Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: jhob on 11 May, 2015, 02:31:33 pm
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Just discovered this today:
Outside:
(https://s3.amazonaws.com/f.cl.ly/items/0V0p1m2m2p3E2x2m1I2d/crack-0001.jpg)
Inside (crack extends right through):
(https://s3.amazonaws.com/f.cl.ly/items/0O051K0G3I2V1i331J0e/crack-0002.jpg)
Clamp was always tightened to 5Nm using torque wrench and carbon paste was used.
Not good eh? I would consider this un-rideable at the moment. I've got in touch with the manufacturer about sorting it out. Will see what they come back with.
Leaves me without a bike for the moment though, gutted. :(
Sympathy and advice welcomed :'(
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Commiserations, that doesn't look good, although I can't see how it could have failed like that unless the seat post is too small so that as you tighten the clamp it cracked the tube, or too short. Neither of those seems that likely though.
Obviously you need to see what the manufacturer has to say first but there are companies that do carbon repairs so that would be worth looking at - google is your friend. I am assuming that the crack is in the seat tube above the join with the top tube, and if so that should not affect the structural rigidity of the bike, just the ability to keep the seat post in position, so a repair should be possible - I read an article last year about a company in America that specialised (they claimed) in repairing bike frames for the big teams with much bigger cracks in them than yours, but they didn't say what the repairs cost!
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what brand is it?
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This might be useful:
http://carbonfibrerepair.com/recent-work/#cycling (http://carbonfibrerepair.com/recent-work/#cycling)
and these:
http://www.carboncyclerepairs.co.uk/contact-carbon-bike-technics_3.html (http://www.carboncyclerepairs.co.uk/contact-carbon-bike-technics_3.html)
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Commiserations, that doesn't look good, although I can't see how it could have failed like that unless the seat post is too small so that as you tighten the clamp it cracked the tube, or too short. Neither of those seems that likely though.
Obviously you need to see what the manufacturer has to say first but there are companies that do carbon repairs so that would be worth looking at - google is your friend. I am assuming that the crack is in the seat tube above the join with the top tube, and if so that should not affect the structural rigidity of the bike, just the ability to keep the seat post in position, so a repair should be possible - I read an article last year about a company in America that specialised (they claimed) in repairing bike frames for the big teams with much bigger cracks in them than yours, but they didn't say what the repairs cost!
That was what I surmised too, can't quite understand how it happened. I just checked the seat post with calipers and it's 31.55mm in diameter, which I would have thought was within tolerance for a 31.6mm tube.
I am looking at my options, and carbon repair is one. Not quite sure how much that will cost as of yet and might not be viable. We shall see...
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
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This might be useful:
http://carbonfibrerepair.com/recent-work/#cycling (http://carbonfibrerepair.com/recent-work/#cycling)
and these:
http://www.carboncyclerepairs.co.uk/contact-carbon-bike-technics_3.html (http://www.carboncyclerepairs.co.uk/contact-carbon-bike-technics_3.html)
thanks!
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
Don't tell zigzag ;)
My guess is Dengfu will offer you an unrealistically high repair charge, or offer to sell you another
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
Don't tell zigzag ;)
My guess is Dengfu will offer you an unrealistically high repair charge, or offer to sell you another
Is there history here with the company?
I shan't be buying another bike from them...
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
Don't tell zigzag ;)
My guess is Dengfu will offer you an unrealistically high repair charge, or offer to sell you another
Is there history here with the company?
I shan't be buying another bike from them...
Its just a very good example of why I hold the views I expressed in this thread:
https://yacf.co.uk/forum/index.php?topic=89772.msg1845295#msg1845295
Don't get me wrong, stuff breaks, but if you've bought it direct from China you're fucked if you expect any sort of meaningful comeback.
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If you get no joy, then drilling a small hole to stop the crack propagating should be fine.
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
Don't tell zigzag ;)
My guess is Dengfu will offer you an unrealistically high repair charge, or offer to sell you another
Is there history here with the company?
I shan't be buying another bike from them...
Its just a very good example of why I hold the views I expressed in this thread:
https://yacf.co.uk/forum/index.php?topic=89772.msg1845295#msg1845295
Don't get me wrong, stuff breaks, but if you've bought it direct from China you're fucked if you expect any sort of meaningful comeback.
