Aftermarket frames

[Sammajoor]

The piece where the seatpost enters is 15cm at the point where it snapped (will add picture with measuring tape if intrested), I use a EC90 seatpost with a 31.6 diamater which is the exact same as the frame, the most common minnimum insert for a seatpost (incliding mine) is 10 cm, so the break is a good 5cm under where even minimum insert should be,in this frame I used 36cm of the actual seatpost so there was a good 14cm in the frame an aboutt +- 1cm between where it broke, and for the last time I do not abuse frames or bikes

 

All I am trying to illustrate is that this is a convergence of circumstances that made the frame disintegrate as it did, this was not a simple fall and break incident. I am a heavy weight by all standards, I have had a few spill with my bikes, and not once did the frame break like this

[29" MAN]

Ofcourse, but thats just the thing, as the owner of the bike I know what the frame/bike has been through, and that is just the thing, nothing that has or should have lead up to a break like this, that is why I'm questioning the strength of these frames as I only weigh 65kg with a body fat of 2.9% ... know what I'm saying, I'm by all means lightweight

Edited November 9, 2011 by 29" MAN

[Big H*]

Did it go snap - crackle - pop??????

[stratus5]

The important measurement is from the top tube, not that funny vertical bit sticking out above it. What is that by the way?

 

It really looks to be the bare minimum ... this frame has broken only two or three cm below the tube junction junction. Frames are not designed to take much torque at this point. All tubes are designed for either compression or tension forces, not much rotational shear.

 

A aluminium frame will be better at standing up to short seatposts, but carbon .... not so good. As a rough rule at least 10cm of insertion below the junction is required, or about 4 times the diameter of the tube to be really safe. This should probably be printed on the frames, not on the seatposts!

 

A measurement of the length of remaining piece below the top tube would be interesting.

[gummibear]

Ofcourse, but thats just the thing, as the owner of the bike I know what the frame/bike has been through, and that is just the thing, nothing that has or should have lead up to a break like this, that is why I'm questioning the strength of these frames as I only weigh 65kg with a body fat of 2.9% ... know what I'm saying, I'm by all means lightweight

 

What did the frame hit that made the BB area splinter like that?

[stratus5]

If the seatpost broke first, the frame would have folded up around the BB, which is probably what caused the splintering

[Kranswurm]

Did it go snap - crackle - pop??????

N2O finis?

[29" MAN]

That top piece is 8.5cm on the bottem then obviously 6.5cm, intresting theory though! It was more like a crash ... BANG ... WTF! The bit in stratus5's picture was the first to go and the bottom bracket was still dandeling by the internal housing so it kept it in tackt to a point where it splintered and teared the carbon. Maybe I should sell the frame to the highest bidder that he/she can decide for themselves?

Edited November 9, 2011 by 29" MAN

[GrumpyOldGuy]

Ofcourse, but thats just the thing, as the owner of the bike I know what the frame/bike has been through, and that is just the thing, nothing that has or should have lead up to a break like this, that is why I'm questioning the strength of these frames as I only weigh 65kg with a body fat of 2.9% ... know what I'm saying, I'm by all means lightweight

 

Hmm, a body fat of 2.9%......I doubt it very much, this is almost internationally competitive body building lean, and certainly below national competitive levels.

 

With that kind of bodyfat level you would barely be able to walk up a flight of stairs without stopping for a nap, let alone race endurance events like a bicycle race.

[Iron]

[/b]

 

Hmm, a body fat of 2.9%......I doubt it very much, this is almost internationally competitive body building lean, and certainly below national competitive levels.

 

With that kind of bodyfat level you would barely be able to walk up a flight of stairs without stopping for a nap, let alone race endurance events like a bicycle race.

 

LMAO

[gummibear]

[/b]

 

Hmm, a body fat of 2.9%......I doubt it very much, this is almost internationally competitive body building lean, and certainly below national competitive levels.

 

With that kind of bodyfat level you would barely be able to walk up a flight of stairs without stopping for a nap, let alone race endurance events like a bicycle race.

 

[Minion]

It really looks to be the bare minimum ... this frame has broken only two or three cm below the tube junction junction. Frames are not designed to take much torque at this point. All tubes are designed for either compression or tension forces, not much rotational shear.

If the saddle was hit from front or back, none of those tubes would be taking rotational sheer. It it was hit from the side, the top tube and to a lesser extent the seat stays would have had some sheer loading.

[Minion]

This should probably be printed on the frames, not on the seatposts!

Yet it isn't and even the most thorough of frame manufacturers, Cervelo, only mentions the seatpost minimum insertion point in the manual.

 

If the frame manufacturer has a seat post insertion requirement that deviates from the industry norm they most say so. If they don't and the customer follows the norm of using the seatpost insertion mark and the frame fails, the fault is the manufacturers, not the customers.

[Caerus]

'go down this road' No pun intended hey Velo

By the way I still have these two lying around. If anybody wants to test the theory out for themselves.

 

 

If they are 26" I will be willing to test them out

[29" MAN]

[/b]

 

Hmm, a body fat of 2.9%......I doubt it very much, this is almost internationally competitive body building lean, and certainly below national competitive levels.

 

With that kind of bodyfat level you would barely be able to walk up a flight of stairs without stopping for a nap, let alone race endurance events like a bicycle race.

 

Probably true, maybe if I was 18 years old, oooh wait I am, well still I would have to be about 1,9m tall, oooh wait that I am as well! Wow guess there goes that theory seeing as I'm not short, fat or old, I'm just wondering now how you got old because it was certainly not through being smart

[Skaap]

thehubsa detective's at work..... awesome!