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  1. #1
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    XTR M975 poor power. How to improve?

    The 2009 XTR (M975?) disc brakes on my XC bike have had very poor stopping power since the day they were installed. At first I thought they just need more miles to bed-in the pads...but I was wrong. Then I thought they needed to be bled again so I changed to the Yumea brake lines...no better.

    What can I do to give these brakes some real stopping power?

    Is there a new brake pad compound of rotor that is known to help? Maybe Swissstop 16S or EBC Red?

    Ideally I don't want to add any weight to the system and I hate squealy brakes but I don't mind if the pads and rotors have a short life span in exchange for lots of power.


    Thanks
    Attached Thumbnails Attached Thumbnails XTR M975 poor power. How to improve?-xtr_dbs.jpg  

    Last edited by R332; 12-05-2012 at 11:20 AM.

  2. #2
    RTM
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    I guess your comment about not adding weight was meant to head off the suggestion of a larger rotor, but generally that is an inexpensive and guaranteed way to add power. especially in the front.
    "The bitterness of poor quality remains long after the sweetness of a low price is forgotten." - Benjamin Franklin

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    Quote Originally Posted by RTM View Post
    I guess your comment about not adding weight was meant to head off the suggestion of a larger rotor, but generally that is an inexpensive and guaranteed way to add power. especially in the front.
    Good point! Currently using 180 F and 160 R. Perhaps I could go to a larger front rotor but in a light weight (Hope?) brand?

  4. #4
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    Your pads may be contaminated. It only takes a small amount of oil or grease (which could get on the rotors during transport, for example) to foul the pads. As you generally want a spare set on hand anyway, I would try a new set of pads and see how it feels after following the manu's bed-in procedure. Be sure to clean the rotors before allowing the new pads to touch them (and yes, oils from your hands can be a contaminant).

    Good luck,
    Pete
    I can barely get my mouth around it.

  5. #5
    RTM
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    Quote Originally Posted by R332 View Post
    Good point! Currently using 180 F and 160 R. Perhaps I could go to a larger front rotor but in a light weight (Hope?) brand?
    sure. I personally don't stress a lot about rotor weight as the truly lightweight ones can get expensive in a hurry. An extra 100 grams is probably not going to ruin your ride and may save you $100 total, but that's a personal decision. you could put the 180 on the rear and (if it will fit) a 203 up front...if that doesn't work you have other issues. that's a setup worthy of a DH race bike.

    also wanted to mention, many times issues caused by what guys think is brake weakness can actually be alleviated by looking up the trail a lot further, giving yourself more time to prepare and asking less of the brakes. added benefit of making the entire riding experience more fun, fast and fluid while you're at it. of course there are times when you squeeze and not much happens. and that sucks. So, if your brakes are not performing and the bleed is good, the larger rotor is definitely your next step.
    "The bitterness of poor quality remains long after the sweetness of a low price is forgotten." - Benjamin Franklin

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    Quote Originally Posted by R332 View Post
    Good point! Currently using 180 F and 160 R. Perhaps I could go to a larger front rotor but in a light weight (Hope?) brand?
    I have the same calipers (running "STI" Levers) with red EBC pads and 183mm hope rotors and they have great stopping power, if anything a little to much so I'm looking for less gravy pads with more modulation.
    Last edited by patineto; 12-06-2012 at 10:51 AM.

  7. #7
    RTM
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    Quote Originally Posted by Pedalphile View Post
    Your pads may be contaminated.Pete
    great point Pete.

    so - R332 - bear in mind all my statements are made with the assumption that the brake & pads are mechanically sound.
    "The bitterness of poor quality remains long after the sweetness of a low price is forgotten." - Benjamin Franklin

  8. #8
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    Quote Originally Posted by RTM View Post
    sure. I personally don't stress a lot about rotor weight as the truly lightweight ones can get expensive in a hurry. An extra 100 grams is probably not going to ruin your ride and may save you $100 total, but that's a personal decision. you could put the 180 on the rear and (if it will fit) a 203 up front...if that doesn't work you have other issues. that's a setup worthy of a DH race bike.

    also wanted to mention, many times issues caused by what guys think is brake weakness can actually be alleviated by looking up the trail a lot further, giving yourself more time to prepare and asking less of the brakes. added benefit of making the entire riding experience more fun, fast and fluid while you're at it. of course there are times when you squeeze and not much happens. and that sucks. So, if your brakes are not performing and the bleed is good, the larger rotor is definitely your next step.

