29er for dh racing

still going?

If you want to convince the world that the bigger wheels is ammazingballs for everything eva then please go away quietly and prove it somewhere, then we wills till have a choice of what to buy as 1 mans amazing is anothers fad/crap.

we may all be stuck there old fogies with no idea of progress or we might mot care. By the time some of us buy a new bike 29 may be old hat and a new idea may have come along. If however you change bikes like pants then carry on buying the newest bestest thing just keep it to yourself ten when you are sooooooo much fastererer than us we will just thing u iz amazing like 😉

was watching a bloke pull some wicked whips, ultra flat tabletops and tyre grabs at some cheeky jump lines in the Forest of dean on cotic Solaris 29er

it’s all about the rider not the bike

Yeah and I saw a video of someone doing trials stunts on a road bike. Doesn’t make it the best tool for the job though does it.

Don’t think you’re going to see 29″ wheels on dirt jump bikes and BMXes any time soon.

bwarrp the sarcasm was strong in mt post, i’ve ridden champery its a proper DH track not a fire road with 100 yards of rocks like that fontana joke.

29ers have to have a longer wheelbase, unless you want mad toe rub… as soon as things get tight and technical, you’re bummed.

Once a 29er wins at Champery, Glencoe or a Slopestyle contest, then maybe I’ll believe the hype, but in the meantime, I’ll protest that the gullible amongst you are unwittingly pushing up the price of all bikes as they create a false panic and thus exclusivity to the different sizes, which justifies niche tax.

Ok read all these arguments loads of times but the thing I want to really know is why the water bottle?

probably to take a drink on the kilometer long fireroad drag some of which is actually uphill apparently, DH race my arse.

Love the wheelbase comments. I wonder how Spagnolo got that mile long Summum down for a podium at the Worlds at Champery…

This place is like a clueless cult. My Mum understands bike geometry better than half the people on here LOL!

Waterbottle gives more centralized mass on the bike, improving handling.

I daresay when compressed, the summum was no longer than a 24″ cruiser 🙂 not to mention the improved life of shoes when not being rubbed to death by ferris wheels

To be fair I thought maybe it was to add a bit of weight to the centre of the bike. Just seems an odd thing on a dh race pedally or not. I don’t know. I thought it was photoshopped at first. Don’t really care what size wheels/bike anyone rides. Good fun watching this thread though.

Just seems an odd thing on a dh race pedally or not to call it a DH race

FIFY

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 **** 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
http://www.vitalmtb.com/videos/features/ONE-LAP-Evan-Turpen-Pro-GRT-Fontana-2013,20286/E-T,699 if you can make the rocks then the lightest bike standing is what you need. (IE anything that is not a DH bike)