zonatandem

Have owned/ridden steel, alu, ti, carbon; not just in single bikes but also in tandems (that take a lot more stress than singles).
Our preference is carbon fiber. Yes, we live in a 'warm' climate . . . 100+ degrees in summer and have ridden as 'warm' as 117 degrees.
Have pedaled over a quarter million miles, 200,000 of those on tandems. Have broken 2 steel frames and one steel fork. Currently have 9,000+ miles on a full custom c/f tandem . . . our $$, and our butts, are on carbon!
Rudy and Kay/zonatandem

froze

Well when you get over 200,000 mile on your CF tandem you let us know. I've seen CF frames and forks fail too, and they don't fail gradually like steel but suddenly resulting in very serious crashes.

froze

I don't either considering you can buy Aluminum bars, stems and post that weigh just as much as CF items weigh and pay a lot less money.

zonatandem

Custom carbon fiber?!!!

ViperZ

You do realize that the modern Formula 1 racing cars and Indy cars chassis are built out of a carbon fiber monocoque....?

If it's strong enough for that, it can certainly handle a simple bicycle frame application.









Entire carbon tandems are a bit rare because they are very expensive to make. Making just the body panels of those race cars are the price of a high end German sports car.







As for the carbon touring bike, any bike can be toured given the right hardware.

zonatandem

Asides from strong, c/f is light too . . .
Oh yeah, ariZonaTandems also builds c/f triples that convert to tandems (utilizing S&S fittings).
At least we have choices!!!

ViperZ

And stiff.... The flex characteristics can be designed by orientation and cloth lay up. With carbon it's easy to make a bicycle frame stiff to lateral deflection (side to side bottom bracket movement) yet allow the frame to be compliant and flex longitudinally (up and down) to give a smoother ride.

Its harder to do with ferrous tubes, but not impossible, such is the shaped tubes we see. However it tougher to control and tune than it is with carbon.

zonatandem

The Santana Beyond tandem that is posted above has carbon fiber tubes inserted into titanium tubes (a process invented by Vyatek in Arizona). The Zona or ariZona Tandems posted, are full carbon, including the lugs and/or sleeves. Dropouts and other fittings are titanium.
Currently the Davis Double Lite tandem weighs in at a mere 23.4 pounds.
More info @ arizonatandems.com
BTW any material can and will eventually fail, so the horror stories of breaking frames can apply to all materials.

gmason

Sorry, but no it isn't!!

DannoXYZ 

Yeah, but if you had subjected a steel frame & fork to the same forces that broke the CF, the steel frame/fork would've been completely twisted into a pretzel. It's not just how something fails, it's also what causes them to fail.

I get into this argument all the time with race cars and 1000-series DOM vs chromoly tubing for roll-cages. Naysayers are always claiming that when chromoly fails, it snaps suddenly. Well, same thing, by the time chromoly breaks, the DOM tubing would've failed much, much sooner. Easy test was done with car-crusher at junk-yard. Two identical 510s had same cages built with DOM and the other chromoly. Same series of crush tests were done on them at 10k, 20k and 40k pounds. At the first test, both cages bent about 2", but the chromoly snaps back while the DOM takes a permament dent. At 20k, the chromoly takes a 4" permanent bend, but the DOM has crushed 10" down past the driver's shoulders. At 40k, the chromoly finally snaps at the shoulders, but the DOM has crushed all the way down to the driver's lap...

Viper, show the the clip where they slam the tub headfirst into the barrier!!!

cs1

Correct, when carbon flexes it has catastrophic failures.
That's why springs are made out of steel because they get flexible and limp.
The only reason for a carbon fork is because it's lighter and looks C L. It doesn't perform better than a well designed steel fork.
Tim

garysol1 

I bet that is one hell of an entertaining ride.........Maybe when the kids are out of the house

nova

There are warning signs youve just not learned to spot and hear them. Ive doen a little work with carbon fiber and kevlar layups with friends. What you will notice is a foggyness in the resins or hair line cracks all over it well before it fails. If its failing at a joint youll hear creaks and groans coming from the joint. This means its heading for failure. Now my experiance is limited to working with wings on a guys drag car who use to live near me. Im sure failure signs are the same though.

