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Help Damaged carbon top tube

Ludwig

Speeding Up
Oct 9, 2008
871
0
Hello all,

It has been a while since I have posted here, and in fact a while since I stopped following the site (just too depressive when one cannot get onto the bike).

My back pain gradually improved and by Golden Week I managed to survive almost entirely without pain killers (NSAIDs). I couldn't wait to try out what my back would say to me getting back onto the bike. After taking down the height of the saddle by quite a bit (it had definitely been to high!), I was able to ride with just modest pain. It was nice to do a leisurely 25km through Setagaya-ku, despite being caught in one of these afternoon rains we are having so often these days.

The other day I went one step further and did Otarumi and Yabitsu, 105km and 1,200m in all. Peanuts in my old time, but quite exhausting when one is not in form. The back held up fine, except for that long descend from Yabitsu into Hadano.

Finally, this Tuesday I had the honourable task of guiding a group of German mountain bikers with TV crew in tow through Tokyo. The pace was so slow my back was in no position to complain! If only the weather had been better that day...

And if only my back wasn't again deteriorating day by day. I'm back at a level where even high doses of NSAIDs don't help that much any longer. Maybe that bad disk was torn once again, though there is no single event I can point to that really caused a sudden deterioration.

As if all of this was not enough, I had the further misfortune of my bike, standing in our genkan to dry after all that rain, to collapse onto the genkan step, leaving significant marks in the top tube. Photos below.

How serious do you think this is? How can I tell whether this is real structural damage or only the outer carbon shell/cover being broken? When I know on the tube, the sound does not change wherever I knock, which gives me a little bit of hope. But I wouldn't want to have the bike suddenly collapsing under me on one of my fast descends...

Any advice welcome! Cheers, Ludwig

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Ludwig, I was expecting much more shocking pics. My first impression and based on your earlier comment that you did not hear any unusual sounds when you knuckeled it down, is that the damage is only cosmetic, i.e. the protective "clear varnish" has crackled just like an oil painting because of the impact . I don't believe your CANYON is dead at all!
 
Hi Ludwig - great to hear you're back on the bike! But sorry to hear the pain is coming. Maybe it's just a little 'too much, too soon' syndrome?

About your Top Tube:

1) It appears to have taken a bit of a hit - if it fell squarely on the stair edge (looks like that) , and towards center of tube - it likely delaminated some of the section.

2) On the positive side - this is not a very severe damage and will not likely cause any issue. The tube is stressed very small there - and carbonfiberplastic doesn't just 'fall apart' - it will slowly degrade to the point where it could finally tear apart. Meaning, you'll get plenty of notice.

3) Personally, I'd get this repaired sooner than later, since you don't want to cause further delamination ( and larger repair sections). probably the best choice is CALFEE in California, but there are also facilities in Japan, too (Graphite Composites) and even very economical, we can do in our factory in Xiamen. But, local is best, if you can, because the cost of shipping will nearly exceed the cost of repair. So - spending the money on repair labor is better option.

4) You could even DIY this - Tokyu Hands actually has a nice selection of resins and some fiber. Since tube is not damaged all the way though, you are not going to be using internal support bladder or anything like that. Just sanding down, then doing a fairly simple patch repair followed by a clear coat. I have some repair resin and cloth here - and you're welcome to have some. You can 'cook it' easily with just incandescent lamp and tinfoil shield.

Rough costs to be expected for this type of injury:

1) Simple patch repair - 20,000 yen
2) Clear Coat - 10,000 yen
 
Ludwig, those cracks look cosmetic, but there is something like a layer of carbon displaced UNDER the clear coat, which could actually be a sign of structural damage - on the left side of the 1st pic, and to the bottom of the 2nd one.

Surely you can try doing a stress test yourself, like sitting on the top tube :) and I am not a carbon specialist, but better take it to one, before riding again.
 
A friend had a carbon frame with a damaged top tube and Nalshima referred him to a Japanese custom framebuilder who did a fabulous job of patching it very reasonably
 
Ok - The tap test is nonsense and this is coming from one of the largest manufacturers of carbon frames out there.

The reason for this is that you have no actual way of knowing if the sound it is giving off is because of a structural crack or because you tubing twists, flares or thin/thickens at that point.

Also if the laminated top coat has cracked or pealed the coin tapping will yield yet another sound as you pass over the cracked laminated section.

Yair had exactly this problem with his Trek - we took it to the Hachioji Trek centre who proceeded with the coin tap test - and announced the frame was perfectly fine! My response to this was that he was talking bollox and the frame should be sent to Trek.

This they did and the tiny little crack that Yair was told was a cosmetic crack was actually a structural failure.

So if you really want to know if the frame is fine then the only way to find out is to send it off to Canyon who will X-ray it or run it through the structural integrity test again.
 
Yes indeed, tap testing means nothing. We spent a few weeks helping a 'famous japanese framebuilder' to test a non-destructive testing procedure using Ultrasonic measurement device. The Ultrasonic measurement device was pretty good at spotting large irregularities.

Thermography is the most common method used to examine and test this type of structure. It will show up the minute craks or voids clearer than either XRay or Ultrasonic.

There are 2 ways to look at this - fanatical and practical.

Fanatical - try to determine the exact nature of issue to the matrix level then apply a repair procedure that will exceed the known or expected stresses of the repaired section.

Practical - sand it down to expose the layup and examine with magnyfying glass and use some simple dye test to determine the extent of any cracking. Then patch with a penetrative resin system and perhaps fiber, if required, matching the original layup schedule.

