craigjames Posted February 18, 2010 Report Share Posted February 18, 2010 Thats right simple bmx are looking at producing a plastic stem?! crazyyyyyyyyy Would this work for a trials stem? Could it be just as strong but lighter? Quote Link to comment Share on other sites More sharing options...
jt123 Posted February 18, 2010 Report Share Posted February 18, 2010 I wouldn't trust it on my road bike, nevermind bmx Quote Link to comment Share on other sites More sharing options...
l33th3tr33 Posted February 18, 2010 Report Share Posted February 18, 2010 expect a fail video.........soon. Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted February 18, 2010 Report Share Posted February 18, 2010 Tis pretty swish that...I don't think it's a coincidence that it's the smallest reaching stem I've ever seen though..! Can't beat a bit of metal Adam. Quote Link to comment Share on other sites More sharing options...
Leistonbmx Posted February 18, 2010 Report Share Posted February 18, 2010 Wish I could see it's not real and just a rendering. Look at the enlarged photo. Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 18, 2010 Report Share Posted February 18, 2010 Looks fairly standard for a BMX stem reach-wise, probably nearer the shorter than longer end of the scale though obviously. Even so: f**k no. Quote Link to comment Share on other sites More sharing options...
Trials Punk Posted February 18, 2010 Report Share Posted February 18, 2010 At the end of the day, why not? As long as they manufacture the stem to handle a certain amount of stress, similar to that of an alu stem then theres no difference. Technology advances, better materials are made available. Wonder if people thought the same thing when the first aluminium frame came out? Quote Link to comment Share on other sites More sharing options...
MadManMike Posted February 18, 2010 Report Share Posted February 18, 2010 Shame it'll probably be about £100... Quote Link to comment Share on other sites More sharing options...
psycholist Posted February 18, 2010 Report Share Posted February 18, 2010 (edited) If it's done right there's no reason it wouldn't work. Lexan or UHMWPE (Or Ultra-high Molecular Weight anything really) would be two plastics I'd look at... Plastic BMX and MTB pedals have been around for ages too (And not just the crappy ones on cheap bikes). Keep in mind that BMX stems are usually a solid block of aluminium, so complete overkill for the loads involved (Given longer stems for MTB's are hollow tubes), so there's room to downgrade the material for that application. Edited February 18, 2010 by psycholist Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 18, 2010 Report Share Posted February 18, 2010 It appears they have used PC ( polycarbonate.... ) known for its strength and often referred to as bulletproof. This has been used by evil bikes ( e.13 chainguard anyone ?) and Truv to great success. Whether it's up to use under load I'm not sure.....I'd also be worried about the threads pulling out. Polycarbonate Stats 6061 aluminium stats - As used on the tartybikes forged stem and many others. This is in the T6 variant, although probably the most suitable for this application. You can see that PC is lighter than 6061....but the tensile yield strength ( I think the most relevant figure? ) is far lower at 40.7-73.5 MPa compared to the 255 of 6061. Theoretically if used well this material could be as strong as aluminium, but I reckons it would be more suited to something like a direct-mount DH style stem, where there would be far less leverage acting on it? Quote Link to comment Share on other sites More sharing options...
jt123 Posted February 18, 2010 Report Share Posted February 18, 2010 Plastic BMX and MTB pedals have been around for ages too (And not just the crappy ones on cheap bikes). But plastic pedals have got a metal axle running through them, and they're still shit my first pair of gusset PCP pinheads snapped after 1 month. Quote Link to comment Share on other sites More sharing options...
BlueSmokeyJoe Posted February 18, 2010 Report Share Posted February 18, 2010 Considering the number of half wits that manage to strip the threads in frames/forks etc that are made of metal, I can't see this lasting too long. Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 18, 2010 Report Share Posted February 18, 2010 Keep in mind that BMX stems are usually a solid block of aluminium, You need to look at modern BMX stems if you think that's still the case... But plastic pedals have got a metal axle running through them, and they're still shit my first pair of gusset PCP pinheads snapped after 1 month. That's because those pedals are shit, no matter who's name is put on them. The Animal Hamilton pedals are still the best plastic pedals out, apart from maybe the Fly Rubens. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted February 18, 2010 Report Share Posted February 18, 2010 At the end of the day, why not? As long as they manufacture the stem to handle a certain amount of stress, similar to that of an alu stem then theres no difference. Technology advances, better materials are made available. Wonder if people thought the same thing when the first aluminium frame came out? And it wouldn't be half as susceptible to fatigue as aluminium is. Probably not, aluminium has been used for a hell of along time as a structural member in Aerospace and the automotive before it ever got used on a bicycle. Correct me if I'm wrong, but I haven't seen plastic very commonly used as an alternative material. Who knows though... Shame it'll probably be about £100... No reason it will be inordinately expensive.....the Truv PC bash's are pretty cheap, certainly not a huge amount more than their aluminium counterparts. If it's done right there's no reason it wouldn't work. Lexan or UHMWPE (Or Ultra-high Molecular Weight anything really) would be two plastics I'd look at... Plastic BMX and MTB pedals have been around for ages too (And not just the crappy ones on cheap bikes). Keep in mind that BMX stems are usually a solid block of aluminium, so complete overkill for the loads involved (Given longer stems for MTB's are hollow tubes), so there's room to downgrade the material for that application. Yesh, forgot about the pedals.....top example. Like you say, it would be fine on something experiencing a relatively small moment. But that torque and thus shear force would be proportionally increased the longer the stem is. Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 18, 2010 Report Share Posted February 18, 2010 I've still seen plastic BMX pedals shatter, by the way. The forces a stem is put under are massively, massively different to what pedals would be under. Quote Link to comment Share on other sites More sharing options...