The visable signs are similar to old fishing poles and the cracks they develop but on carbon fiber its not as noticable.
With carbon fiber failures its typically not the fiber that fails its the resin that binds the carbon that does.
This is why if you catch it intime you can repair it. A coatign of new resin over the old will fix it right up returning about 90 to 100% of the original strength.

froze

Of course I realize that certain race cars, aircraft, aerospace, and racing boats are built with CF...BUT that stuff is not the same quality that is being used in bikes and the bike CF is layered a lot thinner: why? to save weight and money. If you used the same CF used on formula cars your bike would be weigh a lot more then a steel bike frame would! But then it probably would be far stronger then a steel framed bike. Also a bike made of race car carbon would cost a fortune and I don't think too many people would spend about $15,000 for a bike frame. Colnago proved that when they came out with a limited addition carbon bike that was made of the same stuff Ferrari used in their race cars just thinner, and that Colnago was $15,000 on sale! They didn't sell many and the ones that did sell were mostly to collectors including a LBS that I knew in Bakersfield California.

Retro Grouch 

There are plenty of carbon fiber tandems available for sale, I can think of three major brands just off the top of my head, but the price thins out the market a bit.

MichaelW

You could build a carbon touring bike but it wouldnt be ultra-light, just as steel tourers are heavier than steel racers.

You need a mounting point for heavy luggage that does not rip out of the frame. You need material thick enough to whisthstand some abuse by airport staff and the occasional crash. This kind of abuse is not meted out to F1 cars or military jets, they are handled correctly by trained engineers at all times.
I doubt that carbon would offer a significant weight saving over current steel tourers. You also have the problem of the low toughness of carbon. It can be damaged by scratching against a post or brick wall.
I think carbon is probably an easier material to repair in the field than anything else. All you need is a repair kit of carbon or glass fibre tape and epoxy resin.

The custom/high-end tourer market is pretty small and the cost of developing a bike strong and reliable enough for touring is not worth the trouble.

ViperZ

The current carbon fiber bicycle frames are already stronger and lighter, and they don't cost a fortune, relatively. The Cervelo R2.5 can be had for around $2000

Scott, Calfee, Giant, Trek, Cervelo, all make sub 1000g (<2lb) carbon frames, Steel frames are typically 1500g (3.3lb). The carbon frames are Plenty strong enough and there are carbon tandems.


Weren't you the one saying make it an they will come?


Oh, yes you did


Ask and ye shall receive:

Drayko

So did the dummy not make it?

TallRider

So let's get this straight: in a lab environment, carbon fiber can be stronger per weight than any metals. Lab environments also do not usually involve pebbles chipping paint (and breaking a fiber or two), nicks, dings, etc. Which is why I wouldn't trust carbon fiber stuff long-term. Carbon handlebars and seatposts contain warnings not to scratch the things, for crying out loud!
In the end, a lot comes down to application and budget. If you're racing and getting new frames regularly (and having mechanics check your carbon fork for hairline cracks etc. on a nightly basis) then carbon is the way to go. Although I'm not sure how much better it is than top steel frames, in real practice. Savings of 1 lb. or so. My guess is that a number of pro riders would ride steel if it were up to them. Point is, for most of them, their sponsorship is from a bike company that stands to make more money selling carbon frames than it does steel... so the company wants the pro riders to ride carbon. It's somewhat comparable to Abebe Bikela, who won the Olympic marathon in 1964 while running barefoot. (Over Rome's cobblestones!) In 1968, he won again, this time wearing Puma shoes - because Puma sponsored him, they paid him to wear their shoes as advertisement.

Also, Carbon may be able to be tuned to have better ride characteristics than good steel, though I'm not entirely convinced on this. Theoretically, the possibility certainly exists, and a lot of people have testified to it in practice, but placebo effects tend to be very strong. I'd love to see some double-blind testing.

But on durability. When carbon fails (which, admittedly is much less common with top carbon bikes today than 10 years ago), it tends to be catastrophic. It snaps instead of gradually cracking and bending. Also, if a bike were built for lifelong use, I think steel would last longer (provided that it's rustproofed), and wouldn't be too much heavier.

Finally, a technical clarification: steel does not weaken as it is flexed repeatedly, provided that the flexing is under a certain threshold. As was noted above, this is why springs are made of steel. ALUMINUM does weaken as it flexes; it has no "stress threshold" and every bit of flexing it does, weakens it. That's why aluminum frames have to be built with huge tubes, and generally have to be somewhat harsh, because if they were flexible enough to give a comfortable ride, they would be weakening as they were ridden.

ViperZ

The dummy survived

DannoXYZ 

Just look at the safety-record of IRL/CART/F1 series using CF tubs compared to NASCAR using steel... enough said...

wagathon

I know you belive what your're saying, but fiber-reinforced resin--whatever its positives and negatives--is not like glass.

TallRider

True that. It doesn't start cracking like metals do, or get clean cracks like glass. But when the reson holding the fibers together starts to be less clear (internal crinkling), it's a sign that it'll soon be going. So I guess "hairline crack" isn't the best term to use here.