prairiepedaler

Want to see the BRC headtube failure? I don't have pictures of the GT Timberline with the snapped dropout. Tossed it years ago.

https://cimg2.ibsrv.net/gimg/bikefor...600aabc6be.jpg

https://cimg4.ibsrv.net/gimg/bikefor...27d1f245f8.jpg

https://cimg5.ibsrv.net/gimg/bikefor...1141a375d8.jpg

kroozer 

My son snapped the chain stay of his late 80's Fisher steel MTB urban commuter this year. I was kind of surprised, but so what, get another one for $50-100 and you're good for another 5 or 10 years. I have started stocking up on old MTB frames.

GhostRider62

Do you have data or are you just talking?

Frames break. You are wrong.

GhostRider62

No. Just ride a lot more than most people and in all manner of weather.

repechage

from the appearance though, put away wet

GhostRider62

Ok. You win.

Darth Lefty 

Just shift your perspective from “Classic & Vintage” to “Old & Economical” and find another one.

merziac

"a lot more than most people",

merziac

prairiepedaler

Hard to say which side failed first. You can pull the joints apart and when repositioned they "click" back into place. Which means maybe welding without having to worry about alignment is possible. Nevertheless, I have to hustle and procure a replacement.

ThermionicScott 

It happens. Just get it fixed, dude.

repechage

The drive side shows a similar failure to what some Treks have had.
The rust and thin bright spot shows how little was doing the job for quite some time.
Once one side went, take your pick which, the other was overpowered.
Black paint does not help. rust indicates it stayed wet for a while, repeatedly.
That thin cast stay top eye with the stress risers from the cast in text did not help.

Bad Lag

FWIW, the rusty, broken stay end broke first. It has had time to corrode. The broken braze joint is fresh (unoxidized, new).

prairiepedaler

@repe & BL,

I'd say that is a reasoned assessment. One can see how this part of the frame could act as a "nook" for moisture to congregate over time. This failure was set in motion long before I got the frame. For considering future frames with similar stay attachments, I'm going to have a closer inspection there with a magnifying glass.

Should I take a wire brush and remove the rust between the two halves before welding it? I'd like to try and remove as little material as possible for best alignment and brushing might get it to bare metal without filing. The paint will be stripped from the surrounding area.

mechanicmatt

My guess is a good metal brushing will get most of it and not remove too much material.

cooperryder

A similar scenario happened on a 1985 or 86 Schwinn Cimarron while riding it.

I thought it was a flat a first.

That bike had a lot of use before I bought it.

Bonzo Banana

Doesn't matter what the material it can be designed strong or it can be designed light. The first bike I ever bought myself new when I was in work was a Raleigh Royal. I wanted the lightweight model with butted tubes which I think was close to £200 at the time back in the 80s but I was also 16 stone. The shop was completely honest they said I was likely too heavy for the bike and the frame may fail early and the lighter wheels may not cope as well. They had a model called the Raleigh Royal Export it had more basic high tensile steel tubing, higher spoke wheels and much thicker tyres and no butting on the frame and was £130. I took their recommendation and went with the considerably cheaper bike.

Nowadays if feels much more confusing as the bike market has become much more dishonest it seems. Many people pretend lightweight parts and frames can be as strong or long lasting but that is rarely true. Tube butting is a way of losing weight on a frame but it won't be as strong as straight gauge and over time will likely suffer fatigue more and fail earlier. If you have a steel frame then butted tubes where they are thin will be much more vulnerable to corrosion and failure.

I remember reading about fuji-ta's basic steel frames. Fuji-ta are the largest bike manufacturer in the world by volume. They make low cost steel frames which a few years ago were only about $4-5 they are robot welded and phosphate dipped and despite selling in huge numbers they pretty much have no failures according to them. Less than 0.1% which compares very favourably to their other frame materials. I'm sure they aren't as cheap now as Chinese manufacturing is more expensive now and general inflation. They are using more advanced steel for some frames (not chromoly). I think something like 1040 so close to chromoly in strength but significantly cheaper or were back then. Such 1040 frames had huge take up in China but were not as popular for export in many markets where aluminium was preferred and this seemed to surprise them.

Steel frames are still the workhorses of the world across South America, Asia, Africa etc. People buy them and get decades out of them despite getting a huge amount of abuse. Those frames aren't really focused on being lightweight though just strong. This is the type of bike Giant makes for Africa. I've noticed many people compare steel bikes on forums as if they are all the same. Some older chromoly steel mountain bike frames with butted tubes were relatively weak compared to straight gauge high tensile steel frames because they were designed to be light and would suffer from fatigue fairly quickly so had an expected finite lifespan. Chromoly tubes typically corrode just as fast as high tensile and are often thinner even in the areas not butted to be thinner. I'm just making the point realistically you would expect a lightweight chromoly butted frame to have a finite life and fail before a typical high tensile steel frame. If both frames suffered from corrosion and were stored in the same shed unless one had better corrosion protection than the other you would expect the chromoly frame to be unsafe sooner probably by a factor of years possibly decades.




https://www.fuji-ta.com/hi-ten-steel...nd-alloy-frame

https://valvejob.wordpress.com/2020/...-frame-tubing/

VtwinVince

This is why I am constantly meticulously inspecting my bikes before riding them as a general habit.

repechage

There are rust removal solutions that can be purchased ready to go (home despot, or other places) or oxcalic acid solution, aka wood bleach, that will get you most of the way there, most take a day to work, a bit temperature dependent.
There is a complete thread on oxalic acid.
But to answer directly, CLEAN makes strong. Wire brush after would not hurt. TIG welding or "brass" brazing. most likely a reaming or file work on the inside of the tube.
a wheel or dummy axle in the rear dropouts would be smart too.

mrv 

I had to retire this one.
A friend gifted me a near identical replacement framset ….without the cracks…. Of course.
Used for commuting. Camping. Touring. General abuse.
These things happen. I guess.

Miele Man

I was told by the owner of a well known bicycle shop in Madison, Wisconsin that such a failure was fairly common with that era of MTB.

Cheers

prairiepedaler

Hmmm, that's interesting.

prairiepedaler

Here are some photos of the bike when it was operational. I configure all my main rides like this. I'll be stripping down the Elkhorn soon and probably squirrelling it away to practice brazing on in the future or giving the frame away to the local granola LBS. Probably the latter.

prairiepedaler

Yeeouch! That's a steel frame which fractured that way?

ThermionicScott 

While we're talking about checking things over, I'd make sure there isn't a crack starting on the spider of that crank.