest. YMMV.

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    Quote Originally Posted by smilinsteve View Post
    Brakes fade from excessive heat. Bigger rotors stay cooler.
    That isn't always the case. Rotor material, design, venting and pad material are more important.

    When the temperature at the interface between the pad and the rotor exceeds the thermal capacity of the pad, the pad loses friction capability due largely to out gassing of the binding agents in the pad compound. The brake lever remains firm and solid but the bike will not stop as fast.

    This can be overcome by carbon rotors and pads and better rotor venting designs. Thermal capacity can be exceeded on any size rotor. It is all about venting and materials.
    - The only thing that keeps me on a bike is happiness.

  27. #27
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    Sweet Titus!! I never would have thought about a Lefty on anything but a Can. Awesome fork I used to have a Phophet and loved it.
    The jury's in on this one 185mm up front and 160mm rear.
    Time to go to work so I can buy some parts!
    Only if I got paid to hang out in my garage and tweak on my bikes...

  28. #28
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    Quote Originally Posted by OmaHaq View Post
    That isn't always the case. Rotor material, design, venting and pad material are more important.

    When the temperature at the interface between the pad and the rotor exceeds the thermal capacity of the pad, the pad loses friction capability due largely to out gassing of the binding agents in the pad compound. The brake lever remains firm and solid but the bike will not stop as fast.

    This can be overcome by carbon rotors and pads and better rotor venting designs. Thermal capacity can be exceeded on any size rotor. It is all about venting and materials.
    That all looks fine and is good info! But, there's no need to overcomplicate things.
    You said:

    Someone said something about "brake-fade"... rotor size has nothing to do with it.
    Which is not true.

    I said:

    Brakes fade from excessive heat. Bigger rotors stay cooler.
    Which is true.

  29. #29
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    Quote Originally Posted by OmaHaq View Post
    That isn't always the case. Rotor material, design, venting and pad material are more important.

    When the temperature at the interface between the pad and the rotor exceeds the thermal capacity of the pad, the pad loses friction capability due largely to out gassing of the binding agents in the pad compound. The brake lever remains firm and solid but the bike will not stop as fast.

    This can be overcome by carbon rotors and pads and better rotor venting designs. Thermal capacity can be exceeded on any size rotor. It is all about venting and materials.
    I see your point but I think you're complicating the basic argument: a bigger version of the same rotor will be cooler.

  30. #30
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    I run 203 mm front and rear with BB7's, I am 315 so I like the 203's but with stock bb7 calipers I had issues with control over the rotors getting the brakes to apply the grip to the rotors with finnese. The biggest improvment for me was to shim the cables out with spacers at the caliper arm that applies the brake on the calipers. It gives alot more leverage effectively giving you more control in braking. It helps alot for control and overall power to modulate and stop the way you want to.

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    Quote Originally Posted by boomn View Post
    I see your point but I think you're complicating the basic argument: a bigger version of the same rotor will be cooler.
    For making a brake system stop better nothing beats a bigger rotor for overall efficiency.

  32. #32
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    Quote Originally Posted by OmaHaq View Post
    That isn't always the case. Rotor material, design, venting and pad material are more important.

    When the temperature at the interface between the pad and the rotor exceeds the thermal capacity of the pad, the pad loses friction capability due largely to out gassing of the binding agents in the pad compound. The brake lever remains firm and solid but the bike will not stop as fast.

    This can be overcome by carbon rotors and pads and better rotor venting designs. Thermal capacity can be exceeded on any size rotor. It is all about venting and materials.
    This is why I like my heavier front rotor. It's a 160, but I think it works better due to its mass (bigger heat sink and more surface area compared to other 160s) and more cross holes (vents for outgassing). It seems to do very well at high speed, which for me is anything above ~25mph. Below that, I probably could not tell a difference.

    Quote Originally Posted by Realslowww View Post
    I run 203 mm front and rear with BB7's, I am 315 so I like the 203's but with stock bb7 calipers I had issues with control over the rotors getting the brakes to apply the grip to the rotors with finnese. The biggest improvment for me was to shim the cables out with spacers at the caliper arm that applies the brake on the calipers. It gives alot more leverage effectively giving you more control in braking. It helps alot for control and overall power to modulate and stop the way you want to.
    Could you have accomplished this with the speed dial lever? Or was that not enough adjustment?

    Thanks,
    -F

  33. #33
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    Not mentioned yet: generally, a larger rotor will give longer pad life, too. I'm 215 pounds and run 185/160 on both my bikes, one is Elixir R and the other is BB7. It seems to be a good combo of modulation and overall power for me.

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    Quote Originally Posted by Realslowww View Post
    I run 203 mm front and rear with BB7's, I am 315 so I like the 203's but with stock bb7 calipers I had issues with control over the rotors getting the brakes to apply the grip to the rotors with finnese. The biggest improvment for me was to shim the cables out with spacers at the caliper arm that applies the brake on the calipers. It gives alot more leverage effectively giving you more control in braking. It helps alot for control and overall power to modulate and stop the way you want to.
    Quote Originally Posted by Fleas View Post
    Could you have accomplished this with the speed dial lever? Or was that not enough adjustment?
    Couldnt you have done this by adjusting the pad spacing? BB7s with Speed dial levers give you an immense amount of adjustability in feel and performance.
    No need for shims or spacers, run a full length housing from the lever to the caliper, set the spacing on the pads to make the calipers as grabby as you want and then spin the Speed Dial on the lever to make the lever feel as mushy as you want. Personally I set my pads right to where they're about to rub, and then set the brake levers halfway in on the dial so equalize feel front to rear and allow good modulation.

