Author Topic: Chainstay badly hit during a ride  (Read 8592 times)

carbonazza

Re: Chainstay badly hit during a ride
« Reply #15 on: June 07, 2016, 07:07:32 AM »
Are you still happy with the repair?

It worked well yes, I was riding as hard as before 24h after the repair.
I did check regularly the fix and around when cleaning the bike initially, but then forgot about it.

Unfortunately, I broke the frame about a year later( seatstay in 3 parts beyond repair ).
If you are lucky on the position of the crack, it is quite easy for a DIY repair, I guess compared to reshaping/welding aluminium or titanium.
I would do it again for sure if it happens again.

@Jerryno, good reminder!
I was surprised too to see the guy doing the sanding indoor and without mask.
The same applies when cutting bars or a carbon fork tube.
I do that outside, caring about the wind, with gloves, glasses and mask.
Probably overkill, but it doesn't last long.

SportingGoods

Re: Chainstay badly hit during a ride
« Reply #16 on: June 07, 2016, 02:35:16 PM »
Thanks for the feedback.

May I ask if the chainstay that you broke in 3 pieces is the same as the repaired one? The reason I ask is because sometime you can create a weak point by adding a super strong part. Let's say you have a 30 cm long rod, uniform. Under pressure it will flex all along the length of the rod. If you add a super rigid part in the middle, then the pressure will not be distributed evenly but concentrated locally, outside the strong segment. And it breaks!
That's for instance a reason why double butted spokes are "stronger" then plain spokes. DB are not really stronger but they better absorb forces and will break under stronger constraints then plain spokes.
« Last Edit: June 07, 2016, 02:37:07 PM by SportingGoods »

carbonazza

Re: Chainstay badly hit during a ride
« Reply #17 on: June 08, 2016, 08:19:38 AM »
I repaired the chainstay on the left side.
But then broke the seatstay on the left side too, falling clipped on an unlucky rock with all my weight on it.
I doubt both are linked.

SportingGoods

Re: Chainstay badly hit during a ride
« Reply #18 on: June 13, 2016, 10:20:28 AM »
Thanks for the update!

Now, I've had time to sand my seat stay and... it's damaged. A circular crack, but not 100%, only 50% of the circumference (outer side).



Honestly, that frame is rock solid. I crashed really hard on the rocks. I'm surprised it's still holding strong. It would probably do with a ghetto repair (try to force some epoxy in the crack and call it good) but I plan on repairing it with the fish pole kit. I will order it now.

carbonazza

Re: Chainstay badly hit during a ride
« Reply #19 on: June 13, 2016, 03:55:40 PM »
I wouldn't ride it anymore until fixed.

However when I broke my seatstay in 3 pieces, I was able to ride back to the parking lot for about 5-10km.
Sometimes the tire was touching the wishbone linking the two seatstays, but just on important bumps.
Seatstays seems there just to keep the chainstays in place. Probably why they are so skinny.

Your crack definitely looks a good candidate for a carbon "sparadrap" :D
Good luck with fixing this!

SportingGoods

Re: Chainstay badly hit during a ride
« Reply #20 on: June 14, 2016, 02:27:40 AM »
I have ordered the kit yesterday, it looks like an express shipping (2 days). It rains most of this week, so I plan on taking it easy and not riding the bike till fixed. The last thing I want is to break completely the frame because I did not wait for 2 days to fix it.
That race was really hard on the bike (and very much on me too :)). I have already replaced the RD pulleys (stuck in mud from km 20 out of 80), the chain (after a week in petrol it was still full of crap and stain), the grips (nicely damaged). Nothing expensive but no doubt this race is one of the most difficult in France... that's what pro-cyclist say, they must be right!

Thinking twice about it, Carbon is probably the easiest frame to fix on your own. A bent/dented Aluminum seat stay would have been more expensive to repair.

carbonazza

Re: Chainstay badly hit during a ride
« Reply #21 on: June 14, 2016, 12:34:18 PM »
That race was really hard on the bike (and very much on me too :)).
Is it a race in the Alps? Which one?
You had snow right :) ?

SportingGoods

Re: Chainstay badly hit during a ride
« Reply #22 on: June 15, 2016, 02:26:12 AM »
Yes, it is precisely in the Vercors section of the Alps. A very wild place difficult to access (that's where the "resistants" were hiding and established their HQ during WWII).
The race is know as the "Mythic" and this year it was also the XC Marathon National Championship. Every year, winners says that it's one of the most difficult race (and those guys are World champion level).

No snow but it's been raining for the last 4 weeks. It was muddy as hell (as I mentioned, I have killed my RD pulleys and chain - stuck in mud from km 20 up to 80 :) ). Many people fall in the muddy section. They don't know their chance :) it's nothing compared to falling in the rocks!
« Last Edit: June 15, 2016, 02:30:15 AM by SportingGoods »

carbonazza

Re: Chainstay badly hit during a ride
« Reply #23 on: June 17, 2016, 04:06:51 PM »
it's nothing compared to falling in the rocks!
Thanks for the info. We are in a kind of perma-mud here in Belgium since October, I don't even remember what a rock is :)

SportingGoods

Re: Chainstay badly hit during a ride
« Reply #24 on: June 20, 2016, 02:52:38 AM »
Done! Nicely repaired with the kit. You really need to look at the seat stay to realize it has been repaired. A friend had a look and was amazed, she expected a big patch!

So, right after removing the shrink tape (very glossy but you can see the spiral pattern of the tape wrapped around)

A close up on the "junction" (at the same stage, post shrink tape removal), you can see the different weave

Gently sanded and repolished, ready to rock'n roll


Thanks much Carbonazza for sharing info on this kit, it has saved my frame!

carbonazza

Re: Chainstay badly hit during a ride
« Reply #25 on: June 20, 2016, 10:20:42 AM »
Nice repair! Glad it helped you.
It reinforce this kit as a very good option for everyone to fix cracks on their frame.