With the benefit of hindsight, I would now agree with you.
At the time I bought the frame last year I was skint but needed a new frame so price was a major factor. I did my research and DengFu repeatedly came up as having excellent customer services and frames that were well liked and appeared reliable. I hedged my bets that the chances of having an issue were low. Looks like I might have lost that hand.
We'll see what response I get from them anyway....
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Well, good luck and I hope it works out well. Keep us posted.
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If you get no joy, then drilling a small hole to stop the crack propagating should be fine.
Not sure that is wise. You'll be drilling through the fibres and compromising them. I don't think I'd want something so close to my ballsack likely to shear off into a shard.
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I assume the worst case scenario would be the collar area shearing and the seat post suddenly descending into the seat tube. Rather like having the seat post clamp loosening.
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I've just had a thought for a repair if DengFu aren't any help:
Epoxy the crack up to stop it spreading. Get a 31.6 - 27.2 metal shim (could even epoxy that to the frame). Use a 27.2 seatpost.
That should be safe and secure shouldn't it?
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What have you got to lose? (Based on the assumption further failure would result in a seat post sliding down)
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Commiserations looks like you have just been a tad unlucky. Hope it is sorted.
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What have you got to lose? (Based on the assumption further failure would result in a seat post sliding down)
Voided warranty.... going to wait first to see if the warranty is actually worth anything in practice...
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If you get no joy, then drilling a small hole to stop the crack propagating should be fine.
Not sure that is wise. You'll be drilling through the fibres and compromising them. I don't think I'd want something so close to my ballsack likely to shear off into a shard.
Agreed. The drill technique is for metal to stop crack propogation. CF is a woven fibre, totally different.
For it to have gone like it has, I suspect bad materials design as well as poor manufacturing.
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Just been reading that a number of cannondale MTB frames have failed in a similar fashion:
http://forums.mtbr.com/cannondale/jekyll-carbon-seat-tube-crack-828418-2.html
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What have you got to lose? (Based on the assumption further failure would result in a seat post sliding down)
Voided warranty.... going to wait first to see if the warranty is actually worth anything in practice...
I would be seriously worried that what you have to lose could severely effect your significant other (if you have one!) and future child bearing abilities .....
Total failure doesn't bear thinking about. Don't risk it!!!
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What have you got to lose? (Based on the assumption further failure would result in a seat post sliding down)
Voided warranty.... going to wait first to see if the warranty is actually worth anything in practice...
I would be seriously worried that what you have to lose could severely effect your significant other (if you have one!) and future child bearing abilities .....
Total failure doesn't bear thinking about. Don't risk it!!!
Total failure would be no worse than seatpost slipping down - I could then just pretend that it's a bmx!
Future childbearing abilities (or lack thereof) have already been taken care of!
The inner sleeve and epoxy idea I am pretty confident will work in the event that don't get a repair/replacement. I'm not expecting one so this will likely happen sooner rather than later.
Lesson learnt here anyway...
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Just been reading that a number of cannondale MTB frames have failed in a similar fashion:
http://forums.mtbr.com/cannondale/jekyll-carbon-seat-tube-crack-828418-2.html
Had a brief read of that thread. Cannondale and Trek mentioned.
Failure in the same place.
I think this suggests a fundamental design flaw in the seatpost/clamp area.
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The difference being that Trek and Cannondale will be extremely interested in this issue in order to rectify it. To the point of wanting frames sent back.
I'd be amazed if Dengfu care.
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Seemingly Cannondale were pretty shit from reading that thread, offering only a discount on a new frame and blaming the seatpost.
HongFu (realised it's HongFu, not DengFu I bought the bike from) have replied requesting more photos, which they now have.
I at least have my backup plan if nothing happens with HongFu.
Been a bit put off carbon now, think I'll start saving the pennies for a Van Nicholas...
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If you are after a repairer HQ Fibre Products in Norfolk have a good reputation on the TT forums. They've repaired a sheared chainstay for a clubmate and a disc wheel that I cracked. http://www.timetriallingforum.co.uk/index.php?showtopic=32930
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Is the internal diameter of the tube consistent or does it get wider below the clamp area? What sort of clamp did you have?
