Cracked frame - how safe is this?

[Wyatt Earp]

If you are as old as I am you just call it SLX

You see, I am old enough to have be one of the blessed owners of these Columbus SLX tubed bikes

[KABOUS]

They are pretty bombproof are'nt they ? They just don't like the sweat when you use them on a trainer- Good idea to wax them and rinse after a sweat session.

[Danger Dassie]

You see, I am old enough to have be one of the blessed owners of these Columbus SLX tubed bikes

 

I had a Bridgestone with Tange tubing ... *nostalgia*

[Daideron]

Thank you mr Bornman, I appreciate your input. I was just curious as to what you would think of the wear and tear on those carbon lugged titanium frames. You say they present their own problems though? Would you care to elaborate on that as I am interested in hearing what you mean?

Christie? I agree with you on aluminium. Personally I love a well made Aluminium bike. The Cannondales offer such a nice ride (the older CAAD3's and 4 are what I rode) and so responsive. However that said I do still love the ride of a nice steel bike. Danger Dassie, I had a Colnago in the mid 1990's with a Tange tubeset bought from Alan van Heerden cycles. Was surprsied to see it was not Columbus, but Alan assured me it was just as good if not superior to the Columbus tubing. Oh, and if anyone has an old steel Bianchi "MAX" frameset, or a Merckx "Leader" in a size 54/55cm please let me know?

 

In the early 1990's when Titanium was all the rage, the Merlins were such a sexy sight! The unpainted tubes were like nothing I had ever seen before! I remember reading an article in the American Bicycling magazine where they had done a review on all the latest fanciest exotic bike parts. One of the parts on test was a pair of Carbon handlebars, and I remember them saying that they flexed so much that the testers were scared riding them! Now, 20 years down the line, I cannot remember the last time I rode without a carbon bar! Where will we be in the next 20years?

Mr Bornman, whats your take on a Magnesium frame? Ala the Kirk's from the 1990's?

[Minion]

Thank you mr Bornman, I appreciate your input. I was just curious as to what you would think of the wear and tear on those carbon lugged titanium frames. You say they present their own problems though? Would you care to elaborate on that as I am interested in hearing what you mean?

I think one of the problems is that bonded lug is a weaker point in the frame. The Ti-epoxy bond in the lug is not as strong as the epoxy-epoxy bond on a carbon-carbon lug and definitely not as strong as the brazed bond on a steel-steel lug.

 

 

On the subject of carbon-Ti bike, the Independent XS with carbon tubes and Ti lugs sits very high up my list of desirable bikes:

http://www.ifbikes.com/OurBikes/Road/XS/

[Johan Bornman]

Thank you mr Bornman, I appreciate your input. I was just curious as to what you would think of the wear and tear on those carbon lugged titanium frames. You say they present their own problems though? Would you care to elaborate on that as I am interested in hearing what you mean?

Christie? I agree with you on aluminium. Personally I love a well made Aluminium bike. The Cannondales offer such a nice ride (the older CAAD3's and 4 are what I rode) and so responsive. However that said I do still love the ride of a nice steel bike. Danger Dassie, I had a Colnago in the mid 1990's with a Tange tubeset bought from Alan van Heerden cycles. Was surprsied to see it was not Columbus, but Alan assured me it was just as good if not superior to the Columbus tubing. Oh, and if anyone has an old steel Bianchi "MAX" frameset, or a Merckx "Leader" in a size 54/55cm please let me know?

 

In the early 1990's when Titanium was all the rage, the Merlins were such a sexy sight! The unpainted tubes were like nothing I had ever seen before! I remember reading an article in the American Bicycling magazine where they had done a review on all the latest fanciest exotic bike parts. One of the parts on test was a pair of Carbon handlebars, and I remember them saying that they flexed so much that the testers were scared riding them! Now, 20 years down the line, I cannot remember the last time I rode without a carbon bar! Where will we be in the next 20years?

Mr Bornman, whats your take on a Magnesium frame? Ala the Kirk's from the 1990's?

 

Edman said it all.

 

As for Magnesium? I doubt there was ever a pure (or high content in anyway) magnesium frame. It was most likely an aluminium alloy with some magnesium in it. Magnesium is more suitable to castings and forgings than drawn tubes. American Classic once marketed a magnesium rim. It was aluminium with some Mg in the mix. I think your example frame would be the same.

 

Magnesium and Scandium is wildely misrepresented in most components. It is usually mostly aluminium with tiny bits of mag and scandium in the alloy. Other stuff found in common aluminium alloys is vanadium and zinc, but none of those sound as sexy as scandium and hence, are not mentioned.

[Christie]

I've got some magnesium samples on my desk. One is 99% Mg, and the others are different Mg alloys with a bit less Mg content. We did a series of tests on them in our lab. The pure sample has an amazing amount of structural damping, but it is very very flexible and weak - I can bend it by hand. The other Mg alloys are all stiffer and stronger, but they have poor damping - the same or worse than the aluminium reference sample I used. My conclusion was that Mg offers no real engineering advantage over aluminium and carbon/epoxy, unless it is for a component where low mass is needed and strength is not important, and has a geometry that requires casting. In a cycling context, using Mg for bicycle frames must be connected with some form of marketing BS, I suspect.

Mg has some extra problems, like salt water corrosion and it is dangerous to work with because shavings are flammable.

 

I think an interesting frame material would be aluminium-lithium(2-3%) alloy. These alloys have got 10% lower density and 10% higher stiffness than standard structural alu, but nobody has made a bicycle frame out of it yet. I guess in the carbon era, investing a lot of $$$ to make a high-end alu frame won't pay off. Also, Li dust is explosive, like Mg.

[Big H*]

Edman said it all.

 

As for Magnesium? I doubt there was ever a pure (or high content in anyway) magnesium frame. It was most likely an aluminium alloy with some magnesium in it. Magnesium is more suitable to castings and forgings than drawn tubes. American Classic once marketed a magnesium rim. It was aluminium with some Mg in the mix. I think your example frame would be the same.

 

Magnesium and Scandium is wildely misrepresented in most components. It is usually mostly aluminium with tiny bits of mag and scandium in the alloy. Other stuff found in common aluminium alloys is vanadium and zinc, but none of those sound as sexy as scandium and hence, are not mentioned.

 

I have a reloading press that has Strontium in the alloy. A lot af that around as well?

[Crash Gordon]

Ah, right. Will 10km running once a week get me a sub three?

If you run fast maybe.....

[Li Mu Bai]

If spell check don't pick it up, it's correct.

 

set your spell check to "English" then...

[Caerus]

Here is a hydroformed Titanium beauty

[Johan Bornman]

Also, Li dust is explosive, like Mg.

 

 

That should quell that old cliche of bullet-proof this and that, for once and all.

[Daideron]

Thanks for the feedback Mr Bornman, really appreciate it. Find it very informative.

[maddox]

I noticed a couple of cracks on my Litespeed (on both side of the chainstays) on Saturday. Still rode 1Tonner with no problems. I'm now in a predicament as to whether I continue riding this (up until DC). A warranty claim could take months with Litespeed and I don't have a second bike.

 

For those of you that know titanium and have experience with cracks please let me know your thoughts on how safe this is to ride.

 

thanks.

 

 

I'd like to have this frame fixed. Can anyone recommend someone in Cape Town?

[barrykm]

Thanks guys...my dream of one day having a custom-built titanium frame has now been somewhat moderated..

 

(see http://www.enigmabikes.com/)