iatola says Posted June 19, 2005 Report Share Posted June 19, 2005 Carbon fibre is a very useful composite. It can prvide 6 times the tensile strength of steel with much much less weight. Current handle bar trends are leaning towards Carbon now with ONZA catering for the masses not just the minted using it. It is a band wagon many of us have jumped on. Yet ive seen many bars, snap. It is not nice, ive also seen people with carbon splinters across there chest. So why when there is soo much stress on 29/30" bars due to the leverage are we pushing lightweight bars in trials. Composites can provide massive strength but are polarised (means strength is directional) Where as metal which is granular has equal strength throught. Why have we not seen and equal or greater push to save that extra 100 or 105 grams on stems. Ive never seen a stem break. Racing bikes use carbon stems, they dont break. Ok so its more stress than on a racer, but there is real potential for carbon stems which is not being taken. I'd make them if I had a way of heating polyacrylonitrile to 1100 degrees. I dont think Gas mark 9 will cover it though. Trev (By the way I ride street (real street not pansy UCI style street) and dont care how much my bike wieghs) Quote Link to comment Share on other sites More sharing options...
philking Posted June 19, 2005 Report Share Posted June 19, 2005 I must admit it is a very good thought... i mean a stem is approx 1/5 the length of the bars and therefore is 1/5 less likely to break (my reasoning may be a bit incorrect, but thats the idea). So it is a very good point.... why not carbon stems? Anyone who knows please post, it is an interesting point. Quote Link to comment Share on other sites More sharing options...
Caleb Posted June 19, 2005 Report Share Posted June 19, 2005 I dont understand what you are asking people. Is it why no trials company has produced a carbon fibre stem? if so . . I suppose its because it has so much stress applied and is so small its easier to make them with more readily available materials and traditional methods. Stems have been made with carbon effect for aesthetics but i suppose as carbon has the weak stereotype going around it they wouldnt be too popular anyway. Look at the coustellier? forks the cf ones they looked real nice but had a huge price tag because of the materials and methods used to make them, i suppose expense would be another high factor in buying the stem, and markets dont want to make this risk when they know alluminium will sell. Quote Link to comment Share on other sites More sharing options...
JT! Posted June 19, 2005 Report Share Posted June 19, 2005 Didn't know you could get a carbon fiber stem. Anything that needs threds it isn't a good idea with carbon, so thats where the problem could lie. Quote Link to comment Share on other sites More sharing options...
iatola says Posted June 19, 2005 Author Report Share Posted June 19, 2005 (edited) the equation Force x Distance. If you aplly this to stress on bars, especially on high BB bikes where you ride over the front alot then the stress on the bars is far greater because you have 14/15" of leverage each side. Now a stem is much shorter than 15" at least on stocks. And stems can be made from Carbon JT! they use metal inserts for the threads. Carbon stem link " Bike huts" new carbon stem is about £40 quid Edited June 19, 2005 by iatola says Quote Link to comment Share on other sites More sharing options...
JT! Posted June 19, 2005 Report Share Posted June 19, 2005 the equation Force x Distance. If you aplly this to stress on bars, especially on high BB bikes where you ride over the front alot then the stress on the bars is far greater because you have 14/15" of leverage each side. Now a stem is much shorter than 15" at least on stocks. And stems can be made from Carbon JT! they use metal inserts for the threads. Carbon stem link " Bike huts" new carbon stem is about £40 quid ← In that case i think that there isn't a reason, it's the same reason there wasnt carbon bars a few years ago. Make one? ^_^ Quote Link to comment Share on other sites More sharing options...
Littleharrys Posted June 19, 2005 Report Share Posted June 19, 2005 (edited) Yeah I snapped my Azonic shorty stem last summer. It was v strange, it snapped from the bottom upwards when pulling up on the back wheel. If you want a picture (The last in the slide show) http://spaces.msn.com/members/littleharrys...t&_c=photoalbum If it doesnt work(which happens alot) message me - littleharrys@hotmail.com Harry. Edited June 19, 2005 by Littleharrys Quote Link to comment Share on other sites More sharing options...
