skiron_2500

Hello there!

A crack has developed along the top of the seat post lug of my 1987 ALAN. (When I bought the bike second hand in 2010, the crack was one third of what it is now, stemming from the seat post. Over time, it developed into what you can see here.)

I have accepted that this means the failure of the frame, or else hanging it on the wall (god damn, it's beautiful!). Yes, I know that these frames can't be welded; and yes, I have a steel-framed bike. But I was wondering if I could wrap a hose clamp around this lug, and use the frame for gentle rides, until failure occurred.

However, I could only do this if the failure was slow and safe (e.g. the top tube started to rattle), and not if the failure was to be sudden and violent (e.g. the top tube suddenly separated from the lug, half of the bike lurched forward, and I fell into the front wheel and the road).

So, does anyone have the experience and/or engineering know-how to answer? What would it be -- slow or sudden failure?? Help would be greatly appreciated!!





^ The crack up close.


^ The crack from further back.



^Assorted hose clamps--up to the task?

wojowojo16

I would not trust my life on a $0.45 hose clamp...

1st Post...woohoo...

I'm by no means an expert, but I am mechanically included....that is not a solution I would be comfortable with. Those hose clamps tend to slip if over tightened, they are meant to hold a rubber type of hose in place, nothing more.

bikemig 

+ 1 on this first post.

308jerry

It appears to be a complete failure. You know about it and have been watching it. Now the catastrophic part or how big of a total catastrophic failure is up to you. That thing is toast, hang it on the wall......

randyjawa 

To dangerous to ride, in my opinion. Though it can break one's heart, sometimes you have to bit the bullet and retire the frame. Bummer!

Sapperc

Get it repaired at a professional frame shop. Spend the money to restore it or stop riding it. That is an accident waiting to happen.

blamester

That can be repaired. But it could easily go wrong.
You gotta have a plan.
The hose clamps are not a good idea tho clamps may be an option. It's a permanent repair you need not temporary.
If you can't do it yourself bring it to a few places who might and see what they think.

Last ride 76 

No I don't think hose clamps are remotely up to the task. I use them in my work and know their limitations. Don't expect them to do anything helpful if that joint fails.
Where I think you could find stop-gap gap relief, is with 1/2" single layer woven nylon webbing straps. Bike would look ungainly, and ugly as sin, by the time I felt I had secured it sufficiently, but I think, properly done it would be safe to ride.
Personally, I would only use this as a stop-gap, until I got a replacement frame.
Perhaps more appropriate as an emergency wilderness solution.

davester

It's dead, Jim.

jeirvine 

Those lugs are glued to the tubes. I don't think the strength of the glue was the problem with Alan frames, but rather lug cracking like this. I don't see why the crack couldn't be similarly glued together. You'd need to clean it out, and find some sort of appropriate epoxy that could be flowed in. But I bet it could be done and be fine, if done right.

3alarmer 

...I'm uncertain if this is appropriate in this case. One of the characteristics of various space age adhesives is that many of them will only work within certain tolerances. So it's entirely possible that the expansion of the lug as the crack progresses has affected the fit between the lug and the frame tube beyond whatever space age adhesive was originally used to join them. I don't know enough about the glue used to further opine.

Other than to say I wouldn't ride that to the grocery store.

sdn40

Nine injury free years with a cracked lug is a damn nice run. Are you sure you want to push your luck ?
Sometimes one can dabble outside their area of expertise. Sometimes not. Which one do you think applies here ??
Expert frame builder for an evaluation, or bust

Paletti

honestly id be cheaper and safer to just buy a new frame. Those don't fetch too much. No way I'd ride a bike with a broken lug.

TenGrainBread

The only way to fix it safely would be to dissolve the epoxy, remove the lug from the tubes, and either replace with a new lug or do a TIG weld repair on the crack, which would involve welding with aluminum filler rod, heat treating, and then sanding and polishing down to the original profile and finish. Then the lug would need to be re-epoxied back onto the tubes in an appropriate fixture. Unless you're willing to spend thousands of dollars on this repair, it's not going to happen. You can't just bring this to your local framebuilder to have repaired. Most framebuilders do not weld aluminum, and do not work with epoxy construction. Even if you approached a seasoned aluminum framebuilder like Ventana or FTW, I doubt they would take the project on as it involves a glued frame.

It's just a bike. There are others that will ride just as well. Hang it up and start a new project.

scarlson 

ALAN frames were "screwed and glued" meaning that the tubes had a sort of tapered thread (similar to National Pipe Thread (NPT)) that was right-handed on one end of the tube and left-handed on the other end, allowing the frame tubes to be screwed into the lugs like a turnbuckle. I think this is why they broke in this way. The lugs are either cast or forged, and not great performers in tension, but they're forced to take a constant sorta tensile preload from the tube being screwed in until the lug stretches around its circumferance (closer to yielding, takes less force to put it into yield).