    For general trail riding, the 180mm is awesome up front. Minimal weight gain, maximum performance gain. 180/160 is a good balance since your front brake should be doing 90% of your stopping and anymore power in the rear just increases your potential to skid the rear tire.

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    Quote Originally Posted by Fleas View Post
    This is why I like my heavier front rotor. It's a 160, but I think it works better due to its mass (bigger heat sink and more surface area compared to other 160s) and more cross holes (vents for outgassing). It seems to do very well at high speed, which for me is anything above ~25mph. Below that, I probably could not tell a difference.



    Could you have accomplished this with the speed dial lever? Or was that not enough adjustment?

    Thanks,
    -F
    I don't know,I know for free I made the braking system work alot better by shimming the caliper arms out. There is no need for me to do anything else because this trick solved my issue with braking control and it was free.I run cheap levers and have no need for exspensive levers with this trick but I am a play rider. You can do both and even get better results but I think you will find this works better than doing it at the bars just from a physics standpoint!

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    Quote Originally Posted by GTscoob View Post
    Couldnt you have done this by adjusting the pad spacing? BB7s with Speed dial levers give you an immense amount of adjustability in feel and performance.
    No need for shims or spacers, run a full length housing from the lever to the caliper, set the spacing on the pads to make the calipers as grabby as you want and then spin the Speed Dial on the lever to make the lever feel as mushy as you want. Personally I set my pads right to where they're about to rub, and then set the brake levers halfway in on the dial so equalize feel front to rear and allow good modulation.

    For general trail riding, the 180mm is awesome up front. Minimal weight gain, maximum performance gain. 180/160 is a good balance since your front brake should be doing 90% of your stopping and anymore power in the rear just increases your potential to skid the rear tire.
    Try it,I think you will like it. You can shim out as little or as much as you like to get the power feel combo you want,I am at 3/4 of a inch at the momment. All that fine tuning went out the window when I did this because it gives me way better feel and control at the lever so if the pads are slightly out of adjustment it is no problem in the control department because you have much better sence of feel with you hands at the lever so you know much more accurately when the wheel is bordering on lockingup..

  37. #37
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    Quote Originally Posted by Realslowww View Post
    Try it,I think you will like it. You can shim out as little or as much as you like to get the power feel combo you want,I am at 3/4 of a inch at the momment. All that fine tuning went out the window when I did this because it gives me way better feel and control at the lever so if the pads are slightly out of adjustment it is no problem in the control department because you have much better sence of feel with you hands at the lever so you know much more accurately when the wheel is bordering on lockingup..
    I see where this would improve your modulation at the same time as it increases your maximum braking force. That would be like bumping up the range on the Speed dial lever (which are actually pretty darn cheap). If you dial those one way, you get more cable pull = the brake contact is "faster" (less modulation), lower max force (lower leverage). If you dial the other way, you get less cable pull, more modulation, more force - but you'll likely have to run your pads closer to your rotor. You might be on to something using more cable pull and getting more modulation (slower contact), but also getting high force. You at least got me thinking about my own set-up. The only drawback might be lever travel, but you probably have big hands, too, so it works for you. I'm glad to hear someone out there is thinking and trying stuff.

    See? Don't poo poo the mechanicals everybody.

    -F

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    Hope

    Quote Originally Posted by Fleas View Post
    I see where this would improve your modulation at the same time as it increases your maximum braking force. That would be like bumping up the range on the Speed dial lever (which are actually pretty darn cheap). If you dial those one way, you get more cable pull = the brake contact is "faster" (less modulation), lower max force (lower leverage). If you dial the other way, you get less cable pull, more modulation, more force - but you'll likely have to run your pads closer to your rotor. You might be on to something using more cable pull and getting more modulation (slower contact), but also getting high force. You at least got me thinking about my own set-up. The only drawback might be lever travel, but you probably have big hands, too, so it works for you. I'm glad to hear someone out there is thinking and trying stuff.

    See? Don't poo poo the mechanicals everybody.

    -F
    Those calipers should come from the factory with longer arms,the front was not a problem for me but the rear was. I could not brake slide the rear the way I wanted in corners and this solved the problem. I did the front around a half inch and the rear 3/4, the more you shim the better the control.

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    Quote Originally Posted by Realslowww View Post
    Those calipers should come from the factory with longer arms,the front was not a problem for me but the rear was.
    I doubt the design point is 315-lb riders.
    Kudos to you for solving your issue in the smartest way. Do you have a pic of the shims? I'd be interested to see them.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  40. #40
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    Quote Originally Posted by Realslowww View Post
    Those calipers should come from the factory with longer arms,the front was not a problem for me but the rear was. I could not brake slide the rear the way I wanted in corners and this solved the problem. I did the front around a half inch and the rear 3/4, the more you shim the better the control.
    315lb rear brakes slider? I'm sure that makes for keeping the trails nice.