    Good info!

    My issue is component related, not the rider I might not be the next World Champion but I can hold my own on the trail and the last five sets of disc brakes I have owned all performend well.

    Time to go pad shopping. Any recommendations?

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    I had a set of those some time ago, they were made for racers who don't care if a brake is poor or not, just how much it weighs.

    I didn't like how the levers clamped to the bar, especially a carbon bar. The bolt was very tight in the threads and it was impossible to judge torque.

    The calipers were things of beauty, the levers not so much, but the power was far too low for anyone but pro racers in my view. i ended up with 203 F+R and they were still crap. Really crap.

    Sell them!

    These are the only Shimano brakes i have been disappointed in, and if buying now, i would choose the big S or Hope.
    You can't make a racehorse out of a donkey, but you can make a fast donkey.

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    Quote Originally Posted by A MAN CALLED HORSE View Post
    I had a set of those some time ago, they were made for racers who don't care if a brake is poor or not, just how much it weighs.

    I didn't like how the levers clamped to the bar, especially a carbon bar. The bolt was very tight in the threads and it was impossible to judge torque.

    The calipers were things of beauty, the levers not so much, but the power was far too low for anyone but pro racers in my view. i ended up with 203 F+R and they were still crap. Really crap.

    Sell them!

    These are the only Shimano brakes i have been disappointed in, and if buying now, i would choose the big S or Hope.
    As discouraging as your post is I have to agree with you.

    It will be sad to see the sexy Yumea bits leave my bike but I need more power.

    What are the ultimate XC disc brakes these days? Something with far more power and hopefully the same or less weight compared to my M975 set.


    Thanks
    Last edited by R332; 12-05-2012 at 03:54 PM.

  11. #11
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    That was far from Shimanos best effort when it comes to brakes. The XT version from that same era was awesome. Swiss stop pads might help a fair bit. And I feel the SHimano rotors work better with their brakes than after market ones. IIRC the Yumeya brake lines were the same as XTR. The Saint brake lines are the ones that are reinforced and will give better lever feel.

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    Weird I'm about 240pounds with gear and they stop me on a dime, the only reason I did not go 160mm in the back is that I already have the red Hope rotors in 183mm, but if I was starting from scratch I get 160mm for the back..

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    Quote Originally Posted by A MAN CALLED HORSE View Post

    I didn't like how the levers clamped to the bar, especially a carbon bar. The bolt was very tight in the threads and it was impossible to judge torque.
    Do the "STI" version like this ones suffer from the same problem..

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    Quote Originally Posted by patineto View Post
    Weird I'm about 240pounds with gear and they stop me on a dime, the only reason I did not go 160mm in the back is that I already have the red Hope rotors in 183mm, but if I was starting from scratch I get 160mm for the back..
    Do you have the 970 brake like the OP or the newer 980/5 brake that's been on the market for the last two years. Those two brakes couldn't be more different.

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    Quote Originally Posted by customfab View Post
    Do you have the 970 brake like the OP or the newer 980/5 brake that's been on the market for the last two years. Those two brakes couldn't be more different.
    Actually I think the levers are 975 but maybe I'm wrong, have no idea on the calipers

    Here are the calipers, look the same as the OP or not...
    Last edited by patineto; 12-06-2012 at 10:42 AM.

  16. #16
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    Quote Originally Posted by customfab View Post
    That was far from Shimanos best effort when it comes to brakes. The XT version from that same era was awesome. Swiss stop pads might help a fair bit. And I feel the SHimano rotors work better with their brakes than after market ones. IIRC the Yumeya brake lines were the same as XTR. The Saint brake lines are the ones that are reinforced and will give better lever feel.
    Hmmmmmm, the Yumea website says "39% more rigid hose" and they must mean vs XTR since that is what the Yumea is designed for. Regardless the brakes don't meet my expectations so unless the Swiss Stop sintered pads can perform miracles I will be in the market for new disc brakes.