Even if some of the fibers have been compromised and there is matrix reduction, a simple patch at this area will probably be fine. Honestly, it's surprising how tough composite tubes are, and how well they respond to repair.

I'd say 90% of this repair is actually in the finishing layer. So just about ANY decent frame finisher will be able to do this and a very good job of it.
 
Ludwig, those cracks look cosmetic, but there is something like a layer of carbon displaced UNDER the clear coat, which could actually be a sign of structural damage - on the left side of the 1st pic, and to the bottom of the 2nd one.

Surely you can try doing a stress test yourself, like sitting on the top tube :) and I am not a carbon specialist, but better take it to one, before riding again.

Like Sergei, I now also noticed the ring-shaped line deeper under the coating...and that could be more alarming. But maybe it was there from the beginning, i.e. part of the weave pattern?
 
Like Sergei, I now also noticed the ring-shaped line deeper under the coating...and that could be more alarming. But maybe it was there from the beginning, i.e. part of the weave pattern?

Yes, it's nothing to do with the cracks. I can't see what damage may have been done below the coating. Should I peel it off and see?

Thank you all for your quick responses. Still wondering what the most practical thing will be to do...
 
Totally out of my league here, but is there any kind of snake-eye video camera that you could pull the seat and run into the top tube to see the inside?
 
Ludwig, I'm happy to take a look at this for you. Anytime next week is best. In all cases, you'll need to sand down the clear coat to get to the actual fiber reinforced layer for inspection or repair. You can do that easily yourself with some fine (400) wet/dry paper and make sure you mask off the area so you don't scratch up the good section. For the round tube, it's fast and easy, since you can cut a strip and sand it much like polishing a shoe. I prefer doing this 'wet' as it's less dusty and the water will actually let you see evidence of cracking further as it penetrates the matrix and shows darker color.

For doing this production way - they use airpowered mini belt sander - it goes down to the layup very fast. Then you clean and dry thoroughly. Flatten the area a bit into the matrix, cut your path material, pre-preg it, prime, patch, bag and vacuum. Then cook it for a couple hours. Then after it's cured, sand back down to match the surface and clear coat.
 
Yes, it's nothing to do with the cracks. I can't see what damage may have been done below the coating. Should I peel it off and see?

Thank you all for your quick responses. Still wondering what the most practical thing will be to do...

Ludwig, I would not touch it - send it off to Canyon and have them deal with it.
 
Very interesting thread.

Thanks lads.

I am merely a spectator with all this, but look forward to seeing how things can be resolved. And good luck with all this, Ludwig.
 
Thank you all for your advice, especially Tim for the detailed suggestions.

I contacted Canyon and they insist that the photos show clear structural damage, and go on to offer that they will sell me a new frame :) They don't want to deal with the damaged frame.

I'm inclined to just sell the frame to someone interested in repairing it (after closer inspection along the lines Tim suggests) and quitting road bikes altogether.

I guess with this unfortunate event, someone is telling me I should not ride these bikes again. My back now hurts again as much as six months ago, and I cannot go on paying with half a year of pain and slow recovery for every small ride I take. I might try what riding up-right on a mountain bike does to my back, or on a recumbent (as David has already kindly offered).

When I have time I will put the Canyon, my cyclocross and all the nice new parts that I bought just before the pain started nine months ago and never put to any use (wheels etc.) into the Classified section.
 
Ludwig, I'm really sorry to hear about your misfortunes. When I read you had been on some short rides I had my fingers crossed in hope that you were on the road to improvement, and once again we could hit the climbs of Nagano and Niigata this summer. What a shame your back is giving you such grief, I can't imagine how frustrating it must be for you. Sounds like hiking will be the best option for you. I wish you all the best and hope your back gets better soon. If you don't mind I may throw you some touring questions about Nagano now and then.
 
Ludwig, sorry to hear that you are still unable to ride. One other suggestion, have you tried building up mileage/testing your back on a trainer? Without the bumps and need for steering input, it *may* help build up tolerance for road riding. And if you start feeling pain, you can stop straight away, rather than still having to get home, further aggravating it. But, I have no medical qualifications, so feel free to ignore the suggestion!
 
Ludwig, sorry to hear that you are still unable to ride. One other suggestion, have you tried building up mileage/testing your back on a trainer? Without the bumps and need for steering input, it *may* help build up tolerance for road riding. And if you start feeling pain, you can stop straight away, rather than still having to get home, further aggravating it. But, I have no medical qualifications, so feel free to ignore the suggestion!

Even the medics don't really fully understand my case, so any input is welcome! The serious, discogenic pain does not get aggravated by any position in particular. It's pretty independent of what I do. Also, my back muscles seem to be still fine and unlike with hernia, it's not the lack of muscular support that is causing the issues. So I can't train up my back. The forward position simply seems to stress the discs directly, and one of them has lost its outer support ring, so any serious stress damages the disk again and causes permanent pain. Also, the nerves that had grown into the disk and had been killed by the thermal treatment, have likely grown back by now. Since the disk can't really repair itself and the nerves are back, this problem is bound to last for many years, until age has shrunk the disk so much that there is not much left to be painful. It seems a pretty hopeless case. I have the avoid the forward position under any circumstances. Or just have the disk removed altogether - though that itself carries all sorts of other risks (including a new source of permanent pain).

Mike, thanks for your kind words as well. Sure, happy to help with any route advice. Also hope we can still go for some hiking at some point - as long as I stay upright, I can do that any time.
 
I would definitely give a recumbant a try before packing in cycling altogether. Would be a real shame to be totally done with riding.
 
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