Titanium or carbon - which one for longevity?

Mad Monkey

I know that the ideal number of bikes is 1 more than you currently own - I have proven that since I took up cycling just over 3 years ago - first a mountain bike, then a hybrid (Halfords Carrera Subway 2), 1 year ago a road bike (Halfords Carrera Vanquish with Tiagra gear). Maybe I am fooling myself that if I buy a "good" road bike I won't want to change it every year, but at 53 I would like to buy a bike that will see out my cycling days, say 20+ years? I am thinking of something with a bias towards comfort and a relaxed cycling position rather than speed and an aggressive aerobatic stance - if I were buying a Specialized I would buy a Roubaix. I want a triple chainset rather than the double I currently use (if Shimano then Ultegra), because I won't find hills any easier as I get older.

Apart from commuting (which I would probably continue to do on the Vanquish) and holidays I mainly cycle through Essex countryside, typically 50-75 miles at about 15mph average, so nothing too adventurous. On holiday I do like a few hills! I weigh about 68 kilos, at the moment anyway, so with my weight and riding style I don't really sterss the frame.

The biggest questions is whether carbon fibre bikes have the kind of longevity I am looking for, or would I be better with Titanium? Since I don't stress the frame too much myself my concern is that poor quality roads might lead to a carbon frame fracturing. I am prepared to spend up to £2.5 - £3k (typing it that was seems less that £2500 - £3000), which will certainly buy me a Specialized Roubaix, but with an engineering background I have to admit I do like the thought of Titanium.....

Any thoughts/questions/advice would be greatly appreciated. Apart from the frame material - any suggestions as to which bike would suit my needs?

Thanks in advance for any advice.

ellieb

Put simply: Carbon may break in a crash, additionally, if you do have a prang it may sustain damage that you cannot easliy see. I doubt that any decent carbon frame would sustain too much damge just from a road surface.
Titanium does not corrode and as long as it is well designed & put together (see Litespeed thread) it should last forever. Just in terms of longevity, I would say titanium is the obvious choice.

Mad Monkey

Thanks Ellieb - I am aware I'm probably being too cautious about damage to a carbon frame, but after 3 Halfords bikes it's time to get a proper bike that I will want to use for a decent length of time

Will check out the Litespeed thread.

giant_man

You are being a little cautious I have to say; carbon frames are not as fragile as you may think. They don't just fall apart or crack unexpectedly, or at least shouldn't.

You can damage any frame in a crash of course, but as ellieb says, ti is more durable.

Monty Dog

If it's a keeper and you're not a hammerhead, then titanium is a great idea. That said, carbon bikes are not as fragile as people think - but they don't like crashing or impacts - but look at the pack in any road race these and they'll mainly be riding carbon anyway.

Mad Monkey

Thanks Monty Dog and giant mancp - I know I could get a carbon bike cheaper than titanium, which means I don't have to save for as long

labarum

Don't dismiss the idea of a classically built steel Audax.

It will last a very long time.

Here are some good makers - there are others.

http://www.merciancycles.com/

http://www.robertscycles.com/products.html

http://www.thorncycles.co.uk/models.html

Mad Monkey

Thanks labarum - food for thought, which I will check out. I guess steel is cheaper than titanium - how about weight and road feel?

labarum

The best modern steels are light and ride very well.

I have a hand made audax by Robin Mather, but he has a 20 month waiting list and has closed his order book.

http://www.robinmathercycles.co.uk/

SteveR_100Milers

I think either will last equally well. If ou have an mpact severe enough to break a carbon fibre frame then you wll almost certainly have written off a Ti one in the same accident, and and ally one, and a steel one. It's possible with a well designed CF frame that it will in act surive a bigger impact than a metal frame, since its ultimate tensile strength (UTS) is higher.

