Frame repair

[Cyclo]

One of our rides recently crashed and found a crack under downtube near headtube, as you can see on picture.
This is our first crack so far, and we want to find the best solution for our customer.

The frame is steel, LIFE tubing, fillet brazed.

Is it recommended to repair it? And how can be done? Or the repair won't offer reliability?

Thankyou very much.

18-08-2013, scheur in frame, zonder verf, 06.jpg

[Will Neide]

Whoever built that frame should be able to provide you with some solutions.

If it were a frame of mine, and all that was wrong was that crack, I would sandblast the frame, inspect the frame, replace the tube, re-powder, go for a bike ride.

[steve garro]

If it was one of mine I'd hacksaw off the whole front triangle & replace it at the client's cost.
- Garro.

[Cyclo]

So, normal use of frame can't cause this right?

Thanks!

[Amaro Bikes]

Being fillet brazed it's "easy" to replace the front triangle. And as being involved in a crash, most likely the whole front triangle alignment and integrity is damaged, so best solution is to replace the whole front triangle as Steve said (wise people speak wise words)
In any case, better to make things well and blindly proof so it does not matter if failures happens as much as to get them properly solved. Also, if it's a mtb frame wouldn't be bad idea to use Zona downtube instead of much more delicate Life one (wich should be only used for road or compromise off road).

Cheers

[Amaro Bikes]

So, normal use of frame can't cause this right?

Thanks!

If it has been properly built, quite difficult to happen, specially seeing the shape/place of the crack. But is always difficult to play imagine games without the complete data.
To me it looks more like a front crash wich forced HT "down" so making dt collapse. But it could also be due to fatigue on the HAZ on such delicated tube as life at one of the most demanding places of any frame (ht-dt down part)
Is it road? mtb? being mtb with life it's knocking on troubles door...

I guess customer is asking for warranty and you want to know if damage is frame failure or customer's fault?

[Cyclo]

It's mtb 35 mm downtube LIFE. Customer is waiting for better solution, at this moment he did not talked about warranty, and he recognized a crash and few rides after...

I will switch to Zona on downtube. Or 38mm LIFE...?

[EnginCycles]

It's mtb 35 mm downtube LIFE. Customer is waiting for better solution, at this moment he did not talked about warranty, and he recognized a crash and few rides after...

I will switch to Zona on downtube. Or 38mm LIFE...?

Life and Zona are not up to the task of a mtb. Maybe if it was non suspension correct and 26" wheel. The down tube of a mtb takes a serious amount of abuse. What is a crash on a mtb? Seriously every ride typically involves a crash or crash like conditions. Heck often a crash is easier on the bike than the rider that can keep it upright and not crash. MTB's need to be made to handle all conditions short of going front end first into a non moving object like a tree. How long can a bike handle this and still be under warranty? That is the million dollar question. There is a fine balance between too heavy and not strong enough.

The typical failure for a brazed bike is a buckle not a crack. A welded (TIG) will have a more brittle area in that region but if the structure is made correct no one area will get stressed enough to cause a crack in the HAZ. Stuff happens but usually it is the bike finding the weak link in the equation.

[steve garro]

So, normal use of frame can't cause this right?

Thanks!

Well, that's a loaded question.........
1st of all, was it a frontal impact?
Is there a distinctive crease/bulge?
How about the top tube?

And then you have the builder - this may not be what you want to hear....
* The DT may have been too light for the intended purpose
* Life is what i would call "Race Bike" tubing = it's not meant for abuse, really.
Spec'ing it may have been a bad call.
* the tube could have been over heated, brazed bikes that are overheated generally last about two years of hard riding.
* The fillet could have been undercut upon polishing, this would lead to a premature failure right on the fillet edge
* the thinnest tubing is safly brazed by only the best braziers - go figure.

If you don't know splitting the cost & bumping up the tubing to a heavier gage may be the most cost effective and amicable solution for both parties.

Only way I can tell you 100% is to hold it in my hands, and even then not seeing it being brazed I can't tell you if it was over cooked.

my Dos Centavos,
- Garro.

[Cyclo]

Top tube looks fine. No bulge. Waiting for builder coming back from holidays...

[jon_norstog]

Well, that's a loaded question.........
1st of all, was it a frontal impact?
Is there a distinctive crease/bulge?
How about the top tube?

And then you have the builder - this may not be what you want to hear....
* The DT may have been too light for the intended purpose
* Life is what i would call "Race Bike" tubing = it's not meant for abuse, really.
Spec'ing it may have been a bad call.
* the tube could have been over heated, brazed bikes that are overheated generally last about two years of hard riding.
* The fillet could have been undercut upon polishing, this would lead to a premature failure right on the fillet edge
* the thinnest tubing is safly brazed by only the best braziers - go figure.

If you don't know splitting the cost & bumping up the tubing to a heavier gage may be the most cost effective and amicable solution for both parties.

Only way I can tell you 100% is to hold it in my hands, and even then not seeing it being brazed I can't tell you if it was over cooked.

my Dos Centavos,
- Garro.

+1 on that, Steve. I will say, I use Zona for mountain bikes... and am planning to use some 8-5-8 Zona on an ultralight cruiser for BMX racing next year. It is good stuff.

jn

"Thursday"

[steve garro]

+1 on that, Steve. I will say, I use Zona for mountain bikes... and am planning to use some 8-5-8 Zona on an ultralight cruiser for BMX racing next year. It is good stuff.

jn

"Thursday"

I used to make allot of Zona bikes back when I got orders for 26ers with ATC's of <457mm - I only quit because they dented easily.
Maybe made 50+ of them back in the last century......
Mostly supertherm for DT's now - those can take a whang from a ball peen.....
- Garro.