Titanium Road Bikes

[Le Velo]

Comedian, might be worth talking to the guys at paint my bike to get their opinion as they are very familiar with carbon cracks / repairs and might be able to point out if any of the issues you have with the frame is leading to failure
You could be in for a warranty replacement maybe ? Had the same issue / argument with Trek about a year ago with 2 cracks in the bottom bracket, rear stay and fork where the lugs are fused with the carbon

[Nobody]

Well I don't want to start a carbon hating thread in here. However, I've noticed that my current bike is a little flexible when I stand on the pedals. I've noted several times that over big bumps it flexes significantly and just thought this was a good thing. Anyway, today I stood there with the brakes on and leant on one pedal a bit. We noted that not only does the carbon crank bend, but the whole frame does an impression of a fish. I can see the whole thing bending and people looking from the front claim to see it twist alarmingly. Now I'm not going to panic, about this as...

There is an unfounded popularised belief that carbon does not fatigue. But there is evidence it does.
http://en.wikipedia.org/wiki/Carbon_fibre

Despite its high initial strength-to-weight ratio, one structural limitation of CFRP is its lack of a fatigue endurance limit. As such, failure cannot be theoretically ruled out from a high enough number of stress cycles. By contrast, steel and certain other structural metals and alloys do have an estimable fatigue endurance limit. Because of the complex failure modes of such composites, the fatigue failure properties of CFRP are difficult to predict. As a result, when utilizing CFRP for critical cyclic-loading applications, engineers may need to employ considerable strength safety margins to provide suitable component reliability over a sufficiently long service life.

Ti and steel will only last long-term if built strong enough for the rider's weight. It really comes down to getting something (at least) slightly overbuilt (depending on the quality of the build) if you want it to last.

[Comedian]

Very interesting nobody.

I just went down and compared to my bike to a current defy advanced and while on the same test it still flexed I would say it moved probably only half as much.

I really doubt I'm going to ever be able to say whether it has gotten worse with age or whether its just a dead fish frame.

[Nobody]

I'd be leaning toward fatigue. I'd doubt new frames are that much stiffer than a few years ago.

The good thing about metals is they generally will have the same feel/ride/flex over their life span. I've got a Giant CrMo MTB frame I bought in approx. 1991 which doesn't feel any less stiff than it was new.

[clackers]

There is an unfounded popularised belief that carbon does not fatigue. But there is evidence it does.

Well, let's put some numbers to it, then:

http://www.freewingmasts.co.uk/fwmtabl1.htm

It's all relative, but after a million stress cycles that stainless steel is down to less than half its original strength, the aluminium alloy to a third.

[Nobody]

There is an unfounded popularised belief that carbon does not fatigue. But there is evidence it does.

Well, let's put some numbers to it, then:

http://www.freewingmasts.co.uk/fwmtabl1.htm

It's all relative, but after a million stress cycles that stainless steel is down to less than half its original strength, the aluminium alloy to a third.

Thanks. Not a surprising result from a manufacturer of carbon masts. There appears to be results, but no link to the methodology. It's like Calfee with its "Technical White Paper" on carbon frames, which has been discussed before.
viewtopic.php?t=54908&p=832549

[Le Velo]

http://www.baumcycles.com/archives/1146
The story behind the bikes ..... maybe a little OT but still cool

[__PG__]

I changed the wheels to a set of hand built HED Belgium C2 rims on Chris King R45 hubs as the roads up here in the mountains are anything but smooth. The wheels are another story, suffice to say I believe these are every bit as good as the Fulcrums.

Out of interest, what benefits do you feel from the HED rims and do you think they are caused by the rim width or the different spoking patterns?

[warthog1]

There is an unfounded popularised belief that carbon does not fatigue. But there is evidence it does.

Well, let's put some numbers to it, then:

http://www.freewingmasts.co.uk/fwmtabl1.htm

It's all relative, but after a million stress cycles that stainless steel is down to less than half its original strength, the aluminium alloy to a third.

Thanks. Not a surprising result from a manufacturer of carbon masts. There appears to be results, but no link to the methodology. It's like Calfee with its "Technical White Paper" on carbon frames, which has been discussed before.
viewtopic.php?t=54908&p=832549

Are you still at it Nobody

This section does not cite any references or sources. (June 2012)

From that highly credentialed wikipedia link that you chose to cite as evidence of CF's fatigue limit

I saw this bit in it too

Carbon-fiber-reinforced polymer (CFRP) has over the past two decades become an increasingly notable material used in structural engineering applications. Studied in an academic context as to its potential benefits in construction, it has also proved itself cost-effective in a number of field applications strengthening concrete, masonry, steel, cast iron, and timber structures. Its use in industry can be either for retrofitting to strengthen an existing structure or as an alternative reinforcing (or prestressing material) instead of steel from the outset of a project.

[__PG__]

The issue with carbon fibre used in bicycles is the quality of the resin/expoxy used to glue it all together. For most carbon fibre items, this degrades over time so after a few years your carbon frame will be less stiff than when it was new. Manufactureres of higher-grade carbon (e.g. Enve) supposedly use a better epoxy/resin.

