Johno59

I work for the world's biggest aerospace composite structures manufacturer. We do a lot of resins and adhesives for bonding of glass fibre, carbon fibre to various metals as such as Aluminium and more and more carbon to carbon bonding. In this case the resin bond under the lug has failed and the lug is not strong enough to support the load by itself. Repairing the crack will do nothing, a clamp would be extremely reckless. To repair the join you would have to burn off the bond for the seatpost, seatstays as well as the crossbar. Clean everything, pickle the surfaces with cancerogenic solvents, replace/repair the lug, reapply specific cancerogenic resins, brace it in a jig, cure the entire frame in an ATEX-rated oven at a specific temp for a specific time (any paint or decals would be destroyed) and off you go. Keep the $300K equipment needed to do this legally as the other lugs are probably on the way out as well.

RobbieTunes

I probably rode it about 300 miles, because I thought the shimmy was a loose headset. I tightened the headset, and most of it went away, and it only seemed to be at lower speeds, like approaching a stoplight, etc.

Tightening the headset only covered up the issue, but the crack allowed the glue joint to become loose over a short period of time.

I didn't catch it until I decided to change the headset. I popped the old one out, and the new top/bottom cups slipped right in. Hmm, I got a better look at it, and the cracked head tube lugs had allowed the head tube to separate top and bottom from the lugs, instantly longer!...

squirtdad

in these situations, ask yourself: How good is my health insurance and how is my pain resistance? you may ride fine, or you may have a surprise failure, odds may be in favor of the former, but in the event of the later are you prepared for the end result is it worth it big picture

ymv

79pmooney

Or do it as I suggested for around $25. My repair of that Peugeot cost me near nothing, Someone handed me a piece of CF uni years ago. I keep Gougeon Brothers epoxy on hand. I wasted a cheap home depot brush, used masking tape and cut up produce bags. The Op gets to keep all the paint and graphics. True, he doesn't get to keep the $300k of tools but this same approach wold work on the other lugs/BB just as well. (I did say and will repeat that research and skill are needed.)

Ben

Munny

I've a Vitus 979 that I kept for experiments.
The frame got the horizontal tube starting to get loose, was repaired under waranty by Vitus before failing again.

No 3 weeks warning but immediate sanction with 2 main tubes bent and the owner send to hospital.

I encounter about the same percentage of 979 with issues as Alan's

Currently I own a 787, bought new and an Alan.
Crossed fingers, none of them have an issue
However, I would feel more safe on a failing Alan that on a failing Vitus
On the first one, you'll get safely home. On the second one, potentially ...

dddd

I repaired an Alan frame with this same exact failure at the seat lug.
I took a cast-aluminum seat tube/post clamp that I stretched open, closed over the lug socket and bolted shut using the tension of an M6 bolt.
It seemed like a durable fix and I remember the rider used it for a couple of years of moderate riding before moving out of the area.

These frames are subject to multiple failure points including the head lugs, so an eye should be kept on these lugs.

Dan Chase

I think most of you are a bit far of the mark here...

1. Professional advice is the frames junk.
2. A replacacement frame is few hundred dollars for a good one.
3. The personal cost of trying to pick yourself up after the frame catastrofically smashes your bones into the tarmac when you least expect it will cost a lot more than the frame.
4. We all know if one joint is failing, the rest are about to follow
5. Shoving a bit of two part into the crack with some ebay fibre wrap around it is not a fix.
6. This is not a time for thrift - REPLACE THE FRAME!!!

mpetry912 

A lot of good opinions here. Thank you for at least posting a picture. Whether you repair and ride this frame, or chose to scrap it, has a lot more to do with your acceptance of risk than the viability of any repair suggested above.

Were this a historically significant frame - or a very valuable one - it might be worth the time and effort to do a repair.

I think there's general agreement here that this frame is toast and finding a new / alternative one is your best and safest option.

Mark Petry
Bainbridge Island, WA USA

skiron_2500

Hey, I am replacing the frame. This thread is about whether I can ride the bike until the replacement arrives / till I change the parts over to replacement frame / whether I can use the frame for gentle cycling to the newsagent in the future.

skiron_2500

OK, interesting. I think that I will stick to my second-favourite outdoor activity, hiking, until my replacement frame arrives in the post (I can't use my backup ride, a steel-framed bicycle, because it's at my mum's house). But if I do need to use the ALAN for something urgent, I'll either try this approach or else the nylon-webbing wilderness-technique mentioned above.

Dan Chase

The answer should be no, don`t ride it:



Frame colapse of alan rather than a vitus, but it wrecked the rider...

Johno59

Wrapping carbon fibre around anodized aluminium and applying an adhesive would not hold. You would have to remove the oxidized surface layer on the aluminium and treat it with a powerful solvent to enable the resin impregnated carbon to bond to the lug's surface.
After that you'd have to press the carbon fibre/resin matrix in a mould or use a vacuum pack in an autoclaved oven so as to prevent any air bubbles degrading the final result. Carbon fiber structures need to be monocurquic ie the whole structure takes the load, not just the lug. To get that there, there can be zero voids in the layers making up the final composite layer - after all CF is just another plastic made of glue and burnt nylon.
Don't get me wrong, it is an incredible material with astounding performance so superior to all other materials but it has to be made correctly otherwise you'd be better off using fibre glass and glue.
Mind you treating the outside surface won't help the fact the tubing is no longer attached to the inside of the lug.

dddd

Those were the early days of aluminum frames made in pretty big numbers, and as such were less well-developed in terms of achieving good lifespan. They were marketed as being reliable, but fell short in that endeavor (at least in relative terms).