  41. #41
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    I up'd my front to 185 on my rigid SS to get a little more umph in my brakes, I weigh 165.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

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  42. #42
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    Quote Originally Posted by meltingfeather View Post
    I doubt the design point is 315-lb riders.
    Kudos to you for solving your issue in the smartest way. Do you have a pic of the shims? I'd be interested to see them.
    No I have no pictures,I have alot of parts here from my moto X CR 500 day's.You can shim it out with anything and a little grinding.Nuts should work great

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    For me the biggest issue is proper modulation, which is one of the many reasons I still use the BB7s with the SpeedDial levers. Most hydraulic setups are hit or miss with that and there is such a thing as too much power, for me at least. The balance I found was with the standard 160 Roundagon rotors I couldn't quite scrub enough speed at the bottom of a few really fast descents, so I went to a 203 in front (because I was given one). Now I back the SpeedDials off a touch on the pull ratio (LOVE that feature, which that was an option on ANY hydraulic system) and I still get the modulation range I want but can get all the stopping power I need in the front. If I were going with really hard-grabbing hydros I'd put a smaller rotor on the front to lessen the touchiness of the system.

    For the rear, I'm still using a 160 because it's got enough power for me to lock it up when I want to, that's with the SpeedDial adjustment knob all the way out. For reference, I'm 6'3" 210lbs riding a Karate Monkey SS.
    "I applaud your stupid idea because it is genius." - Eric Sovern, Surly

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    Having read this thread I'm somewhat curious to look into increasing the size of my front rotor. I just built up my first 29er, taking most of the parts from my 26" full sus. I'm currently running BB7 F/R 160mm discs but the idea of moving to 180-200mm front seems like it might be a good move. I'm about 240lbs currently.

    If I do swap out the front rotor the mounting hardware for the caliper, is that included? I'm running a RS Reba 2010, I'd have to make adjustments going to a bigger diameter rotor. Just trying to figure out if I'd need to purchase more mounting hardware or what?

  45. #45
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    Quote Originally Posted by RCook View Post
    Having read this thread I'm somewhat curious to look into increasing the size of my front rotor. I just built up my first 29er, taking most of the parts from my 26" full sus. I'm currently running BB7 F/R 160mm discs but the idea of moving to 180-200mm front seems like it might be a good move. I'm about 240lbs currently.

    If I do swap out the front rotor the mounting hardware for the caliper, is that included? I'm running a RS Reba 2010, I'd have to make adjustments going to a bigger diameter rotor. Just trying to figure out if I'd need to purchase more mounting hardware or what?
    You will need one of these but they are reasonably cheap probably not more than $15:



    Ronnie
    The trouble with having an open mind is that people will insist on trying to put things in it.

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    Cool, thanks for that. By chance do you know of a US site that sells it?

  47. #47
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    Quote Originally Posted by Realslowww View Post
    Those calipers should come from the factory with longer arms,the front was not a problem for me but the rear was. I could not brake slide the rear the way I wanted in corners and this solved the problem. I did the front around a half inch and the rear 3/4, the more you shim the better the control.
    I still dont get what you're talking about with the shim. Are you shimming the pinch bolt out from the arm to lengthen the torque arm and caliper? If you're going to do that, you might as well throw on some road bike flat bar brake levers to maximize the power with the necessary longer cable pull.

    I'd still go with better lines and levers, much safer than cobbling together a setup on something as important as brakes. And I'm saying this as a guy who ways 250-270 depending on my fitness levels. No offense, but I feel like there's gotta be something lacking in your setup if you're not able to get good braking out of 185s or 203s, even weighing a bit more than me.

    For mechanical brakes, its all about the housing preparation; cheap housing flexes and reduces the effectiveness of the brakes. XTR housing and BB7s = awesome power and modulation.

  48. #48
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    Quote Originally Posted by RCook View Post
    Cool, thanks for that. By chance do you know of a US site that sells it?
    Google is your friend.
    Universal sells them.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  49. #49
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    Quote Originally Posted by GTscoob View Post
    I still dont get what you're talking about with the shim. Are you shimming the pinch bolt out from the arm to lengthen the torque arm and caliper? If you're going to do that, you might as well throw on some road bike flat bar brake levers to maximize the power with the necessary longer cable pull.

    I'd still go with better lines and levers, much safer than cobbling together a setup on something as important as brakes. And I'm saying this as a guy who ways 250-270 depending on my fitness levels. No offense, but I feel like there's gotta be something lacking in your setup if you're not able to get good braking out of 185s or 203s, even weighing a bit more than me.

    For mechanical brakes, its all about the housing preparation; cheap housing flexes and reduces the effectiveness of the brakes. XTR housing and BB7s = awesome power and modulation.
    Yaa that is what I am doing and it works great no need for any other mod!

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    I have a set of BB7 brakes on the Air9 and XTR hydraulics on my Tallboy.
    I use the BB7's with a 180mm rotor and changed the brake cables to I-link shiftercables (with the Steinbach Micro V2levers).
    This resulted in a crisp contact point and because the cables have less resistance a smooth lever feel with excellent modulation.
    Also like the adjustable pad distance, big advantage in muddy conditions and the many years of low idiot proof maintainance.

    I only prefer the XTR's on steep technical descents, more power.
    One finger braking in every situation.
    The centerlock rotors are much stiffer compared to the Ashima Aro8 or Windcutters.
    But in wet conditions they have rubbing issues much sooner.

  51. #51
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    Are you shimming the pinch bolt out from the arm to lengthen the torque arm and caliper?
    Quote Originally Posted by Realslowww View Post
    Yaa that is what I am doing and it works great no need for any other mod!
    I'd like to see a picture of that.