Matt Burrows Posted June 19, 2005 Report Share Posted June 19, 2005 I've snapped 2 stems, not fun. I've not heard of anybody snapping Onza carbon bars either? I certainly don't think they are weak anyway? I'm sure somebody will make a carbon trials stem some day, but would it really save that much weight? You can get some silly light alu stems already so I don't see it as being a major deal. Quote Link to comment Share on other sites More sharing options...
JT! Posted June 19, 2005 Report Share Posted June 19, 2005 I've snapped 2 stems, not fun. I've not heard of anybody snapping Onza carbon bars either? I certainly don't think they are weak anyway? I'm sure somebody will make a carbon trials stem some day, but would it really save that much weight? You can get some silly light alu stems already so I don't see it as being a major deal. ← My monty stem is really light compared to my old misson stem (not 1.5"). If it was to be made lighter, it couldn't be by much at all. Quote Link to comment Share on other sites More sharing options...
haydon_peter Posted June 19, 2005 Report Share Posted June 19, 2005 I once found a crack in the front clamp of my Azonic ORC stem... I just changed the front clamp and threw the cracked one in the bin as a friend had an old clamp spare... Quote Link to comment Share on other sites More sharing options...
Mark W Posted June 20, 2005 Report Share Posted June 20, 2005 It does seem like you're trying to imply Onza carbon bars have snapped, and I only know of one person having had that happen? There's such a thin layer of CF on there anyway it's not super weight-savey. Anyway, carbon fibre stems - got one for my mod in my bedroom now. Note: Bedroom - many cracks in the laquer from flex, which worried me too much, to be honest. It had metal bits for clamping areas, and then like a thinner metal bit with a carbonfibre sheath for the actual stem bit. Freaking light, to put it mildly... Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted June 20, 2005 Report Share Posted June 20, 2005 It does seem like you're trying to imply Onza carbon bars have snapped, and I only know of one person having had that happen? ← Ooh, who's that? As for carbons stems, yeah, no reason not to do it. The problem lies in bolding the carbon to some aluminium clamps, as Mark outlined just now. Quote Link to comment Share on other sites More sharing options...
iatola says Posted June 20, 2005 Author Report Share Posted June 20, 2005 It does seem like you're trying to imply Onza carbon bars have snapped, and I only know of one person having had that happen? There's such a thin layer of CF on there anyway it's not super weight-savey. ← No, i am a great believer in Carbon composites and have studied it alot. I do know that there is a somewhat a stangness in the indusrty as many people dont trust it. This is simply ignorance about the mechanical properties. Visit the "lite speed" website and you will be amazed by the preformance of CF. I will be getting Carbon bars this week. Trev Quote Link to comment Share on other sites More sharing options...
IOLO Posted June 20, 2005 Report Share Posted June 20, 2005 the equation Force x Distance. If you aplly this to stress on bars, especially on high BB bikes where you ride over the front alot ← i think your not quite thinking of all the aspects off stress.. and alot higher BB frames use proportionally high stems so there is no differentce. except the stem is a different shape, but there is no more stress than usual.. also be aware that by saying a stem is shorter than bars therefore is stronger.. think about when you land a harsh drop,, you bars have 27"-30" of material to flex and absorb the force, a stem being alot shorter has no length to flex,, therefore rather than absorbing the force is takes it, and the force requires the stem to flex, but it cant so it snaps instead. also. bear in mind that the performance of a component depends alot on the components its used with,, eg.. a carbon stem is not going to break if used with very light weak bars, cos the bars will flex alot, or snap first.. iolo Quote Link to comment Share on other sites More sharing options...