Or so I've been told.

[Comedian]

Well after much agonizing I've joined the Baum waiting list.

[Nobody]

Are you still at it Nobody

This section does not cite any references or sources. (June 2012)

From that highly credentialed wikipedia link that you chose to cite as evidence of CF's fatigue limit

You'll have to be more specific as I don't know what you're rattling on about. Whatever it is though, reference No. 3 at the bottom of the page should cover it (which I'm sure you've seen before).

I saw this bit in it too

Carbon-fiber-reinforced polymer (CFRP) has over the past two decades become an increasingly notable material used in structural engineering applications. Studied in an academic context as to its potential benefits in construction, it has also proved itself cost-effective in a number of field applications strengthening concrete, masonry, steel, cast iron, and timber structures. Its use in industry can be either for retrofitting to strengthen an existing structure or as an alternative reinforcing (or prestressing material) instead of steel from the outset of a project.

And?
Believe it or not, I actually read the article. I'm not trying to hide that CF has it's uses, just don't expect it to be long term fatigue fee when built into a bike frame.

[Nobody]

Well after much agonizing I've joined the Baum waiting list.

Well I hope you get your money's worth out of it. More likely to than spending the same amount on a carbon frame IMO.

[Rich-Ti]

...As long as it's built right in the first place, and doesn't crack...

[Le Velo]

Well after much agonizing I've joined the Baum waiting list.

Welcome to the club

[warthog1]

You'll have to be more specific as I don't know what you're rattling on about. Whatever it is though, reference No. 3 at the bottom of the page should cover it (which I'm sure you've seen before).

End of useful life/recycling

This section does not cite any references or sources. (June 2012)

Despite its high initial strength-to-weight ratio, one structural limitation of CFRP is its lack of a fatigue endurance limit. As such, failure cannot be theoretically ruled out from a high enough number of stress cycles

As you used that "article" to illustrate that carbon is susceptible to fatigue failure, i thought it pertinent to point out that it's author could have pulled it out of thin air.
Just being objective or was that objectionable

[clackers]

Not a surprising result from a manufacturer of carbon masts. There appears to be results, but no link to the methodology.

Well, I did third-year Materials Engineering at uni. All other things being equal, carbon fibre will be better at fatigue resistance than either of those materials. I'd be interested if you can find anything that says differently.

PS I have a foot in both camps, with a carbon roadie and a 'Steel is Real' one. Mixed marriages are so interesting!

[Nobody]

As you used that "article" to illustrate that carbon is susceptible to fatigue failure, i thought it pertinent to point out that it's author could have pulled it out of thin air.
Just being objective or was that objectionable

Oh, I see it now.

Also I was not saying it was susceptible to fatigue failure (although it probably is) just fatigue, which the mast link shows anyway (although optimistically as expected from a manufacturer).

[clackers]

although optimistically as expected from a manufacturer

Well, how do you know? You're the one wanting hard facts and figures. Show us they're false or optimistic!

[__PG__]

Well after much agonizing I've joined the Baum waiting list.

I've been in it since the middle of July. I hope you aren't in a hurry.

[Nobody]

Well, I did third-year Materials Engineering at uni. All other things being equal, carbon fibre will be better at fatigue resistance than either of those materials. I'd be interested if you can find anything that says differently.

PS I have a foot in both camps, with a carbon roadie and a 'Steel is Real' one. Mixed marriages are so interesting!

I've owned a CF bike in the past too. The other two materials being SS and Al, I'm in agreement. If I remember correctly SS is considered one of the most brittle steels (for lack of another good descriptor). Remember the below thread? Not too confidence inspiring.
viewtopic.php?f=34&t=51878

What we need is a fatigue comparison of say 4130 to CF. But the problem is, as soon as anyone posts a CF figure, being such a varied composite, someone else will say that it's a different structure/layup/epoxy etc or that it was last week's CF and today's CF is so much better now.

Although I have a good idea of what I think will and won't last and the reasons for it, it is still something difficult to conclusively prove here, other than showing personal experiences.

[Nobody]

although optimistically as expected from a manufacturer

Well, how do you know? You're the one wanting hard facts and figures. Show us they're false or optimistic!

Show us they aren't.

[Comedian]

Well after much agonizing I've joined the Baum waiting list.

I've been in it since the middle of July. I hope you aren't in a hurry.

I'm not expecting to see it until the middle of next year.

I just hope I can keep the current bike running until then.

[Nobody]

I'm not expecting to see it until the middle of next year.

I just hope I can keep the current bike running until then.

I'm aware that Baum is considered one of the best, but surely there are others you can buy from. Isn't there? They are often cheaper too.

[Comedian]

I'm not expecting to see it until the middle of next year.

I just hope I can keep the current bike running until then.

I'm aware that Baum is considered one of the best, but surely there are others you can buy from. Isn't there? They are often cheaper too.

Yep. But as you rightly observed I wanted a great bike that fits me made with the characteristics I value.

They are expensive but I spend a lot of time on the bike. I reckon they will be cheaper than the 3 year upgrade cycle the industry is pushing. . Plus I get to ride bike porn.