  52. #52
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    Quote Originally Posted by Badassbassangler View Post
    I'm building a rigid Monkey 29er and need advice.
    I'm 220 lbs and don't ride too aggressive but like to go FAST when I have the chance, (without going OTB's).

    What are your thoughts on rotor size and why?

    I'm mostly concerned with burning through pads, (I want to use organic 'cause I heard they're quieter), and also don't want to easily lock up every time I touch the brakes.

    I've ridden 160mm disks only a couple of times, they were XT's and too loud for my taste.
    I hope to use Avid BB-7's...any thoughts??

    Thank you Allmighty Forum!
    IMHO there is a basic physics concept here that is not being addressed. Disc brakes essentially work as levers with the fulcrum being the axle. Thee fore the longer the lever (the lever length is radius of your disc i.e. 180disc = 90mm lever) the more power your brakes will have.
    So bigger disc=more power + larger braking surface =less heat

    A 26er the ratio of wheel to 180mm disc is 3.6 to 1
    A 29ner's ratio to a 180mm disc is approx 4.1 to 1
    A 29ner's ratio to a 203mm disc is 3.61 to 1
    So therefore 29ner set up with 203/180 is just about the same (leverage= power ratio)
    as a 26er setup 180/160..


    Ive ridden all sorts of disc combos this year on my 26er.
    Me Im just under 200lbs btw my favorite is 180f r 160r using xt centerlock discs with deore hydros and organic pads. Centerlocks are less prone to warping than 6 six bolt ...
    On a 29ner imho 203 front 180r would be a good option for your weight, wheel size and riding style. i think
    my .02cs

  53. #53
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    Quote Originally Posted by Reelchef67 View Post
    IMHO there is a basic physics concept here that is not being addressed. Disc brakes essentially work as levers with the fulcrum being the axle. Thee fore the longer the lever (the lever length is radius of your disc i.e. 180disc = 90mm lever) the more power your brakes will have.
    So bigger disc=more power + larger braking surface =less heat

    A 26er the ratio of wheel to 180mm disc is 3.6 to 1
    A 29ner's ratio to a 180mm disc is approx 4.1 to 1
    A 29ner's ratio to a 203mm disc is 3.61 to 1
    So therefore 29ner set up with 203/180 is just about the same (leverage= power ratio)
    as a 26er setup 180/160..


    Ive ridden all sorts of disc combos this year on my 26er.
    Me Im just under 200lbs btw my favorite is 180f r 160r using xt centerlock discs with deore hydros and organic pads. Centerlocks are less prone to warping than 6 six bolt ...
    On a 29ner imho 203 front 180r would be a good option for your weight, wheel size and riding style. i think
    my .02cs
    You have randomly dug up a year plus old thread for that input. Therefore I'd like to ask you please address the fact that at any given speed a 29" wheel is spinning at a slower speed than a 26" wheel. The brakes stops the bike.(plus rider) not the wheels. The energy absorbed by the brakes is due to the total mass, not the wheel radius.
    The trouble with having an open mind is that people will insist on trying to put things in it.

  54. #54
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    Brake disc size is still a function of leverage. Axle is the fulcrum, the radius of the wheel is one lever and radius of the disc is the other ..
    " I don't ride park"

  55. #55
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    As a 205 lb guy, the only weak spot on my bike is the 160 in the back. I need to get a 180 on before next spring.

  56. #56
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    Quote Originally Posted by Reelchef67 View Post
    Brake disc size is still a function of leverage. Axle is the fulcrum, the radius of the wheel is one lever and radius of the disc is the other ..
    This is true for rim brakes - a 622mm rim brake (700c wheel) would have higher brake torque than a 559mm (26" wheel) since the braking force is acting on the rim. Brake torque is the power of the brakes multiplied by the radius that it is acting on, 559mm ISO give or take for 26" wheels and 622mm for 700C/29er wheels.

    Brake torque on a 160mm w/26" wheel is the same as brake torque on a 160mm rotor w/ 29" wheel since the brake pads are still stopping a 160mm rotor.

    You might want stronger brakes due to the increase in rotating mass and the inertia that comes from the increased mass but not because of any ratio from rim diameter to rotor diameter.

  57. #57
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    Quote Originally Posted by GTscoob View Post
    This is true for rim brakes - a 622mm rim brake (700c wheel) would have higher brake torque than a 559mm (26" wheel) since the braking force is acting on the rim. Brake torque is the power of the brakes multiplied by the radius that it is acting on, 559mm ISO give or take for 26" wheels and 622mm for 700C/29er wheels.

    Brake torque on a 160mm w/26" wheel is the same as brake torque on a 160mm rotor w/ 29" wheel since the brake pads are still stopping a 160mm rotor.

    You might want stronger brakes due to the increase in rotating mass and the inertia that comes from the increased mass but not because of any ratio from rim diameter to rotor diameter.
    There are a couple of concepts here that are sometimes tricky to keep separated. Torque and work are not the same thing (even though they have the same units) and you seem to be equating them. Just like force acts through a distance to do work, torque must act through a rotation to do work.

    Disc and wheel size (and the relative size ratio) do not affect the total work done in stopping a bike+rider of X mass. Do it in the same time and the same power has been applied.

    What does change is the relative disctribution of force and angular distance travelled. The smaller the rotor relative to the wheel, the greater the force that will have to be applied at the rotor to achieve a set decceleration.

