|Why oversized bars and stem?||Iwannapodiumgirl|
Jul 30, 2002 1:13 AM
|Can someone please explain to me the cost/benefit of oversize bar and stems?
Whilst I think the aim is to make things "stiffer", is the quality of the ride sacrificed?
ps no wise cracks about things getting "stiffer"... this is a family board!
|I wouldn't let my family on this board. The only reason I||Paul|
Jul 30, 2002 3:27 AM
|believe they make "oversize" bar/stem, is for strength, or just trying to do something to make money. It's heavier then the standard bar/stem. wonder if the pros use it? don't see how that would affect ride quality, less flex, better ride in my book. |
Personally, i wouldn't buy it. I've never had a problem with the standard stuff.
Jul 30, 2002 4:38 AM
|Dman Rinard or some one that did the test showed no difference in stiffness between standard and OS.
Buy what you think looks better
Jul 30, 2002 12:09 PM
|I went from a profile bar and cinelli groove stem to a deda magic bar/stem setup on my merckx and it made a world of difference. The ride quality didn't change, but there was a decided difference in the stiffness of the frontend. The most noticeable was when out of the saddle and sprinting. OS IS stiffer, by a longshot!|
Jul 30, 2002 4:50 PM
|And you just know this, right? To be objective you'd want to be able to measure things and start with some of the better standard components as a basis of comaprison. In the end how can you say that the front end is stiffer yet ride quality didn't change - or aren't the two linked in your world?|
Jul 30, 2002 5:19 PM
|I weigh 180 and pull mighty hard on the bars when out of the saddle. Trust me when I tell you that I noticed a difference. Some of the neophytes who seem to flock to this board wouldn't notice the difference simply because they haven't ridden enough different things or simply just ride their bike and aren't really aware of the differences. These are the same people who say that they're caad3 c'dales are the best riding bikes they've ever been on. See the correlation? The fork did not change, only the bar and stem. When riding on the top of the levers their is NO appreciable difference (vertcal plane). When out of the saddle going for the line, there is less lateral flex in the stem and bars (horizontal plane). If you are telling me that my 17 years on the bike haven't given me some sense of what my bikes are doing or how they feel under me, then you, my friend, are full of the proverbial crap! I was offering opinion and my real world, 250-350 miles a week analysis of what I experienced! If you don't agree, great, but don't deride what I offered up!|
Jul 30, 2002 6:34 PM
|Grxy, of course the ride felt better... Merckx56 changed from a US handlebar to an Italian combo!
Sorry, couldn't resist ;o)
Jul 30, 2002 6:36 PM
|Sorry about the typo Grzy....|
Jul 30, 2002 6:13 PM
|What makes you sure that it is the oversizing that is making the difference. There are all sorts of stems/bars of various stiffnesses out there. Maybe you just happened to pick a naturally stiffer combo. Maybe it's because of the different bolt patterns between the Deda and the Cinelli.|
|read my post above!!!!!!!!!!!!!||merckx56|
Jul 31, 2002 7:21 AM
|I was offering opinion on what I know and have changed to and from! I've ridden MANY different bar/stem combos and this by far the stiffest! The fact that it's oversized leads ME to believe that oversize is the reason why!|
|The Fuzzy Line||grzy|
Jul 31, 2002 11:19 AM
|Notice the fuzzy line between Mr. merckx56's opinion and the instant conclusion that it's due to it being over sized. Yep, that's the scientific mind at work folks - totaly unencumebered by the thought process. Wonder what would happen if we were to give Mr. M two bars of the exact same size, but one was noticable stiffer than the other? What opinion would he hold and more importantly what conclusions would he leap to? What if he were presented with a smaller diameter bar that was actually stiffer than an oversized one? Gentlemen, I give you carbon bars from Kestrel, Easton and others.|
|The Fuzzy Line||merckx56|
Jul 31, 2002 1:14 PM
|i'll send you my broken, piece of shit, flexy easton bar if you want it. the drop broke off in my hand while waiting to go on a ride. i wasn't even pedaling the bike. as for carbon bars and marketing hype...you think oversized is expensive, buy a kestrel bar. the easton was given to me at the show, in vegas, by a rep to try. it broke and wasn't NEARLY as stiff as the magic or newton bars that i ride currently.
