Carbon fibre v Titanium

[Si]

M'lud, I rest my case for the defence of aluminium and carbon fibre...

If that's yer case then I think that Ti is found not-guilty what you describe is hardly lab conditions - we have no idea if the same forces were going through the two bikes or not so it's pretty meaningless. Furthermore, in that photo it's the weld that has gone not the tube - you can weld anything badly and it doesn't matter how strong the tube is, it'll be no stronger than the weld.

I, too, know someone who has busted a Litespeed - he did it by repeatedly doing head high jumps and taking it down a DH course (despite it being a light weight XC race bike) over a number of years - I was amazed that it lasted that long, and certainly wouldn't be put off by the result of his mistreatment of it!

My personal experience is that I've had equal numbers, more or less, of Alu and steel bikes over the years. Have, so far, snapped six or seven Alu frames but no steel frames. Now you might think that this would put me off Alu, but no, my two currently most used bikes are both Alu. That's because I know it's not the material, it's the build quality that matters most - I've two old American built Zaskars and I think that they are as comfortable as and as strong as any of my steel bikes. They were top of the line race bikes in their day but I'm more than happy to tour or load lug with them.

[gilesjuk]

It's not quite that simple I'm afraid. In lab tests done a while ago (C+) there was no discernible difference caused by the material - all differences appeared to be down to the way that a frameset was built.

On road bikes fair enough, there's probably hardly much difference other than weight. But I can certainly tell the difference between my Ti MTB and my Steel one.

The titanium frame and forks are very lightweight, the whole bike is about 10kg (and it's a 29er). It skips around on the surface of the trails and the carbon rigid forks aren't that good at soaking up the bumps. It flies up hills.

My steel frame (this is with the same wheels and tyres too) feels a lot more planted, it grips much better and the steel forks flex really nicely to reduce the bumps.

On a 26er aluminium frame with rigid forks my arms would get battered senseless on bumpy trails.

[hamster]

I would have agreed with this in the past.

Two years ago I built up an Alu Singlespeed (Kona Cindercone) with steel rigid forks. I was amazed to discover that it didn't ride like a road drill. Later I swapped the entire setup to a high end but slightly flexy steel frame (Marin Pine Mtn) - forks, wheels and all. My times for my standard ride were the same, and frankly in the dark I would have been unable to tell the difference.

I don't know where this takes the discussion, other than to test ride and decide which bike you like best - and not to worry about what the frame is made from.

[Si]

It's not quite that simple I'm afraid. In lab tests done a while ago (C+) there was no discernible difference caused by the material - all differences appeared to be down to the way that a frameset was built.

On road bikes fair enough, there's probably hardly much difference other than weight. But I can certainly tell the difference between my Ti MTB and my Steel one.

The titanium frame and forks are very lightweight, the whole bike is about 10kg (and it's a 29er). It skips around on the surface of the trails and the carbon rigid forks aren't that good at soaking up the bumps. It flies up hills.

My steel frame (this is with the same wheels and tyres too) feels a lot more planted, it grips much better and the steel forks flex really nicely to reduce the bumps.

On a 26er aluminium frame with rigid forks my arms would get battered senseless on bumpy trails.

I'd suggest that much of it is down to build rather than material, after all you can get just as big a difference in perceived* feel between two bikes built of the same material.

*excellent, and quite entertaining, article by Brant Richards about this a while back

[Chodak]

something puzzles me - where are all the titanium forks? The stuff is springy, and resistant to fatigue, corrosion and damage, surely ideal for forks? But most titanium bikes have carbon forks, susceptible to damage. The Sabbath tourer has steel forks, as I remember.

Colin, the Sabbath tourer on the Spa website comes with steel fork as standard, Hewitt offered me the choice of forks because Paul had it custom built with lazer etched badges and custom sizing & geometry at no extra cost and just 1 weeks delay in the build process. I chose some carbon cross forks because I don't intend carrying front panniers and because they are comfy, light and much cheaper than Ti. They don't have front panniers, but they do support canti brakes, fat tyres (28mm to 37mm) and mudguards. I've seen Ti forks in Spa once, and Justin Burls offers them too as a special. They are however not cheap - c£400 from Burls I recall!

M'lud, I rest my case for the defence of aluminium and carbon fibre...

Gearoidmuar, let me riposte with Sheldon Brown's view on the matter:

"Titanium, while costly, is generally the most durable material choice, but aluminum and steel are excellent. Nobody's making carbon fiber touring bikes as far as I know, yet."

I would not for one minute say that I'm expert on all frame materials and designs and as I said in my first post, it's primarily down to the designer and build quality rather than the material alone, though I would only go for a carbon bike if I was a racer rather than a 'tourist' or similar. I do agree with Colin that audax bikes probably fit the bill rather than tourer for the kind of tyre sizes the OP was suggesting.

[Gearoidmuar]

M'lud, I rest my case for the defence of aluminium and carbon fibre...

If that's yer case then I think that Ti is found not-guilty what you describe is hardly lab conditions - we have no idea if the same forces were going through the two bikes or not so it's pretty meaningless. Furthermore, in that photo it's the weld that has gone not the tube - you can weld anything badly and it doesn't matter how strong the tube is, it'll be no stronger than the weld.

Well we have one valid comparison. The carbon fibre fork took the whack first and didn't shatter. And, I can assure you that both bikes took identical bangs. But the fact that the weld went is a condemnation of titanium because it's almost impossible to weld well.
I've had 4 steel frames crack and one aluminium.

