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Jcl the 29er crowd is the clueless cult. All the time we here how amazing they ate from the converted...for others they arnt great for what we like to do. Wheelbase doesnt matter so much, rotating weight does as does the physical size of the wheels themselves in relation to body language (complaints about rubbing your arse on the rear wheel on steeps etc) as does the loss of travel, as does the loss of acceleration, loss of turn in, increased aero drag. There are plenty of reasons to dislike 29ers other than wheelbase length.
This place is like a clueless cult. My Mum understands bike geometry better than half the people on here LOL!
JCL, you always wander onto threads on particular themes (such as 29er ones) acting all contrary Mary and slating the knowledge of contributors. why don't you, or your Mum, educate the clueless in a more constructive way rather than acting all arrogant?
true, by the time the forks are at the correct sag the summum with its mentally slack HA is going to have a shorter wheelbase than a stumpy 29er.
This place is like a clueless cult
You knew that years ago. :rolleyes:
Wheelbase doesnt matter so much, rotating weight does
My 29" wheels are lighter than my DH wheels and under a pound heavier than my old 26" AM wheels. Sure there is a little more rotational inertia but that also gives you momentum in stuttery stuff so it's a wash.
as does the physical size of the wheels themselves in relation to body language (complaints about rubbing your arse on the rear wheel on steeps etc)
Haven't had a problem personally and I'm only 5'8". With the centre of gravity being so low I find I can stay much more centralised on the bike without worrying about overweighting the front on steeps.
as does the loss of travel, as does the loss of acceleration, loss of turn in, increased aero drag. There are plenty of reasons to dislike 29ers other than wheelbase length.
Again the CoG being so low means the front to back roll centre is much more stabilized than a 26" with an upto 40mm higher relative BB height. This means your weight isn't effecting the suspension to the same degree a a 26" when you brake or are on a steep up/downs and is ultimately why they feel like they have more travel than they have.
Turn in? Grip is higher (slightly larger contact patch) so I don't get the turn in statement. Sure there is more inertia from the larger wheels but you maybe have to be put 5% more effort in turning compared to a 26".
Loss of acceleration? Maybe (I doubt it) an issue or XC racing but for gravity racing I'd say that the lower rolling resistance easily makes up for accelerative losses.
Aero drag? Come on.
with regards to the wheel weight thing, its not so much the weight but where the weight is on the wheel, the bulk of the weight is in the rim and tyre.
the two could weigh exactly the same but the bigger wheel would still have more inertia.
My 29" wheels are lighter than my DH wheels and under a pound heavier than my old 26" AM wheels. Sure there is a little more rotational inertia but that also gives you momentum in stuttery stuff so it's a wash.
Lighter and weaker than your DH wheels and almost a full LB heavier than your 26 inch wheels! Great! I went from 2200 gram god awful old wheels to 1800 gram Flows and noticed a huge difference!
Haven't had a problem personally and I'm only 5'8". With the centre of gravity being so low I find I can stay much more centralised on the bike without worrying about overweighting the front on steeps.
And it's this precise reason that I find the bikes harder and slower to lean into corners and harder to weight up the front wheel in flat faster corners.
gives you momentum in stuttery stuff
Won't this kind of become negated when braking bumps and trail wear are predominantly caused by 29ers? Bigger braking bumps! WHOOOOOOOOOOOOO
Again the CoG being so low means the front to back roll centre is much more stabilized than a 26" with an upto 40mm higher relative BB height. This means your weight isn't effecting the suspension to the same degree a a 26" when you brake or are on a steep up/downs and is ultimately why they feel like they have more travel than they have.
Again, see above. Weighting suspension is good..... good suspension tunes are there to remove brake dive. What your saying is effectively "I can't control my bike properly and need wheels that compromise handling to make me feel safe"
Loss of acceleration? Maybe (I doubt it) an issue or XC racing but for gravity racing I'd say that the lower rolling resistance easily makes up for accelerative losses.
Rolling resistance helps you use less energy once you've got going and perhaps let's you accelerate a bit faster but the predominant factor that effects acceleration for me is rotating weight.
The hilarious thing though is that what really REALLY reduces rolling restance is rim width....Syntace have just brought out a 40mm wide 1800 gram 26 inch wheel. I'd like to see you do that on a 29er and keep the weights within reason.
"the key to reducing rolling resistance is minimizing the energy lost to casing deformation, not minimizing how much tread is in contact with the ground. All other factors being equal, wider casings exhibit less 'bulge' as a percentage of their cross-section and also have a shorter section of deflected sidewall."
