Skoze Posted January 29, 2012 Report Share Posted January 29, 2012 yes but you are the mother of all trolls so I have learned to ignore you... You're right, I guess testing all those frames from Onza to destruction over the years wouldn't have taught Mark anything about a frame's strengths and weaknesses... Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 29, 2012 Report Share Posted January 29, 2012 yes but you are the mother of all trolls so I have learned to ignore you... Haha, whatever. I still stand by what I said - the way you put that doesn't have any relevance to the way that frames work. To try and show you what I mean a bit more, here is a cat above a pit of death. In the 'bridge' on the left, both the arms are dead straight horizontally, so go the minimum distance required. When the cat's weight is added, because there is no support they just drop down, leading to the cat falling into the pit of death. On the right 'bridge', the arms are raised up. The bridge arms are longer as this distance is greater. When the cat's weight is added, the arms don't give a shit because they can't be pushed down and through each other. Therefore, the cat has a nice stiff structure it can sit on so it doesn't fall into a pit of death.If you imagine that the weight of the cat is actually the force you're putting down through the BB shell, with the seat tube trying to pull down on the top tube/seat stay join, it should hopefully show what I'm getting at a little more clearly... 3 Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 29, 2012 Report Share Posted January 29, 2012 did the kitten on the left survive? I do hope so! 3 Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 29, 2012 Report Share Posted January 29, 2012 What part of "Pit of death" are you failing to understand? 4 Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 29, 2012 Report Share Posted January 29, 2012 If only it had a stronger designed bridge to sit on. 3 Quote Link to comment Share on other sites More sharing options...
bagre15 Posted January 29, 2012 Report Share Posted January 29, 2012 I think that both designs are strong and in each of them the weak spot would be in a diferent place In the angled tubes design the weak spot would be near the seat tube welds In the flat tubes design the weak spot would be near the head tube welds I also think that the in the flat tubes desigg the frame would be more flexy than in the angled design I may be totally wrong, so it worth asking for a real engineer opinion And sorry for my bad english, since I'm brazilian Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 29, 2012 Report Share Posted January 29, 2012 really? I am pretty sure the diagrams and common sense shows otherwise Quote Link to comment Share on other sites More sharing options...
bagre15 Posted January 29, 2012 Report Share Posted January 29, 2012 really? I am pretty sure the diagrams and common sense shows otherwise I'll try to test both designs in a fatigue simulator software and maybe solve this question Quote Link to comment Share on other sites More sharing options...
casualjoe Posted January 29, 2012 Report Share Posted January 29, 2012 The question was solved many 100s of years ago. Quote Link to comment Share on other sites More sharing options...
Chris Borneo Posted January 29, 2012 Report Share Posted January 29, 2012 (edited) I don't know that it's really as simple as the kitten diagram makes out. For one it relies on an equal and opposing force acting on each end of the structure which is not really true to a bike frame. I don't really know which option is best. Think you'd have to use some kind of simulator or a force diagram taking into account all the forces present which I think would be pretty difficult as everyone has a different riding style putting different forces through their frame. Gotta say though, there's enough frames built both ways to suggest that it's maybe not the massive design flaw that some people are making it out to be. On the other hand I do think this bike looks ugly as sin and for that kind of riding style I reckon you'd be better on something with a bit more of a BMX influenced design. Edited January 29, 2012 by Chris Borneo Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 29, 2012 Report Share Posted January 29, 2012 no one is saying it's a massive design flaw, it obviously works well for plenty of trials frames out there. All we are saying is that bigger triangles would be the stronger way to go. My thinking is that the seat stay top tube juction is like a pivot, the closer it is to the bb the weaker the frame will be for a lot of forces, it's no coincidence that frames made even lower usually had strength issues (Onza Limey and Rockman Kortz as examples). 1 Quote Link to comment Share on other sites More sharing options...
sayshell Posted January 30, 2012 Author Report Share Posted January 30, 2012 (edited) so my engineer friend talked about it and discussed why, and I am wrong a regular frame is stronger... or rather just a frame with less actute angles. Since the frame is so narrow its like bending a horizontal stick vertically. However if you built a diamond frame a low seattube height it would be just as weak because the angles would be still very acute. The regular diamond frame is stronger because the vertex near the headtube and rear dropouts are on such a steep angle that the toptube provides less structural support than if they were more shallow. However to change the vertex angle significantly enough to actually improve strength the toptube would have to be quite a bit higher up... so the question is... is the bonus increase in strength worth the extra weight and having a higher toptube? How much does a low toptube actually matter for trials? What is your opinion. I would say yes, however their is a better solution... since the frame is so low the entire frame can actually be turned into a box tube this kills 2 birds with one stone. It will give the strength of a diamond frame, at the cost of adding some weight. By adding a guesset connecting the toptube along the downtube you can make the frame 1 solid piece rendering it utterly indestructible as the tubes them selves are what usually crack and tear. (similar idea to the GU frame) Of course it doesn't need to be fully connected, it would add ridiculous weight. In any case the frame currently using is very strong (based on experience and testing), I will build this into the fifth prototype but right now it is strong enough for my needs, but I do want it to be perfect. This guy is a professional engineer and he is one of those people that can actually think and not just memorize stuff to look smart so I would say his assessment is the best. Dude I don't care what experience Mark has, I am 100% sure if it was actually perfect he would still talk crap like he does about everything ever. He is incapable of giving constructive criticism, he can only look at something in the most negative way possible. I just can't stand people like that. Edited January 30, 2012 by sayshell 2 Quote Link to comment Share on other sites More sharing options...