    So a 160mm rotor on a 29er wheel will see higher forces than the same on a 26" wheel, because at the end of the stop the same amount of heat would have been generated, but less rotor on the 29er wheel would have passed through the brake pads because 29er wheels rotate more slowly than 26" wheels.

    Hopefully that isn't more confusing than helpful.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  58. #58
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    Quote Originally Posted by meltingfeather View Post
    There are a couple of concepts here that are sometimes tricky to keep separated. Torque and work are not the same thing (even though they have the same units) and you seem to be equating them. Just like force acts through a distance to do work, torque must act through a rotation to do work.

    Disc and wheel size (and the relative size ratio) do not affect the total work done in stopping a bike+rider of X mass. Do it in the same time and the same power has been applied.

    What does change is the relative disctribution of force and angular distance travelled. The smaller the rotor relative to the wheel, the greater the force that will have to be applied at the rotor to achieve a set decceleration.

    So a 160mm rotor on a 29er wheel will see higher forces than the same on a 26" wheel, because at the end of the stop the same amount of heat would have been generated, but less rotor on the 29er wheel would have passed through the brake pads because 29er wheels rotate more slowly than 26" wheels.

    Hopefully that isn't more confusing than helpful.
    Great explanation

  59. #59
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    Hope

    "The smaller the rotor relative to the wheel, the greater the force that will have to be applied at the rotor to achieve a set decceleration."

    I translate this as bigger rotor or more powerful caliper = better stopping. Yes?

    Given that assuming your not changing your calipers/levers then a 203/185 on a 29er setup would be roughly similar to a 185/160 on a 26er setup.

    Yes I'm confirming for entirely selfish reasons... Damn me.

  60. #60
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    Quote Originally Posted by GTscoob View Post
    This is true for rim brakes - a 622mm rim brake (700c wheel) would have higher brake torque than a 559mm (26" wheel) since the braking force is acting on the rim. Brake torque is the power of the brakes multiplied by the radius that it is acting on, 559mm ISO give or take for 26" wheels and 622mm for 700C/29er wheels.

    Brake torque on a 160mm w/26" wheel is the same as brake torque on a 160mm rotor w/ 29" wheel since the brake pads are still stopping a 160mm rotor.

    You might want stronger brakes due to the increase in rotating mass and the inertia that comes from the increased mass but not because of any ratio from rim diameter to rotor diameter.
    not wrong
    try stopping a spiinng wheel by grabbing the spokes at the hub, its a lot easier and less painful to grab the longer lever of the wheel's tire instead..

  61. #61
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    Themal solutions gentlemen.

    Ok i borrowed tech from computers, specificly thermal disipation tech.

    Procedure.

    Arctic silver company makes a product called arctic ceramique.

    I user the prepping fluids to prep the rotor to hub mating surface.

    Once that is done i add arctic ceramique between the rotor and hub.

    This will cool the rotor faster. This uses the hub body as a heatsink to disapate heat from the rotor.

    I have not done any temp readings other than by touch. But i can tell they run much cooler.

    I stopped getting fade issue all together. Even on big decent braking, although the hub got noticably warmer, it was not hot persay.

    Ending statement, i think there is alot to learn about how the rotor interfaces with the hub pertaining to heat disapation.

  62. #62
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    And i only use solid rotors, i noticed the drilled rotors hold sand and eventuraly destroy the rotor and pads much faster.

    I have run solid rotors for a year now and the are completely silent still. Bb7 mech setup.

    I also added arctic ceramique to my caliper mounting points. So heat soak goes into the frame better.

    Cant say about carbon tho, no testing from me with carbon.

  63. #63
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    All these gram removals have caused massive wide spread problems in almost all componentry.

    I have learned that if you are not professionaly racing, go for durabilty, in the long you will be much more satisfied with riding maintenance free for many many miles and hours.

    I even went back to using intertubes, tubeless is neat but to much maintenance. To many flats, burps, prsure losses.

    There is a reason the guys at whistler still run tubes. They are just more of a durable tried and true setup.

    Im not knocking the gram reducers, im just saying i dont like spending time and money and feeling like a tweak finatic.

    Set it and forget it. More time riding and laughing.


    Cant tell you how many times i see the gram reducers walking their bikes. I just snicker and keep on riding.

    Carbon cranks, hollow chains, carbon frames, forks and rims. These parts need to stay metalic and strong at least for another 5 to 10 years.

    Durianrider will tell you the same thing. The carbon stuff is just not ready for 170 + riders.

    I am not down with disposable 10,000 dollar bikes. Its all a marketing scheme, think about it.

    Companies get you to spend huge sums of money for this stuff and it doesnt last.

    I ride a 30 lbs bike and love it. The super light bikes feel unstable to me. Like riding cardboard.

  64. #64
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    Your choices should include SLX brakes. The stopping power of the front brake in this set is much greater than any setup with bb7s without regard to rotor size. Noise on a past XT ride is unlikely with the current version XT/SLX brakes when installed with good pads. You will have more power than you need with either a 160 or 180mm rotor.
    Go this route to end braking issues.

  65. #65
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    Right, i agree and it did. But.....

    1 i dont need the extra stopping power. I have ridden a few slx 666 setups but i just think its overkill, maybe even dangerous. Dont need that kind of brake power for a bike, at least not till the slx line can be had for 100.00 ish or so for the entire setup.

    2 the kits are twice the price are mech, kinda cadilac ish.