if you would like to start the personal attacks, we can do that too. i have leapt to one overwhelming conclusion in the past 18 months that i have been frequenting this board, and it is this;
you always seem to doubt what others say or try to poo-poo on an opinion if you don't necessarily agree with it. i personally don't give a flying shit what you think of what I ride or how i my come up with my conclusions. many things are based on opinion, including mine of you! i was merely talking about my PERSONAL experiences with different bars. yours, of course, may vary!
don't be such a cockknob. accept opinions, glean from them what you will and move on. i don't know why i let idiotsticks like you get under my skin, but i do sometimes, especially when personal attacks are unprovoked, such as yours was on me! please try to reign in your attacks on others!
|Pot calling kettle black||grzy|
Jul 31, 2002 2:57 PM
|Think about it. |
You've read so much into things, concluded things that weren't there, generalized and gotten emotional that I think there's only one solution. You need a hug and a nap.
If you give me that broken Easton bar I promise to stick it some place where it will do some good - up your backside. It might help with your "leaping problem."
|IT IS STIFFER!! heres why..||julio|
Jul 30, 2002 9:37 PM
|I'm an engineer - so I'm not making this up or basing my thoughts on feel alone. A round bar with a larger diameter is stiffer in bending than one with a smaller diameter (assuming same material, wall thickness, length, etc.) it's a scientific fact. The larger diameter increases the moment of inertia (I=Pi/64(outer dia^4 - inner Dia^4)), the moment of inertia is used in the denominator of the stiffness relationship, therefore a larger moment of inertia gives you a stiffer beam.
Ever wonder why a 2x4 is stiff in one direction and flimsy in another? Same idea. This is what started the trend in oversized, thinwall tubing like Cannondale uses. See how that diameter value gets raised to the forth power in the equation above - this shows us that wall thickness can be reduced as the outside diameter is increased and it will still be stiff (and light!). This is why things are made from tubing and not solid bars, the material in the middle does very little to increase stiffness.
I haven't ridden enough of these oversized bars to tell you if its physically noticeable, but like most things it probably comes down to personal preference. If you can feel very small deflections chances are you'll feel the difference. Sorry to bust out the equations but a lot of BS floats around here and I though I'd dispell any misconceptions.
Jul 31, 2002 7:00 AM
|it is only stiffer as you say if everything else remains the same(wall thickness, material, etc.). however, the main reason manufacturers go oversize is to maintain stiffness while losing weight. to do this, they thin the wall thickness of the tubing while increasing the tube diameter. a thin-walled oversize tube is not necessarily stiffer than a smaller diameter tube with thicker walls. it can be, but isn't always. it depends on how it's made, and to what extent they thin the tubing walls, or increase the tubing diameter.
as an example, the feb. 1996 issue of bicycle guide did a comparison test of seven mondonico bicycles, each built with a different type of columbus steel tubing. there was a sidebar explaing how the newer lighter, stronger steels were not necessarily stiffer than the old heavy tubes. the stiffness of a tube is proportional to its weight multiplied by its diameter squared. a 1 1/4 inch, 250 gram el-os tube(WxDsquared)=390. a 350 gram, 1 1/8 aelle tube equalled 443. therefor, the lighter, oversize tube was not as stiff as the heavier normal sized tube. it could be, but it would either have to use thicker walls, losing the weight savings, or a larger diameter.
Jul 31, 2002 11:26 AM
|Sure, in theory, all other things being equal the engineering analysis is perfectly valid. Then there's the reality that most of the Deda stuff is poorly designed and and poorly made with bad quality control throughout their manufacturing process. To take a sample of one or two items and draw absolute conclussions and attribute everything only to the engineering principles that you think are at work is simple minded and naive. |
Throw some carbon fiber bars into the mix with at least three times the tensile strength and now we're talking some real improvements.
Jul 31, 2002 1:22 PM
|I wasn't comparing a specific bar, manufacturer, or manufacturing process. Obviously if you buy a low quality bar that was cheaply made and poorly designed it will probably not stack up to a high quality one. I know that all "oversized" bars aren't neccesarily stiffer than standard bars, I was simply explaining the theory behind oversized bars (that's why I said assume similar conditions).
I interpreted the question to be asking, "Is there any truth in oversize bars or is it all marketing hype?" There is truth in it, whatever a specific manufacturer decides to do with it is up to them. Everyone claims to have the best components, do you homework and figure out what's really good and what isn't. You can't assume that because a certain theory or material is used that it was used right.