(Afraid I can't help, I'm just interested in how this might have happened.)
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Been a bit put off carbon now, think I'll start saving the pennies for a Van Nicholas...
Because Ti frames never crack, right? :thumbsup:
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Is the internal diameter of the tube consistent or does it get wider below the clamp area? What sort of clamp did you have?
(Afraid I can't help, I'm just interested in how this might have happened.)
Appears to be consistent, although I have not specifically checked.
Here's an image showing the clamp and general area:
(https://s3.amazonaws.com/f.cl.ly/items/1E3x382v2e3L1g0T0h1u/FM001-crack-0002.jpg)
and why not have one of the whole bike:
(https://s3.amazonaws.com/f.cl.ly/items/1T2t1x3X0d243D023e2X/FM001-crack-0001.jpg)
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Seemingly Cannondale were pretty shit from reading that thread, offering only a discount on a new frame and blaming the seatpost.
HongFu (realised it's HongFu, not DengFu I bought the bike from) have replied requesting more photos, which they now have.
I at least have my backup plan if nothing happens with HongFu.
Been a bit put off carbon now, think I'll start saving the pennies for a Van Nicholas...
Let's hope for a positive response from Hongfu.
Don't be put off carbon. I've heard of more Ti failures than I have carbon. I have 4 cf bikes and 2 ti, by the way. No failures yet.
Van Nic have a bad rep for cracks, but a good rep for honouring warranties.
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The difference being that Trek and Cannondale will be extremely interested in this issue in order to rectify it. To the point of wanting frames sent back.
I'd be amazed if Dengfu care.
Trek did me a generous discount on a new frame when I went into a car and my frame didn't break.
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My gut feeling is that this is a crack caused by compression and would be prevented by having a much larger hole at the end of the slot.
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If anybody knows of a material that is 100% reliable for cycle use, please let me know. I've had steel and titanium saddle rails snap, and I have known both those materials fail when used for frames. I have had two alloy seat posts snap. And I have heard of carbon failures. I don't like the look of carbon (it looks like plastic) but I would not jump to the conclusion that it is always a liability. If I were buying a carbon frame I would look for strength and I would avoid overly light frames and forks. And I would prefer a manufacturer with a reputation for putting things right.
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Interestingly one of the carbon repair companies got back to me with a quote. They offered 2 solutions: build up the carbon around the crack, or use a metal shim and reduce the width of the seatpost - the same solution I was looking at doing myself.
Their quote made it uneconomic for me to get it repaired, at any rate how hard can it be to epoxy a metal shim in place with a bit of araldite?
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what brand is it?
It's a Dengfu (http://dengfubikes.com/).
Don't tell zigzag ;)
My guess is Dengfu will offer you an unrealistically high repair charge, or offer to sell you another
only just seen this. it is unfortunate that it's happened, but can be easily fixed with epoxy and a shim and is not dangerous at all (it's dangerous if the seatpost breaks near the clamp and you fall down on a pipe :hand:). i'd be interested if they really offer warranty replacement, but if it had happened to my frame i'd just fix it myself and be back on the road asap. it will take less time than stripping the bike down and posting the frame somewhere.
i don't believe in bike warranties as they are too much hassle - it's best to have a bike that is least likely to break and if (in the unlikely case) it breaks, fix it or get a new one.
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I suspect that the main (or only) difference between cheaper unbranded Chinese carbon frames and the more expensive well known brands are the warranties (to justify the higher prices).
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Is the internal diameter of the tube consistent or does it get wider below the clamp area? What sort of clamp did you have?
(Afraid I can't help, I'm just interested in how this might have happened.)
Appears to be consistent, although I have not specifically checked.
How much seat pin is there below the '60' mark?
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Is the internal diameter of the tube consistent or does it get wider below the clamp area? What sort of clamp did you have?
(Afraid I can't help, I'm just interested in how this might have happened.)
Appears to be consistent, although I have not specifically checked.
How much seat pin is there below the '60' mark?
Just measured it and there is 14cm below the '60' mark, so plenty.