JCL, you always wander onto threads on particular themes (such as 29er ones) acting all contrary Mary and slating the knowledge of contributors. why don't you, or your Mum, educate the clueless in a more constructive way rather than acting all arrogant?
I've tried a number of times but it goes in one ear and out the other. I'll try and get my Mum to write something.
Those who have been around for ever have seen it all before. I remember people saying disc brakes, rear suspension, 780mm bars, dropper posts etc were all fads and you don't need them etc. I might have been one of them! It's all just fear of the unknown, breaking from tradition etc. I was as anti 29" as anyone but after riding a good one like the Stumpy Evo or Tallboy LTC etc I can't see how you wouldn't think 'holy crap this is nuts!' Maybe if you ride around the trails hitting jumps and having a laugh they're not for you, but if you want to go A-B as quick as possible?, it isn't even close IMO.
well.....780mm low rise (10mm) bars are fads in certain applications. Eg steep as **** courses or 150mm trail bikes that have short head tubes married to tall riders.
For that matter lock ons are ****ing shite as well, I've gone back to good old slips on's. There's a reason MXers don't use them.
Plenty of people who have ridden them agree they are boring to ride on our favorite trails, not all of us are bowled over by them JCL....
I really find it hilarious that people claim they are faster but that all timed reviews so far have indicated the opposite on timed downhill sections.
We need EBC, evidence based cycling.
Maybe if you ride around the trails hitting jumps and having a laugh they're not for you, but if you want to go A-B as quick as possible
1) Is that speed because A) The bikes faster or B) You feel safer and thus more confident being sandwiched between massive wheels (a bit like back braces in horse riding)
2) What happen's if those trails include tight steep sections leading into large gap jumps with directional transitions? Like on a reasonably hard downhill course?
Or do we redesign tracks to be more suitable for 29ers?
3) Also this whole thing about not having to use body english to ride a 29er smacks me of missing the point of riding altogether....or for me anyway.....riding is like dancing....there's great joy in throwing your body around in tune to the trail. Loads and loads of it.
The debate is starting to remind me of the debate that revolves around traction control in motor racing.
P.S. Sorry the scientist in me has to over-analyze and disbelieve everything until it is utterly proven beyond reasonable doubt.... personal experience counts for nothing as other variables other than the experimental arm (29er wheels) such as the placebo effect or increased confidence could effect the outcome.
And it's this precise reason that I find the bikes harder and slower to lean into corners and harder to weight up the front wheel in flat faster corners.
I just don't think this is the case. You have so much more confidence from the CoG stability that you can chuck the bikes around without worrying about grip loss on transitions into corners. The longer chainstays give you more front weight bias so I find it much easier to weigh the front.
Again, see above. Weighting suspension is good..... good suspension tunes are there to remove brake dive. What your saying is effectively "I can't control my bike properly and need wheels that compromise handling to make me feel safe"
You walked right into this one. Imagine how good your suspension could perform if you didn't have to run loads of low speed to stabalise the geometry. Also it's "I need wheels to improve geometry and handling to make me feel safe so I can go faster".
You have so much more confidence
Boom see above, is it the psychology or the physics of the bike making you go faster. Most people would be slower round a track on a Moto GP bike than they would on a CBR1000.
from the CoG stability that you can chuck the bikes around without worrying about grip loss on transitions into corners. The longer chainstays give you more front weight bias so I find it much easier to weigh the front.
The longer chainstay also makes it harder to get the front end up, lazier in corners, lazier in jumps. Etc ad nauseum...short chain stays are generally accepted as a good thing.
CoG stability is not always a good thing, it ends up meaning that you have to fight the bike to lay it over. And give me a break at any decent level of riding you need to be able weight up either wheel and feel the grip easily. Loading the suspension and supporting it with compression is entirely different to making loading it harder by lowering the CoG.
What happen's if those trails include tight steep sections leading into large gap jumps with directional transitions? Like on a reasonably hard downhill course
I'm talking Enduro. Not DH.
Ask any motorsport driver what car is fastest and he'll say the safest, most predictable and confidence inspiring.
How many times has this been posted? http://dirt.mpora.com/news/dirt-magazine-26v29-bonus-feature.html
Ask any motorsport driver what car is fastest and he'll say the safest, most predictable and confidence inspiring.
Yes....race superbikes bikes are safer and easier to ride than GP bikes....softer suspension setups, smoother power delivery, heavier and more stable cornering, often feel as if your perched in the bike as opposed to on top of it. They're definitely faster round the track. For sure.
I think the whole CoG benefit is a low of horse pooh imo and part of the fundamental problem for me in the way 29ers ride. I don't want a lazy bike.
