[Solved] Crack in seat tube CS-041

[dudleik]

Went to a race yesterday with my cs-041, through some pretty rough stuff i came down hard on my saddle and heard a crack from the rear of my bike, happened once again later in the ride. Thinking it may have been the seatpost slipping in the seat tube i thought nothing of it then. Now after cleaning the bike i notice a horizontal crack has formed just where the seat tube intersects with the top tube/seat stays. Would this merely be a crack in the paint due to flex or is it a sign of possible structural failure in the area?

http://s33.postimg.org/qkg4z521b/IMG_1877.jpg

Edit: Got a new frame on warranty from Peter.

[Carbon_Dude]

Looks to be more than just paint, at least the first few outer layers of carbon appears to have cracked as well.  You might want to start looking into a warranty replacement.

[stockae92]

Wondering what size is your frame? I noticed that the 041 has seat stay reinforcement for some sizes.

[dudleik]

Looks to be more than just paint, at least the first few outer layers of carbon appears to have cracked as well.  You might want to start looking into a warranty replacement.

Thanks for your reply. I've contacted Peter, he's waiting for reply from the factory.

Wondering what size is your frame? I noticed that the 041 has seat stay reinforcement for some sizes.

Size is 19". It does indeed have the smallish tube coming from top of the seat tube to the top tube.

[Carbon_Dude]

The small tube should have added bracing for the seat tube.  I'm very surprised the short section of seat tube, above the top tube, flexed enough to crack on the back side.

[carbonazza]

They may have a design issue on that frame.
All modern bike I look at, with a low top tube, have more carbon behind the seat tube between the seatstays( exactly where it cracked ).

Mine cracked at the same place a couple of months ago, for no apparent reasons and was replaced by Peter's factory.
Hopefully it is just a bad batch and you will get yours replaced too.

The new one I received is exactly the same. So this time I will try to find a longer seatpost that will go farther in the seat tube, but it is a pain.
400mm is what I had and came just below the top tube.

[cmh]

They may have a design issue on that frame.

You ain't just whistlin' Dixie...

As mentioned elsewhere, we got an 041 for my wife as a backup bike. She's ridden it maybe four times, and never anywhere too technical, mostly local trails. Plenty of info about her thoughts in the linked post.

A couple weeks ago, I had a buddy try it out so he could check out MTB. He wasn't a fan, but he's a city boy and doesn't like being in the woods. Freak. 

Today, another buddy gave it a try on the same trails, which are _very_ non-technical. It's called the Green Ribbon trail, and it's easily ridden on a road bike with 23c tires. Some roots here and there, but otherwise glassy smooth hardpack. While we were out riding, I hear a loud crack, and look back, nothing seems amiss, huh... guess something just shifted on the bike or something. My buddy jokes that he just broke the bike.

Get home and I'm bringing the bike in the shop and I remember this post, so I run a finger on the area shown in dudleik's photo, and...



Considering all the other issues we had with this frame, I'm supremely unimpressed at this point. I pulled the seatpost out and compared it to this junction, and the post went past where it cracked.

At this point, considering the age of the frame, I would think long and hard before getting an 041.

[stockae92]

base on the pedal you use, I believe you when you say the bike was not ridden "seriously" when it broke ... ;-)

but if the seat post went pass the section where it broke, that means the seat tube has room for the post to "move around", and enough so that it cracked site tube.

[carbonazza]

I pulled the seatpost out and compared it to this junction, and the post went past where it cracked.

How much was it past the junction? The bottom one right?

[carbonazza]

As I became quite worried on rebuilding my CS-041, I contacted Peter about these multiple issues.
He just confirmed they had a bad batch.

The frames before and after that batch do not have the issue.
And the minimum recommended seatpost insert is 100mm like most bikes.
No need to go deep inside.

Waiting for my new rims to build the wheels(a premiere for me...)  and then build time!

[SportingGoods]

Waiting for my new rims to build the wheels(a premiere for me...)  and then build time!

Just a side note here. I have completed my first wheels a couple month ago, for the 24" bike of my son. It was stressful but almost an easy task, and a complete success (the most important part), using this book as a reference. 9£ to guaranty your wheels will be better then any wheel you can buy, worth it to me

Just follow every single recommendation of this book
http://www.wheelpro.co.uk/wheelbuilding/book.php

[carbonazza]

using this book as a reference... http://www.wheelpro.co.uk/wheelbuilding/book.php

Thanks for mentioning it can be easy
I bought the book few months ago, I even built the wooden stand he designed.
The parts should arrive on Wednesday, I'll need a refresh rather quickly!

[SportingGoods]

Very good! I have been lazy and just used the frame/fork to build the wheels. It still worked but a stand is definitely better. You will also need a dishing tool. I've been VERY lazy on this one too, but I really like this solution. 2 mugs/glass and some coins :

[carbonazza]

LOL,  the bike as the stand, and this for dishing, finally the only tool needed is a spoke wrench

[SportingGoods]

Well, I bought 2 tools  a spoke wrench and a nipple driver (not cheap!). Nipple driver is very useful, it really helps to get all the nipples screwed the same way and fast.

My son is very proud of his new wheels (me too!). He needed disk hubs so I could transfer my old hydraulic brakes on his bike. I haven't tried to save any money here and just bought some new rims as well