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E.Merckx SC downtube dented(14 posts)

E.Merckx SC downtube dentedMaverick
Nov 6, 2002 5:34 AM
Hi ppl,

Pls take a look at the attached pictures of my downtube (note the red colored circle)

Do you think the dent would cause damage to the overall frame structure? The depth of the dent is about 2mm.
is the downtube is among the highly stressed portion of a bike frame?

what is the average life of a scandium road frame? i'm a recreational rider, average mileage is less than 200km a week, my weight is 55kilos. taking into account the condition of my downtube how long do you think my E.Merckx SC would last?

Thanks for help
You're the second guy on this forum . . .Sintesi
Nov 6, 2002 6:41 AM
to ding the downtube of his Merckx scandium bike. I suggest starting a club.

Scandium will give you 2 - 3 years hard racing. 5 - 7 years normal riding. 10 years if you baby it. And yes I'm just pulling these figures out of my a$$. ; )
Those numbers are wrongSherpa23
Nov 6, 2002 7:30 AM
I would be very surprised if a 55kg person riding as little as 200km a week would get 5 years out of a 2.3 lb aluminum frame. If that weight is wrong for the EM, someone can let me know.
not exactlyMaverick
Nov 7, 2002 7:26 AM
whats new on this post is the actual picture of my poor downtube, with the dent (not quite visible though)
re: E.Merckx SC downtube dentedTrekFurthur
Nov 6, 2002 6:43 AM
You're relatively light, and your riding volume is low. However, given Sc's reputation, and the low warranty on these frames, I'd keep an eye. By denting the tube, you've created a stress riser (I'm sure I'll be corrected if I'm wrong); if it starts to fail (crack), do you want to be descending at 30+ when it goes.

I put two small dents in the top-tube and one large one in the downtube of my old Specialized Rockhopper MTB; it's still going strong, but it's steel.

In short, I'd be worried, but others may disagree.
re: here is a possible fixpinarello
Nov 6, 2002 6:51 AM
Have a machine shop cut you a piece of steel tubing the same size as your seat post in dia. cut it undersize by 001.Length of the new sleeve should be about 1 inch past the dent in both directions.Make this sleeve thick enough to knock in with a long tool. Remember when knocking it it the tubing is very thin. This should help alleviate both the dent and the integrity problem. Sorry it will add weight. But who is to know. Catapult.
howzat going to get into the downtube? nmbill
Nov 6, 2002 7:08 AM
howzat going to get into the downtube? nmpinarello
Nov 6, 2002 9:42 AM
Sorry thought it was the seat tube. Need stronger coffeeee!
re: here is a possible fixdivve
Nov 6, 2002 7:24 AM
Here's another one. Push a balloon up the down tube through the BB. Then pump it up real hard until the dent pops back out...feel the gin?
re: not going to fix it structurally heres whyThirtyFive
Nov 6, 2002 3:53 PM
metal, whether it be al, ti, fe etc has memory and when deformed, will generally bounce back to the position that it was originally. when metal has been deformed past the point of memory it will take on a new shape and will not return to the original. the reason it will not return is that the metal has actually been stretched. think about it this way. the shortest distance between two points in space is a straight line. a dented tube no longer takes the straight path and thus the metal must actually be longer to join the two points. this is why on an automobile, if the dent is large enough, just 'popping' it back into place does not work. the dent will tend to bow one way or the other because the metal in the dented section has actually been elongated. there are ways to 'shrink' metal. autoshops generally use localized heat and a hammer. someone here once mentioned the use of dry ice (im not a materials guy so i have no idea what this will do structurally). sorry this does not address the original post, but i just wanted you all to know that simply pushing or pulling the dent back into place will not fix the problem
Heck, Eddy Probably Has One On His Bike Too ...Gregory Taylor
Nov 6, 2002 7:28 AM
If you did something to ding the tube, I'd just keep an eye on it and wouldn't worry too much. If the dent just suddenly appeared while you were riding along, or if it starts to grow or change shape on you, then I'd stop riding the frame as something is seriously amiss.
yeah, but he probably rides steel...(nm)merckx56
Nov 6, 2002 8:17 AM
How did you dent it there?PdxMark
Nov 6, 2002 9:48 AM
It's an interesting spot for a dent, or at least to me it is. It's not someplace that would be readily hit if the bike just fell over on flat ground.
How did you dent it there?Maverick
Nov 7, 2002 7:20 AM
mounted a mini pump on the downtube, next to the bottle cage.

while riding, i left leg hit the pump, and the rest is history.