Eldron Posted December 3, 2009 Share I think you need to stop now. You sound like a pentecostal preacher shouting the word without knowing why.11% better' date=' really? what does that mean. Better how? 11% less suspension, 11% faster compression on the fork, 11% lower angle?I remind you that the profile of the compression provdes a graph under which the work done lies. The profile of the graphs of a 26er and 29 er look exactly the same as the object being traversed is exactly the same therefore the work done is similar, therefore a 29er is not better. Its just a big wheel that flexes more and helps you think its' eating the bumps better.maybe theres psychological value in that same as there is in super light weight wheels vs normal 1500gr wheels[/quote'] So I guess that makes you the anti pentecostal preacher then? I said 11.5% BIGGER - the reason I used "meaningful result" is that none of us have the ability to calculate how much BETTER. Your WORK graph is meaningless - a 26/29/34/16" bike will all raise off the ground (work) exactly the same amount if they go over the same bump. The difference will be in the direction of the deflection (attack angle). I'll make it easy for you - a bike riding over NO bump will carry on in a straight line - when it hits a small bump it will carry on but be deflection upwards momenterally - eventually when the bump is at big as the radius of the wheel the front wheel will be deflected vertically. A 29" wheel will ALWAYS be deflected less than a 26" wheel because it's bigger than a 26" wheel. How much you ask? I have no idea. The best I can do is "better". Turn your scalar into a vector preacher man. We could argue this for weeks - even Johan's centre of gravity agrument is open for discussion. I'd agree on his "Chris speaketh crap" sentiment if bicycles were static but when you consider the only thing stopping us from falling over is the rotating wheels then weight of the rider in relation to the rotating wheels becomes meaningful- hey there's that word meaningful again. That said - I think the difference in rider position in relation to the rotating wheels is small enough to be considered insignificant. As with any internet debate you'll have your opinion and "science" - I'll have my opinion and "science" and never the two shall meet. You and Johan stick to your 26ers and I'll stick to my 29er. Problem solved! Eldron2009-12-03 01:11:43 Link to comment Share on other sites More sharing options...
Eldron Posted December 3, 2009 Share eventually when the bump is at big as the radius of the wheel the front wheel will be deflected vertically. Hmmmm - nope. When the bump is HALF the size of the radius it will go vertical. If the bump is the same size as the radius it's face planting time.... Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 3, 2009 Share We could argue this for weeks - even Johan's centre of gravity agrument is open for discussion. I'd agree on his "Chris speaketh crap" sentiment if bicycles were static but when you consider the only thing stopping us from falling over is the rotating wheels then weight of the rider in relation to the rotating wheels - hey there's that word meaningful again. That said - I think the difference in rider position in relation to the rotating wheels is small enough to be considered insignificant. As with any internet debate you'll have your opinion and "science" - I'll have my opinion and "science" and never the two shall meet. You and Johan stick to your 26ers and I'll stick to my 29er. Problem solved! My centre of gravity explanation was simple and concise. Where's the fault and what's there to discuss? You then go on to say that all that keeps us from falling over are the rotating wheels. Not so. This is a common misbelief. You don't fall over 'cause you keep on steering into the fall so that your centre of gravity is directly underneath you again. Think about balancing a vertical roomstick on your hand. You keep on pushing your hand underneath the stick in order to make it stay upright. A bicycle is a two-dimensional broomstick, the two wheels keep it stable in the fore-aft direction and steering keeps it stable in the lateral positions. A unicycle is the perfect broomstick. If you have ever ridden a kid's scooter with skateboard wheels you'll realise that the old rotating wheel myth is just that, a myth. I once had the opportunity to ride a skate scooter, one with no wheels at all, just two blades. I could still balance and the mode of balance was the same as for a bicycle with large wheels. Arguing a scientific thread and using the opinion card to trump is is not nice. It smacks of the debate justifying religion. Link to comment Share on other sites More sharing options...
Eldron Posted December 3, 2009 Share My centre of gravity explanation was simple and concise. Where's the fault and what's there to discuss? You then go on to say that all that keeps us from falling over are the rotating wheels. Not so. This is a common misbelief. You don't fall over 'cause you keep on steering into the fall so that your centre of gravity is directly underneath you again. Think about balancing a vertical roomstick on your hand. You keep on pushing your hand underneath the stick in order to make it stay upright. A bicycle is a two-dimensional broomstick' date=' the two wheels keep it stable in the fore-aft direction and steering keeps it stable in the lateral positions. A unicycle is the perfect broomstick. If you have ever ridden a kid's scooter with skateboard wheels you'll realise that the old rotating wheel myth is just that, a myth. I once had the opportunity to ride a skate scooter, one with no wheels at all, just two blades. I could still balance and the mode of balance was the same as for a bicycle with large wheels. Arguing a scientific thread and using the opinion card to trump is is not nice. It smacks of the debate justifying religion. [/quote'] That is a fair point! Your centre of gravity explanation was too simple and concise - it negated the effect of the spinning wheels. Tell you what - sit in your rotating office and hold a rotating wheel in your hands. Now turn the wheel - if your chair doesn't move then I'll agree that the spinning wheel can be negated from the centre of gravity argument. Link to comment Share on other sites More sharing options...