(https://s3.amazonaws.com/f.cl.ly/items/3u1v0A0s2V1R0d3P202t/DSCF1402.JPG)
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Your post (which you have measured) is close to perfect diameter, very slightly undersize. Is the inner seat tube a little oversize?
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Your post (which you have measured) is close to perfect diameter, very slightly undersize. Is the inner seat tube a little oversize?
I'll not be able to accurately measure the inside of the tube as the calipers can't extend far enough into the tube and taking a reading at the top probably wouldn't be a valid measurement because of distortion caused by the crack.
However it does feels like it's a good fit - not at all loose and with a light friction when inserting the post.
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If you feel that the post is a decent fit, how about simply using epoxy resin to bond it into place? Seems likely to make a more substantial reinforcement than a shim (which would still involve a degree of compression around the new seat post)
I do appreciate that posts can be valuable chattels in their own right, and that even riders with thoroughly well sorted positions occasionally need to make adjustments, when changing saddles for example.
But whatever you do is going to be a compromise, so best to consider all possibilities :)
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If you feel that the post is a decent fit, how about simply using epoxy resin to bond it into place? Seems likely to make a more substantial reinforcement than a shim (which would still involve a degree of compression around the new seat post)
I do appreciate that posts can be valuable chattels in their own right, and that even riders with thoroughly well sorted positions occasionally need to make adjustments, when changing saddles for example.
But whatever you do is going to be a compromise, so best to consider all possibilities :)
I think that would be a step too far for me, especially when the epoxyed shim idea should work equally as well in providing strength to the affected area, whilst also allowing for future adjustment.
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Here's an image showing the clamp and general area:
(https://s3.amazonaws.com/f.cl.ly/items/1E3x382v2e3L1g0T0h1u/FM001-crack-0002.jpg)
Is there also some damage further up the tube, just below the clamp on the right left hand side (as we look at it)?
If it's not a mismatch between the tube and pin then could it just be a weak section, or that the clamp isn't the right shape/size, or is over-tight? I speculate about that because the pin looks to be more scored than I would expect where it was clamped.
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There is a bit of an indentation just below the clamp, but that's just a feature of the frame.
I can see the bit you're referring to. That does look a bit cracked, you're right.
Clamp is definitely the right size, I'm pretty certain I've never over-tightened it. I have a torque wrench and always use that.
Still waiting to hear back from HongFu. At any rate, the metal sleeve fix will cure all damage up there at once.
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If everything is the right size and it's all been treated and tightened properly, then something else is wrong.
In my (lay) opinion the cf tube is not up to scratch. I wouldn't be confident of a glue and shim fix. I'd be inclined to ditch the frame and the pin.
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I had to buy a new clamp for a titanium frame about 18 months ago, and I chose a Thomson clamp because it seemed more thoroughly designed than others, requiring less torque to hold the post. The bolt has a slightly odd angle to it that is claimed to work better. And with a carbon post the bolt goes at the front (away from the slot). It is very well made, and might just help after your repairs.
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I had to buy a new clamp for a titanium frame about 18 months ago, and I chose a Thomson clamp because it seemed more thoroughly designed than others, requiring less torque to hold the post. The bolt has a slightly odd angle to it that is claimed to work better. And with a carbon post the bolt goes at the front (away from the slot). It is very well made, and might just help after your repairs.
Thanks for the advice, just ordered the thomson collar. Sounds like a good investment for any future bike too.
HongFu have gone quiet so I'm just going to make the repairs with the shim myself.
Does anyone have advice for a decent, but reasonably priced, 27.2mm seat post?
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I have a used titanium one which, I'm pretty sure is 27.2 (I'll check this evening) - I'm open to offers, assuming you wanted to move away from C/F.
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Does anyone have advice for a decent, but reasonably priced, 27.2mm seat post?
If you don't mind aluminium: Deda RSx 01 (http://www.wiggle.co.uk/deda-2014-rsx-01-seatpost/)
Or Deda RSx 02 (http://www.wiggle.co.uk/deda-rsx-02-seatpost-2014/) - 10g lighter
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I suspect that the main (or only) difference between cheaper unbranded Chinese carbon frames and the more expensive well known brands are the warranties (to justify the higher prices).
