sxwong

So, I have a crack around my seat post clamp and wondering if there are any recommendations to fix? When I remove the seatpost and relieve the pressure, the crack maybe opens not even a mm. Clamping ability doesn't seem to have been compromised.

Frame is a BMC TT02.

Homebrew01

Can the clamp be replaced, or is it part of the frame ?
Luckily the lower clamp looks ok, so maybe the upper is redundant and can be less tight ?

sxwong

Unfortunately, the clamp is integrated into the frame. The crack compresses when I tighten it into the seatpost and the inside looks fine, doesn't give much when I push or pull it. Just a little worried about it spreading.

I've been considering an epoxy route, but I've never used that stuff before nor do I know it's the right way to go.

drlogik 

Call the manufacturer and explain it to them and ask if this can be covered by warranty...either repair or replace. I would NOT do anything until you hear from them. Ask nicely and you will probably get a favorable response.

fietsbob

You always use a Torque wrench and applied no more than the posted 3 Nm?

dsbrantjr

That is a weird crack since it is in an area which is normally under compression. I would do as drlogik suggests and seek warranty relief.

Andrew R Stewart 

After searching for images of this detail on line (and how I hate to do this work, the OP could have made this aspect more known in his post) it looks like the clamp is an integrated extension of the top tube, not a separate piece as is the typical clamping design (for seemingly good reasons!)


I agree that considerate communications with your BMC dealer, or directly with the company, is the best first step. Include that you have posted here and will follow up with the results. Then do so. And if the results are that BMC claims the clamp has been abused (as in maybe overtightened) then you have to respect this BUT also report it to our group.


I'll just add that this is one more example of a design that has a "cost" not initially considered by the user. There are reasons that after 100+ years of frame making some materials and designs are not commonly used. Andy.

sxwong

Thanks all! I appreciate the help. Just sent an inquiry to their customer service. Looking at their website, it seems I may have fallen out of the warranty dates for this model. I'm probably going to take it to a BMC retailer sometime in October (closest one seems to be about 1.5 hours away) if I don't hear back and/or to my LBS.

dsbrantjr

B-b-but it's so AERO! Think of the milliseconds you will save over an hour ride!

drlogik 

SXwong,

A suggestion that has worked for me in the past: be polite, exclaim that you love the bike, explain that this crack is at odds with the quality that they make, ask if they can "help" in any way with this, either through a repair, replacement in-kind or something similar. Be friendly to. Don't go on the defensive even if they go there, such as saying that it's been abused or over-tightened. State matter-of-factly that it has not. This approach works virtually 100% of the time for me in similar situations even after a warranty has long expired.

Good luck!

CliffordK

Oh, ICK!!!

BMC.JPG

It is still quite possible that the top tube/seat tube is constructed in a couple of parts and epoxied together, but the repair would have to be done at the factory, or a very good frame restoration facility like Calfee if they can get the parts.

So, as others suggested, first talk to the manufacturer. It may be a manufacturing defect. If they don't want to touch it, ask them if you can purchase the clamp module, at least to have in case it gets worse and you need to ship the frame off to Calfee.

If all else fails, you might try epoxy, but it may be difficult to get it thin enough to get it down into the crack. Super Glue might penetrate into the crack better, especially if you can expand the crack a bit. Use a needle or knife or hyperdermic to get it down there.

The good thing is that a failure might mean dropping the seat post. It would probably happen at an inopportune time... Big bump in the middle of a race. But, it probably wouldn't cause an accident, although shifting weight can do odd things on a bike.

squirtdad

OP are you the original owner......if so take it where you bought it. If you are not the original owner chances are you will not get any warranty help. But as noted be polite, factual etc. Also see if you can find a phone number and talk to a person....often more effective than email

as a note of interest: I had a crack in an aluminum electra frame that I bought used.....clearly I had no warranty, I approached electra anyway to see if could get a replacement frame, after many calls, bike at LBS electra dealer, changes in people at electra, promises, changes in promises, and about a year they gave me a replacment bike (lower quality but no complaints) I kept good notes, and was polite and reasonable the entire time.

AnkleWork

According to the literature that's aluminum bonded to a carbon tube. If it's just a separation of the bond then it hardly rises to the level of a "crack" and the failure mechanism would only be further separation, at worst.
I'd just ride it and monitor.

sxwong

@squirtdad I am not the original owner though I wish I were haha. I'm building up this frame for triathlons so it's a bit naked right now.

@AnkleWork Never thought about it this way! This gives me more hope and hoping that this is the case. I took a photo of the "crack" from the other side when I got back. It does look like separation based on the lines but pretty hard to tell with the paint breaks.

Nevertheless, I'm going to take this to my LBS for their opinion sometime this weekend and keep trying to hunt down a number or contact from BMC. Eventually, I'll bring it to that BMC dealer and nudge them to do something.

Thanks everyone, I really appreciate all the help and learning how to deal with this issue! This definitely puts my mind at ease. I'll keep you all updated.

ckarr

if you are not the original owner and you never rode it before (you said the bike is naked and was about to be built up) then i would try to get a refund from the seller, looks like you bought a second hand bike that was a lemon

Rick Imby

I don't think you will ever have a problem with it. It appears to me to be a separate piece that is bonded over the seat tube. In time the stressed outer piece stretched a little and the seat tube did not. Under compression with the post installed. I would have a little different thought if it was a single bolt clamp.

rm -rf

Yeah, it kind of looks like a clamp over the frame tubing, and may not get much worse. Good luck!

I'd use carbon assembly paste on the seat post, which would help hold the seat post in place with less clamping force.

~~~

To fill the crack, superglue is too brittle for this application, and the usual gel version is not really designed to wick into the crack anyway.

Wright Bros

That crack is going to progress until the lug pops off, it's what cracks do.

AlexCyclistRoch

Since this looks like a crack along lamination lines, you might be able to get good results with one of those CF crack repair kits.

sxwong

So, I decided to return the frame back to the seller and look for another frame. Went to get the frame checked out at a couple LBS and they said it was unrepairable due to how the carbon split. The bolt would eventually break off. I think if I really wanted to salvage the frame, I probably would have had to epoxy the seatpost in. Something I didn't really want to do. If I paid $100 for the frame, I would've done otherwise.

I appreciate all the help guys!

fietsbob

Maybe dial back the desires for Carbon, and buying it used ?

but there seems to be a lot of buying that stuff seeking cheaper but, picking up someone else's problems.

ckarr

Say no to carbon, you get a $2000 plastic frame that will only save you 0.5 lbs over a steel frame and the plastic frame will crack and shatter after less than 5 years if you ride your bike daily instead of dressing up in tights and looking like a fool while going on your once a weekend bike ride. Don't forget to shave your legs if you are one of those guys.

trailangel

^^