Things that affect a bike frames useful life is overstress which can cause instant material failure. Generally speaking, CF has a very small plastic region in that the yield and UTS are spaced pretty close to one another. In other words, instead of bending, most CF structures will catostrophically fail. Steel on the other hand tends to have a pretty large plastic region in that once yield strength is hit, they will permanently deform before breaking. However, there are two things to keep in mind here. One is that CF is typically stronger in all aspects than most metals. And secondly, it has a much larger elastic strain region compared to metals, which means CF will simply bend and rebound back to shape. The beauty in CF is that the elastic modulus can be engineered to different values in differenet directions, thus a structure can be micro-engineered and tuned to a much greater extent than metals. (see other threads on FEA analysis... ).

However, CF is very notch sensitive. Once the weave in the layer has been compromised, it loses almost 90% of its strength. A single surface/superficial abrasion is usually nothing to be concerned with as long as it's only a clearcoat scratch. A deeper scratch however can be a problem and if the weave has been cut then that layer is done for. However, most CF structures are layed up in several layers. This is done for several reasons. One is to increase not only the amount of material through cross-section padding and thus increase strength in that respect but also to add some redundancy into the material such that a failure of one layer does not compormise the entire layup. Another reason is that CF is anisotropic in nature and sometimes the prepregs used in the layup are unidirectional as opposed to multidirectional thus it will be stiff in one direction but compliant in another. Rather than using a multidirectional weave which in actuality would limit or make it more difficult to tune the structure, the designer will specify different weave biases for different layers thus creating a more isotropic layup in the end so that it will be stiff in multiple directions.

I'm sure that most of today's bike frames use a themoset bonding method for their CF construction, which means that whilst you might be able to repair sections of a lugged or frame built of sections; a one piece molded rame is a write off nce damaged. One-piece molded thermoset frames cannot be repaired. I think some of the older MTB frames might use a thermoplastic bonding material which is repairable.

Hope this helps.

Mad Monkey

WOW! Luckily I have enough engineering background to understand that, but what you say does make sense. I will certainly widen my research to include CF bikes - one of the advantages of titanium bike builders is that some of them will do custom builds, but then so do many CF bike builders, so that's probably the avenue I will explore. Many thanks all of you for your responses.

synchronicity

Although I've never had the opportunity to ride a titanium frame & I love carbon, I do think I think that titanium has the edge as far as longevity goes...

The resell value is also much better. Just search for "titanium" on ebay --> cycling category and you'll see what I mean (check the "do a search including the title & message" box).

Thermosetting carbon fiber composites can be repaired. AFAIR, it's the thermoplastic ones that cannot. The thing is, it's only worth the effort to repair really expensive kit, due to the labour charge of someone that has to know what they're doing.

Here's a guy in flnland for example that repairs carbon fibre stuff for many people:
http://www.signature.fi/

salsarider79

I'd look at the Sunday bikes. They make some lovely Ti frames, with simialar geometry to the Roubaix. I think if was me (I'd love to have £2.5k-£3k on a bike again) I would look at Ti, especailly as you want it for 20+years. I have two friends that are looking at, or have brought Ti bikes and sold their CF bikes...Either way, Keep up the riding and good luck

SteveR_100Milers

synchronicity wrote:

Although I've never had the opportunity to ride a titanium frame & I love carbon, I do think I think that titanium has the edge as far as longevity goes...

The resell value is also much better. Just search for "titanium" on ebay --> cycling category and you'll see what I mean (check the "do a search including the title & message" box).

Thermosetting carbon fiber composites can be repaired. AFAIR, it's the thermoplastic ones that cannot. The thing is, it's only worth the effort to repair really expensive kit, due to the labour charge of someone that has to know what they're doing.

Here's a guy in flnland for example that repairs carbon fibre stuff for many people:
http://www.signature.fi/

Thermosets do just that, they set permanetly with a chemical reaction to provide the finished material, either by mixing two components or by heating (think bakelite). Once they have set, they cannot be re-processed, e.g. glass fibre, or modern CF composites. Thermoplastics are simply solidified polymers: heat them above their melting point, remould them into a new shape and cool them down to solidify them, for example polypropylene washing up bowls or PET drinks bottles. These materials are usually recycled by grinding into pelllets and then reprocessed by injection or blow moulding. You cannot do this with a thermosetting plastic.