Shebeen Posted December 3, 2009 Share It makes obvious sense to me that a from a geometry sense 14" frame and a 22" frame should not share the same wheel size(but from a manufacturing stance they should). The angles/standover height will be different no matter how you design. In an ideal world, they would have a wheel in proportion to frame size. Following from that, I'm sure many of the YAY for 29ers ride L and XL bikes, and many of the 26 gang are on M/S. With a few exceptions naturally. Five years ago there was quite a price discrepancy in parts, now it's not really the case. So if you're bashing 29ers and ride a small,well then I take your ride opinion with a twist of the robertsons salt shaker. I ride a L 26, my next bike might not be a 29er, but I'll definitely look into it. Link to comment Share on other sites More sharing options...
Minion Posted December 3, 2009 Share Your centre of gravity explanation was too simple and concise - it negated the effect of the spinning wheels. Tell you what - sit in your rotating office and hold a rotating wheel in your hands. Now turn the wheel - if your chair doesn't move then I'll agree that the spinning wheel can be negated from the centre of gravity argument.I suggest you read through Misconception No.2 in the link below:http://www2.eng.cam.ac.uk/~hemh/gyrobike.htm The gyroscopic forces are there but are negligible in comparison to everything else. You can also see from the article that it is possible to build and ride a bike that has no gyroscopic effect at all. Link to comment Share on other sites More sharing options...
Minion Posted December 3, 2009 Share ...and for some fun, one man's attempts to build an unridable bicycle (while providing some insight into bicycle dynamics. http://www.phys.lsu.edu/faculty/gonzalez/Teaching/Phys7221/vol59no9p51_56.pdf Link to comment Share on other sites More sharing options...
NotSoBigBen Posted December 3, 2009 Share Man you 'ubbers are tenacious I give you that ! Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 3, 2009 Share Your centre of gravity explanation was too simple and concise - it negated the effect of the spinning wheels. Tell you what - sit in your rotating office and hold a rotating wheel in your hands. Now turn the wheel - if your chair doesn't move then I'll agree that the spinning wheel can be negated from the centre of gravity argument.I suggest you read through Misconception No.2 in the link below:http://www2.eng.cam.ac.uk/~hemh/gyrobike.htmThe gyroscopic forces are there but are negligible in comparison to everything else. You can also see from the article that it is possible to build and ride a bike that has no gyroscopic effect at all. Oooooh! The elegance of that! I'm definitely bookmarking that link. Sometimes we do need a man with an anorac and a PhD in the background to lend weight to what we say. I love his extra wheel experiment. Link to comment Share on other sites More sharing options...
JasonW Posted December 3, 2009 Share I would still like to see some proper testing using a power meter. Anyone have a 29er with a powertap wheel that they would like to volunteer? First, you would want to ride both bikes on a velodrome at the same power output and then compare times. This will determine whether the "29ers are faster" myth has any truth to it. Second, you would want to ride both bikes up the same steep hill at the same power output and compare times. This willd emostrate what the impact of the 29ers lareger weight is, and whether this outweighs any advantage gianed in the first test. Third, you would want to ride both bikes on a XC circuit, again at the same power output. It needs to be flat as the downhills add too much of a subjective element. The course should be rough and rutted though. Link to comment Share on other sites More sharing options...
_Daemon_ Posted December 3, 2009 Share Who cares... Ride want you want and what you enjoy. Anyone in this thread actually good enough in a race to worry about a couple of seconds here and there either way to 26 or 29er side? I doubt it. 29ers are fun to ride. But it it amazing to me how people opinions on something and throw "scientific evidence" against it, that have not actually done extended rides on a 29er. Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 3, 2009 Share Who cares...Ride want you want and what you enjoy. Anyone in this thread actually good enough in a race to worry about a couple of seconds here and there either way to 26 or 29er side? I doubt it. 29ers are fun to ride. But it it amazing to me how people opinions on something and throw "scientific evidence" against it' date=' that have not actually done extended rides on a 29er.[/quote'] I want to thank you and that other village idiot for the blanket insults chucked at the few of us trying to verify or debunk the arguments made for 29er wheels. The fact that we (I) haven't ridden one doesn't disqualify me from challenging scientific statements. I am sure 29-ers are fun to ride. Most bikes are fun to ride and I have no scientific argument against that. It is a pity that some people cannot appreciate how others have cultured the ability to separate opinion from fact. There is a difference between "nice ride" and "better climbing ability". This is Tech Q&A. If tech scares or bores you, there is always Chit Chat. Link to comment Share on other sites More sharing options...
