|Are carbon handlebars good for road vibration dampening ?||PeterRider|
Nov 20, 2002 10:55 AM
|People say a lot about carbon forks, but do carbon handlebars help as well or is it peanuts ? What carbon handlebar do you recommend, where to buy it ? |
|re: Are carbon handlebars good for road vibration dampening ?||Juanmoretime|
Nov 20, 2002 11:27 AM
|I have a set of the Easton EC 90's and really like them, the hand postions are great. If you are somewhat extended with your current stem they make the reach to the hoods a little further. It was OK for me although I've heard some complain about having to go to a 10 mm shorter stem. I don't notice much road vibration and with my previous bar I did get some numb hand.I don't get the numbness with this bar although I also went wider on this bar. I bought mine on Ebay for $89 from 02 bike. They have that price out there all the time which is better than the $160 everyone else is charging. At $89 it's worth getting. The price puts it in the ball park of a high end aluminium bar. If I had to pay full retail, I wouldn't go carbon.|
|re: Are carbon handlebars good for road vibration dampening ?||pmf1|
Nov 20, 2002 11:31 AM
|I recently installed an Easton bar on my wifes bike. She claims it makes a difference. Easton came in 40 which is why I chose it. I'd get an Easton or Kestrel. You can attach an aero bar to the Kestrel regular bar (not the lite one, nor the Easton). They are pricey, but supposedly last a long time vs. the 2 years an aluminium bar lasts. Get them wherever they are cheapest.|
|"2 years an aluminium bar lasts"||PaulCL|
Nov 20, 2002 12:09 PM
|Huh?? My aluminum bar is about four years old and going strong. Same for my stem of five years. An olds wive's tail that these need to be replaced every two years.
I must admit that I have a real hesitation putting a carbon bar on my bike. just some unfounded fear, I suppose...
|"2 years an aluminium bar lasts"||pmf1|
Nov 20, 2002 12:24 PM
|"I must admit that I have a real hesitation putting a carbon bar on my bike. just some unfounded fear, I suppose... "
And this would be what, a new wives tale?
After 2-3 years of hard riding, its not a bad idea to change aluminium bars. They keep on going strong until they don't.
|"2 years an aluminium bar lasts"||cxer|
Nov 20, 2002 2:38 PM
|I replace my bars every year or 2 years. It's just a time bomb after that.
Bars aren't the 500gm tanks they used to be.
Nov 20, 2002 5:20 PM
|So, my current bars (TTT 220) are 5 years/42K miles old. The last set (TTT Superlegerra) was 10 years/55K miles old. Set before that was 16 years/90K miles old. I'm still waiting for the bomb to go off.|
|a CF bar can fail as easily as an aluminum one||bobobo|
Nov 20, 2002 6:58 PM
|No magic bell will ring before the carbon fiber fails and no one has shown even a hint of evidence that carbon fiber bars are any more durable than aluminum ones. If you look at most of the catastrophic failures recently on roadbikes with seatposts and bars, the majority of these failures are carbon fiber bars not aluminum.|
|where's your proof||Starliner|
Nov 20, 2002 7:29 PM
|i "If you look at most of the catastrophic failures recently on roadbikes with seatposts and bars, the majority of these failures are carbon fiber bars not aluminum"
Where did you get this information? Or is this as dumb a statement as the one about replacing your bars every two years?
Bar replacement is more dependent on whether or not you've crashed, rather than how many miles you've rode.
|search (gasp) MTBR||weiwentg|
Nov 20, 2002 7:56 PM
|some magazine tested a variety of MTB bars; they basically subjected the bars to vibrations until they failed. I cannot remember the magazine, nor can I remember the title of the post. but the result was that the Easton EA70 had the longest fatigue life, and that the EC90 had a much shorter fatigue life. furthermore, the EC90 had a very large variability in lifespan.
on the face of it, when you consider the durability of CF forks, you wouldn't think that CF handlebars would be delicate little things. they're not exactly delicate, but (at least on mountain bikes) they seem to be less durable than aluminum bars. while I am certainly not about to replace my bars every two years, I don't think Kerry's statement qualifies as dumb (based on my limited, admittedly secondhand knowledge).
|where's your proof||altidude|
Nov 20, 2002 11:10 PM
|I know many very experienced riders who routinely replace their bars every couple years and not because of crashes and I would not call any of them dumb. Perhaps yours is the dumb statement?|
|in the pudding...||merckx56|
Nov 21, 2002 1:05 PM
|I rode a set of Easton carbon bars for 2 months and the drop broke off in my hane while waiting to start a ride. I pushed on it and it just broke off. They sent me a new bar and it went quickly to the shop to trade for some Newtons!