Skoze Posted January 30, 2012 Report Share Posted January 30, 2012 Dude I don't care what experience Mark has, I am 100% sure if it was actually perfect he would still talk crap like he does about everything ever. He is incapable of giving constructive criticism, he can only look at something in the most negative way possible. I just can't stand people like that. Having spent a week in a rover 200 with him I beg to differ. But hey, i'm not gonna try and change your views dude! Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted January 30, 2012 Report Share Posted January 30, 2012 he would still talk crap In hypocrite news... 1 Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 30, 2012 Report Share Posted January 30, 2012 Dude I don't care what experience Mark has, I am 100% sure if it was actually perfect he would still talk crap like he does about everything ever. He is incapable of giving constructive criticism, he can only look at something in the most negative way possible. I just can't stand people like that. Feel free to point out where I've been negative about your frame, or where I've "talked crap" about it. I haven't said a single thing about your frame in this entire thread. I said I thought with your idea about frame heights was wrong, the same idea which was then proven to be wrong by your engineer friend. Quote Link to comment Share on other sites More sharing options...
sayshell Posted January 30, 2012 Author Report Share Posted January 30, 2012 This was what i was kinda getting at. I'm now fully decided this is a bike for riding nothing but curbs and flatbanks on. This video better better prove us wrong. yeap 50 minutes of headbanging should proove that. Seriously though less than half the vid is biking, but its also a longer vid so it equates to a decent amount of riding. If people aren't interested I won't sell it. I don't care... I don't need the money. I am just creating the opportunity to have a mod available you can buy for a reasonable price that allows you to do a wide variety of riding, something I was never privileged to have in my riding experience. If you like 20" their isn't much of a market for non TGS bikes other than bmx, which eliminate tgs. Think of it like this if you are interested in doing more than TGS on a 20" what bike do you ride? You bought a TGS bike and just ride it non-tgs which was designed entirely for tgs... This is better than anything you can buy, even if their are flaws it will outperform any TGS mod you can buy at street riding, while still maintaining the ability to do trials. 1 Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted January 30, 2012 Report Share Posted January 30, 2012 If people aren't interested I won't sell it. I don't care... I don't need the money. I am just creating the opportunity to have a mod available you can buy for a reasonable price that allows you to do a wide variety of riding, something I was never privileged to have in my riding experience. Quote Link to comment Share on other sites More sharing options...
sayshell Posted January 30, 2012 Author Report Share Posted January 30, 2012 (edited) Feel free to point out where I've been negative about your frame, or where I've "talked crap" about it. I haven't said a single thing about your frame in this entire thread. I said I thought with your idea about frame heights was wrong, the same idea which was then proven to be wrong by your engineer friend. You are aware being right for the wrong reason doesn't make you correct? It is quite fair to say that neither of us understood the correlation fully of how the angle of the vertex transfers power before the engineer intervened. It is the LOWNESS of the frame (the short seattube distance), that accounts for the weakness in vertical stress when landing on 2 wheels. If I were to make a diamond frame with a 3" seattube vs a triangle frame with an 8" seattube the triangle would be stronger. So no you are also wrong, a triangle frame could be stronger than a diamond frame depending on the seattube height. Its the acuteness of the angle that reduces its ability to transfer power. If you understood it you would have explained it correctly and I would have understood and agreed with you because common sense verifies this principle... and I was actually using this principle to justify that it was stronger which is INCORRECT BECAUSE.... I applied the principle incorrectly and by creating a straight toptube/seatstay inadvertently mad the toptube/downtube angle more acute in the process actually reducing strength from the frame slightly. In the instance of a low trials frame such as one like this whether it is diamond shaped or triangle shaped it will still be weak for vertical stress applied in a flat landing, however it will be MUCH stronger than a regular diamond shaped frame in a rear wheel first vertical type landing BECAUSE the downtube/chainstay angle is much more obtuse. So the question is balancing the stresses out. I based my reasoning largely on how most low trials frames are switching to the triangle design, and failed to research this better and rationalized it as stronger. But you are also wrong, because like I said being right for the wrong reason makes you just as wrong as being wrong for the wrong reason. Now in the unlikely event that it is just a mere coincidence that absolutely every single post for the last what 4 years??? has been 100% without a single exception criticism... one tends to think 1 of 2 things... 1) This person beieves that the purpose of a forum is to educate based only on constructive criticism 2) This person antagonizes certain people based on politics and personal grudges... Since I have seen you make positive posts in other people's threads and you can look BEYOND just what is flawed then I would say number 1 is my conclusion... In the event you are actually NOT antagonizing me, and really out of the KINDNESS OF YOUR HEART trying to help me improve my design so that my life is easier, then I sincerely apologize, and retract saying you are a troll. I believe though.... that you are a troll because the evidence points more towards that. However if you will honestly state that you are not antagonizing me then I will go by what you say because I believe in extending trust. Talking crap consists of antagonizing people. Some guy makes a video of 40 tricks and mess one up and all you talk about is the one messed up thing, you obviously have a negative prejudice (not saying you did this just making an example up on the spot). Not basing this entirely on this thread, but over many years of absolutely nothing but "constructive criticism" which happens to ALWAYS without a single exception is negative... put your self in my shoes. I am inclined to believe that any post I possibly make you will spend your time carefully nitpicking to find a flaw, hence your opinion in general I am inclined to omit because if I listened to what you say I would just quit riding and give up on life. You need to get a better attitude man... You don't always have to be right for people to respect you... and if you didn't antagonize me and constantly try to make me look stupid I WOULD respect your opinion highly because you do have lots of useful knowledge and experience. Edited January 30, 2012 by sayshell 2 Quote Link to comment Share on other sites More sharing options...