    I was good with cantilever and V setups but i was forced to go disc due to frame and fork tech changes.

    I just cant justify massive insta stop for double the cost of BB7 mech setup. Its just not needed.

    I notice alot of people finatisize over these component changes but alot is just not needed.

    Its a monitary extraction system lol. Im not down with the fleecing.

    People raging over low poe, weight, insta flip brakes, clip on pedal / shoes.

  66. #66
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    This is 2013, What year are you from ??


    Quote Originally Posted by mjs1231 View Post
    Right, i agree and it did. But.....

    1 i dont need the extra stopping power. I have ridden a few slx 666 setups but i just think its overkill, maybe even dangerous. Dont need that kind of brake power for a bike, at least not till the slx line can be had for 100.00 ish or so for the entire setup.

    2 the kits are twice the price are mech, kinda cadilac ish.

    I was good with cantilever and V setups but i was forced to go disc due to frame and fork tech changes.

    I just cant justify massive insta stop for double the cost of BB7 mech setup. Its just not needed.

    I notice alot of people finatisize over these component changes but alot is just not needed.

    Its a monitary extraction system lol. Im not down with the fleecing.

    People raging over low poe, weight, insta flip brakes, clip on pedal / shoes.
    I have a 6 Berth & 2 Berth Motorhomes that I rent out . They are based in Tauranga, New Zealand

  67. #67
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    160mm vs. 180mm rotor Pro/Cons?

    Quote Originally Posted by mjs1231 View Post
    Right, i agree and it did. But.....

    1 i dont need the extra stopping power. I have ridden a few slx 666 setups but i just think its overkill, maybe even dangerous. Dont need that kind of brake power for a bike, at least not till the slx line can be had for 100.00 ish or so for the entire setup.

    2 the kits are twice the price are mech, kinda cadilac ish.

    I was good with cantilever and V setups but i was forced to go disc due to frame and fork tech changes.

    I just cant justify massive insta stop for double the cost of BB7 mech setup. Its just not needed.

    I notice alot of people finatisize over these component changes but alot is just not needed.

    Its a monitary extraction system lol. Im not down with the fleecing.

    People raging over low poe, weight, insta flip brakes, clip on pedal / shoes.
    you have such a piercing and visionary intellect
    yawn...
    Last edited by meltingfeather; 04-14-2013 at 02:59 PM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  68. #68
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    hu?

    Quote Originally Posted by muzzanic View Post
    This is 2013, What year are you from ??
    lol what year are you from ? lol. dumb question deserves dumb answer.

    well I from right here right now of course lol.


    do you know what the % of riders just in the US are that use hydro disc brakes on mountain bikes ?

    its a joke.


    for 200- 300 just for brakes on a bike ahahahahah i would rather steal yours lol.

    sell on ebay, then buy some silver.

  69. #69
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    160mm vs. 180mm rotor Pro/Cons?

    Quote Originally Posted by mjs1231 View Post
    for 200- 300 just for brakes on a bike ahahahahah i would rather steal yours lol.
    Thievery is classy for sure.
    You might not be prepared to believe this, but $200 isn't a lot if cash to drop on brakes for some people. I know... I know... sit down... breathe... take a Valium, you'll be OK.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  70. #70
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    Quote Originally Posted by mjs1231 View Post
    lol what year are you from ? lol. dumb question deserves dumb answer.

    well I from right here right now of course lol.


    do you know what the % of riders just in the US are that use hydro disc brakes on mountain bikes ?

    its a joke.


    for 200- 300 just for brakes on a bike ahahahahah i would rather steal yours lol.

    sell on ebay, then buy some silver.
    Have you wondered, at times, why you have so many neg-reps with so few posts?

    It's because you are unintelligible, obtuse, and belligerent.

    Fix that sh!t, okay?
    Scarlett Johansson loves my hummus.

  71. #71
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    lol im not workin the stats.

    truth is treason in the empire of lies.

    well guys, go ahead and buy the priciest stuff you can find lol

    i see that your worried about reps.

    maybe you should just work the angle and be neutral on every post you make.

    im sure this will raise your group think score.

    IJS

    you don't need hydrolic brakes to stop well.

    oh and I know the argument, your rim may explode when going down a mountain

    or

    disc is the big ooow ahhhh next advancement gadgetry

    the truth is, for 99.999999 people it makes almost zero difference.

    wait wait, you cant stop with v brakes ?

    you cant stop with cantilever ?

    people stopped fine for decades. I don't see mass deaths due to v brakes, do you ?

    I mean what are you guys saying ?

    ya sure hydrolic stop better but its not worth the extra dough

    I've read all the marketing trash, seen the specs, still don't really care.

    still think it nothing but fanaticism.

    reminds me of what durianrider said, weight weenies jrkn off to titanium spindals.

    gram heads. component junkies ahahahaha


    kills me every time i think about it. lol.

    wait wait..... don't forget to criticize me on my spelling lol

  72. #72
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    Quote Originally Posted by mjs1231 View Post
    DRAMA
    I rode just fine with cantis and v-brakes

    Can I ride better with hydraulic discs? Later braking due to better modulation and a bit more power. Yup, I'll take that, please. Let's not even get into rain and mud.

    Would I still ride mtb if I had to ride rim brakes for some odd reason. Yup, I'd still ride.