CF bars are shite in my opinion!
Nov 21, 2002 9:52 AM
|Young's modulus for CF is on average at least three times that of aluminum. This has been measured and verified in labs around the world for years now. Furthermore the resistance to fatigue is greatly improved and is a huge reason why most advanced structures requiring high strength to weight ratios have gone to CF. Look at modern military aircraft, F1 racing cars, and Americas Cup boats if you need proof - it's not about money, it's about maximum performance. Now having said all that any engineer is fully capable of making classic design errors in making something too light, not fully understanding the properties of a material, and not testing the product. The bike industry is notorious for thinking that one can simply use a different material without adjusting the design and expect zero failures. Most of these companies have minimal R & D budgets and have a bunch of psuedo engineers that barely got through a marginal program dreaming up their products. They foist marginal designs on the unsuspecting public while they're in their infancy. Is it any wonder that some of this stuff fails? To simply look at the failures and blame the material is completely niave. |
FWIW - I've been running carbon fiber wave sailing masts for almost ten years in the grinding Northern California surf and although I've had my ass handed to me more times than I care to remember I've never broken a mast even though I've destroyed every other piece of equipment including my body at times.
|what's youngs modulus have to do with failures?||altidude|
Nov 21, 2002 3:59 PM
|Youmg's modulus is a measure of elasticity or inelasticity of a material, in other words how stiff or flexy a material is, what the heck does that have to do with a bar failing???????? What marginal enginerering program did you attend that told you Young's Modulus had anything to do with a components strength or failure?|
Nov 22, 2002 6:45 AM
|But about 10 years old (nm)||Kerry|
Nov 22, 2002 2:34 PM
|Something tells me you're not an engineer.||niteschaos|
Nov 25, 2002 12:31 PM
|Youngs moduls is of incredible importance in material selection. Young's modulus is found when you graph stress over strain. The slope of the line (where stress increases at a linear rate) is called Young's Modulus. The area on the line is called Toughness. You have to know a few other things about the material, but the Young's Modulus and the Toughness will tell you alot about how it will handle loads.|
|Area under the line nm||niteschaos|
Nov 25, 2002 12:32 PM
|For Pete's sake ...||the other Tim|
Nov 25, 2002 2:37 PM
|I hope all you "engineers" work on systems that don't affect human safety. Young's Modulus is ds/de (where s=stress, e=strain) BELOW the stress required for plastic deformation. ds/de does not have to be constant (straight line graph). It is a measure of STIFFNESS; it doesn't tell you anything about a material's failure since it only applies to pre-failure deformation. Toughness is the amount of work needed to cause rupture. It is the integral (area under the ENTIRE curve) of s(e) from zero to the rupture point (often long past the proportional region).
Handlebars (especially Al ones) have essentially failed once the YIELD stress has been reached. This is where deformation is no longer elastic, and the bars will not return to their original shape. Because of their toughness, they may be able to withstand a considerable deformation before rupture, but that will only require more work (energy) and not necessarily more stress.
The yield stress and fatigue resistance, not Young's modulus or toughness, determine when a handlebar has had it.
Nov 25, 2002 4:58 PM
|So, given a section made of CF and one of aluminum which one are you going to prefer, all other things being equal? You can look at it either way: equal weight or equal cross sectional area, but the result is still the same. |
We can split hairs until the cows come home, but the fact remains aluminum is a pretty inferior material in terms of fatigue resistance, structural rigidity, corrosion, etc., but it has one huge redeeming quality - it's fairly cheap for it's weight and thus it's relatively easy to over build (hopefully) bike components from it.. Is it any wonder why it is used in so many mass produced bikes which ultimately fail?