JD™ Posted January 30, 2012 Report Share Posted January 30, 2012 and constantly try to make me look stupid I WOULD respect your opinion highly because you do have lots of useful knowledge and experience. it's not Mark making you look silly mate, honest. Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted January 30, 2012 Report Share Posted January 30, 2012 I find Ali far more negative than Mark usually, but I know he's been trying to correct that. Kittens in the pit of death can't help matters though... that poor kitten . Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted January 30, 2012 Report Share Posted January 30, 2012 In the instance of a low trials frame such as one like this whether it is diamond shaped or triangle shaped it will still be weak for vertical stress applied in a flat landing, however it will be MUCH stronger than a regular diamond shaped frame in a rear wheel first vertical type landing BECAUSE the downtube/chainstay angle is much more obtuse. The chainstay/downtube angle is almost solely down to geometry though (with minor tweaks for dropouts and weld positions if you want to get into that shit), where as the others can all be applied to the same frame by bringign the toptube up. After seeing Rich Pearson sidehop my old Inspired up a 45" wall with relative ease I don't think that your target 'market' as such is going to have any real issues with it, so if it strengthens the frame, makes it look better and adds functionality it seems the way to go Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 30, 2012 Report Share Posted January 30, 2012 I find Ali far more negative than Mark usually, but I know he's been trying to correct that. Kittens in the pit of death can't help matters though... that poor kitten . I'm hurt Quote Link to comment Share on other sites More sharing options...
Mark W Posted January 30, 2012 Report Share Posted January 30, 2012 You seem to think I care a lot more about you than I do, which is strange. I don't think I've been outright 'negative' towards you and I definitely haven't set out to specifically try and f**k you around, but obviously I've wounded you somehow. I would say I was sorry, but I wouldn't mean it so I won't bother. I hate seeing people bullshit, and it appeared that that's what you were trying to do with interesting 'justifications' for things in your little semi-sales pitch earlier. I said I disagreed with your stick analogy. It didn't seem right to me, and to a few other people it seems, and all I did was point that out. You then had a dig and implied that I was talking shit about your frame when I hadn't said anything about it. Now you're trying to twist you talking shit about me as being my fault, again by making more shit up about me (e.g. your "example" you decided to conjure up). If you're just going to keep doing that I can't really be bothered trying to clear anything up with you. You seem to think I have a massive interest in who you are or what you do, but you're pretty mistaken there. From making one comment in your thread you now seem to think I'm specifically targeting you and you've turned it all round on to me, even though other people said the same thing? Seems like it might be the other way round... From a personal point of view, I'd rather see people giving constructive criticism (which you just said I give to people, despite earlier saying I don't?) than just bullshitting their way through things. While we're talking about that, the only constructive criticism I think I've ever put your way was something about bitch cranking in stuff, and that was 'cos I thought your riding would look better without it (as would and does anyone's riding without cranking into stuff). You seem to want to try and push yourself and the way you ride, so I thought I'd point that out. If I just said "Your riding is shit" or something totally groundless like that then I can appreciate you might have an issue, but getting one partially negative comment (meant in a 'good' way) about a video and then seemingly basing "4 years" worth of feelings on that seems a bit weird. Quote Link to comment Share on other sites More sharing options...
monkeyseemonkeydo Posted January 30, 2012 Report Share Posted January 30, 2012 I'm hurt I'm sorry Ali, but it's ok 'cos the kitten didn't really die in the pit of death and is back for a hug: Quote Link to comment Share on other sites More sharing options...
Ali C Posted January 30, 2012 Report Share Posted January 30, 2012 kittens a f**king awesome! 1 Quote Link to comment Share on other sites More sharing options...
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