And on what evidence do you base that suspicion?
It is pretty well-documented that an open-mold frame is not necessarily the same between manufacturers. There are huge differences between ratios of carbon to resin and the quality of both ingredients. Not to mention quality control.
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I suspect that the main (or only) difference between cheaper unbranded Chinese carbon frames and the more expensive well known brands are the warranties (to justify the higher prices).
My Canyon has a 6 year warranty. Six years - that's a long time for a bicycle frame, and longer than you get for some steel frames.
They also make frames for Pro Tour teams. I'm pretty sure that they are very different from unbranded Chinese carbon frames.
The (stainless steel) moulds for Colnago frames are made in Italy and then shipped to Taiwan, so there is another difference to the open mould frames.
Cheap carbon frames compared to high end branded cf frames are like the difference between a fillet brazed steel 853 frame and a tig welded hi-ten gaspipe, in both materials and manufacturing methods. Both are bike frames, though.
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Both Canyon and (all but the top model) Colnago are made by Giant.
I've got a range of CF frames at home, from the highest-end, to a cheapo Ribble Chinese job, with a giant, a Kinesis, and a Trek in between.
They are very far from being the same.
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The deed is done:
(https://s3.amazonaws.com/f.cl.ly/items/473d3N0z2N1P053f2e1R/2015-05-14%2013.55.41.jpg)
Just waiting on hearing about Jurek's seat post, if that's not a goer I'll take Biggsy's suggestion on the deda post.
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Deda RSX02 ordered. Decided 10g was worth £1.50
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I've got a range of CF frames at home, from the highest-end, to a cheapo Ribble Chinese job, with a giant, a Kinesis, and a Trek in between.
Aren't Ribble made by Deda / Dedacciai? If they are (and I think they are!), even they are a step above the really cheap carbon frames you get on eBay. Of course, Deda carbon frames are not made by Deda in Italy but some sub-contractor in Taiwan or China (I don't know which sub-contractor, though).
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I've got a range of CF frames at home, from the highest-end, to a cheapo Ribble Chinese job, with a giant, a Kinesis, and a Trek in between.
Aren't Ribble made by Deda / Dedacciai? If they are (and I think they are!), even they are a step above the really cheap carbon frames you get on eBay. Of course, Deda carbon frames are not made by Deda in Italy but some sub-contractor in Taiwan or China (I don't know which sub-contractor, though).
They certainly used to be made by Deda in the era of the Scuro, Nero etc, but I am not convinced they are still using Deda. The build quality of my Ribble Sportive 365 isn't as good as the old Deda built stuff. Besides, Deda are now quite interested in marketing their own high end frames.
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I consider that I've had my hands burnt with a cheap frame now. Whatever the next frame I get is, it will be a higher quality one.
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The thing is you can pick up a carbon frame from Ribble of Planet X for about £350 these days.......with a meaningful warranty.
What did your Hongfu cost you (including customs)?
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It was about £330. I did look at planet x at the time and they didn't have anything near that sort of range, save for a few end of line frames not in my sizes. Carbon frame prices seem to have plummeted in the last year.
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Besides, Deda are now quite interested in marketing their own high end frames.
I understand that one of the De Rosa models is actually a Deda, and not much of a secret.
Ribble have a very wide range of carbon frames now, even if some of them are Deda I doubt they'd all be.
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The repair has held up over 50 miles so far. No creaking or other untoward noises. Very happy with how it's turned out thus far.
Thanks for the advice everyone, it was very helpful.
Here's some photos of the repair:
(https://s3.amazonaws.com/f.cl.ly/items/432G102s2w0L440Q0g0o/bike-0001.jpg)
(https://s3.amazonaws.com/f.cl.ly/items/272V3Z19472y3002262u/bike-0002.jpg)
(https://s3.amazonaws.com/f.cl.ly/items/0p3x2W2f0d3a3u3C2B0o/bike-0003.jpg)
(https://s3.amazonaws.com/f.cl.ly/items/321D0u3g31252i1R3c2d/bike-0004.jpg)
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HongFu finally got back to me and offered a $100 refund towards getting it fixed. I've accepted and they've paid.
