Titanium, can it be improved?

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fromtrektocolnago
Posts: 1145
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

@ reippuert. I'm building a Titanium Firefly and going the gravel bike route with 32 mm tires , disc brakes and thru-axle. In talking with the bike shop who is helping with the build it seems a number of people are ditching the n+1 rule and using this type of bike as their do-it all bike. Something like this could be outfitted with enve 3.4 disc wheels.
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Colnago C-64 disc(ultegra) with Bora 35 wheels

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reippuert
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Location: Copenhagen, Denmark

by reippuert

fromtrektocolnago wrote:@ reippuert. I'm building a Titanium Firefly and going the gravel bike route with 32 mm tires , disc brakes and thru-axle. In talking with the bike shop who is helping with the build it seems a number of people are ditching the n+1 rule and using this type of bike as their do-it all bike. Something like this could be outfitted with enve 3.4 disc wheels.


I've looked into the pure gravel geometries: a tad too long chainstays, angles too slack, BB drop and stalk is right though
I've also looked into pure cross geometries: a tad too long chainstays, BB drop way too high up and stalk way to short. Angels are right though.

I still looking for a desired stock geometry and the right featureset.

current interesting stock geometries are: Kona Roadhouse, Genesis Equilibrium and Salsa Colossal - they just miss a beat here an there. The Litespeed T5 might quilify as well. Unfortunately the Soma Tripple Cross was only made in limeted number - the geometry and material in KVA stainless looked really nice.
--
mvh. Morten Reippuert Knudsen @Merlin Works CR, Chorus 15, Reynolds 46/66

cmcdonnell
Posts: 278
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

Still riding my 2005 Ghisallo and no problems so far. It's been consigned to winter duties now and has a lovely ride, just a shame it had very little tyre clearance. It's not particularly stiff but that makes it very comfortable and it's only an issue in a sprint so not an issue in training. Also have a Litespeed T1 and find it much stiffer but noticably heavier. The 10 years of development is noticeable as it's quicker and equally comfortable and only a few hundred grass heavier which I really can't notice. I love both bikes but the T1 is a much better bike, just gutted that the T1SL came out 2 months after I bought the T1
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

fromtrektocolnago
Posts: 1145
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

reippuert wrote:
fromtrektocolnago wrote:@ reippuert. I'm building a Titanium Firefly and going the gravel bike route with 32 mm tires , disc brakes and thru-axle. In talking with the bike shop who is helping with the build it seems a number of people are ditching the n+1 rule and using this type of bike as their do-it all bike. Something like this could be outfitted with enve 3.4 disc wheels.


I've looked into the pure gravel geometries: a tad too long chainstays, angles too slack, BB drop and stalk is right though
I've also looked into pure cross geometries: a tad too long chainstays, BB drop way too high up and stalk way to short. Angels are right though.

I still looking for a desired stock geometry and the right featureset.

current interesting stock geometries are: Kona Roadhouse, Genesis Equilibrium and Salsa Colossal - they just miss a beat here an there. The Litespeed T5 might quilify as well. Unfortunately the Soma Tripple Cross was only made in limeted number - the geometry and material in KVA stainless looked really nice.


well i'll still be riding my c-59 so no issue for me. the firefly will be for gravel rain and snow.
that said the guys i'm working with know i like the c-59 and said the new bike as spc'd should ride similarly. we'll see
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Colnago C-64 disc(ultegra) with Bora 35 wheels

XCProMD
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Location: Cantabria

by XCProMD

highdraw wrote:There is one immutable fact. Sorry to the Ti loyalists. To me having owned 5 Ti bikes...it is simply an OK material.
Almost a jump ball with steel...all said I probably prefer the ride of good steel bike to that of Ti. But from my experience I will take carbon for competitive riding and Al for an overall road bike all day long to either Ti or steel.