From my recent shop efforts:
There are other failings of using oversized materials, as when chainline is compromised by a front derailer's inability to retract as far as might be needed when using a triple crankset.
It recently took me a fairly extensive amount of time and effort to correct the excess chainline offset of my Trek hybrid's triple crankset, due in part to the oversized 35mm seat tube diameter. I had to first establish that a traditional bottom-swing front derailer would be able to retract 2mm further inward than the bike's original top-swing front derailer, and then I had to exploit this benefit by selecting (and precisely re-centering using a fixed-cup spacer) an 8mm-shorter (113mm vs. 121mm) Octalink ES-30 bottom bracket.
With all of the test-fits and measurements, plus searching for the exact-best bottom bracket and front derailer, I spent hours achieving all of a 4mm reduction in crankarm position at each end of the bottom bracket.
It sure is nice now being able to smoothly use a little more of the cassette's range without shifting off of the big ring(!), but I can't recall ever having to try so hard at this with any steel-framed bike.

sabele

I have to agree it is now wall art. I wouldn't put my ass on it.

Marci

I believe if it was a horse they would call that a widow maker. Is your life and accident insurance paid up? Oh and if it does fail will the rest of the components of the bike be worth transferring to the new frame? Or will they be toast too. Not to mention the months of pain... I've had broken bones and injuries, not worth it. Some things you do not heal from.

CliffordK

There is this company that apparently deals with Vitus repairs.

Untitled Document

It woudn't hurt to contact them about the Alan.

Even if they don't want to take on the project, they may have some ideas.

Miele Man

Yes you can ride that BROKEN lug frame with the now loose top tube that COULD fail at the head tube at any moment you are riding it. The RISKS FAR OUTWEIGH the the benefits of trying to keep that frame alive for a short time longer. It's now WALL AT only.

You can NOT PROPERLY REPAIR that frame without disassembling the seat lug from the frame.

DO NOT RIDE IT!

Cheers

79pmooney

Apparently you missed the part where I said "(I did say and will repeat that research and skill are needed.)" even though you quoted it.

79pmooney

If you wrap the lug (with skill) with enough CF to match the strength of the lug at the area cracked, that lug becomes simply a spacer. The CF is far stiffer so it takes all the load. With a good wrap (see any Calfee bamboo bike for great examples) that repair will be permanent and since the it is separated from all the other lugs by long lengths of tubing, the increased stiffness there is not going to send additional stresses to the other lugs. I am not talking about dressing up the outside of the lug, I am talking about effectively replacing the lug's function with a new CF lug wrapped around the original. Yes, that original lug is still the connect with the tubes. But the job of keeping that lug tightly screwed around those tobes will now be done entirely with the CF.

cudak888 

Every single Alan and the multitude of rebadged Alan frames out there are cursed to a similar fate, and it only becomes more and more prevalent as the years go on.

These things belong up there with the AVA and ATAX death stems and the Viscount death fork. Ride at your own risk, and when it cracks, just put it away for good.

-Kurt

CliffordK

The top tube is mainly under compression, except a few rare cases such as during a crash. And, the down tube is normally under tension.

The frame may well hold together under normal riding, although one could get odd behavior such as a shimmy descending, and could be stressed under hard front braking (use the back brake).

Anyway, it may well be rideable, but inadvisable.

cudak888 

Some riders tend to push themselves up on the saddle by pressing against the bars in the drops. Wouldn't you say that hould surely offset some of the compression, if only for a moment, just like the brakes (as you noted)?

Both are enough to get a rider in trouble.

-Kurt

Fahrenheit531 

I just think it's cool you love the bike enough to consider any and all of this stuff in the name of just a few more rides.

But let it go, man. Gotta be another one out there.

cudak888 

One of the LBS has been sitting on no less than three of them since new - a few ALAN badged and a few Guerciotti badged. They've been hanging up for at least 13 years just by my watch, never mind how long they've been there prior to myknowledge of them.

Nobody in their right mind will pay NOS prices for one, so they'll sit for another 13 years, presumably.

-Kurt

CliffordK

I don't know. It would be interesting to build a bike with a number of pressure/tension gauges around the frame, and put it through its paces.

I presume the "Slingshot" bicycles are stable enough to have actually made it into general production (road and MTB versions), although I'm not sure what they're like to ride.

A little different concept, with a hinge at the toptube/seattube junction, and a simple cable for the downtube. But tension on the DT means compression on the TT.



Looking at a normal double triangle frame, the chainstays/seatstays would act as a large lever/pivot, essentially transmitting the entire rider weight onto the TT compression. And, it may not be easy to interrupt that compression pressure.

I can't say what I would do if I was "car-free", and riding that bike as primary transportation. As it is, I probably have an old steel frame that I could move my components over onto in an afternoon, and discard that frame. But I might consider trying to temporarily stabilize the joint while waiting for a replacement frame to arrive. And ride slowly and carefully.