The toughness for aluminum isn't anything to even write home about - now stainless steel, there's some toughness.
I believe the original thread stated that there is no real difference between aluminum and carbon fiber handle bars which most of us know is simply not true.
|Doh||the other Tim|
Nov 25, 2002 5:36 PM
|I have no doubts that CF is superior to Al for handlebars, masts, and many other applications where light weight, strength, rigidity and fatigue resistance are important. But we both know that Young's modulus has nothing to do with failure. And toughness has nothing to do with a handlebar's useful life either (or chewing gum would be a good candidate).
Knowing how Al behaves under repetitive stress, I'm most amused by those who are "waiting for the time bomb".
My personal experience with Easton CF bars, however, has sent me back to AL for the present. The first pair came with holes in the epoxy that exposed fibers (you could see it through the plastic packaging). The replacements seemed fine, and I used them for a couple of months, until they slipped in a properly torqued stem clamp. Easton has added a friction material to the clamping area, and Veltec promptly replaced mine when I asked about the slipping. The invoice from Veltec showed the P/N for the returned bars as "/EASTONSCRAP". The third pair has an OD that's way too large to get the brake clamps over. I'm sure you could hang a full-sized SUV from them though.
Nov 27, 2002 11:35 AM
|Been using the Easton Monkey Light CF bar on the MTB for a year and half now. It's suffered all sorts of indignities like being ghost riden down trails, crashed into trees & rocks, dragged through the mud, left out in the rain, but there have been zero problems. Unfortuantely I can't say the same about aluminum bars I've owned. I've also had aluminum road bars fail. The slippage thing can be an issue, but all you need to do is keep the bolts properly torqued. Remember that the recommended torque setting from the stem mfr. is for an aluminum bar, not a carbon one and the stem mfr. is most concerned about the bolts stripping out of the stem (i.e. Deda). The issue is friction between the mating surfaces, nothing more. With a beefy stem design slippage is not an issue. A poor layup job never should've escaped the quality control dept. at Easton, but a few pin holes in the matrix is no big deal. The important thing is that the actual fibers which carry the load are fixed. The funny thing is that no one really complains about a poor quality aluminum bar since the error results in heavy bars as the dies wear during the extrusion process. Anything that gets returned by a customer will be scrapped for laibility reasons - they have absolutely no idea what you've done to it and to let someone else use it would be legally irresponsible. |
In the end how can you say that a CF handle bar is untrustworthy, but you have no issues with a CF fork? Couldn't all of the issues with the handle bar also apply to the fork (i.e. slippage, layup, etc.)? Seems like a double standard to me. Why aren't we *all* still using aluminum or steel forks?
You know full well that chewing gum doesn't have any toughness, by the definition, since there isn't any significant area under the stress strain curve (think about at what psi gum yields - single digits if you're lucky)
|Haha, I thought the chewing gum thing would get past you.||the other Tim|
Nov 27, 2002 4:25 PM
|The point was simply that lots of unsuitable materials have high toughness because they exhibit miles of (plastic) strain before separation. I want bars to have a high yield limit, stiffness and fatigue resistance, and CF does deliver those.
Those weren't pinholes in bar #1; there were several voids about 0.25" in diameter. The bars probably never would have failed, but I returned them to the vendor without even installing them ... just because. When I asked Veltec about the slipping w/ bar #2, I expected them to recommend a higher torque, but they wanted to replace them, and it seemed like an issue they were familiar with. I had never used a torque wrench on a bar clamp before, but these were my first CF bars, and I installed them according to spec. If I had done it by "feel", they probably wouldn't have slipped. The whole thing just left me with a bad taste for Easton. I still don't have any issues with their engineering, or CF in general, but their quality is out of control. I'll probably give Krestel or Cinelli a shot.
I complain about poor quality Al bars. I complain about everything.