Al has come a tremendous distance in the last 5 years. If there was ever a reinvented material it is Al. Carbon bikes have continued to get better. So why not Ti or steel? Guys it isn't about the material. What has the improvement of Al bikes relative to carbon...like the Spesh Allez smart weld or CAAD 12 or Emonda Al taught us? That geometry trumps frame material. In engineering parlance this means mechanical properties through differential section stiffness matters more than material properties such as modulus of elasticity, yield strength, material hardness and density. How is this proven? Because with exception of a few grams of weight, the performance of an Al bike can almost rival that of carbon...carbon being almost the perfect bike material in terms of modulus of elasticity, yield strength relative to weight and of course material density. Achilles heel of carbon of course is abrasion resistance and more precipitous yield without deformation closer to its yield point but of course its yield point is higher than all the other materials...less propensity to dent...one trait offsets another say in a crash.

Fact is...material properties are vastly different between Al and carbon...carbon is much stronger with much higher modulus of elasticity than Al...and yet with the right shape and quantity of Al, performance can be closely matched.

In the final analysis Ti is a better candidate for frame material compared to Al but in the end the opposite is true for the simple reason of formability. Al can be formed to emulate its carbon brother. If you put a new Allez side by side with a Tarmac, its hard to tell them apart. An Allez is basically an Al Tarmac. Its the geometry that matters at the end of the day more than the material properties or otherwise Ti or even Steel would be preferred. But Ti and Steel for all intents are stuck in the stone age of straight sections. Yes, price no object both materials could perhaps be formed and welded to look like a carbon or new Al bike with their dramatically changing tube sections front to back of the bike which give both their superior performance after decades of refinement...but manufacturers haven't figured out how to do this with either Ti or Steel or at least the technology is not cost competitive. Ti and Steel are stronger materials and harder to form than Al and of course carbon is molded to whatever shape a designer believes is optimal.

For all the Ti lovers out there...go out an ride a new Al race bike. You will be blown away by the performance and ride quality. My 2014 Secteur I just built rides better than my carbon Roubaix and any Ti bike I have owned.
And of course virtually all modern bikes have a carbon fork...for a reason.


I almost totally agree.

XCProMD
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by XCProMD

reippuert wrote:
XCProMD wrote:Any idea of that T1SL reliability?

The limits with titanium and steel are fatigue and buckling. In the case of Ti add deflection.

At 2E6 cycles the fatigue resistance of a well executed fillet weld in Ti is around 60MPa. Mitering is crucial as root propagation is something you don't want. A good weld has to crack from fatigue from the toe.

The load spectrum on a bike depends a lot on the user. A pro can beat a thin Ti frame in very little time. The first crack is usually the toe of the weld of the bridge joining the chainstays or the toe of the weld between right chainstay and dropout. MTB's crack at the seat tube-top tube junction as well.

The thinner you go, the higher the stresses are in the material, and as I said, there is only a number of cycles a Ti weld can withstand above 60MPa


I can't see why the 1000g T1SL shouldn't be reliable.

I know the legandary sub 800g Ghiasello from the early 00's where neither reliable nor duarble - but in 2006/2007 Merlin/Spectrum was able to produce the Tom Kellog designed CR Works range weighing 1050-1300g (from small 6.4 to XL 3/2.5) that where very reliable and hyper durable.

I have a the 2006 Merlin CR 2.5/3.5 in size ML (equivilant of a size 55-56cm non-compact).
The frame weight is 1115g, the ti 6/4 version was only 1080g. Both framesets used non butted tubeing, both frames where 'mass produced'. You can hit it with a large hammer and it will survive; you can throw it directly into an airplaine without a soft or hardshell suitcase and it will survive, you can crash it and it will survive.
Its sufficiently stiff when ascending and decending the Ventoux with a 95kg rider and 10kg of luggage (credit card touring). It even fits 27mm Pave tyres.

Its been 10 years since Spectrum/Tom Keollog designed the Merlin Works CR range and today you should be able to save additional weight and increase stiffness even further by incorporating:

PF30 BB shell
A milled tapered headtube design
Different dropouts
A lighter aluminum deralliuer hanger compared to non-replaceable TI hanger.
Butted tubing instead of plain gauge (sensible for racing, not for a do-it-all & last-forever frameset)

- add to it that the CR Works range had relatively long chainstays, a beefy brake bridge and a brigde in the chianstays where additional weight can be saved.

