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Dura Ace C24 wheels – sticky brakes issue

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  • June 24, 2014 at 8:17 am #21755
    Zermattjohn

    Hi all – I’ve been experiencing shuddering/throbbing brake issues with this wheelset. I’ve got Dura Ace brakes too, and the pads are new but I get a real “pulsing” feel when braking. Its pretty disconcerting and sometimes means that the rear locks up it it grabs the rim. It almost feels like the wheel is out of true, or has oil on half the rim, neither of which is the case. I’ve used Ultegra wheels and the issue doesn’t occur, so its got to be something to do with either the rim being faulty, or the brake pads being incompatible. However the rim on both Ultegra and Dura Ace C24 is alu…? Anyone else experienced this issue? I’ve had a few pairs replaced as the supplier agreed there was a problem, but it keeps happening with each replacement. Pulling my hair out – the wheels are great when you don’t want to slow down!

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  • November 29, 2016 at 8:51 pm #800797
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    SRRC

    I’m a bit late to see this

    I’m a bit late to see this thread!

    I had a pair of C24 Tubeless with exactly this problem from new. It’s difficult to spot but close inspection showed a 12mm section of braking surface which was not smooth. It looked a bit like a cobweb in the surface where the finishing process during manufacture hadn’t been done properly.

    Wiggle changed them without a fuss and their replacements are fine.

    November 27, 2016 at 9:31 pm #800795
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    matthewn5

    Have you tried wiping with

    Have you tried wiping with vinegar on a tissue? Something I do occasionally if the braking has gone off on my Campag/Fulcrum wheels.

    November 18, 2016 at 5:13 pm #800793
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    clarinet5001

    I have solved this issue, see

    I have solved this issue, see my reddit post. It seems to apply only to Dura Ace and RS80/81 CL wheels, NOT Ultegra or C24 TL wheels. 

     

    My apologies for resurrecting such an old thread but I think it’s important to get this out there, as so many people complain of the same issue. 

     

    The reason behind Shimano's C24 CL front wheel braking issues
    by incycling

    May 26, 2015 at 2:30 pm #800791
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    mikaits

    https://www.youtube.com/watch
    https://www.youtube.com/watch?v=s8QHW36zjmU
    Dura Ace C50 Wheelset Braking Issue

    May 26, 2015 at 2:26 pm #800789
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    mikaits

    Hello from Greece.
    I am
    Hello from Greece.
    I am having the exact same problem on my front wheel (Shimano Dura Ace WH9000 C50).
    I have already tried 2 different sets of wheels, but the problem is the same:
    1)When the wheel is at normal (environment) temperature the problem is tiny / almost “invisible – inaudible”!
    2)The problem appears and increases constantly as the rim’s temperature rises by the friction of the brake pads to the rim (during a long braking period on a ride downwards a mountain).
    3)The “bulge” seems to appear on the rim’s joint (which on Dura Ace WH9000 C50 is pinned and not welded), so when the brake pads meet this “bulge” vibration occurs.
    4)If breaking is strong and long lasting the “bulge” is obviously expanding so vibration becomes so strong that it effects breaking efficiency.
    5)There is a point that the wheel blocks instantly when brake pads meet the “bulge” !!!
    I have already faced a fall, because of this issue, as I was riding downwards a 980m mountain (with 10% – 16% inclination).
    The wheels became so hot that the “bulge” blocked completely the front wheel so the front wheel skidded during a fast turn.
    Fortunately my speed was low, so I was not injured……
    But my bike suffered some damage!
    It is well known that any poorly constructed joint (pinned or welded) can create brake pulsing…
    But we are talking about Shimano Dura Ace which is the flagship of Shimano technology!!!!

    August 8, 2014 at 4:44 pm #800787
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    philshems

    I had exactly this problem on
    I had exactly this problem on the front wheel of a pair of RS80 C24s. Braking while descending was particularly unpleasant

    I had the wheel checked over by wheelbuilding guru Paolo Coppo (http://paolocoppo.drupalgardens.com/). He found that the spokes were evenly tensioned and the wheel was true, but he when checked with a micrometer, there was a lot of side-to-side movement of the rim between each spoke. He concluded that the rim isn’t rigid enough to be supported by such a small number of spokes.

    In a nutshell the wheel either needs more spokes or a stiffer rim. This seems to make sense, as I have a pair of Ultegra 6700 wheels, which are effectively the same wheel but with a heavier rim, and there isn’t the slightest trace of pulsing when braking.

    As a footnote I’ve since had a pair of 24 hole HED Ardennes rims built up on Dura Ace hubs by Paolo, and they knock spots off both the RS80s and Ultegras. They roll better, brake better, are more comfortable and they can be repaired whenever needed. All for the same sort of money and just a teeny bit more weight!

    August 8, 2014 at 12:15 pm #800785
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    jason.timothy.jones

    the Concept of a Rim Rubber
    the Concept of a Rim Rubber is sound, what you get for your money is rubbish.