craigjames Posted February 18, 2010 Author Report Share Posted February 18, 2010 A simple metal insert would solve the problem of thread pulling out, wouldn't take a lot to sort that surely? It has been and is being tested, surely a clip of it failing would have been put somewhere? Be interesting to see how long it holds up and how it fails if and when it does. Quote Link to comment Share on other sites More sharing options...
Leistonbmx Posted February 18, 2010 Report Share Posted February 18, 2010 You do realise only on of the holes is tapped and this has to be a fake right? Quote Link to comment Share on other sites More sharing options...
craigjames Posted February 18, 2010 Author Report Share Posted February 18, 2010 You do realise only on of the holes is tapped and this has to be a fake right? Aye i did notice that, could be a fake i guess....... Quote Link to comment Share on other sites More sharing options...
rupintart Posted February 18, 2010 Report Share Posted February 18, 2010 (edited) Pedals see SIGNIFICANTLY more stress than any stem. Using the plastic pedal as an example is also a horrible comparison. The modern BMX stems are made from like 9-10 oz of aluminum. You can't tell me you have a lot of faith in something that's a double the weight of a beer can, but you have no faith in a high quality PVC stem simply because of it's material???? All things are likely to have some failure rate, but I don't think that stem, aside from some idiot tightening the shit out of it stripping the threads, it fail. Can't wait to see how this stem fares though. I'll reserve my judgement after i see some videos of it's use. Edited February 18, 2010 by rupintart Quote Link to comment Share on other sites More sharing options...
davey1991 Posted February 18, 2010 Report Share Posted February 18, 2010 Oh dear, its turned into a who knows more war. It could be a good idea, only time will tell. I think it may work quite well, aslong as its not given to todays heavy handed bike rapists, then itll get cross threaded, snapped, and it'll explode. Quote Link to comment Share on other sites More sharing options...
David Posted February 18, 2010 Report Share Posted February 18, 2010 Quote from that link: "You have probably figured it out by now, the previous post about the Eject v4 PC stem was just a renderning and nothing but a post in the news for fun." "We will stick to the Alloy stems." Quote Link to comment Share on other sites More sharing options...
Leistonbmx Posted February 18, 2010 Report Share Posted February 18, 2010 Told you. Go on. Get on your knees... Quote Link to comment Share on other sites More sharing options...
D A N N Y Posted February 18, 2010 Report Share Posted February 18, 2010 Plastic stem = Plastic teeth ! Quote Link to comment Share on other sites More sharing options...
Mark W Posted February 19, 2010 Report Share Posted February 19, 2010 Pedals see SIGNIFICANTLY more stress than any stem. Plastic pedal bodies, which is what people were refering to, will not see as much stress as a stem. The modern BMX stems are made from like 9-10 oz of aluminum. You can't tell me you have a lot of faith in something that's a double the weight of a beer can, but you have no faith in a high quality PVC stem simply because of it's material???? Yes, I can. In much the same way that I wouldn't necessarily want to have a frame that's tubing was made from 'high quality' paper instead of metal, there are different materials that are suitable for different applications. Just because it's 'high quality' doesn't mean that it's good for that purpose, and equally, simply making it using the same design as a metal stem wouldn't actually be using that material to the best of it's abilities, in the same way that making a direct copy of an aluminium frame out of, say, ti wouldn't make it a good frame. Either way, not real, doesn't matter. Quote Link to comment Share on other sites More sharing options...
John Shrewsbury Posted February 19, 2010 Report Share Posted February 19, 2010 http://thecomeupbmx.net/new-products/new-simple-stem/ Quote Link to comment Share on other sites More sharing options...
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