_Daemon_ Posted December 3, 2009 Share Who cares...Ride want you want and what you enjoy. Anyone in this thread actually good enough in a race to worry about a couple of seconds here and there either way to 26 or 29er side? I doubt it. 29ers are fun to ride. But it it amazing to me how people opinions on something and throw "scientific evidence" against it' date=' that have not actually done extended rides on a 29er.[/quote'] I want to thank you and that other village idiot for the blanket insults chucked at the few of us trying to verify or debunk the arguments made for 29er wheels. The fact that we (I) haven't ridden one doesn't disqualify me from challenging scientific statements. I am sure 29-ers are fun to ride. Most bikes are fun to ride and I have no scientific argument against that. It is a pity that some people cannot appreciate how others have cultured the ability to separate opinion from fact. There is a difference between "nice ride" and "better climbing ability". This is Tech Q&A. If tech scares or bores you, there is always Chit Chat. No problem I am here all day! Link to comment Share on other sites More sharing options...
Minion Posted December 3, 2009 Share Who cares...Ride want you want and what you enjoy.... 29ers are fun to ride. But it it amazing to me how people opinions on something and throw "scientific evidence" against it' date=' that have not actually done extended rides on a 29er. [/quote']I agree 100% with the part in bold. I've never ridden a 29er (hell, my 26er is somewhat neglected) so I can't comment on whether or not it's fun to ride. The problem (and I'm sure JB, GL and others will agree here) is not whether or not the 29er is more fun to ride or whether or not it is better than the 26er etc., etc., etc. The problem is with the baseless 'science' that is trotted out, by various marketing departments, as the reason for the difference (and is then lapped up and repeated with glee by consumers).Edman2009-12-03 02:31:15 Link to comment Share on other sites More sharing options...
GoLefty!! Posted December 3, 2009 Share Who cares...Ride want you want and what you enjoy. Anyone in this thread actually good enough in a race to worry about a couple of seconds here and there either way to 26 or 29er side? I doubt it. 29ers are fun to ride. But it it amazing to me how people opinions on something and throw "scientific evidence" against it' date=' that have not actually done extended rides on a 29er.[/quote'] I want to thank you and that other village idiot for the blanket insults chucked at the few of us trying to verify or debunk the arguments made for 29er wheels. The fact that we (I) haven't ridden one doesn't disqualify me from challenging scientific statements. I am sure 29-ers are fun to ride. Most bikes are fun to ride and I have no scientific argument against that. It is a pity that some people cannot appreciate how others have cultured the ability to separate opinion from fact. There is a difference between "nice ride" and "better climbing ability". This is Tech Q&A. If tech scares or bores you, there is always Chit Chat. I have ridden the things, had one for a whole weekend and can conclude that what you feel and what is actually happening are very different. Sort of like the difference between fact and the truth. And I agree, this is Technical Questions and Answers so here we have technical discussions. Perhaps there should be another section called MArketing Questions and Answers where the touchy feely stuff can be debated in circles. In this part of the forum there are certain scientific truths (note not facts) used in arguements. Opinions are welcome but opinions do not need to be defended. Once they are defended then you believe the opinion to be fact (note not truth) and you should be prepared for healthy debate along scientific and engineering principals.If you (the adhoc poster) chooses to continue the pursuit of opinion as fact then there is little hope for you. You will be classified as a lonely old person looking for a conversation. Now someone proposed using a power meter as an absolute test. this is fine but we must remember to correct the gearing on the 29er so that the development per pedal revolution is within 2% of each other (some of you do love your percentages so I threw one in to get you off). this will negate any gearing advantages offered by a big wheel. Now we can compare apples with apples. Link to comment Share on other sites More sharing options...
GoLefty!! Posted December 3, 2009 Share "The problem is with the baseless 'science' that is trotted out, by various marketing departments, as the reason for the difference (and is then lapped up and repeated with glee by consumers)."Amen. If someone says I like a 29er because it works for my XL frame then that is sufficient.Its when people start taking about how much better, the future blah blah blah, quoting pseudo science, thats when I roll my sleeves up. No problem with feelings and opinion, but those are not fact and certainlynot truth. Leave it at feelings. Its nothing more than feelings... Oh I feel a song coming on Link to comment Share on other sites More sharing options...
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