The tapered plain gauge size specific top and down tubes Tom Kellog designed for Merlin in 2006 is still state of the art as of 2015 and the reason why he could design a durable high perfomance lightweight frame
Tom owns the intelectual property which is why neither Seven, ABG (Litespeed, ex Merlin) or Competitive Cyclist (todays Melin) can use those tubes - today only Specrum can use them.

But 10 years has passed and im sure it can be improved (especially for racing) if the same design resorces where allocated in 2015 - next obvious step would be to look into the remaining tubes.

A sub 1000g raceday TI frameset anno 2015 for a 60-80kg rider shouldnt be a problem - however most people buying a 3-5000$ custom TI frameset wants the frame to last for 10-15 years so they tend to want 'extras' for everyday usage and options for a heavyer build that will be indestructable.


I never wrote a comma about static yield or tensile strength. My post is about fatigue.

60MPa @ 2x10E6 cycles. That is what the discussion is about because that the limit of a Ti frame unless you find a way of getting rid of welds or apply HFMI.

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mrowkoob
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by mrowkoob

Both materials have their pros and cons. I don't see ti beating carbon fiber on the market. On the contrary carbon fiber will develop much more from where it is now. That does not mean you cant enjoy your ti bike as much as ever. You just wont see them in the prootour. UCI 6.8 will go away too in a matter of time.

If you click below on "a new retro" you can see what I did to my Team Lotto Vortex.
The unbearable wallet lightness of being a weightweenie

sharkman
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by sharkman

Both materials have their pros and cons. I don't see ti beating carbon fiber on the market. On the contrary carbon fiber will develop much more from where it is now. That does not mean you cant enjoy your ti bike as much as ever. You just wont see them in the prootour. UCI 6.8 will go away too in a matter of time.


+1, Ti is and will stay a niche frame material. Litespeed probably was the last to try in pro competition with Lotto. Due to team wishes/demands they went to far and at least the team bikes where a good warning of how not to use titanium for reliable and predictable bike behaviour.

Rush
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by Rush

Pretty sure my Ti frame has hydroformed chainstays.
All I can say is that the tube shape ain't circular.
Image
Image
Image

rpenmanparker
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by rpenmanparker

My Kellogg-signed 54 cm Merlin Works CR frame weighs 1,207 g. I wonder where the extra weight came from. I bought this one used, so I can't be sure of the model year, but the decals are mostly black with white outline and the C of the CR is red with white outline. I am pretty sure it is from around 2006 or so.

Image
Last edited by rpenmanparker on Thu Dec 24, 2015 8:29 pm, edited 1 time in total.
Robert

rpenmanparker
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by rpenmanparker

Keep in mind that Ti tubes could easily be very complex in shape and gauge variation without hydroforming if they were double seamed, that is welded from two open halves. The open halves could be rolled and forged to obtain the complex inner structure desired. Considering that seamed steel tubing has never really been shown to be inferior to seamless, I don't see why this technique isn't employed.
Robert

reippuert
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by reippuert

sharkman wrote:
Both materials have their pros and cons. I don't see ti beating carbon fiber on the market. On the contrary carbon fiber will develop much more from where it is now. That does not mean you cant enjoy your ti bike as much as ever. You just wont see them in the prootour. UCI 6.8 will go away too in a matter of time.


+1, Ti is and will stay a niche frame material. Litespeed probably was the last to try in pro competition with Lotto. Due to team wishes/demands they went to far and at least the team bikes where a good warning of how not to use titanium for reliable and predictable bike behaviour.


