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popluhv 12-17-06 11:19 PM


Originally Posted by dustinlikewhat
kind of off topic, but a curiosity of mine...

so I'm completely ignorant on titanium, it seems as though it's quite light, and quite strong, so why not use it instead of carbon fiber? is it because you can mold carbon fiber into aerodynamic shapes? it's always seemed to me that carbon fiber is to easy to break, but as I said, I'm ignorant in this area of things...

Yeah, I think the idea is that aerodynamics is far more important in track racing than weight is.

moki 12-17-06 11:33 PM

I'm the OP. The subject is a joke and a reference to DW. I've necer heard of teschener before, and I just thought that was a really cool f'n bike. Just like the cervelo (uhhh!) and look and that wicked hot calfee that just went on ebay.

With the stem, I guess you could get a negative rise by using spacers and a flipped angled stem. Personally, I like the aesthetics of a deep drop, but there must be a reason that most modern track bikes used on the track aren't so. Out on a limb. I think it's because you can expand your lungs more if you aren't super hunched down. That, and I think front end stiffness is improved with a shorter headtube.

Oh, and I have 4 bikes and not a single scrap of CF on any.

Judah 12-17-06 11:33 PM

titanium also makes for quite the noodle bike. at least the ones I've ridden...

that teschner is dope. the deep drop stem is a thing of the past. look at many of the top track racers, many of them have neutral or *gasp* riser stems. people on this forum are nothing if not slaves to aesthetic...

Learn_not2burn 12-17-06 11:39 PM

That bike is the ish. An affordable copy of the Look basically.

As for the titanium as people have said priority on the track is stiffness and aerodynamics. Weight is of little importance except specific occasions. CF owns in stiffness. Also, it's easily moldable into aero shapes.

As far as geometry discussions go, check FixedGearFever, there are some world class riders over there that actually know what's up. DW is also the man.

savier_pdx 12-18-06 12:00 AM

you're all missing the point. the real question here is, with a 650c front, could this baby do bar spins? if so, i will buy it.

sfcrossrider 12-18-06 01:19 AM


Originally Posted by savier_pdx
you're all missing the point. the real question here is, with a 650c front, could this baby do bar spins? if so, i will buy it.


For the win!

dutret 12-18-06 06:51 AM


Originally Posted by Judah
titanium also makes for quite the noodle bike. at least the ones I've ridden...

Nothing but steel is stiff enough for me I've fount that not only ti but carbon and aluminum to just make noodely unrideable bikes. http://gallery.roadbikereview.com/da...14IMG_2379.JPG http://www.giroposte.com/PageMill_Im...92purpleAl.JPG

dustinlikewhat 12-18-06 05:50 PM

ahh, cool. I've never had the money to even touch something titanium, so thanks for the heads up. I used to race bmx when I was younger, and there was this company called titan (I believe) who had a half front and half rear fork. Their frames were titanium, so I just assumed it was strong.

Aeroplane 12-19-06 08:01 AM


Originally Posted by dustinlikewhat
Their frames were titanium, so I just assumed it was strong.

Titanium is strong, it's just not as stiff as other materials in certain configurations.

There is a big difference between the two qualities. Glass is really stiff, but it's not strong. Rope is very strong, but is not very stiff. That's one (heavily simplified, riddled with misrepresentations) way to look at it.

Momentum 12-19-06 08:37 AM

Dutret's is another. Basically all the frame materials can make stiff or floppy bikes, depending on what you do with the material.

Hocam 12-19-06 09:10 AM


Originally Posted by Momentum
Dutret's is another. Basically all the frame materials can make stiff or floppy bikes, depending on what you do with the material.

Carbon fiber is actually a really cool material because the it gets its strength from the way the fibers are oriented. If you have a block with all the fibers in one direction and put tensile stress (pull it) on the direction of those fibers it will be extremely strong in light, but go against the grain and it will just pull apart very easily. By layering the fibers you can actually control the strength in different directions and design the frame for the actual stresses it will be under, instead of having relatively equal strength in every direction which is only really controlled by the thickness of the material.

Unlike carbon fiber there is not as much variance in the thickness and shape of the tubes with steel, Ti or Al, mainly because the frames are based around drawn or welded tubes and you can only vary them so much (double and triple butting and aero profiles ect.). So with carbon fiber you can control the strength of the material in different stresses and have a huge control over the tube shape and thickness through layering the fibers. Because of that you can make an extremely stiff frame with much less weight than the other materials and with much less hassle.

Also, comparing Steel and Ti and Al, the young's elastic modulus (E) has the most influence over their properties. The elastic modulus is a simplified relationship between the amount of stress (tension or compression) the material goes under and the amount of strain (% lengthening or shortening). The higher the E the less deformation or flex you get for that amount of stress. Modern steels have the highest (~195 GPa)then titanium (116 GPa) then waaaaaay at the bottom 6061 with 70 GPa. That tends to be the reason why Al frames have super big tubes (cannondale hoooo), they need a higher second moment of inertia to resist bending (takes too long to get into).

