Another one bites the dust: 95 Explosif

TheAntsPants

Devout Dirtbag
The bike started making some ominous and very loud cracking sounds a few days ago whenever I put the pedal to the metal or hopped off a kerb. Sounded like something was at the end of its life and about to go. Frantically checked around the welds, BB spindle, cranks, pedals, handlebars, stem... nothing. Kept riding, fiddling with headset, swapping rear wheel, tightening bolts... still nothing. The only place I couldn't see well was the BB, so off come the cranks, then I notice the massive crack in the middle of the down tube. :facepalm: Didn't think to look in the middle of a tube :shock:

After exactly 2 days short of 5 years of near constant abuse by me, and Deity knows how much by previous owners, another one bites the dust. Already had to replace the drive side dropout after it snapped. This is the second Explosif I have destroyed through wear and tear. The other ('9:cool: also suffered a crack but at the bottom of the seat tube after more than a decade of hard yakka.

Might have to look in to a more robust frame. Anyone got a spare Hei Hei or King Kahuna lying around? :LOL: :LOL: :LOL:
 

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greencat

Senior Retro Guru
Did that originate from the bottle boss? I have often wondered if a heavy bottle of water moving around could eventually cause stress cracks in some frames. I lost a tange prestige frame in the 90s after a friend ran into me causing some cracks around one of the bottle bosses - one of them eventually lengthened causing a failure awfully like yours.
 

mk one

Old School GrandMaster
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Never seen one crack there before, come to think of it i havent really seen any broken steel Kona's. Rode them for many years, dirt jumping, street riding and dh, never had any trouble :?
 

hamster

Retro Wizard
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The reason is that the boss introduces a stress concentration in the thinnest part of the tube. Fitting gear bosses below the butt of road frames could cause cracking. Probably the boss wasn't completely wetted with braze. The bottle loading wouldn't be the problem, it would be riding loads flexing the frame.

But it's a tribute to how well-built they are that it's a rarity even after 25 years.
 

simon dee

Dirt Disciple
Re:

gah, gutted. One of those hero-like frames I wish I'd kept hold of. Pm'd about disposal of the remains :)

Simon
 

adroitstif

Devout Dirtbag
That's an unhelpfully shaped crack. At first I thought you could get some of those split S&S couplings fitted where the split is? Then you'd have both rescued the bike and converted it into a train-and-aeroplane-friendly folder. But I imagine the couplings need a clean cut, not a organically-formed winding crack.
 

TheAntsPants

Devout Dirtbag
Re:

Yep. Looks like it started at the boss. Crack is a spiral that runs the full circumference but separated by a couple of cm of metal. Only used a small water bottle except on the rare epic ride, but it looks like that stress riser and fatigue is what did it in.

Happy to donate the frame, or bits of it, but it's in Sydney. Simon Dee has first dibs. Otherwise, I'll run a full autopsy in the name of medical research some time in the future.

It was a brilliant ride and I'll be hard pressed to find a retro replacement that comes close, at least in this neck of the woods. Until something comes along, I'll be riding a 97 Kilauea that was intended for Junior. :|

RIP
 

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Milpool

Dirt Disciple
We don't have enough Kona's here to be splitting them, that's very unfortunate! I hope you can find a replacement somewhere.
 

gibbleking

Old School Grand Master
looks lie corrosion at the boss started the crack and the daily stresses finished it off....oooof..
 
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