Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-09-12, 08:28 AM   #1
delcrossv 
Senior Member
Thread Starter
 
delcrossv's Avatar
 
Join Date: Nov 2011
Location: Scalarville
Bikes:
Posts: 1,459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Titanium frames and aging

I've found a titanuim framed trike for my wife (who can't balance a two wheeler) and in asking around I got this response:

"But titanium ages (becomes brittle) and it might be hard to find someone who can weld titanium."

First I've heard of this- I know about hydrogen embrittlement in welding Ti, but never heard that the tubing gets brittle.
Anyone notice older Ti frames cracking?
__________________
Lightning P-38 / M5 M-Racer/Ryan Vanguard
delcrossv is offline   Reply With Quote
Old 07-09-12, 09:08 AM   #2
fiataccompli
Steel Member
 
fiataccompli's Avatar
 
Join Date: Jul 2008
Location: Knoxville, TN
Bikes: N + 1
Posts: 1,446
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Did you hear that from someone who sells carbon fiber bikes?
fiataccompli is offline   Reply With Quote
Old 07-09-12, 09:12 AM   #3
delcrossv 
Senior Member
Thread Starter
 
delcrossv's Avatar
 
Join Date: Nov 2011
Location: Scalarville
Bikes:
Posts: 1,459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by fiataccompli View Post
Did you hear that from someone who sells carbon fiber bikes?
LOL. I know about CF failure modes too.
__________________
Lightning P-38 / M5 M-Racer/Ryan Vanguard
delcrossv is offline   Reply With Quote
Old 07-09-12, 09:38 AM   #4
gizzsdad
Fat but Fit!
 
Join Date: Apr 2007
Location: Iowa
Bikes: Lynskey R340, Lynskey R230, Fisher Zebrano
Posts: 174
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Considering that most folks consider Ti a lifetime frame - count me as skeptical of this claim.
gizzsdad is offline   Reply With Quote
Old 07-09-12, 10:16 AM   #5
DCB0
Banned.
 
Join Date: Apr 2011
Bikes: CCM Torino 76
Posts: 937
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
From whom did you hear this and do you have good reason to trust his/her opinion?

I used to work for a company that had its own brand ouf Ti bikes manufactured, and the failure rate of the frames was much much lower than the aluminum bikes we sold. I have never before heard this statement about Ti becoming brittle. I got myself a Ti frame while I worked there and it is the only MTB frame I have ever had that has lasted longer than 2 years without breaking.
DCB0 is offline   Reply With Quote
Old 07-09-12, 10:27 AM   #6
delcrossv 
Senior Member
Thread Starter
 
delcrossv's Avatar
 
Join Date: Nov 2011
Location: Scalarville
Bikes:
Posts: 1,459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by DCB0 View Post
From whom did you hear this and do you have good reason to trust his/her opinion?

I used to work for a company that had its own brand ouf Ti bikes manufactured, and the failure rate of the frames was much much lower than the aluminum bikes we sold. I have never before heard this statement about Ti becoming brittle. I got myself a Ti frame while I worked there and it is the only MTB frame I have ever had that has lasted longer than 2 years without breaking.
I have no reason to especially trust that person's opinion aside from he is in the bike business. There's a lot of "gas" going around-I've seen some here with folks saying that Ti frames have cracked on them. So I thought to ask the question directly.

FWIW I've seen nothing in the literature on this but I'm not a metalurgical engineer. having a bad weld is one thing- that's pretty common with bad technique.
__________________
Lightning P-38 / M5 M-Racer/Ryan Vanguard
delcrossv is offline   Reply With Quote
Old 07-09-12, 11:52 AM   #7
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 4,895
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
It can fatigue and crack as will aluminum and less often steel. If it was welded properly (shield gas in and outside the tube until the temp dropped below 800F) it should be ok.
davidad is online now   Reply With Quote
Old 07-09-12, 12:12 PM   #8
DCB0
Banned.
 