CoG stability is not always a good thing, it ends up meaning that you have to fight the bike to lay it over. And give me a break at any decent level of riding you need to be able weight up either wheel and feel the grip easily. Loading the suspension and compensating for it with compression is entirely different to making loading it harder by lowering the CoG.
I've never heard a higher CoG called a benefit before... I still think you can load the suspension just fine. It's a bike after all. If a Supercross rider can have an effect on the suspension of a 200lb dirt bike, a mountain biker can have more than enough effect on a 30lb bike.
That test proves one rider was faster than the other, not whether 29 wheels are faster. The controls are fundamentally flawed.
I love the fact I studied science.
I've never heard a higher CoG called a benefit before... I still think you can load the suspension just fine. It's a bike after all. If a Supercross rider can have an effect on the suspension of a 200lb dirt bike, a mountain biker can have more than enough effect on a 30lb bike.
I have, they redesigned the Honda GP bike with a higher CoG to get it to tip over quicker. Not really a problem with MTB's but I feel that it does contribute to some of what I feel is the lazyness in handling that I've gotten from all the 29ers I've ridden.
Yes....race superbikes bikes are safer and easier to ride than GP bikes....softer suspension setups, smoother power delivery, heavier and more stable cornering, often feel as if your perched in the bike as opposed to on top of it. They're definitely faster round the track. For sure.
Bizarre analogy.
I think the whole CoG benefit is a low of horse pooh imo and part of the fundamental problem for me in the way 29ers ride. I don't want a lazy bike.
Go and watch Mr Hill etc at a DH race dragging their chain guides through ground... They seem to think CoG is pretty important.
Go and watch Mr Hill etc at a DH race dragging their chain guides through ground... They seem to think CoG is pretty important.
Funnily, a lot of riders have gone back to 14 inch BB's.
There's a theoretical argument against everything, what I want is more fun from 29ers and to see timed runs with proper controls, over several different tracks. Then, I'll make up my mind.
Till then the benefits (beyond giving n00bs more confidence and rolling over objects more easily....unfortunately the latter isn't a golden bullet) have yet to be proven.
Go and watch Mr Hill etc at a DH race dragging their chain guides through ground... They seem to think CoG is pretty important.
I did, he didn't he was up and floating above the ground way faster than anyone else.
That test proves one rider was faster than the other, not whether 29 wheels are faster. The controls are fundamentally flawed..
The comments are the important part. Steve Jones is also faster on the 29".
There's a theoretical argument against everything, what I want is more fun from 29ers and to see timed runs with proper controls, over several different tracks. Then, I'll make up my mind.
My bike is nearly built. Stumpy Evo 26" V's Evo 29" . I'll post up the Strava times.
Strava can introduce bias as it's not a great timing system.
The fact that you would be doing it alone would introduce selection bias. A 29er might be faster for you, due to your build or riding style or whatever? Or it might be faster because subconsciously you decide to ride faster on the 29er to prove your point.
No, the only time you will convince me is if someone does properly timed runs with a selection of at least 60 randomly chosen riders from a pool of amateurs and professional riders. Bikes with equal setups would be distributed, a range of courses would have to be ridden to take into account different types of terrain.
Then other people would have to do the same in other countries (Seeing as how individual RCT's are often biased anyway despite the best intentions) and then I could finally carry out a meta-analysis of the results.
The comments are the important part. Steve Jones is also faster on the 29"
No they arn't if you look at the data James Richards was faster on his 26er whilst Box was faster than James on both 26 and 29 inch bikes and put his best times in with the 29er.
Which means that one rider was faster on his 26er, one rider was faster on his 29er and one rider was faster than the other.
Proves **** all.
What's even more hilarious is a quick glance at the data makes me think even more bias was introduced into the data by swapping the riders onto different opposing wheel sizes half way through. The general picture of the runs is of decreasing run times right to the very end (Which means a potential variable was the run number itself...eg warming up).... if that isn't a study designed with a certain outcome in mind I don't know what is.
Overall rich's time decreased by about 4 seconds despite moving to a 26er half way through and Box's time decreased by about 6 seconds whilst moving to a 29er half way through. LOLZ that's statistically significant proofs right there! 
I guess we should all go and by 29r's then or we will all be unhappy. If your a convert be glad you have purchased an advantage. Use it well win prizes, piss on our chips. Good luck to you all.
I just love the fact that I got to use my biology degree for critically appraising and destroying a dirt mag article. Heh
The comments are the important part. Steve Jones is also faster on the 29".
Yeah it proves Steve Jones doesn't know shit about how to setup a non-biased study and I would quite happily tell that to him personally. Feeling faster does not always mean you are actually faster and the clock only tells the truth when the design of the testing is correct to begin with.