That's an excellent point about forks.
|An Engineer's Opinion! To the rescue!||mazobob|
Nov 23, 2002 8:40 PM
|Having over 20 years in nondestructive test engineering. I have seen numerous failures and you CAN Have a failure with age. I recently tested a set of bars that had been in Louisiana for 3 years and 15,000 miles. They had 6 HAIR LINE Cracks and the bomb was READY TO GO OFF!!!!! I have test numerous carbon bars with ultrasound and have yet to find a problem. Do I change my bars? You bet your sweet ass!|
|An Engineer's Opinion! To the rescue!||altidude|
Nov 23, 2002 9:29 PM
|Numerous CF bars with no failures???? Yeah, go tell that to the Australian triathelte who nearly killed himself 2 weeks ago on a big high speed descent when his nice CF seatpost failed and cattled prodded him in his you know what just before he went down. Any material component can fail with enough repetitive stresses put upon it combined with improper design.|
|An Engineer's Opinion! To the rescue!||grzy|
Nov 25, 2002 5:06 PM
|Listen to what you said: the failure wasn't a function of the material but rather the design. |
How novel - seems I made that point earlier. Try and mount your seat on a wooden tooth pick and it will fail. Is this a fault of the material? Nope. Learn to distinguish cause from effect it will serve you well.
Point is CF is inherently stronger and more fatigue resistant than aluminum and when designed properly you should be able to produce superior products .Ask yourself how many aluminum Cannondale or Specialized frames have cracked under normal use. That people don't spend the brain power to do this isn't a fault of the material. There are lots of high dollar programs with good R & D budgets that do this - just b/c there are a bunch of hacks in the bike industry doesn't prove a thing.
|2 years ?||Leroy|
Nov 21, 2002 4:53 AM
|I've got an old 3t forma - got to be pushing 7 or 8 - that seems just fine. I'll let you know if it breaks. What's the old wife say about CF shelf life?|
Nov 22, 2002 12:30 AM
|I'm one of many that replace bars on a regular basis. Ok, I would leave my bar on for 8 years if I only rode a couple hundred miles a year. Exactly how long do you intend to keep riding a bar? Until it breaks? You'll tell us if it breaks? Your face will tell everyone if your bar breaks!
Many racers are putting in 10-15,000 miles per year. It's not a big deal whether you replace them or not. For some people, $30-$70 per year or 2 is not a big deal.
|Re: Wake up||Leroy|
Nov 22, 2002 8:40 AM
|What else should be replaced on that basis? Aluminum frames?, Carbon forks ? Whole bicycles? Why have we not heard the outcry from all the consumer product safety types? Never having seen or heard of such breakage from anyone I know, or anyone I know to be credible, I just do not believe it. Does the airforce know how fragile aluminum parts are? All due respect, but this just sounds like "racer" grandiosity, or a racer with a sponsor. I guess if it makes you feel better you should replace...|
|Re: Wake up||Wattie|
Nov 24, 2002 8:20 AM
|I guess that I might not be "credible" according to your criteria (though you don't say what they are), but I have had painful and very real experience of an aluminium handlebar breakage. I had just hit the bottom of a fairly steep hill at about twenty-three miles an hour and stood on the pedals to attack the first part of the gradient, when my bars snapped about halfway along the top. Needless to say I hit the tarmac very hard. I consider myself very lucky indeed because it happened without any warning whatsoever and, had I been on a busier road, it could have thrown me into the path of a car or truck. As it was I was able to ride home, despite the pain, and luckily it was only a couple of miles which I negociated with considerable difficlty given that half my handle bars were hanging by the brake and gear cables. The bars were about four years old and were ITM 225s. I for one will always replace bars on a regular basis. And obvioulsy one should make a habit of replacing them if you crash. I don't know if I am a credible witness, but I do know I was actually very lucky. Ironically I had read an article only a few days earlier about just this issue and had ben rather cynical about the likelihood of such a failure. I know better now.|
Nov 24, 2002 11:44 AM
|Guess I'll check out the old 3t's.|
|"2 years an aluminium bar lasts"...was this spoken by Yoda? (nm)||ColnagoFE|
Nov 21, 2002 1:11 PM
|Crash you will...road rash you will get. ;-) nm||OffTheBack|
Nov 25, 2002 9:49 AM