    I use a normal pencil eraser from the supermarket, it does take all the very fine grist and crap away quite nicely, I cant say it make braking much better, but the rims look sexy

    I use the same thing on my Diamond Steel (the type used for honing knives) this makes a remarkable difference

    August 8, 2014 at 11:50 am #800783
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    Zermattjohn

    Yep, I’m now on my 5th pair
    Yep, I’m now on my 5th pair of these wheels! I got some SwissStop green pads, definite improvement on the Dura-Ace pads but still the same issue, particularly on the front. I was recommended to try sanding the pads this week, so have done so, not tried out yet. I also got a rim-rubber which is possibly the daftest item in my bike-toobox, doesn’t seem to do very much more than soap and water does…! If this still goes on after these latest attempts I think its time for a full refund and to buy something else.

    August 8, 2014 at 11:38 am #800781
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    Rebem

    Exactly the same problem here
    Exactly the same problem here with my Dura Ace C50 9000 wheels. I’m on my second set and Shimano Australia said they were aware of a problem but not everyone experiences it. I’ve tried:
    – Kool Stop Salmon pads and that helped the most but not great still
    – Very fine sanding of the brake track which helps slightly
    – Truing the wheel – I have a set of dials on my truing stand and you can see a very slight blip in a couple of places on each wheel but no more than other wheels. It’s more of a surface problem than a truing issue I think.
    – Tightened everything as per everyone’s instructions (head stem, skewers etc.)
    – Less tyre pressure
    – More tyre pressure
    The front is worse than the back and much worse at slower speeds. After recent rain fall it has become very pronounced again, even with the Kool Stops on.

    Frustrating for a $1,500 set of wheels!

    June 27, 2014 at 10:59 am #800779
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    harman_mogul

    DaSy is right. Use SwissStop
    DaSy is right. Use SwissStop pads and clean your rims regularly with the rim rubber.

    I have 7850s and RS80s and do not suffer from this braking problem either on the steel bike (105 brakes) or the carbon bike (6700 brakes).

    However I do suffer from this problem on the front wheel of the fixed bike, which has a 28H IRD Cadence magnesium-alloy rim (Shimano 600 brakes, Kool Stop Salmon pads). This has been extensively investigated and my conclusion is that it’s a wind-up effect: the wheel seems to hit a resonant frequency with the steel fork, setting up a shimmy in the longitudinal plane.

    The 16/20 spokes in the Shimano wheels under discussion are highly tensioned and if even slightly out of tolerance on the +ve side, this must impart a lateral run-out to one side, then the other.

    June 27, 2014 at 10:36 am #800777
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    Anonymous

    The old 7850 CL C24 wheels
    The old 7850 CL C24 wheels used to actually have a caveat in the user instructions that said they didn’t recommend the use of their own Dura Ace pads. They are notoriously abrasive, and the thin and fairly delicate rim surface of the CL wheels gets eaten pretty quickly.

    I see a fair few wheels with grabby rims, and usually a good going over with a rim rubber and then clean with water sorts them out, especially if they are new.

    [url=http://www.chainreactioncycles.com/swissstop-swissclean-rim-cleaner/rp-prod42618?utm_source=Google&utm_medium=Shopping&utm_name=UnitedKingdom&gclid=CL3cmb_dmb8CFVIPtAodbygAow&gclsrc=aw.ds] Swissstop Rim Rubber[/url]

    I would recommend going to Swissstop Greens on theses rims, they are so much gentler on the surface, and braking performance is generally better.

    June 27, 2014 at 8:12 am #800775
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    Zermattjohn

    ABS on a bike – that’s a good
    ABS on a bike – that’s a good way of looking at it. I agree, perhaps the braking surface is almost “too” good, and Dura-Ace brakes/pads themselves are pretty grabby on my Ultegra wheels (which admittedly have a year’s more wear on the rim). In terms of heat dispersion, I discount that as it happens the instant I apply the brake, rather than builds through the braking period.

    Interesting, though I’d rather it didn’t happen.

    June 27, 2014 at 7:40 am #800773
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    jason.timothy.jones

    I have the same problem with
    I have the same problem with RS10’s, what is strange though is when I put a different wheel on that does not pulse, there is a significant reduction in breaking. Apart from the actual wheel, everything else is the same, so this leads me to think its something to do with the breaking surface. Heat dissertation could be a cause as the rotating energy is transferred to heat energy, especially as it seems this is a rear wheel problem, but Im struggling to accept that it would be some much that its so noticeable.

    For me, the better performance outweighs the pulsing, and its kinda like having ABS on a bike.

    Has anyone asked Shimano

    June 26, 2014 at 4:32 pm #800771
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    tonyhogg

    Having major problems with my
    Having major problems with my c24 wheels, already had them back to my LBS for a really loud ticking noise under braking, that got sorted, now the rear wheel is screeching under braking, loads of buzzing vibration through the saddle, it’s like you say grabbing the rim and feels sticky. I’ve cleaned the rim and its just getting worse and worse, disgraceful from shimano on wheels that are so expensive.

    June 26, 2014 at 10:13 am #800769
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    Zermattjohn

    But its there from the 1st
    But its there from the 1st day, so no wearing at all until the 1st brake squeeze. Plus, never felt this on other wheels that must be built in a similar way…

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