Also, ***I think*** and DW can probably either prove me wrong or back me up here, but Ti tubes don't use the large diameters that aluminum does and vary wall thickness instead, which is why they tend to be more flexy and not super stiff like Al (tube diameter plays a big part in stiffness). Not only that but Aluminums E is so low, they need to make the tubes extra stiff to prevent non-eleastic deformation.
****I think****

I am not a frame builder so I'm not 100% sure about that last paragraph, maybe someone else can give some input.

pitboss 12-19-06 09:23 AM


Originally Posted by Judah
titanium also makes for quite the noodle bike. at least the ones I've ridden...

that teschner is dope. the deep drop stem is a thing of the past. look at many of the top track racers, many of them have neutral or *gasp* riser stems. people on this forum are nothing if not slaves to aesthetic...

If it matches your shoes, it must be TRACK!

pitboss 12-19-06 09:42 AM

Don - that sounds like a bunch of Detroit claptrap regarding the magical carburetor NOT existing. What are you hiding from us? That the next wave of frame technology will incorporate the fourth element, Plasma?

Stop with the cryptic BS and get to the point, man! Or should we all just come to NAHBS?

fix 12-19-06 10:13 AM


Originally Posted by dutret
Nothing but steel is stiff enough for me I've fount that not only ti but carbon and aluminum to just make noodely unrideable bikes.

Obviously you are right. That's why the pro tour rides steel!

auk 12-19-06 10:17 AM

Duret, the least you could have done is post pics of bike that were NOT the earliest generations of said materials. Come on, the Vitus and the Giant with lugged alu/carbon? This is not the early 90's.

Both materials now enjoy being built into some of the stiffest frames you will find. Stiffer than steel? Usually.



Originally Posted by dutret
Nothing but steel is stiff enough for me I've fount that not only ti but carbon and aluminum to just make noodely unrideable bikes. http://gallery.roadbikereview.com/da...14IMG_2379.JPG http://www.giroposte.com/PageMill_Im...92purpleAl.JPG


p3ntuprage 12-19-06 10:20 AM


Originally Posted by Walkercycles
No, the next element actually involves lava reconstituted into tubing. Hawaii will be the framebuilding capital of the world!

Or, you could just come to NAHBS and see what the future is....


DW

reference to gitzo's basalt tripods? or did i miss the joke?

fsnl
sparky

dutret 12-19-06 10:22 AM


Originally Posted by auk
Duret, the least you could have done is post pics of bike that were NOT the earliest generations of said materials. Come on, the Vitus and the Giant with lugged alu/carbon? This is not the early 90's.

Both materials now enjoy being built into some of the stiffest frames you will find. Stiffer than steel? Usually.


yeah that was kind of my point.


EDIT: and just to be even more clear by "kind of" I mean exactly.

I chose two outdated flexy examples of cf and Al to point out the the flaws of Judas' absurd statement that ti makes noodles. Yes a lot of early ti bikes(and some current touring ones) aren't the stiffest out there but the same could be said of early Al or CF. Ti, Al and CF are all made into incredibly stiff frames now and just because you can find a noodle made out of ti does not mean that ti frames are doomed to being flexy any more than with CF or Al.

EVEN MORE EDIT: apparently I was still not clear enough. the words above those pictures were purely sarcastic. I do not think that steel is the only material that can make stiff bikes. In fact I think ti, al, and cf all make better light stiff frames then steel does. I enjoy riding bikes made out of all these materials(and just wish I had more oportunities to ride ti ones.)

p3ntuprage 12-19-06 10:28 AM

close enough to a possible truth though:

http://www.gitzo.com/Jahia/site/gitzo/pid/4696?rId=2

fsnl
sparky

onetwentyeight 12-19-06 10:54 AM

dutret - i thought you rode an aluminum frame... the fuji track pro?

dutret 12-19-06 11:08 AM


Originally Posted by onetwentyeight
dutret - i thought you rode an aluminum frame... the fuji track pro?

Nope. I will be riding that giant next week though and hopefully this once or twice.
http://images.competitivecyclist.com.../e1_zoom_1.jpg
(note this bike is anything but a noodle.)

Hocam 12-19-06 01:57 PM


Originally Posted by Walkercycles
The issues of diameter and wall thickness is fairly easy to explain.

So, back in the late 80s, most of the Ti frames were barely oversize tubes. Now, they are more common with 1.5 inch downtubes and such. This gives them the thinner wall and the stiffer feel in the frames.

DW

Ah I haven't seen many Ti bikes, didn't know they were doing the oversized tube thing too. Seems like the thinner walls idea is asking for dents to me, and aluminums crumple tendancy keeps me riding steel.

That is until I finally break the TdF scene and have a need for carbon fiber.

dutret 12-19-06 01:59 PM


Originally Posted by Hocam
Ah I haven't seen many Ti bikes, didn't know they were doing the oversized tube thing too. Seems like the thinner walls idea is asking for dents too me, and aluminums crumple tendancy keeps me riding steel.

ultra-stiff lightweight steel is just as bad as Al if not worse. OS Ti at least seems substantially more durable but I have never owned one.

Hocam 12-19-06 02:06 PM


Originally Posted by dutret
ultra-stiff lightweight steel is just as bad as Al if not worse. OS Ti at least seems substantially more durable but I have never owned one.

Makes sense, can you still change the dropout spacing as easily on the new steels as you can on older ones? And can you do that on Ti bikes too? I'm pretty sure it isn't recommended with Al but am a little clueless on the new stuff.

thenewblk 12-19-06 02:32 PM

I like my thick downtube. It's really stiff.

Aeroplane 12-19-06 02:45 PM


Originally Posted by thenewblk
I like my thick downtube. It's really stiff.

I call mine a "downtube" too. Heh.


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