Carbon Wheels From China

Discussion in 'Cycling Equipment' started by Colnago62, Jul 31, 2014.

  1. Colnago62

    Colnago62 New Member

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    I ran into a buddy of mine on a ride a few days ago and he was riding on his new carbon wheels. We climbed this road that has about a 900 ft descent from the top. His wheels started putting out an awful smell and he said that the rims were real hot. Tomorrow he plans on doing the RAMRODhttp://redmondcyclingclub.org/RAMROD/RAMROD_course_information.html having really never descending on these wheels. I am no carbon wheel expert. Do they normally emit a burning odor and heat up like that? New equipment before a big ride can sometimes end badly.
     
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  2. dabac

    dabac Well-Known Member

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    Can just as well be the pads. CF rims have different friction characteristics, and need pads suited for the task. CF rims and heat is a debated subject. On one hand, it's entirely possible to create CF laminates with good properties in heat, OTOH, there HAVE BEEN rims that have failed during descent. Seemingly heat-related. Either way, good brake technique is always useful on bigger descents. Bursts of hard braking leads to less heat build-up than continuous light braking.
     
  3. CAMPYBOB

    CAMPYBOB Well-Known Member

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    'Which' Chinese carbon fiber wheels did your friend buy? What brand?

    I have a training partner that bought some 'Dura Ace' knock-offs from a chicom website. The wheels were garbage. The black surface of the brake track wore away to a yellow substrate material (fiberglass? some other glass reinforced polymer? carbon fiber mixed with filler resin?) and the rear rim cracked on one of his first couple of rides. These were NOT shimaNO wheels, which are of good quality and usually very safe wheels.

    Other nameless or knock-off chicom wheels seem to be of very good quality for the inexpensive prices they command. Many riders rave about their cheap Chinese wheels and brag about their durability and features. There is a wide variation in quality, so it would help to know a little more about those wheels. And how and when your friend uses his brakes.

    As Dabac said, the smell may be coming from the pads. Carbon clincher braking and descending techniques are an often discussed subject. This is not so much an issue with tubular/sew-up tires, although the glue topic of heat buildup during braking while descending is. If your friend has sew-ups it might be the glue that is heating up and causing the smell.
     
  4. jhuskey

    jhuskey Moderator

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    ." These were NOT shimaNO wheels, which are of good quality and usually very safe wheels".

    Who are you and what have you done with Bob?
     
  5. Colnago62

    Colnago62 New Member

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    They didn't have a name on the wheels. He mentioned he got them from China. The descent is not a hair raising one, so I can't imagine him being hard on the breaks the whole time. I wonder if he changed his pads out to carbon specific? I asked him what kind of pads he was running and he gave me a puzzled look. Well, the big ride is today, so either it's an issue or it is not.
     
  6. AyeYo

    AyeYo Member

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    I've noticed numerous people on group rides over the last month with some burnt up smelling carbon wheels (or brake pads) on what I would consider some very mild descents. We're talking hills not large enough to even warm up the brakes on my bike and I can smell the burning whatever (smells like burning plastic to me) from these guys when I'm ten bikes back.
     
  7. Colnago62

    Colnago62 New Member

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    That's what's weird to me also. I don't remember smelling stuff like this and he is not the first guy with carbon wheels I have road next to. It just seemed out of what I consider normal behavior for carbon. I have heard some of the guys who race saying that in big descents, guys can smell the pads and heated up rims, which makes sense given many times they are descending in a large group and the need to brake is greater.
     
  8. Froze

    Froze Well-Known Member

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    CF wheels cannot dissipate the heat anywhere near as fast as aluminum rims, thus if you're doing a lot of descending with constant braking the rim will continue to get hotter and hotter and could blow a tire and or start the delamination process on the rim. This is why disk brakes are all the rage now because CF rims have reached their limit on how much they can do to avoid issues with heat so the disk brake takes the heat off the rim and puts instead on the hub...think about that for awhile.

    However I would suggest that the smell you smell is probably the pads, car pads will smell too when used too much. But all of that has to do with the rim getting really hot compiling the issue of the pads getting hot and thus the burn smell.
     
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