IOLO Posted June 20, 2005 Report Share Posted June 20, 2005 (edited) I once found a crack in the front clamp of my Azonic ORC stem... I just changed the front clamp and threw the cracked one in the bin as a friend had an old clamp spare... ← is that a carbon roady one ? Edited June 20, 2005 by IOLO Quote Link to comment Share on other sites More sharing options...
Towler Posted June 20, 2005 Report Share Posted June 20, 2005 It would be cool, just the bolt threads would be annoying to tackle. Quote Link to comment Share on other sites More sharing options...
TrashZen Posted June 20, 2005 Report Share Posted June 20, 2005 Yeah I snapped my Azonic shorty stem last summer. It was v strange, it snapped from the bottom upwards when pulling up on the back wheel. If you want a picture (The last in the slide show) http://spaces.msn.com/members/littleharrys...t&_c=photoalbum If it doesnt work(which happens alot) message me - littleharrys@hotmail.com Harry. ← Couldn't see the pic..didn't work, could you send me a pic for my trashed parts gallery? Id'like to see that ^_^ Quote Link to comment Share on other sites More sharing options...
picki Posted June 20, 2005 Report Share Posted June 20, 2005 (By the way I ride street (real street not pansy UCI style street) and dont care how much my bike wieghs) ← thats funny.... :lol: dont spose that carboned up bianchi has a carbon stem does it? Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted June 20, 2005 Report Share Posted June 20, 2005 I can safely say that onza carbon bars are stupidly strong: in the time I have had 2 sets I have twisted a pazzaz stem, snapped a pair of giant forks and killed one set of tensile cranks. Also I've had new wheels one blown up, one nicked. On the subject of carbon stems, it's a relatively good idea, but personally after seeing bars delaminate, carbon splinter etc etc. I don't know if I'd trust it. :lol: Quote Link to comment Share on other sites More sharing options...
haydon_peter Posted June 20, 2005 Report Share Posted June 20, 2005 is that a carbon roady one ? ← No the Azonic ORC is an alu stem. Linky to the stem on the CRC web page The newer stems (See pic in the link above) have ugly looking welding on them but back in the day they looked much nicer and were used by quite a lot of riders... Quote Link to comment Share on other sites More sharing options...
SQuiT-man Posted June 20, 2005 Report Share Posted June 20, 2005 Yeah I snapped my Azonic shorty stem last summer. It was v strange, it snapped from the bottom upwards when pulling up on the back wheel. If you want a picture (The last in the slide show) http://spaces.msn.com/members/littleharrys...t&_c=photoalbum If it doesnt work(which happens alot) message me - littleharrys@hotmail.com Harry. ← That is EXACTLY what happened to mine on my DH bike, also last summer, apart from mine went from the bottom upwards when I did a 3 foot drop. It was truely confusing as to how it happened, considering the force was going downwards, and the stem broke upwards, held on by a slither of metal at the top of the stem, which suddenly went solid-feeling again in the new position. Hard to explain, but it was freaky. Quote Link to comment Share on other sites More sharing options...
Backgren Posted June 21, 2005 Report Share Posted June 21, 2005 wiggle have 5 carbon road stems. just go on their site and search "carbon stem" to have a look. They look exactly like eny other road stem, and upside-down they could work (at least geometricaly) for trials. Quote Link to comment Share on other sites More sharing options...
iatola says Posted June 21, 2005 Author Report Share Posted June 21, 2005 Upside down is no worries. most 3TTT stems even come with interchangable graphics too so it doesnt look upside down. I run and upside down/ right way round roady stem and it be pimp. Like it loads Trev Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted June 21, 2005 Report Share Posted June 21, 2005 It's not the fact it's upside down, it's the fact it's a a roady stem that's bothering him Trev. :P" Quote Link to comment Share on other sites More sharing options...
Tartridge Posted June 21, 2005 Report Share Posted June 21, 2005 it's the fact it's a a roady stem that's bothering him Trev. :D" ← Guess Road Stem. Echo Control Trials Stem. Same thing :P Quote Link to comment Share on other sites More sharing options...
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