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carbon crank scratched - concern?
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! -- Ted Heise West Lafayette, IN, USA |
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#2
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carbon crank scratched - concern?
On Friday, April 24, 2020 at 10:41:10 PM UTC+2, Ted Heise wrote:
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! -- Ted Heise West Lafayette, IN, USA That just looks like a scratch on the clear coat. I wouldn't worry. Lou |
#3
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carbon crank scratched - concern?
On Friday, April 24, 2020 at 10:58:14 PM UTC+2, wrote:
On Friday, April 24, 2020 at 10:41:10 PM UTC+2, Ted Heise wrote: Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! -- Ted Heise West Lafayette, IN, USA That just looks like a scratch on the clear coat. I wouldn't worry. Lou Get some car polish and it will look better. Lou |
#4
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carbon crank scratched - concern?
On 2020-04-24 13:41, Ted Heise wrote:
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! I'd be more concerned about that apple-shaped outline above the scratch, very visible in the 2nd photo link. Personally I do not like carbon components where structural failure could cause a lot of grief. I'd get new metal cranks, even if it's just for peace of mind. I guess this guy was lucky: http://www.bustedcarbon.com/2009/02/...falls-off.html -- Regards, Joerg http://www.analogconsultants.com/ |
#5
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carbon crank scratched - concern?
On 4/24/2020 3:41 PM, Ted Heise wrote:
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! Ask your dealer to examine the crank to see if it's merely a cleat scratch or if it is indeed cracked. If it's cracked, ask about warranty. Examine the other three as well (direct sunlight and a magnifier). -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#6
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carbon crank scratched - concern?
On Friday, 24 April 2020 17:01:03 UTC-4, Joerg wrote:
On 2020-04-24 13:41, Ted Heise wrote: Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! I'd be more concerned about that apple-shaped outline above the scratch, very visible in the 2nd photo link. Personally I do not like carbon components where structural failure could cause a lot of grief. I'd get new metal cranks, even if it's just for peace of mind. I guess this guy was lucky: http://www.bustedcarbon.com/2009/02/...falls-off.html -- Regards, Joerg http://www.analogconsultants.com/ There were a lot of busted metal alloy crankarms too. Cheers |
#7
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carbon crank scratched - concern?
On Friday, April 24, 2020 at 1:41:10 PM UTC-7, Ted Heise wrote:
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! If that arm fails, you have three others. I wouldn't worry. Seriously though, it looks like a scuff to the clearcoat. But do like Andrew says and take a close look. I've failed two CF cranks at the pedal eyes. The threaded inserts tend to separate from the surrounding carbon lay-up or crack or the carbon cracks. One crank was OE SRAM Red on a Cannondale and the other was an ISIS POS FSA that I got on sale (and regretted). I wouldn't bother with CF cranks. With your Ti bike, you need these: https://www.youtube.com/watch?v=hx2rAWz_u3k And the $150 30mm threaded BSA bottom bracket and spacer kit (times two). -- Jay Beattie. |
#8
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carbon crank scratched - concern?
On 25/4/20 6:41 am, Ted Heise wrote:
Hi all, A couple of days ago I noticed a scratch on a carbon crank. Pics are he http://www.panix.com/~theise/IMG_7765.jpg http://www.panix.com/~theise/IMG_7766.jpg It's on my tandem, so I'm especially senstive to safety. The scratch does not feel as if it has much depth to it. I think it may have happened when I lost my balance getting off, and could potentially have banged it with the Speedplay cleat on the bottom of my shoe. Should I be concerned about failure? As an aside, I wasn't paying enough attention when I ordered this bike. I specifically wanted titanlum for resistance to cosmetic damage, but would have preferred *not* to have carbon components (also for resistance to handling damage). Thanks for any advice! It doesn't look worth worrying about, but if you're still concerned, why not take it to a CF frame repairer and ask their opinion? They can probably repair the scratch relatively cheaply too, if you want. Titanium and aluminium are not immune to breakage. Both are notch sensitive. That means if you scratch either metal, the scratch will likely be the source of a crack, if the metal is stressed highly enough and often enough. Steel doesn't suffer the same sort of problem. It will rust though. -- JS |
#9
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carbon crank scratched - concern?
On 25/4/20 10:21 am, jbeattie wrote:
I've failed two CF cranks at the pedal eyes. The threaded inserts tend to separate from the surrounding carbon lay-up or crack or the carbon cracks. One crank was OE SRAM Red on a Cannondale and the other was an ISIS POS FSA that I got on sale (and regretted). I wouldn't bother with CF cranks. Wow you have a bad time. I pounded out another 120km today over rough roads and climbs up to 15% with my Campagnolo UT cranks. Never been a problem. Do the threaded inserts come adrift when you remove or tighten pedals, or just happens while you're riding? I use my chain lube wax & oil mix to lubricate my pedal threads, and only tighten them on to the crank with maybe 10 Nm of torque? They are never difficult to remove, and don't unwind of their own free will. I have seen pedals loosen, but only because the pedal bearings were near seized. Not on my bike. -- JS |
#10
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carbon crank scratched - concern?
On Saturday, April 25, 2020 at 1:39:51 AM UTC-7, James wrote:
On 25/4/20 10:21 am, jbeattie wrote: I've failed two CF cranks at the pedal eyes. The threaded inserts tend to separate from the surrounding carbon lay-up or crack or the carbon cracks. One crank was OE SRAM Red on a Cannondale and the other was an ISIS POS FSA that I got on sale (and regretted). I wouldn't bother with CF cranks. Wow you have a bad time. I pounded out another 120km today over rough roads and climbs up to 15% with my Campagnolo UT cranks. Never been a problem. Do the threaded inserts come adrift when you remove or tighten pedals, or just happens while you're riding? The threaded insert either cracked or separated from the surrounding lay-up or both. SRAM acknowledged the problem -- which is not uncommon bonding dissimilar materials. It happened during riding an not disassembly. I use my chain lube wax & oil mix to lubricate my pedal threads, and only tighten them on to the crank with maybe 10 Nm of torque? They are never difficult to remove, and don't unwind of their own free will. I have seen pedals loosen, but only because the pedal bearings were near seized. Not on my bike. The problem is not with the pedal seizing. I use ordinary anti-seize on my pedals -- with washers to avoid CF damage. BTW typical torque spec for pedals is 30-40 Nm -- or even higher for some mfg. -- Jay Beattie. |
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