Regarding Tengrain's comment, you may not even be able to weld the alloy of aluminum these are made of. Lots of older aluminum stuff was Dural, which is a trade name for 2024 series aluminum alloy (contains lots of copper), which is not weldable (many plane parts are made of it, and they rivet those together for example). Even if it isn't Dural you have no idea what alloy it is so you have no idea what filler to use to get a decent weld, and you only have one shot so you can't experiment. No welder would do it for anyone other than him or herself, for a laugh.

In my experience machining metal, you MIGHT be able to fit what is known as a "corset" (two alu half shells that can be drawn together with bolts) around the lug and squeeze it together as a repair. You'd need to machine this to fit the lug exactly, and maybe machine the lug to a uniform surface to better interface with the "corset". A tall order. Not worth it. I would do it on my bike, again, for a laugh, but I would never do it for anyone else. It might last a week, might last ten years. They'd sue me when they ignored the warning signs and it failed on them.

If you love the ride of your ALAN you might want to consider the possibly more reliable, definitely cheaper, Vitus 979. These weren't screwed together, just glued, and the tube fits outside the lug, which I think is a better design. Lots of ALAN frames have cracked lugs but I've never seen a Vitus 979 with a cracked tube at a joint. The normal (very rare) failure for a Vitus 979 is to come unglued, which is quite uncommon for the normal aluminum ones. Steer clear of the "carbone" though.

In conclusion, the "screwed and glued" construction trades one failure mode (coming unglued, as the non-screwed Vitus 979) for another (cracking at the lug). Pick your poison. I love the ride of these old bonded frames, but they're not going to last forever.

Dan Chase

Hate to say, that frame as dead as the Dodo`s... these early carbon/alloy frames are prone to failure - even if it just starts to creak you should consider getting off... if one joint is failing this bad the others arn`t far behind - I guess you`ve seen the pics of other Alans and Look frames letting go when they fail? I have a bairly ridden `86 Look TVT and its in perfect condition, but I still check it all the time and ride it with some caution (though it is the smoothest riding frame I have...)

Sorry, Dan.

gugie 

Scrolled down to see if anyone had said it yet, you beat me to it.

Aluminum cracks, catastrophic failure could be right around the corner, and will give no warning.

cudak888 

Intact and NOS ALAN frames are out there. Hang this one on the wall and transfer the components to another.

Then await the impending doom on frame #2 (Sorry, I don't have faith in these).

-Kurt

delbiker1 

A safe failure? With a bicycle you will be riding? I

non-fixie 

A friend of mine is an Alan fan and an avid rider. He owns quite a few, with and without cracks and told me he's not particularly worried about the cracks ("they all do that"). He was still alive three weeks ago.

79pmooney

There is a permanent repair you could do. Wrap the lug with carbon fiber and epoxy Use unidirectional CF and encircle the lug at the crack. If I were doing it, I'd also wrap the rest of the lug, using layers in several directions to spread loads. With enough CF wrapped around the cracked area to mimic the original lug, the lug will go on long after the bike has died of other causes. And with skill and care (and careful masking, the job could be done to look quite good (though quite different from the rest of the bike. But when you are riding, it is hidden between your legs so there is that.)

This does require both research and skill. If it were my bike, I might well do it. (I saved a Reynold 501 sport Peugeot that way that had cracked both chainstays just behind the support. Extended the wrap both back along the chainstay a few inches and forward, around the BB and up onto the seat tube and down tube. Put 8000 miles on the repair (until I retired the frame for other reasons). After the repair it was the world's stiffest BB'd Peugeot. Fun ride! Now I do have some skills in that area. Built many polyester fiberglass boats from barrels of resin and rolls of mat, cloth and roving. And a lot of furniture and other items from wood and boatbuilding epoxy (and a boat or two). Not much CF but it is just another slightly harder to work with fabric.

Ben

RobbieTunes 

My Centurion Carbon-R has suffered a similar failure. My first indication was a slight shimmy in the front end, that didn't seem to go away. As the tubes loosen in the lugs, I think you'll inch closer to a sudden let-go.

skiron_2500

Thanks a lot for this. So, it sounds like there would be some warning signs from the frame.

How much riding did you do / how much time elapsed between the crack appearing and the shimmy beginning?

(I've already bought a replacement frame--a Vitus 979--and was wondering if I could use the bike gently until the Vitus arrives in the post.)

skiron_2500

Fascinating, thanks! After this frame has been hung on the wall for a while, I think I might have a go at the project you describe. It would make for an interesting custom bike, maybe a bike for running local errands. I've got quite a good hand for re-upholstery, and have 'wrapped' armchairs and other pieces of furniture before, along with customising bags and clothes, so it might well be something I could do. Thanks again for sparking such an interesting idea!

skiron_2500

Three weeks sounds good! That's about how long my replacement Vitus frame will take to arrive in the post :'-)