    What is the hot set-up these days? I have MY2011 XTR discs on another bike and they are amazing but maybe there is another option that is even better in terms of power-to-weigh ratio? I love to save grams

  17. #17
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    Quote Originally Posted by R332 View Post
    Hmmmmmm, the Yumea website says "39% more rigid hose" and they must mean vs XTR since that is what the Yumea is designed for. Regardless the brakes don't meet my expectations so unless the Swiss Stop sintered pads can perform miracles I will be in the market for new disc brakes.

    What is the hot set-up these days? I have MY2011 XTR discs on another bike and they are amazing but maybe there is another option that is even better in terms of power-to-weigh ratio? I love to save grams
    I think it's a toss up between the 980 XTR race and the Formula R1. The Formula's are Made in Italy and as a result can be finicky like all things Italian.

    Perhaps the Yumea line is the same as the Saint line.

  18. #18
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    Quote Originally Posted by R332 View Post
    Hmmmmmm, the Yumea website says "39% more rigid hose" and they must mean vs XTR since that is what the Yumea is designed for. Regardless the brakes don't meet my expectations so unless the Swiss Stop sintered pads can perform miracles I will be in the market for new disc brakes.
    The EBC reds are really grippy and also cheap..

  19. #19
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    I have the 975's on two bikes 160/140 & 180/160, like others have mentioned - not the most powerful brakes out there.I've tried many different pads & the best, especially on the front is EBC Gold pads. Don't waste your time looking for these in NA - many list them for sale but no one has stock. I got mine from Highonbikes out of UK, cheap & I had them in a week.
    I also have the XTR 985 Race & these are awesome - lots of stopping power.

  20. #20
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    I've gotta agree with xc71. EBC pads are the way to go for a definite performance increase. I put Goodridge hoses on mine too which was also a big help. Seems to have a better feel at the lever with that. Closer to that of the 980/780 series brakes. Still not as good, but closer. These guys have the EBC pads: EBC Disc Brake Pads XTR M965 XT M765 Gold @ eBikeStop.com. I just got some from them about a week ago.

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    Quote Originally Posted by scottap2003 View Post
    I've gotta agree with xc71. EBC pads are the way to go for a definite performance increase. I put Goodridge hoses on mine too which was also a big help. Seems to have a better feel at the lever with that. Closer to that of the 980/780 series brakes. Still not as good, but closer. These guys have the EBC pads: EBC Disc Brake Pads XTR M965 XT M765 Gold @ eBikeStop.com. I just got some from them about a week ago.
    SOLD! First I will replace the front and rear pads with EBC Gold sintered. If that doesn't give me enough power I will get new XTR brakes.

    Thanks for the help

  22. #22
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    Mate I just installed the latest XTR M988 Trail brakes and they are superb! I am only using the Avid HS1 rotors that were already on my bike. I could barely stop with the XO brakes now I have had to downsize my rear rotor to a 140 and should probably put the 160 on the front for fear of shooting over the handlebars with the 180 that is on there. I am on a medium CDa.e flash carbon 1 and weight about 185lbs.

  23. #23
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    The EBC Gold sintered pads have arrived!

    Any tips for how to bed them in for best performance and no noise?


    Thanks

  24. #24
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    post 4 for photo.

  25. #25
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    I'm a shop wrench, and if those XTR's are not braking properly, and usually they stop as good as the same gen XT's, then you must check;

    1- bleeding
    2- Shimano OE rotors, RT66 or floating ones
    3- sintered pads usually are the best
    4 Check for even caliper spacing and even piston movement, usually they suffer from a dominant piston, take pads out, pull lever until pistons show, clean with a swap or equivalent and mineral oil, push in, reinstall.

    The new gen, though not as sexy looking, are the best out there, IMO.

    Good luck!
    The world needs a huge socio-economic change...be it. We all need to ride more....

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