Real crack, yay/nay?

ugo.santalucia

Just spotted this beauty mark on my wife's bike. It is a crack, but is it paint only? My thinking is that given this is a wedge seatpost system, that spot should not be particularly stressed and certainly not compressed, so might only be paint... initial contacts at the phone with the LBS where the bike was purchased not extremely positive, with the owner implying possible user error before even seeing pictures. We then sent photos and we are awaiting reply, but it seems to me they're trying to place fault, rather than help... we'll see... thoughts?

First.Aspect

Crack.

Sorry.

oxoman

Ugo, might be worth removing seat post and having a look from the inside if possible. Are we talking carbon or Aluminium frame as well. Sadly some bike shops will baulk and pass the buck regardless of whose fault it is. Maybe time to find a better bike shop as well.

ugo.santalucia

First.Aspect said:

Crack.

Sorry.

could it not just be superficial? I struggle to see how the wedge pushing against the seatpost would cause the seat tube to crack in that spot

MattFalle

what's it like from the inside - really difficult to tell from that.

what frame material?

ugo.santalucia

oxoman said:

Ugo, might be worth removing seat post and having a look from the inside if possible. Are we talking carbon or Aluminium frame as well. Sadly some bike shops will baulk and pass the buck regardless of whose fault it is. Maybe time to find a better bike shop as well.

I will if the shop refuses to help... at this stage I don't want to touch anything, before their "forensic team" have a look and assess whether there is user's fault. At the phone they already mention they're going to inspect the seatpost for marks, to see whether it has been over tightened or over extended...
I never touched it, but let's see...
BTW, it's carbon

joe2019

ugo.santalucia said:

First.Aspect said:

Crack.

Sorry.

could it not just be superficial? I struggle to see how the wedge pushing against the seatpost would cause the seat tube to crack in that spot

If you don't like the answer, don't ask the question
It's a crack.

i.bhamra

Could well be superficial (but of course might be more serious), have seen similar before on a Dolan carbon frame where the seat post enters frame. It was inspected and advised it was just the paint cracking due to flex (I'd never have spotted it if the frame wasn't white!). Dissapointing that the shop are immediately pointing the finger back at at you, you'd have to tighten in the wedge a fair bit to cause a crack like that. Doesn't mean the frame is not defetctive though....

I'm not sure it's possible to make a proper assesment from a picture either so you may be in for an extended period without the bike while it's checked out. I'd personally keep using it now that you've made the shop aware but keep a close eye on it for signs of propagation over time.

First.Aspect

I don't know where else you would expect a crack to be?

elbowloh

Looks like a crack to me. Sorry

ugo.santalucia

First.Aspect said:

I don't know where else you would expect a crack to be?

I thought the wedge design was aimed to avoid compressing the frame at the "rim", as it happens with the traditional system. The stress experienced there should be strain, which carbon should be able to take almost indefinitely.

ugo.santalucia

i.bhamra said:

I'm not sure it's possible to make a proper assesment from a picture either so you may be in for an extended period without the bike while it's checked out. I'd personally keep using it now that you've made the shop aware but keep a close eye on it for signs of propagation over time.

At the moment the bike is on a trainer, so can be used, and given Brexit and Covid it is indeed likely any replacement would leave wife without a bike for months...
I did enquire about keeping the frame while a replacement rolls in, but the shop owner was more interested in avoiding any liability at the phone, although he did mention it might be possible " if... if ... if... " ... anyway... we'll see how it pans out

monkimark

Can you peel back the top cover and check if the 'crack' runs over the top of the frame? Might give more of a clue without having to loosen or tighten anything.

As an aside, I think you mean 'tension' when you say 'strain'. Stress and strain are 2 different things (not nitpicking but it might make things clearer when speaking to bike shops etc)
https://brilliant.org/wiki/terms-in-physics-stress-and-strain/

ugo.santalucia

Second phone call with the shop, managed to speak to a much more useful person who asked for a picture of the frame number to "initiate the warranty claim", so that seems a much more positive attitude...

redvision

Have to agree with the comments above I'm afraid Ugo, looks like a crack to me.

I remember reading several articles a few years ago (when a well known bike manufacturer had issues with cracks around the seat post) explaining why this area was vulnerable to cracks - common sense really when you think about the stresses on it.

Hope it's not the case for you but from the image I think it may be. Fingers crossed the warranty covers it and is honoured though.

DeVlaeminck

ugo.santalucia said:

i.bhamra said:

I'm not sure it's possible to make a proper assesment from a picture either so you may be in for an extended period without the bike while it's checked out. I'd personally keep using it now that you've made the shop aware but keep a close eye on it for signs of propagation over time.

At the moment the bike is on a trainer,

I wouldn't tell them that !

ugo.santalucia

DeVlaeminck said:

ugo.santalucia said:

i.bhamra said:

I'm not sure it's possible to make a proper assesment from a picture either so you may be in for an extended period without the bike while it's checked out. I'd personally keep using it now that you've made the shop aware but keep a close eye on it for signs of propagation over time.

At the moment the bike is on a trainer,

I wouldn't tell them that !

We did, they don't seem to have a problem with that. Let's face it, 90% of carbon bikes sit on a trainer this time of the year. If that is not allowed, then they should come with a warning sticker!

thistle_

ugo.santalucia said:

At the moment the bike is on a trainer, so can be used, and given Brexit and Covid it is indeed likely any replacement would leave wife without a bike for months...