This is quite useful for more info.

http://www.plasticsindustry.org/industry/defs.htm

http://www.azom.com/details.asp?ArticleID=401

Parsnip49

By the sounds of it, a roubaix would be ideal.

Maybe look at a Cervelo RS if you want something a bit more exotic (pricey, but cervelos are gorgeous)

Im a CF nut, but then again i dont plan on keeping my bikes 20 years.

I wouldnt be put off by the idea of carbon being fragile - it wont spontaneously explode if you look at it wrong. Saying that, for a 20 year bike, id go for a alloy steerer, not a carbon one - i would have no qualms about a CF frame/fork though.

SteveR_100Milers

Well, there is a good reason why Airbus and Boeing are using more and more CF materials, and that is that they simply have a much longer service life than aluminium alloys, and offer a better strength / weight ratio than even Al-Li alloys. I'd have more faith in a well designed CF frame lasting longer than a well designed aluminium or steel frame, and as long as any Ti frame.

James1823

I'd go for Titanium. Although Carbon won't be damaged or fractured by anything other than a major crash. Litespeed, Enigma, Serotta all look pretty good. I think you can get Serotta bikes made to measure from Cycle fit. Definitely tempting if I was getting a 'bike for life'

Koomy

First post here, been lurking a while.
Hi to All.
Another vote for Sunday bikes here.
I was also looking for a bike to last me a good few years, and decided on Titanium.
I recently got the September model, which I am very pleased with so far.
The frame guarantee is lifetime on manufacturing faults for original owner.
Also I believe there is a 'half-price frame replacement’ offer if the frame is damaged in an accident.
That’s not a bad warranty!
Cheers
K

Mad Monkey

Thanks all - good advice for me to consider. Koomy - did you get a chance to try a ride before buying? I have read the review on BikeRadar and they certainly seemed pretty impressed - also one at RCUK on the Silk Road, though I think the Septermber geometry would suit me more. Having bought 3 bikes from Halfords with the amount of advice you expect from them (It's a bike....) I really want to be certain I get the right size etc.

I still have some saving up to do, which gives me time to do some research.

Thanks again folks.

blorg

I have both carbon (road) and titanium (tourer.) You can get a light carbon bike cheaper than you can get a light ti bike. I love the lightness and speed of the carbon bike (as well as the pricetag) but if you are looking at a 20-year timeframe and are not looking for the lightest bike possible I think I would lean towards Ti. Titanium does have the advantage over steel that it doesn't corrode.

Koomy

Hi Mad Monkey,
No, I did not get a test ride on the September.
I went up to Fatbirds in Hunstanton as they were offering discounted prices on Sunday bikes (I was pushing my budget by going for Titanium!).
It was a 5 hour round trip but was pleased I went.
Unfortunatly they did not have a Sunday in my size, but they let me have a test ride on Van Nicholas (can't remember the model) to get an idea of the 'feel' of Ti.
We compared the geometry and size and I went ahead with an order for the Sunday Sept in XL size.
They had the bike built within a week (Ultegra SL) and I went back up for a 'final-fit'.
As I said, very happy with the bike and with the service from Fatbirds.
The other difference of the September vs the Silk Road is addition of mudguard and panier mounts, and of course the extra clearance for the mudguards.
Cheers
K

wildmoustache

FWIW I rode my first Ti bike three weeks ago. An Enigma. It did ride very nicely and seemed smooth but in all honesty my Look pulls the balls off it. the Ti bike just felt sluggish and a bit spongy in comparison. The only major difference in spec was Chorus on the Ti and Record on the Look. Ti only about 300g heavier.

Lysander

I have just ordered a Condor Classico steel bike with full Record. I already have a carbon and alloy bike so I couldn't really justify the expense of getting a Ti bike. I was determined to get either steel or Ti as my alloy Ciocc developed two cracks in the downtube. Although I had it for seven years so can't complain. If I look after it it should give me 20+ years of use. Its a lovely bike and even with full Record the price doesn't seem that bad. Its also made in Italy and I'm afraid I'm a sucker for all that Italian marketing hype.