That at least covers my costs for the new seatpost and collar and is better than I was expecting. Actually roughly on a par with what Cannondale were offering their customers who experienced similar frame issues.
So, all in all, I'm pretty pleased with the outcome.
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$100 is probably a very good result given that the frame is still usable now that you have managed to repair it. I was really expecting them to live up to the last bit of their name - F U.
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$100 is probably a very good result given that the frame is still usable now that you have managed to repair it. I was really expecting them to live up to the last bit of their name - F U.
Yeah, I was expecting the same. I'd all but given up, happy just to have a usable frame.
It's a very reasonable resolution on their part, not bad customer services.
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it's good to see they honour their warranty promise. reimbursing the repair costs is much better and convenient than requesting to send the frame to them "for inspection" as majority of big brands tend to ask (from what i read online).
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it's good to see they honour their warranty promise. reimbursing the repair costs is much better and convenient than requesting to send the frame to them "for inspection" as majority of big brands tend to ask (from what i read online).
They haven't honoured their warranty.
They've offered £60. That wouldn't even cover half of the repair.
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it's good to see they honour their warranty promise. reimbursing the repair costs is much better and convenient than requesting to send the frame to them "for inspection" as majority of big brands tend to ask (from what i read online).
They haven't honoured their warranty.
They've offered £60. That wouldn't even cover half of the repair.
It would probably cover two or three repairs in China ;)
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Or two or three whole frames.....
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in an ideal world they would ship a new frame to you with next day delivery and pay your appointed (competent) bike shop to transfer components across to a new frame so you can ride your bike again within few days. only, how realistic is that and how many branded manufacturers offer such service? ::-)
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I consider their resolution pretty reasonable really. I didn't have to argue hard to get the offer, it was quite willingly given, although it did take a while.
Guarantee has been honoured in my view.
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I'm not sure I agree. A honouring of the guarantee would have given you back a repaired frame, rather than an adapted frame. I don't think £65 would pay for the cost of a repair. However, I am pleased but surprised that they have offered any money at all, and I think it is commendable on their part.
I've only twice had a frame with problems, and that was a Planet X cheapo Kaffenback steel frame. On the first frame I couldn't get a back wheel in with a 12t (or higher) smallest sprocket because there was no clearance. A whole batch had this fault. They replaced it at their expense, with a few freebies thrown in for my trouble.
The frame they replaced it with was the newer sand colour, and I bought a set of carbon canti forks for it (at reduced price again). There was an issue that was a bit more esoteric in that I felt that the steering was weird and the bike had something of a mind of its own. They replaced it without quibble (although they did return it to a bike shop they used at the time before they had their own workshop, and the bikeshop agreed with my complaint)
They picked the bike frames up from me, and the replacements were delivered within two weeks.
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I think a lot of it has to do with expectations. I had low expectations, that were exceeded. Had I bought a frame from a name manufacturer in this country then I would expect an awful lot more, as I would have paid a lot more with the expectation of greater come-back should something go wrong.
It's fortunate that I was able to repair it myself fairly easily, and that the sum offered covered all of my costs.
Most of all I'm just glad to have a working bike at the end of it.
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Guarantee has been honoured in my view.
I think a lot of it has to do with expectations. I had low expectations, that were exceeded.
Most of all I'm just glad to have a working bike at the end of it.
So a happy chappy and surely that is all that matters.
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I think a lot of it has to do with expectations. I had low expectations, that were exceeded. Had I bought a frame from a name manufacturer in this country then I would expect an awful lot more, as I would have paid a lot more with the expectation of greater come-back should something go wrong.
PX will do you a carbon frame for £250 ;)
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I think a lot of it has to do with expectations. I had low expectations, that were exceeded. Had I bought a frame from a name manufacturer in this country then I would expect an awful lot more, as I would have paid a lot more with the expectation of greater come-back should something go wrong.
PX will do you a carbon frame for £250 ;)
I did look at them at the time I bought the frame and their cheapest frames started at £500, prices have fallen a lot in the last year.
I paid about £350 all in for the HongFu frame. There would not be the same economic argument to buy from China now.