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

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

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

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/

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

On Friday, April 24, 2020 at 2:01:03 PM UTC-7, 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/

I agree and that is why I'm using Ultegra cranksets now. They are so light that the savings of carbon is minimal at best. I also discovered that my aluminum Cannondale stem and Specialized bars are LIGHTER than my single piece integrated carbon bar. Wondrous things having a scale - when you look at the so-called claimed weights and actually measure them you discover large differences.

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

On Fri, 24 Apr 2020 17:25:27 -0500,
AMuzi wrote:
On 4/24/2020 3:41 PM, Ted Heise wrote:

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?

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).

Thanks for the feedback, Andrew. As it happens, I bought the bike
from a distant dealer, so having him examine it is not a very
practical option. I'm not very impressed with the shops here, but
there's a place in Indianapolis that has a pretty good reputation.
Looks like your place is more than a four hour drive, or I'd think
about bringing it to you.

To Jay's point, I should probably look at the pedal spindle
attachment points too. We are not excessively heavy (probably 325
pound team weight), but do stand a lot on hills.

--
Ted Heise West Lafayette, IN, USA

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.

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