Join Date: Apr 2011
Bikes: CCM Torino 76
Posts: 937
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by davidad View Post
It can fatigue and crack as will aluminum and less often steel. If it was welded properly (shield gas in and outside the tube until the temp dropped below 800F) it should be ok.
Steel fatigues and cracks, too, if subjected to stress above a certain point - which is likely for lightweight steel frames.

I would think a recumbent trike would generally be overbuilt enough to keep stresses in the frame low, but it varies from bike to bike.
DCB0 is offline   Reply With Quote
Old 07-09-12, 12:32 PM   #9
Staggerwing
Senior Member
 
Join Date: May 2007
Bikes:
Posts: 252
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
From what I've read, most of this issues with titanium bikes cracking is directly attributable to poor welding technique. More specifically, proper technique calls for purging the inside of the tubing, along with the exterior puddle, with argon gas.

Nice little write-up over on Firefly's site:
http://fireflybicycles.com/1112
Staggerwing is offline   Reply With Quote
Old 07-09-12, 12:40 PM   #10
jerrycan42
Senior Member
 
Join Date: Jul 2012
Location: Waterloo
Bikes: 2005 Norco CRR2, 1994 Kona Cindercone, 1999 Cannondale R1000D
Posts: 427
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
IIRC, doesn't ti, in general, have a much higher fatigue threshold than steel or aluminium? I seem to recall some 1st gen rear suspension bike where the rear swing arm was just bending ti (sans a point fulcrum of sorts).... Oh if only I could find that article...
jerrycan42 is offline   Reply With Quote
Old 07-09-12, 12:44 PM   #11
woodway
Squeaky Wheel
 
woodway's Avatar
 
Join Date: Nov 2008
Location: Woodinville, WA
Bikes:
Posts: 1,460
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Seems that if Ti got brittle with age, we would have a whole bunch of airplanes falling out of the sky...
woodway is offline   Reply With Quote
Old 07-09-12, 02:08 PM   #12
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,932
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 352 Post(s)
Quote:
Originally Posted by delcrossv View Post
I've found a titanuim framed trike for my wife (who can't balance a two wheeler) and in asking around I got this response:

"But titanium ages (becomes brittle) and it might be hard to find someone who can weld titanium."
There's all sorts of nonsense said about all frame materials. Ti is used in some extremely harsh environments, and holds up very well there, surpassing even the best steel alloys.

However there is some truth in the issue of welding being more difficult than either steel or aluminum, so that might be a factor if you're planning lots of modifications.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 07-09-12, 02:10 PM   #13
Chombi 
Senior Member
 
Chombi's Avatar
 
Join Date: Jul 2009
Bikes: 1986 Alan Record Carbonio, 1985 Vitus Plus Carbone 7, 1984 Peugeot PSV, 1972 Line Seeker, 1986(est.) Medici Aerodynamic (Project), 1985(est.) Peugeot PY10FC
Posts: 10,876
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
I think he got it cofused sith Magnesium that does degrade with age.
Most classic race/sport car owners who own cars with magnesium wheels know this very well and are forced to retire wheelsets on their cars after they get a certain number of years old so they can still drive/race their cars safely. My uncle had to change out the Halibrand magnesium wheels on his 1965 427 Cobra a couple of years ago because of this.

Chombi
Chombi is offline   Reply With Quote
Old 07-09-12, 03:39 PM   #14
Drew Eckhardt
Senior Member
 
Drew Eckhardt's Avatar
 
Join Date: Apr 2010
Location: Sunnyvale, CA USA
Bikes:
Posts: 5,135
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 62 Post(s)
Quote:
Originally Posted by jerrycan42 View Post
IIRC, doesn't ti, in general, have a much higher fatigue threshold than steel or aluminium?
Yes.