Question everything and believe in nothing my friends, I'm off to get breakfast.
Did Mitch win by 5 seconds? That's a huge gap. 😯
They would have all been faster on fatbikes! But UCI won't allow them because the big brands don't make them, and they gotta keep the big $ brands happy!
It's not really a huge gap when you consider Mitch was also much much faster than James when riding a 26er as well.
See the other thread, spec are making a fat bike. Also look at the course
if you can make the rocks then the lightest bike standing is what you need. (IE anything that is not a DH bike)
Oh man the comments section in that Dirt Mag article prove what gullible idiots people can be.
I think citing Dirt as a reference is probably even worse than wikipedia. Love the mag but they're rarely sure what they think let alone why they think it.
(also, there could be a hidden paragraph at the end of the article refuting the whole thing, which nobody can see because they decided to print it in charcoal ink on a black background, because of Design)
Also look at the courseif you can make the rocks then the lightest bike standing is what you need. (IE anything that is not a DH bike)
The bottom bit looks well gnarly! 😆 😆 😆
Pretty impressive that Gwinn finished second riding a DH bike
All arguments aside, the technical sections of that course look great fun. The less said about the rest of the course the better.
The less said about the rest of the course the better.
Whaaaaaat????? Surely not.
Our expert (who has ridden everything) says that;
Fontana is another world
😆
More seriously, Gwinn must have been hanging at the end pedalling his DH bike over all that and finishing 2nd. He is remarkable.
The spilts are interesting too. Gwinn is faster in the first (rougher) section, Mitch smashes it in the second (pedally) section.
Gwinn is faster in the first (rougher) section
Gwinn must have been hanging at the end pedalling his DH bike
Buowharhar buowhahahahaharrrrrrrrrrrrrrrrrrrrrrrrrrr
I don't care what size wheels anyone is riding but I'd like to correct a glaring error: The centre of gravity of a 29er is not lower than that of a similar 26er, it's actually higher.
All other things being comparable, aye. I think people are confusing the BB-drop effect with COG (taller wheels meaning that for the same BB height you're dropped further below the axles)
I've just seen the track. Congratulations to Arron Gwin for getting second on a DH bike!
All other things being comparable, aye. I think people are confusing the BB-drop effect with COG (taller wheels meaning that for the same BB height you're dropped further below the axles)
If you run flats you can also go some of the way to having this effect by running silly thin pedals such as Point ones or crampons.
But yes the actual CoG of a 29er is higher - however being lower relative to the axles makes them harder to tip from side to side I think.
Also, as the CoG of a 29er is higher isn't this going to negate some of the extra grip from the larger tyres at high lean angles. Let's say for the same weight a 2.3 29er running 21mm internal diameter rims.... you could run 2.4 or larger diameter tyre....and you run that with a rim with a 33mm diameter internal width.....which is going to have more grip/stability and when?
I'd argue on high speed flat (non bermed turns) turns the latter is going to have more grip as the bike would have a lower centre of gravity, the increased diameter of the tire would negate some of the grip advantages, the increased rim width would add more stability by decreasing tire deformation which would in turn allow you to run lower pressures.
Or get some Geoff Apps specials
[img]
wat da **** are those lol
Do they work?
I must have them for the sheer lolz but they look very pedal strikey.
Sod the pedal striking, is there not a huge dead spot in their rotation around the cranks?
bwaarp - Memberwat da **** are those lol
Do they work?
I must have them for the sheer lolz but they look very pedal strikey.
No chance of pedal strike when fitted to a Geoff Apps bike with a 15" high bottom bracket!
mikey74 - MemberSod the pedal striking, is there not a huge dead spot in their rotation around the cranks?
In fact the effect of these swing-pedals is to give a significant dead-spot reduction. Even more so when used in combination with optimally oriented elliptical chain rings.
This bio-mechanical research from Belgium found that a 30mm drop swing pedal like those used by Apps can improve pedal-stroke power output by up to 3.2% When combined with elliptical chain rings as on Apps' bikes a rider can improve pedal-stroke power output by up to 5.1%
www.noncircularchainring.be/pdf/Biomechanical%20study%20-%20Project%20002%20Vista%20Pedal.pdf
You have to realise that Geoff Apps was designing and building 29er off-road bikes in 1981 and 650b bikes in 1979. So on that basis drop-pedal/elliptical crank-sets should hit the market somewhere around 2043. Or even earlier if only the mainstream bicycle manufacturers stop ignoring his ideas.
All other things being comparable, aye. I think people are confusing the BB-drop effect with COG (taller wheels meaning that for the same BB height you're dropped further below the axles)
Mass (rider) + same BB height + higher wheel axle height = lower CoG.