    Ultimately, what is your point? Can you state it in a single sentence? Thanks.
    Last edited by juan_speeder; 04-14-2013 at 04:26 PM.
    Scarlett Johansson loves my hummus.

  73. #73
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    Hi all.
    I have new XT-M785 brakes and i'm really confused about what size rotor i should use on the front. I have bought a 160mm XT SM-RT86 Ice-Tec rotor for the rear which will be ideal. But i'm not sure weather to go with a 160mm or 180mm for the front. After reading loads of threads on forums its starting to make my brain hurt.lol. Some people are saying a bigger rotor means more power but less modulation, but others are saying a bigger rotor gives more power and better modulation. What would be best to run with the xt brakes? I don't want to go with the 160mm and end up with not enough power, but i also don't want to go with the 180mm and lose some modulation. Are xt brakes powerful enough with the 160mm XT SM-RT86 Ice-Tec rotor?

    I'm about 200lb and don't do a huge amount of downhill as we don't have any decent size hills in my area, but i would like the power to stop when i do hit a hill. As result of my motorcycle days i do love to leave my braking very late and don't fancy chucking myself over the bars and using my face to do the final bit of braking. I don't want to ruin the dashing good looks and i hate having to eat and drink through a straw.lol.
    So which size rotor gives the best power to modulation ratio? The power and control to pull the odd stoppie here and there would be good to.
    Any advice would be great.
    Thanks

  74. #74
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    At 200lbs, I think you should run a 180mm rotor in the front. 160mm would be fine, but 180mm is better unless you are counting every gram. I have XTs with 180 Ice Tec front and rear and the power is very very good, and then modulation is great...not good, great. Take the extra power of the 180 and hold the better resistance to fading in reserve in case you go to a place with long downhill.

  75. #75
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    v brakes ftw

    TDF still using v brakes doing 45 down hill. I have ridden disc in the rain and mud. No difference at all.

    Save you money. Let corporate shell out the big brand name bikes. Thats the only people riding them anyway. Pushing the carbon fiber glass bikes.

    Glass freaks on glass bikes. Masterful.

    I saved hundreds on brakes and used it to buy a new fork.

    And you freaks with your screaming disc brakes can go hang ur selfs. That sound is horrific.

    Videos on glass bikes shattering right on the tarmac. Incredable.

    Down hill guys replacing the bottom bracket bearings after two runs.

    I mean wtf. You have to be a idiot to buy into that type of trash durability.

    I dont care if ur bike floats.

    Glass freaks shell out giant cash for the dumbest stuff.

    Did you see the tdf riders this year ? My god they were skinny.

    Why not just start hiring midgets to ride tbf ?

    Better yet, lets just remove the feet and shin bones. Mount the kneecap with a clipless

    Drill some holes in the front of the torso so they breath better.

    I mean my god, these freaks are on .........

    Epo
    Testosterone
    Hgh
    steroids
    Stimulants
    On and on.

    Freaks and nothing more.

    The cold hard facts are these types of people should not be idleized ever.

    So get ur disc brakes, carbon frame, bars, steerer, cranks.

    Pay out the backside and make sure when it all shatters to put a vid on youtube. I need a good laugh.

    Please please post how much it all costed you.

  76. #76
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    Quote Originally Posted by Haymarket View Post
    At 200lbs, I think you should run a 180mm rotor in the front. 160mm would be fine, but 180mm is better unless you are counting every gram. I have XTs with 180 Ice Tec front and rear and the power is very very good, and then modulation is great...not good, great. Take the extra power of the 180 and hold the better resistance to fading in reserve in case you go to a place with long downhill.
    ^^x2.
    two of my bikes are xt hydro 180mm up front, and bb7 160 in the back.

  77. #77
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    Quote Originally Posted by mjs1231 View Post
    TDF still using v brakes doing 45 down hill. I have ridden disc in the rain and mud. No difference at all.
    No, they are not. As if whatever they use has any bearing to mountain biking anyway...
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  78. #78
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    recalls

    Quote Originally Posted by Jayem View Post
    No, they are not. As if whatever they use has any bearing to mountain biking anyway...
    Giant Recalls 2013 XtC Advanced SL 29er Mountain Bikes & Contact SLR Seatposts


    More carbon fiber recalls AHAHAHAHAHAHAHAH

    GIANT RECALLS DUE TO CARBON FIBER PARTS FAILING

    LOL disc brakes and carbon fiber glass bikes for glass freaks.

    Jesus people are desperate and stupid.

    The seed was planted in you mind as a child, you never figured it out.

    Now the endoctranation is complete. So take the drugs, the vaccines, the marketing lies, dont forget to eat your gmo's and love government.

    Worship the federal reserve, best of all make sure you pay thousands of dollars for carbon fiber parts and disc brakes.

    Remember, if your not a trendy, you cant have fun on a bike and without disc brakes you just cant stop.


    Oh and dont forget to drink the fluride laced tap water, its good for your teeth right ?

    Trendies are the spat of the earth. Dumb, easily led, and easy to part them with thier money.

    Corporate sheep. With disc brakes ahahahahahahahahah

  79. #79
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    Quote Originally Posted by mjs1231 View Post
    Giant Recalls 2013 XtC Advanced SL 29er Mountain Bikes & Contact SLR Seatposts


    More carbon fiber recalls AHAHAHAHAHAHAHAH

    GIANT RECALLS DUE TO CARBON FIBER PARTS FAILING

    LOL disc brakes and carbon fiber glass bikes for glass freaks.