American Bicycle Group also sponsered a european top U23 in the mid 0'ers - an Irish team i think, rideing Merlin CR and TR Works.
--
mvh. Morten Reippuert Knudsen @Merlin Works CR, Chorus 15, Reynolds 46/66

reippuert
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by reippuert

rpenmanparker wrote:My Kellogg-signed 54 cm Merlin Works CR frame weighs 1,207 g. I wonder where the extra weight came from. I bought this one used, so I can't be sure of the model year, but the decals are mostly black with white outline and the C of the CR is red with white outline. I am pretty sure it is from around 2006 or so.

Image


I never did weigh mine as a raw frame, i just refer to the then pulbicied specs.

The decals of your sixe M looks like it's a 6/4 or a newer 3/2.5 version - Mine doesn't have the red letters, mine are smoke-blue and has 3/2.5 in the letters. Yours might be a 2007 or 2007 model. I seem to remember that they dropped the 6/4 in 2007 or 2008.

When i collected in the shop (only imported CR/TR Works frame/bike in denmark) they did weight the frameset though.

Frame, uncut fork, headset, front deraillure clamp and seatopst clamp - belive it came in somewhere in the 159x's gram range which was the one of the lightest size 55-56cm framesets they had weighted in 2006. (The shop carried Principia, Litespeed, Spezialized, Cervelo, Pinarello and Opera)
--
mvh. Morten Reippuert Knudsen @Merlin Works CR, Chorus 15, Reynolds 46/66

rpenmanparker
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by rpenmanparker

reippuert wrote:
rpenmanparker wrote:My Kellogg-signed 54 cm Merlin Works CR frame weighs 1,207 g. I wonder where the extra weight came from. I bought this one used, so I can't be sure of the model year, but the decals are mostly black with white outline and the C of the CR is red with white outline. I am pretty sure it is from around 2006 or so.

Image


I never did weigh mine as a raw frame, i just refer to the then pulbicied specs.

The decals of your sixe M looks like it's a 6/4 or a newer 3/2.5 version - Mine doesn't have the red letters, mine are smoke-blue and has 3/2.5 in the letters. Yours might be a 2007 or 2007 model. I seem to remember that they dropped the 6/4 in 2007 or 2008.

When i collected in the shop (only imported CR/TR Works frame/bike in denmark) they did weight the frameset though.

Frame, uncut fork, headset, front deraillure clamp and seatopst clamp - belive it came in somewhere in the 159x's gram range which was the one of the lightest size 55-56cm framesets they had weighted in 2006. (The shop carried Principia, Litespeed, Spezialized, Cervelo, Pinarello and Opera)


You can't read the decal on the seat tube, but it says 3/2.5
Robert

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mythical
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by mythical

Rush wrote:Pretty sure my Ti frame has hydroformed chainstays.
All I can say is that the tube shape ain't circular.
Image
These chain stays are definitely not made through hydroforming and the truth may not seem as romantic. All it takes is a pretty standard 1 or 1.125-inch bi-ovalized Grade 9 titanium tube (there are 2 versions).

Back in 2010, Darren and I were standing around a table and talking about the idea, he liked it so I drew up a mold in CAD in a few minutes and within a few days he had some made. Then I took a stock tube, used the mold in a vice to squeeze it length-wise, then rotate the tube 90 degrees and squeeze again, and voilà, your chainstays were born. Baum saw this seat stay design worked, implemented it straight away and found the gain in stiffness and ride quality noticeable, so they started implementing it for customer bikes. Baum can vary the ride characteristics with tube diameter and wall thickness so to make it adaptable to customer wishes. Much obliged. :wink:

The difficulty with these chain stays (as opposed to S-bend stays) is that the frame needs to be perfectly aligned in its jig upon welding so as to not be out of alignment afterwards. Darren Baum has nailed both the welding and the alignment! :thumbup:

I have many more ideas for improvements for a titanium frame but it'll have to wait until the investment capital is at my disposal. My personal predictions for a stiff, compliant and aerodynamically optimized titanium frame are that this is possible at a weight of around 900g for 56cm frame.
“I always find it amazing that a material can actually sell a product when it’s really the engineering that creates and dictates how well that material will behave or perform.” — Chuck Teixeira

by Weenie


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