Lately I have noticed a distortion in the paintwork just below the lug on the downtube of my converted Mondonico. It lines up about level with the tip of the lug on the underside of the tube but runs neatly across the top of the tube.
It looks like a slight depression band in the tube surface and I probably wouldn’t notice it at all if it wasn’t for the depth of the pearl finish in the paintwork. No visible crack just a nice smooth distortion.
I’ve seen pics of frames failing here, looks nasty when they go and as it is my street bike i don’t fancy it folding on me hopping a gutter or something in traffic.
Anyone seen this before??
If Blakey reads this any tips for home DIY NDI…a bit of mag particle or convert my microwave oven into an xray test set…
If there is no crack, I wouldn’t be too concerned but I’d keep monitoring it.
Don’t be too worried about downtubes failing. A friend’s Mondonico had the downtube separate from the headtube lug at about 80 kph descending into Mt Alford in the middle of the bunch. The speed wobbles were quite impressive. He made it to the edge of the road and down to about 10 kph before he fell off into the grass, no muss, no fuss.
You can buy Ardox white lacquer and black mag ink from the industrial bargain $2 shop in the dodgiest end of Cannon Hill shopping centre (at least you could last year)
But you’ll have to figure out how to get yourself a suitable electro/permanent magnet.
Plus MPI only shows surface breaking defects. Likewise, dye penetrant (see: oil and whiting) which is a simple one to do yourself too.
There’s always radiography/ultrasonic, but they need more equipment, training, isotopes etc!
As LWAB says, just monitor it carefully, keep an eye on the paint for cracking.
Bought a new helmet a couple of months ago so as long as i land on my head and not my face i should be OK.
Thanks to LWAB and Blakey, both men who know their stuff.
There’s a joke in here somewhere about how many cracks Blakey’s seen before but I’m sure it’s been said before.
Or you could throw your helmet out and go race, that way there’s a better chance of living up to your name Crashdummy :evil:
I don’t think not wearing a helmet increases the probability of a crash, just the seriousness of the consequences, Andy White is a (very happy to be) walking and talking case in point.
In my first MTB race in quite a while last weekend i showed i still deserve the name i was given, first lap carrying as much speed as I could through a rock garden i bounced off a boulder and bit it pretty hard. luckily there aren’t many nerves or blood vessels in the shin.
I hope you don’t have my old mondonico then?