    Jesus people are desperate and stupid.

    The seed was planted in you mind as a child, you never figured it out.

    Now the endoctranation is complete. So take the drugs, the vaccines, the marketing lies, dont forget to eat your gmo's and love government.

    Worship the federal reserve, best of all make sure you pay thousands of dollars for carbon fiber parts and disc brakes.

    Remember, if your not a trendy, you cant have fun on a bike and without disc brakes you just cant stop.


    Oh and dont forget to drink the fluride laced tap water, its good for your teeth right ?

    Trendies are the spat of the earth. Dumb, easily led, and easy to part them with thier money.

    Corporate sheep. With disc brakes ahahahahahahahahah
    What relevance does your diatribe have on the topic at hand?

  80. #80
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    @haymarket + ElwoodT
    Thanks for the advice, i decided to go with the 180mm up front and just ordered it, hopefully be here tomorrow or the next day.

  81. #81
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    I just noticed i posted in the 29er bikes section. whoops.lol. I only have 26" wheels, will the 180mm rotor up front still be ok for 26" wheels?

  82. #82
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    160mm vs. 180mm rotor Pro/Cons?

    Quote Originally Posted by Volcomist View Post
    I just noticed i posted in the 29er bikes section. whoops.lol. I only have 26" wheels, will the 180mm rotor up front still be ok for 26" wheels?
    Never dawg.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  83. #83
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    160mm vs. 180mm rotor Pro/Cons?

    I was riding 180front 160 rear.
    I just switched to to 180/180
    Big improvement in rear modulation .
    Go for it
    " I don't ride park"

  84. #84
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    Quote Originally Posted by mjs1231 View Post
    Themal solutions gentlemen.

    Ok i borrowed tech from computers, specificly thermal disipation tech.

    Procedure.

    Arctic silver company makes a product called arctic ceramique.

    I user the prepping fluids to prep the rotor to hub mating surface.

    Once that is done i add arctic ceramique between the rotor and hub.

    This will cool the rotor faster. This uses the hub body as a heatsink to disapate heat from the rotor.

    I have not done any temp readings other than by touch. But i can tell they run much cooler.

    I stopped getting fade issue all together. Even on big decent braking, although the hub got noticably warmer, it was not hot persay.

    Ending statement, i think there is alot to learn about how the rotor interfaces with the hub pertaining to heat disapation.
    That's kinda interesting, I'm surprised that people haven't done more with heat sinks. Could build a pretty good heatsink into a hub with CNC machining.

    Could even install some heat-pipes, which use low boiling point liquid to cryo-cool by phase change from liquid to gas, and the gas condenses on the cooler heat-sink end of the tube.

    Quite a few motorbike caliper housings have vanes to work as a heatsink, also. Could probably retrofit a small computer heatsink, for example a northbridge passive heatsink, fitted onto a brake caliper housing with thermal compound would get it a bit cooler.

    Could even design a caliper with water cooling and possibly even fit the cooling pump to run off the rotor. Would be kinda cool, brake calipers with little radiators clipped or even wrapped onto the fork stantion.

  85. #85
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    Quote Originally Posted by bishopdante View Post
    That's kinda interesting, I'm surprised that people haven't done more with heat sinks. Could build a pretty good heatsink into a hub with CNC machining.
    I was pondering this on my ride yesterday, but then I thought about the spokes. Rotor connected to the hub, hub connected to the spokes, there has to be some pretty good heat dissipation there, given it's all metal and connected? This thread now reminds me of when I overclocked a graphics chip for an old custom built computer and glued a heat-sink to it. Worked most of the time.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  86. #86
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    180mm fronts and 160mm rears for me - I also have been trying different pads, and now I run one of each type in the caliper. One side sintered (sp?), the other organic.

  87. #87
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    Quote Originally Posted by bishopdante View Post

    Could even design a caliper with water cooling and possibly even fit the cooling pump to run off the rotor. Would be kinda cool, brake calipers with little radiators clipped or even wrapped onto the fork stantion.
    My wife gets a kick out of the homemade contraptions like that, that I always seem to come up with. But that one is a doozy!

  88. #88
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    Quote Originally Posted by Sean831 View Post
    the brakes will probably still wear at the same rate, unless temperature has an effect on how quickly they wear out. but i dont think thats too big of a difference
    I don't know all the factors that go into disc wear, but since the circumference of the 180mm brakes is larger (by about 11%) shouldn't the disc last ~11% longer (under ideal conditions)... if not even longer since it is staying cooler?

    IF the 180mm discs do last 11% longer, then wouldn't it actually be cheaper in the long run, if the discs are the same price?

  89. #89
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    Quote Originally Posted by kjmccarx View Post
    I don't know all the factors that go into disc wear, but since the circumference of the 180mm brakes is larger (by about 11%) shouldn't the disc last ~11% longer (under ideal conditions)... if not even longer since it is staying cooler?
    If they have an 11% greater circumference, they are also going to travel through the pads 11% faster, unless you ride your bike 11% slower once you put on the larger rotors.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
    29er Tire Weight Database

  90. #90
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    Quote Originally Posted by meltingfeather View Post
    If they have an 11% greater circumference, they are also travel through the pads 11% faster, unless you ride your bike 11% slower once you put on the larger rotors.
    Everyone knows you're supposed to ride 11% slower when using 180mm rotors.

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