Quote:

I seem to recall some 1st gen rear suspension bike where the rear swing arm was just bending ti (sans a point fulcrum of sorts).... Oh if only I could find that article...
Ibis. 5" of travel from frame flex.
Drew Eckhardt is online now   Reply With Quote
Old 07-09-12, 05:59 PM   #15
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 28,917
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
A Ti frame that is made and welded of a proper alloy using proper welding techniques(emphasis on proper in both cases) can easily be an heirloom. I have a '96 vintage Litespeed Catalyst with about 75,000 miles on it and it is still in perfect shape and i know of other litespeeds with well over 100,000 miles so mine isn't a rarity. So a good frame by a good maker will last nearly indefinitely. Litespeed, Titus, Moots, Seven and others make very durable Ti frames.

That said, a poor choice of alloy (CP grade instead of 3Al/2.5V or 6Al/4V) and/or welding without adequate attention to inert gas shielding can and has produced brittle, crack-prone frames. One of the first commercial Ti frame, the Teledyne Titan from the early 70's was made of "standard diameter" CP grade titanium and developed a well-deserved reputation for early failure. Also, some '90's Russian frames made of CP Ti and without adequate welding care were also very failure prone.
HillRider is offline   Reply With Quote
Old 07-09-12, 07:35 PM   #16
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: In Central IN
Bikes: RANS V3, RANS V-Rex, RANS Screamer
Posts: 13,394
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
The title led me to believe that this thread would be about older guys lusting after titanium bikes.

Been thinking that the ti version of my V-Rex would be nice to ride...................



Just an observation: Not much discussion of broken/breaking ti frames seen on BF. Of course, not a ton of ti frames.
Attached Images
File Type: jpg ti-rex.jpg (51.2 KB, 10 views)
__________________
RANS V3 - Ti, RANS V-Rex - cromo, RANS Screamer - cromo
JanMM is online now   Reply With Quote
Old 07-09-12, 08:24 PM   #17
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Bikes: I never learned to ride a bike. It is my deepest shame.
Posts: 3,769
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Back-Handed Defense of Ti Frames

I love my Ti frame. But it is in the process of failing. I am still riding it, but the top bit of the seattube, between the tops of the seat-stays, the stress of me riding and landing heavily on the super extended seatpost is bending back quite noticeably. I am a big guy.

I have seen a couple other ti frames that had failed, due to crashing and manufacturing defects. But is very very seldom.

I am curious - who is the maker of this trike?
LarDasse74 is offline   Reply With Quote
Old 07-10-12, 08:17 AM   #18
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 4,895
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
Quote:
Originally Posted by woodway View Post
Seems that if Ti got brittle with age, we would have a whole bunch of airplanes falling out of the sky...
Airplanes are made with aluminum and are inspected regularly because the material has a finite fatigue life.
davidad is online now   Reply With Quote
Old 07-10-12, 08:53 AM   #19
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,932
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 352 Post(s)
Quote:
Originally Posted by davidad View Post
Airplanes are made with aluminum and are inspected regularly because the material has a finite fatigue life.
Yes, ..... and no.

Aluminum, and other metals do have a fatigue life, but that's based on stress cycles, not on time. If you parked a plane on the tarmac for 5 years, there'd be no fatigue of the aluminum.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 07-10-12, 09:07 AM   #20
woodway
Squeaky Wheel
 
woodway's Avatar
 
Join Date: Nov 2008
Location: Woodinville, WA
Bikes:
Posts: 1,460
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Quote:
Originally Posted by davidad View Post
Airplanes are made with aluminum and are inspected regularly because the material has a finite fatigue life.
Well, kinda. Airplanes are made up of many materials. A 787 is 50% composites, 20% aluminum and 15% titanium. You can bet that Boeing would not be using titanium metal on that airplane is there were any concerns about the metal becoming brittle with age. Read for yourself here:

http://www.boeing.com/commercial/aer...icle_04_2.html

Titanium has been widely used in military and commercial aircraft for many years for it's strength, light weight and resistance to corrosion and fatigue.
woodway is offline   Reply With Quote
Old 07-10-12, 03:37 PM   #21
secretagent
Senior Member
 