[hubgearfreak]

Furthermore, in that photo it's the weld that has gone not the tube

that may be so of the cross bar, but the down tube looks like it may have a small crease in it?

anyhow, you're quite right that one anecdote isn't at all significant.

[mankymitts]

It does make a huge difference what the frame is made of.


Titanium has some of the qualities of steel but lighter and doesn't rust. But frames can crack around the welds. It depends on quality and how you ride.

gilesjuk - do you have more info/sources of info on Ti frames cracking at the welds? I am now on my 3rd Ti frame, the other 2 having cracked at the weld around the bottom bracket. I am grateful for the lifetime warranty and service that the manufacturer provides but when I have made the warranty claims I am told that they have never heard of this happening. I was beiginning to think "Is it me?" until I saw your post.

MM

[Gearoidmuar]

I saw a post once from one of the Thorn people who said that they all crack (the titanium frames)

[PH]

But something puzzles me - where are all the titanium forks? The stuff is springy, and resistant to fatigue, corrosion and damage, surely ideal for forks? But most titanium bikes have carbon forks, susceptible to damage. The Sabbath tourer has steel forks, as I remember.

You'd think it was the perfect fork material wouldn't you, I did.
I bought ti Audax forks from Enigma this time last year, they were recalled a few months ago with concerns about build quality and they've recently decided not to offer replacements as they can't get any made to their satisfaction.

[PH]

[color=#BF0080]
I've posted this before, but I and a friend were hit by a car which did a U-turn across us at speed as we were passing it, it being in a parked position.
My hand was wrecked by going through the windscreen and he somersaulted over the car and lay unconscious on the road for a couple of minutes.

Each time you post this it makes me laugh. There's a whole set of criteria for choosing a bike, but if you have a collision with a car all bets are off, anything can happen.
Maybe it was the spring of the ti frame that somersaulted him over the car, rather than going straight into it

[mark a.]

Mountain bikes have been doing ok with carbon frames for years. Certainly carbon forks for MTB use have been generally fine and dandy - and they take a hammering. There are also YouTube videos of people whacking carbon frames with hammers to minimal effect but the aluminium one denting immediately.

However, for every story of a carbon frame withstanding the mother of all crashes, there is another story of carbon bikes exploding just by looking at them. Also, whereas people have a general idea of what effect a slight dent would have on a steel or alu frame, the smallest nick in the outer lacquer of the carbon frame causes consternation.

Ti MTBs seem to be growing in number too. However, the whole "frame for life" idea has long since been thrown out of the window with those weld cracks.

Me? I'm not sure if I can even afford an aluminium MTB, let alone carbon or titanium so it's all academic.

[Gearoidmuar]

[quote]Each time you post this it makes me laugh. [quote/]

Well keep laughing because everytime someone posts nonsense about how indestructible titanium is, you're gonna see this picture. I feel duty bound to let people know about this. When I researched this on-line, I discovered that there was, in the practical sense, a huge problem with titanium. It's theoretically wonderful, but weld... not great in practice. Titanium is to metals what Gordon Brown is to British politics. Huge brain, fantastic experience, dogged...... but what's happened the economy??

[hamster]

Any frame regardless of material will typically break at the weld area - it's where the load is, after all.

For any weld in any material, if it is done badly the tube wall is thinned. This further weakens the most highly stressed area. As a general rule, welded areas are weaker than unwelded. There have been bad Ti frames out there with poor weld quality, just the same as bad Alu or steel ones. A poorly-designed and fabricated frame will break, a well-designed one made under controlled conditions will not, regardless of material.

Looking at the broken Ti frame in the picture, bearing in mind the heavy crash damage, it's not surprising. It is very reminiscent of 531db crashes. It is a pity that the forks didn't break and sacrifice themselves - but carbon forks are probably a bit over engineered as this forum (and others) is full of carbon fork horror stories.

There is no 'wonder material' that is everything to everybody. What matters is sensible material selection for purpose. I have steel, Ti and Alu bikes. They all ride well for their intended job. There is no absolute wonder property about a single material - that's manufacturers' PR or lazy journalism.

[Si]

M'lud, I rest my case for the defence of aluminium and carbon fibre...

If that's yer case then I think that Ti is found not-guilty what you describe is hardly lab conditions - we have no idea if the same forces were going through the two bikes or not so it's pretty meaningless. Furthermore, in that photo it's the weld that has gone not the tube - you can weld anything badly and it doesn't matter how strong the tube is, it'll be no stronger than the weld.

Well we have one valid comparison. The carbon fibre fork took the whack first and didn't shatter. And, I can assure you that both bikes took identical bangs. But the fact that the weld went is a condemnation of titanium because it's almost impossible to weld well.
I've had 4 steel frames crack and one aluminium.

You've no way of knowing that it was an identical impact - so the comparison is totally invalid.
Ti is not almost impossible to weld - the number of applications that use welded Ti show this. It might be harder than boggo steel, but so is Alu and the quality steel tubes.
As I've said, small scale, and abstract anecdotal evidence is meaningless. To try to draw any conclusion based upon the odd snapped frame here and there really is a waste of breath. You don't know the histories of the frames and you don't know what forces were being applied when they failed - thus it's just random unsupported speculation.

Sorry, but your case has been well and truly laughed out of court and is beating a hasty retreat with tail between legs!