SteveR_100Milers

wildmoustache wrote:

FWIW I rode my first Ti bike three weeks ago. An Enigma. It did ride very nicely and seemed smooth but in all honesty my Look pulls the balls off it. the Ti bike just felt sluggish and a bit spongy in comparison. The only major difference in spec was Chorus on the Ti and Record on the Look. Ti only about 300g heavier.

Which just proves that the design is as important than the material it is made of. There are plenty of "soft" and "hard" frames in all of the major frame materials. I recently rode a borrowed Tarmac S works and almost rattled my man parts off it on a 10TT; made my Cayo feel like an armchair; which is hardlyy the last word in long distant comfort. I'd wager that say a Time VXR would be like riding something made from solid tbes it's that hard!

Blorg wrote:

but if you are looking at a 20-year timeframe and are not looking for the lightest bike possible I think I would lean towards Ti

I still don't understand the obsession wth Ti and longevity - CF will last just as long, it just has a different (not lower) failure mode.

simplesimoncardiff

Spcialized Carbon frames have a lifetime guarantee on them - good enough for me!

synchronicity

SteveR_100Milers wrote:

synchronicity wrote:

Thermosetting carbon fiber composites can be repaired. AFAIR, it's the thermoplastic ones that cannot. The thing is, it's only worth the effort to repair really expensive kit, due to the labour charge of someone that has to know what they're doing.

Here's a guy in flnland for example that repairs carbon fibre stuff for many people:
http://www.signature.fi/

Thermosets do just that, they set permanetly with a chemical reaction to provide the finished material, either by mixing two components or by heating (think bakelite). Once they have set, they cannot be re-processed, e.g. glass fibre, or modern CF composites. Thermoplastics are simply solidified polymers: heat them above their melting point, remould them into a new shape and cool them down to solidify them, for example polypropylene washing up bowls or PET drinks bottles. These materials are usually recycled by grinding into pelllets and then reprocessed by injection or blow moulding. You cannot do this with a thermosetting plastic.

Thanks but I'm already well aware of those properties. I studied Materials Science at uni for 4 years full time, followed by 6 more years of doctorate research in the same faculty.

Another thing to consider with CF composites is polymer degradation. The top coat yellows after a while. At least my 7 year old CF frame has (a little). :x

They scratch more easily too. Whereas Ti can be brought back to new with a bit of steel wool. It's a lot more difficult to do that with a painted or clear-coated CF frame.

Then there's the problem of corrosion of aluminium fittings. You don't get any of that on a ti frame.

redddraggon

synchronicity wrote:

Thanks but I'm already well aware of those properties. I studied Materials Science at uni for 4 years full time, followed by 6 more years of doctorate research in the same faculty.

What's with cycling and materials scientists? They seem to go together.

I've got another year left of my undergraduate degree

synchronicity

Cool. Best of luck!

Actually, it's got nothing to do with luck.
It's all about aptitude, attitude and study.

SteveR_100Milers

synchronicity wrote:

Cool. Best of luck!

Actually, it's got nothing to do with luck.
It's all about aptitude, attitude and study.

I studied it because it was so easy to get onot a degree course as no one wants to study it! Glad I did, far more interesting (and dare I say valid in the real world) than pure mechanical engineering

synchronicity wrote:

Another thing to consider with CF composites is polymer degradation. The top coat yellows after a while. At least my 7 year old CF frame has (a little).

You can add UV stabilizers (IIRC fatty acids or similar are added) that will delay the weathering effects on epoxy resins (I am assuming that your frame is like the majority of CF frames and uses an epoxy based bonding resin not a polyester). This should prevent "bloom".
Additionally, car manufacturers have been using clearcoat lacquer systems that provide UV resistance to protect the paint, and these are used on most modern CF frames ( for example my Focus Cayo has a thick clearcoat lacquer cover).