Frame failure experiences

[Elev12k]

"Luckily" enough, the seat tube extends "quite a bit" above the top tube on this frame (random picture of an older MY with U-brake mounts):
View attachment 937266

If there is enough room to extend the slot and the tube is the right diameter for a seperate clamp, cutting a bit of sounds like an option worth consideration if you would like to use the frame in the future.

 

[highlandsflyer]

Have you any idea why it cracked in the first place? Wasn't it there when you bought it? Yes, you have options thanks to that extended seat tube, I have carried on riding much shorter ones with similar issues. Your picture wasn't very revealing, hence my premature asseveration. If you are happy the rest of the frame is sound, do your damnedest to make it live.

 

[foxb13]

Have you any idea why it cracked in the first place? Wasn't it there when you bought it? Yes, you have options thanks to that extended seat tube, I have carried on riding much shorter ones with similar issues. Your picture wasn't very revealing, hence my premature asseveration. If you are happy the rest of the frame is sound, do your damnedest to make it live.

No idea why it cracked. The crack was probably there when I bought the bike, I've simply overlooked the most basic inspection. But persistent rumours BITD were that most of the Scrambler Lines built have broken. Giving Lapierre customer support headaches, as Lapierre was distributing Scrambler Line, before buying it and quickly shutting it down. I don't know whether Lapierre shut Scrambler Line down because of too high failure rate or not. As I said, it was rumours. And I failed at gathering evidences of broken Scrambler Lines (to this day). Was it a particular model: Thévenard, Taillefer, Yearling, ...? A specific year: they changed from U-brake to canti bosses, from classic seatstays to monostay/wishbone on the Thévenard for example, ...? A manufacturing change: were all Scrambler Lines assembled using ATS (Azote Tubing System) process where internal lugs (which material?) were colded in liquid nitrogen and inserted into the tubes (which ones? Main triangle only?) before being welded. Where were they more prone to break? Lot of questions without clear answers. One sensible information I was able to get (cannot remember the source anymore; was it blog, website, magazine, book, ...?) was that Aviatube 6106 aluminum alloy, by contrast with more classic 6061 T6, was lacking a heat treatment to restore the crystal structure. Now, is the lack of heat treatment inherent to a specific alloy or rather its use, I don't know. And is this lack of heat treatment the cause of the crack in the seat tube, I've no clue.

 

[Woz]

A first for me, it seems

View attachment 936908

1990 Scrambler Line ATB (French framebuilder, as the name doesn't imply). Made of Aviatube (a Pechiney brand) 6106 aluminum alloy (not 6061, as e.g. Kein or Cannondale). Bought two years ago and just noticed the crack in the seat tube while cleaning up the frame tonight. Unknown history, but the frame did come with the original carbon seatpost manufactured for Scrambler Line by TVT - Technique du Verre Tissé (yet another French company), so not a problem of wrongly-sized part. And from the marks on the raw carbon, the insertion length seems to always have been more than adequate. What to do now? Drill a tiny hole at the end of the crack to prevent it from propagating further (seen that on some Yeti A.R.C.s)? And then, good luck locating someone here in France willing/able to repair such an antique aluminum alloy frame...

Perhaps worth a repair - I feel your pain - if you are not in a major city a good repair will be a headache, involving postage etc. to people who know what they are doing. As a side line, try to tap in who is good in aeronautics zones like Toulouse and Bourges.

Saving AL demands a lot more thought IMHO. I'm in France too and distant from everything. If you were in Paris region you could pick.

@bikeworkshop - one of the best active threads ever Will get you a beer at the Inn.