That Bicycling tubing comparison article sounds interesting. I wonder why none of the magazines write anything of substance anymore. It seems like every article is 1/2 a page long and barely scratches the surface. I guess pretty pictures sell more mags..
Jul 31, 2002 3:51 PM
|Not that many people have enough of a technical back ground to understand the articles much less write them. Pretty much the trend in the bicycling press is the USA Today approach - give 'em a quick and simple sound bites that they might remember. Really it's an insult to anyone with average intellegence, but hey I guess they know their market demographics. The magazines are beholden to their advertisers and they avoid saying anything negative least they put their advertising revenue at risk. The whole bicycle industry is a tad on the incestuous side of things - not unlike many industries. |
Many times people want to focus in on just one aspect of a design and ignore everything else - the oversized bar issue is becoming a classic. Here's Deda a relatively new manufacturer fast becoming known for dubious quality and engineering. Besides Campagnolo and Ferrari, Italy is also the land that brought you Fiat. But hey, they sponsor lots of pros and their stuff shows up in lots of photos - some people call this marketing.Their 215 bar doesn't weigh anything close to 215 grams (it's namesake) and their original Newton stem was voluntarily recalled for the bolts stripping which they liked to blame on ham-fisted mechanics (where did we all come from suddenly). So rather than deal with the obvious problems they punt and push the oversized concept and cloud the picture. Is the bar stiffer b/c of the larger diameter or more material than planned or both?
Typical aluminum tubing is extruded through a die under pressure and over time dies wear and the extrusion wall thickness grows. It costs money to replace dies thus the weight problem. To put a bulge in a section requires either swaging down the ends or expanding the center and cold working issues come into play. Now either the wall thickness in the center is reduced or the the thickness in the ends is increased, but uniformity in the wall section is not maintained, as in a unifrom diameter tube, and how this transition is handled does matter. Hmmmmm, more complex than one might have thought. Certainly not something the poets at Bicycling mag are going to tackle. Now many engineers know that plain aluminum is actually quite soft and what really matters is the alloy components and more importantly the specific heat treatment process. If you botch the heat treatment by welding or poor quality control suddenly the material properties are lost, but this is true for any aluminum bar manufacturer. Then there's the whole element of fatigue and the fact that aluminum doesn't last long when flexed and cycled. You can in fact buy two bars that weigh the exact same but are vastly different in price due to the manufacturing processes and will be obvious in their stiffness. So when someone simply says and oversized bar is stiffer it is a gross simplification that may not necessarily be true. It would be like saying my last car was a Fiat, it was a piece of junk. I bought a Mercedes and it's great. Therefore German cars are obviously much better than Italian cars. While the conclussion might be true in the end, the reasoning that got you there is flawed. Left out of the anaylysis were things like Ferrari, Lamborghini, etc.
It's relatively simple to measure bar stiffness. Hang a known weight on a bar mounted in a rigid steel fixture and measure the deflection with a dial indicator. Of course you'd need a slew of bars so that you have statistcally valid results. A simple test is to walk into your LBS grab some bars, place one side on a carpeted floor and stand on it with your feet. with both hands grab the drop by the other side and tug upwards. It's pretty easy to feel and see what's flexy and what's not. Try a carbon bar just for comparison against any aluminum bar - the results are amazing. Sure carbon is expensive, but not when one figures it last at least 2 or 3 times longer than aluminum and there's a performance advantage. Why if aluminum were so great why do we even bother with expensive
|i believe they were deda bars||rufus|
Jul 31, 2002 5:40 PM
|that were breaking during the tour's team time trial. i can't remember the team, but three riders had their aero bars break, and i saw one banesto rider's break just as he came up to the line. also rumsas' loose bolt during the final time trial.
personally, i believe that you can go too far in the quest for light weight, and some of these bar manufacturers may be pushing that line.
|Thanks for the comments...||Iwannapodiumgirl|
Jul 31, 2002 3:02 PM
|it appears prima facie that, all things equal yada yada yada oversize bars and stems will be stiffer - this is what I am looking for.
Yet I note the comment that it depends on wall thickness, so I guess it is back to the various manuf. specs.
Thank you to everyone for their opinions.
Grzy, thanks for making the chat, shall I say, interesting!