Orbit Gold Medal Frame Snapped

[echolalia]

Cycling today and noticed a slight wobble in front wheel. Wheel was fine and tyre not flat. Pedalling away (not on a major road thankfully) the frame creaks then shears. SNAP! Downtube comes apart moves under legs then top tube bends as can't handle weight. So lucky that it happened when it did. Bloke in the bike shop reckons there was perhaps some impact near the lugs to cause a weak point. Shame frame fit me well. Amazing how thin Reynolds 531 steel seems.

[gaz]

Eeek.

Are you OK?

[PhilD28]

At least it's steel and repairable. 2 new tubes, though not a cheap job.

[Bonefishblues]

At least it's steel and therefore recyclable

[ChrisButch]

Oddly enough the only frame I've ever had snap under me was also a 531 Orbit (531C actually) - although in that case the break was in the seat tube about 15mm above the BB.

[borisface]

When I used to race back in the late 1980's I snapped two orbit 653 frames both went in the same place - the drive side chainstay near the bottom bracket. No crashes involved. I suspected at the time that they may have over-heated the tubes in the production process.

[Brucey]

Cycling today and noticed a slight wobble in front wheel. Wheel was fine and tyre not flat. Pedalling away (not on a major road thankfully) the frame creaks then shears. SNAP! Downtube comes apart moves under legs then top tube bends as can't handle weight. So lucky that it happened when it did. Bloke in the bike shop reckons there was perhaps some impact near the lugs to cause a weak point.....

bit of T-cut....?...

'bloke in bike shop' may be correct re impact but any impact could have been weeks months or years ago. If it was severe enough paint will have cracked on the top tube as well, usually just behind the head lug.

But it doesn't need an impact at any time to start a failure of that type; any tiny flaw will do. IME such failures have an element of fatigue to them. Usually a small crack gradually becomes a much larger one as you ride, and the bike starts to wobble furiously; this is nature's way of telling you that something is wrong, and maybe you should climb off and take a look.

It isn't at all unusual to find that the majority of failure in the down tube is such that the parts will fit together quite well; typically only the very last bit that breaks will be plastically deformed. This is a good sign that the crack grew by fatigue. If the crack has been months in the making, it isn't unusual to find that part of the crack surface is corroded; this is probably the oldest part of the crack.

I broke a frame last year in a similar way. Mine did not break in the top tube, because (alarmed by the wobbling) I'd climbed off and spotted the crack before the down tube separated entirely. There was about 1/4" of tube (at the upper surface) that hadn't cracked yet. I strapped up the down tube so that the straps were taking part of the load and tried to carry on (slowly). This lasted a few hundred yards only, but when the DT separated, the top tube didn't bend because the straps took the load at the down tube long enough to allow me to stop. I repaired the frame and I am still riding it.

In my frame there was clearly a place where the crack started (at the bottom where I would be less likely to see it) and that had been there long enough to corrode. I suspect that the demise of the frame (which was decades old, two or three times older than your Orbit) was assisted by the fact that I'd contrived to have a front brake that sometimes juddered badly for a few months. This put some horrible stresses into the frame; enough perhaps to turn a small defect into a crack that would grow in normal service. A loose/rattly headset might have done the same thing.

BTW that looks to be about a 24" frame. If so, that is about as big as I would make a frame in 531C tubing (or comparable) to which any rear load would be attached on a regular basis. Also, Orbit frames of that vintage do seem to be more likely to break than many; maybe they were built in a rush or perhaps were more likely to be overheated during building or something. Some folk also seem to be more like to break frames by wrestling with the handlebars as they ride, and with a rear load on, the repeated twisting load in the frame (which can do the fatigue damage) is greatly increased. In any event that part of the down tube is very highly stressed in a traditional DF, and is arguably one of the most likely to break.

Nothing lasts for ever.... glad you were not hurt.

cheers

[foxyrider]

Regardless of when it was bought that frame was built prior to my time at Orbit, I worked there from 1997 at which time nearly all new build frames were lugless.

That doesn't mean there weren't plenty of lugged fraames in the store from the Birmingham days, a lot were scrapped as the build quality was often terrible. Others were re engineered into serviceable frames (often it was stuff like misaligned rear triangles. By the decals it wasn't one of those).

So the frame is at least 20 years old, maybe not an economical repair but certainly do able.

[subandean]

I have a 1986 Orbit Gold Medal Extra, a comfortable ride, much improved by good quality components.
I am going to the garage to give my frame a thorough check!
Orbit have a chequered history with many mis-aligned frames in their early days.
The original paint blistered and came off my frame, allegedly because they omitted the base coats to save money. It went back to Orbit and the respray has lasted.
The original forks sheared at the base of the steerer fortunately not as I was descending a hill or in traffic. They were replaced by Orbit and have been OK.

[mercalia]

well fit some of collapsable bike fittings what do you call them? and you have a bike that will fit in your car boot?

[echolalia]

Thankfully no injury. Anyone know when this bike originates? Guessing early 1990s.

A person on the train home asked "Is that a folding bike?" then was able to take it on the tram home as a folding bike.

Some new couplers I think the frame will be alright!

[SilverBadge]

So lucky that it happened when it did. Bloke in the bike shop reckons there was perhaps some impact near the lugs to cause a weak point.

That's where a front impact can bend a frame, also vaguely remember something metallurgical about the weakest part of a welded or brazed join being away from the hottest area. Tallish head tube so the forces of leverage are reduced. Guess the replacement is sentimental vs economic.

[Cunobelin]

well fit some of collapsable bike fittings what do you call them? and you have a bike that will fit in your car boot?

S& S coupling:



I have them on my Thorn Nomad and they are brilliant

[markjohnobrien]

Shame it's broken as a lovely looking frame: always liked those colours.

Most important thing, though, is that you are ok.

[echolalia]

. . . 'bloke in bike shop' may be correct re impact but any impact could have been weeks months or years ago. If it was severe enough paint will have cracked on the top tube as well, usually just behind the head lug.
. . . . etc . . . .
Nothing lasts for ever.... glad you were not hurt.
cheers

Thanks for that, very informative. Ive used the bike a few times to move house temporarily so it has had a few heavy loads on the back. Scrap the frame best option do you reckon?