Maybe, or maybe not. The distributor might have a frameset or two available.
That was the case with my power meter and when I needed a replacement fork so she might be lucky.

ugo.santalucia

It is concerning that a bike that has been ridden maybe 20 times, never touched the seatpost since the shop fitted it... it's already developing cracks... sounds like this stuff is really made of cheese

imposter2.0

ugo.santalucia said:

It is concerning that a bike that has been ridden maybe 20 times, never touched the seatpost since the shop fitted it... it's already developing cracks... sounds like this stuff is really made of cheese

Frames that fail, usually fail early. Most don't though.

ugo.santalucia

imposter2.0 said:

ugo.santalucia said:

It is concerning that a bike that has been ridden maybe 20 times, never touched the seatpost since the shop fitted it... it's already developing cracks... sounds like this stuff is really made of cheese

Frames that fail, usually fail early. Most don't though.

That's the thing with this thin carbon frames... metal typically fails of fatigue, so you expect a metal frame to fail after 7 years of use and you tend to look out for signs of fatigue, in most cases it will be in the skip before then... but with carbon it's not fatigue... they just fail out of poor manufacturing... it's a PITA, because the warranty claims are never trouble free and I fully expect a long and painful wait for a replacement... which might even be of a different colour, one that wifey doesn't like...

david37

looks like the sort of crack that's caused by over extending the seat post. but its difficult to claim that unless the other side is showing similar.

it used to appear a lot on aluminium frames where the seat post didn't extend beneath the point where frame came together.

of course it might be a paint thing but hard to tell without looking properly. Forensic team suggests some kind of expensive mechanical and materials science specialists with detailed training, expensive equipment and a large database of similar failures to compare to. Or it sounds like a sloping shoulders dept staffed by knobbers talking with confidence about stuff they know nothing about.

1 ditch your LBS irrespective of their final position

2 if you've only ridden it 20times send it back anyway.

ugo.santalucia

david37 said:

looks like the sort of crack that's caused by over extending the seat post. but its difficult to claim that unless the other side is showing similar.

it used to appear a lot on aluminium frames where the seat post didn't extend beneath the point where frame came together.

of course it might be a paint thing but hard to tell without looking properly. Forensic team suggests some kind of expensive mechanical and materials science specialists with detailed training, expensive equipment and a large database of similar failures to compare to. Or it sounds like a sloping shoulders dept staffed by knobbers talking with confidence about stuff they know nothing about.

1 ditch your LBS irrespective of their final position

2 if you've only ridden it 20times send it back anyway.

Seatpost is quite low, hardly higher than the bars, so that's definitively not the issue.

As for the LBS, well my wife wanted a bike last summer and there was nothing around, so she spotted that one at a local LBS and she grabbed it, it wouldn't have been my first choice, but it's a reputable brand, so I had no objections... in the future, we hope to have a bit more choice... to be honest I would rather build a bike myself rather than letting a shop doing that... they've even fitted the Shimano chain the wrong way round, with the drilled part of the plate exposed... horror!

dj58

It's a Giant and your wife is the original purchaser, so making a warranty claim should be straightforward. The potential problem will be dependent on the person/s in the LBS doing the inspection/assesment and their level of competance/expertise. Or are they going to send it to Giant UK? Then as you say do Giant UK have any service frames in stock.

thistle_

ugo.santalucia said:

I fully expect a long and painful wait for a replacement... which might even be of a different colour, one that wifey doesn't like...

As long as it's a colour and size that you like there are upsides to every situation

ugo.santalucia

dj58 said:

It's a Giant and your wife is the original purchaser, so making a warranty claim should be straightforward. The potential problem will be dependent on the person/s in the LBS doing the inspection/assesment and their level of competance/expertise. Or are they going to send it to Giant UK? Then as you say do Giant UK have any service frames in stock.

The other person in the shop was happy to proceed with photos only... they have now submitted a warranty claim... let's see what happens. It should be straightforward, they must see cracks day in day out.

First.Aspect

ugo.santalucia said:

dj58 said:

It's a Giant and your wife is the original purchaser, so making a warranty claim should be straightforward. The potential problem will be dependent on the person/s in the LBS doing the inspection/assesment and their level of competance/expertise. Or are they going to send it to Giant UK? Then as you say do Giant UK have any service frames in stock.

The other person in the shop was happy to proceed with photos only... they have now submitted a warranty claim... let's see what happens. It should be straightforward, they must see cracks day in day out.

More to the point, the failure modes on these frames will be well known. You won't be the only ones.

darkhairedlord

Just buid her a croix de fer. With a planet x fork.

ugo.santalucia

First.Aspect said:

ugo.santalucia said:

dj58 said:

It's a Giant and your wife is the original purchaser, so making a warranty claim should be straightforward. The potential problem will be dependent on the person/s in the LBS doing the inspection/assesment and their level of competance/expertise. Or are they going to send it to Giant UK? Then as you say do Giant UK have any service frames in stock.

The other person in the shop was happy to proceed with photos only... they have now submitted a warranty claim... let's see what happens. It should be straightforward, they must see cracks day in day out.

More to the point, the failure modes on these frames will be well known. You won't be the only ones.

The interesting thing is that carbon frames of the 1990s were pretty much bulletproof... the C40, those Specialized and Trek frames are for the most still around

First.Aspect

ugo.santalucia said:

First.Aspect said:

ugo.santalucia said:

dj58 said:

It's a Giant and your wife is the original purchaser, so making a warranty claim should be straightforward. The potential problem will be dependent on the person/s in the LBS doing the inspection/assesment and their level of competance/expertise. Or are they going to send it to Giant UK? Then as you say do Giant UK have any service frames in stock.

The other person in the shop was happy to proceed with photos only... they have now submitted a warranty claim... let's see what happens. It should be straightforward, they must see cracks day in day out.

More to the point, the failure modes on these frames will be well known. You won't be the only ones.

The interesting thing is that carbon frames of the 1990s were pretty much bulletproof... the C40, those Specialized and Trek frames are for the most still around

They also weighed twice as much.

MattFalle

light, cheap and whatever that bloke said, pick 2