Join Date: Feb 2010
Bikes:
Posts: 101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
SR-71 Blackbird 80% Ti, I'd imagine a bit more extreme stress than a bike frame undergoes?
secretagent is offline   Reply With Quote
Old 07-10-12, 04:02 PM   #22
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 28,917
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Quote:
Originally Posted by secretagent View Post
SR-71 Blackbird 80% Ti, I'd imagine a bit more extreme stress than a bike frame undergoes?
True, but since it hot so hot during every flight it "anealed" itself each time. But, you are correct, Ti was chosen for it's construction to withstand both the heat and stresses that Al was unsuiteable for.
HillRider is offline   Reply With Quote
Old 07-10-12, 07:12 PM   #23
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Bikes:
Posts: 11,606
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Quote:
Originally Posted by delcrossv View Post
"But titanium ages (becomes brittle) and it might be hard to find someone who can weld titanium."
Whoever said this was thinking simplistically and may not know their metallurgy. First, you need to determine the exact titanium alloy used:

CP - commercially pure, weakest, but still roughly the same fatigue-life as steel, much more than aluminium

3/2.5 - 3% aluminium and 2.5 vanadium, most commonly used in bike-frames, about 5-10x the fatigue-life of chromoly steel

6/4
- 6% aluminium, 4% vanadium. strongest used in bike-frames, has 20-30x the fatigue-life of chromoly steel

Basically, if you would consider buying an aluminium or steel frame, pretty much any titanium frame will outlast them. Problems with titanium frames have never come from the material. Rather from design and manufacturing issues. Such as insufficient back-flushing of the tubing or not using a welding chamber. This causes hydrogen embrittlement of the joints that can result in cracks later. Aluminum and steel frames also face these issues as well.


BTW - the 167bhp NCR Leggera supermoto is based upon a Ducati and weighs in at 300-lbs, or 150-lbs less than the factory bike. It has a 10-lb titanium frame and a titanium swingarm made by welding custom-formed sheets together (weighs 1/2 the original aluminium unit). Every single nut and bolt on that bike has been replaced with titanium versions, many hollowed-out for even more weight-savings. I won't mention anything about the plentiful use of carbon-fibre in the latest Ducatis or GP bikes...

Last edited by DannoXYZ; 07-10-12 at 07:23 PM.
DannoXYZ is offline   Reply With Quote
Old 07-10-12, 07:42 PM   #24
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Bikes:
Posts: 11,606
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Quote:
Originally Posted by woodway View Post
Well, kinda. Airplanes are made up of many materials. A 787 is 50% composites, 20% aluminum and 15% titanium. You can bet that Boeing would not be using titanium metal on that airplane is there were any concerns about the metal becoming brittle with age.
Not to mention the titanium is used in the highest stress area of the planes, the jet-engine turbine-fan blades!!!
DannoXYZ is offline   Reply With Quote
Old 07-10-12, 09:31 PM   #25
Burton
Certified Bike Brat
 
Burton's Avatar
 
Join Date: Jan 2011
Location: Montreal, Quebec
Bikes:
Posts: 4,251
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
As far as I know, all the tubing used to manufacture bicycles is aircraft quality. Specifically it starts as stock tubing normally used for hydraulic lines internally in aircraft wings. There are some parts and areas on aircraft that are easy to access and that get regular maintenaince - this isn't one of them. So if anyone is having fatigue issues with their titanium bikes - its a manufacturing issue - either a welding quality issue or a product design issue. The material is sound.

Kona dabbled in titanium bikes for a short period of time. They didn't drop titanium because of fatigue issues - THEY were dropped by their tubing supplier because the orders were to small to be worth dealing with relative to their regular aerospace customers.

Last edited by Burton; 07-10-12 at 09:36 PM.
Burton is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 05:27 PM.