Viewing 36 posts - 41 through 76 (of 76 total)
  • Any scientific studies on lap times with different wheel sizes?
  • coolhandluke
    Free Member

    The real question is which is more fun and luckily the answer is all of them depending on what you are doing.

    Here here!

    Now can we stop this kitten killing spree?

    chilled76
    Free Member

    My original question was has anyone done a scientific experiment and could you link to it… not can we re-visit the merit’s of fun vs marketing vs marginal gains again.

    Thanks to those who have answered what I asked. The response about vs a mate who has two bikes is interesting and what sparked me to ask as I have a mate who I ride with regularly who has moved to a 29er and suddenly seems a fair bit fitter than before.

    mikewsmith
    Free Member

    On the flat/rolling stuff it’s probably faster but thats the bit where it’s more noticeable. The missus went to a Tallboy from a Blur LTc which is 2kg lighter and shorter travel so apples and oranges really. She does motor on up the hills and on the smooth these days but not on the tech so much.

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    GEDA
    Free Member

    But you cannot do a scientific study as faster in one area may mean slower in another.

    Take the example of skis. There are loads of different types and the ones that are fastest for Olympic downhill skiing would not be great or fun for most people or fastest in all conditions.

    Tyre pressure has more influence than wheel size in my opinion. (Speaking from experience after pumping my 29er tyres up too hard this morning and being pinged all over the place.)

    mrblobby
    Free Member

    It would not in any way show that one of two (three? More?) different bikes ridden at the limit of rider skill and endurance would always be faster everywhere, every time or even same place/time as it’s just not possible. By the time you’ve standardised the variations out you’re left with a ‘test’ so meaningless as to be ‘I like this one better’.

    Think this is why it’s useful to look at top level of competition. You have a lot of rides who are evenly matched in terms of ability. And you have the best bike available, whatever the wheel size, optimally set up for each rider. And in that arena (be it DH, XC or Enduro) all wheel sizes can get competitive times, and no one wheel size is dominant over the other in terms of lap/run times.

    schmiken
    Full Member

    Scott (beware of marketing!) has a wheel size matters thing up at the mo, effectively saying that 650 are quicker over courses requiring a lot of stop/start and acceleration, 29ers are faster over smoother courses. Surprisingly unbiased compared to other brands.

    schmiken
    Full Member
    Northwind
    Full Member

    mrblobby – Member

    Think this is why it’s useful to look at top level of competition. You have a lot of rides who are evenly matched in terms of ability. And you have the best bike available, whatever the wheel size, optimally set up for each rider.

    Really? I don’t think any of that is true tbh

    mrblobby
    Free Member

    Interesting that the Scott stuff doesn’t say that Nico Schurter is riding 650b because he’s tiny and couldn’t get on with 29ers. Though it does say Geoff goes for 29ers because he’s taller. So optimal wheel size determined by rider size…?

    Edit…

    Really? I don’t think any of that is true tbh

    How so?

    IA
    Full Member

    So optimal wheel size determined by rider size…?

    There was an interview with the Scott WC team manager(?) during the olympic (or might have been a WC) XC where this was the conclusion he said they’d come to from their testing, and that this was why nino was on 650b – it suited him and his physique best.

    From a personal point of view, I bought a cheap 29er to try out and liked it. So replaced by 26″ enduro bike too, and liked that new bike too. I am tall tho, but find them more fun. No idea if they’re any faster, feel easier to ride in some situations, which may or may not make them faster…

    kimbers
    Full Member

    theres a funny dirt article somewhere where they tell you 29ers are faster and go on to detail a test where they seem to be slower

    here it is

    http://dirtmag.co.uk/news/dirt-magazine-26v29-bonus-feature.html

    mrblobby
    Free Member

    There was an interview with the Scott WC team manager(?) during the olympic (or might have been a WC) XC where this was the conclusion he said they’d come to from their testing, and that this was why nino was on 650b – it suited him and his physique best.

    Yet you see some tiny riders on 29ers. Emily Batty comes to mind.

    woodsman
    Free Member

    I can’t see how performance in wheel size as the OP suggests can be measured on anything other than road, as there are so many variables on the dirt. To say my mate is quicker on such a wheel size and slower on others, only proves that he prefers a certain type.

    Masses of variables to make it in any way accurate to calculate. Faster in one way and slower in another is my opinion of all wheel sizes. Choose one that suits your riding preference, or multiples if you’re fortunate enough to afford them.

    I ride 26 on the dirt, because I’m 5’8″ for a start, and more importantly perhaps, is that I love tight, super tight twisty single track. Gravity singeltrack and open descending yep, bigger wheels do seem more capable from what I’ve observed.

    Northwind
    Full Member

    @mrblobby- why assume that all the top riders are equal? That seems incredibly unlikely. And they won’t all be on the “best bike” unless all the bikes are also equal. In reality they’re riding the best bike their sponsor offers them which isn’t the same thing, and is also no guarantee that it suits them (see: aaron gwin). And for the same reason the setup isn’t going to be optimum for everyone.

    jameso
    Full Member

    effectively saying that 650 are quicker over courses requiring a lot of stop/start and acceleration, 29ers are faster over smoother courses. Surprisingly unbiased compared to other brands.

    No suprise there, no test needed to show that really but it’s a fair generalisation. Rehashing a load of stuff I’ve read and looked into here rather than the results of my own calcs from scratch, but another way of saying it is that light wheels need less power to accelerate to a given speed but also decelerate easier (bumps or braking), heavier wheels hold more momentum at that speed – so need more power to get going but stay there more easily.
    All it has to do with wheel size is that all things equal, a larger wheel will be heavier. The slower rotation of a bigger wheel at any speed means the diameter isn’t the issue, only the weight. There’s the idea that ‘wheel weight counts double’ but that doesn’t work out really, once moving at a given speed it’s simply mass like any other part of the bike, it’s only felt when accelerating.
    But there’s also tyre pressure and rolling resistance to look at, a wider rim and tyre with a larger OD can be quite a bit heavier yet handle a lower PSI to roll with less resistance, so it gets complicated when that variable is included, it also affects rider comfort so the longer the ride the less fatiguing a bike with large OD, wider, heavier tyres and rims may be.
    I have no idea how to show how that all balances out, I’d just go on feel and impressions. My wheels roll fast and handle rough ground well but aren’t light and I’m happy with them for the riding I do.

    mrblobby
    Free Member

    @mrblobby- why assume that all the top riders are equal? That seems incredibly unlikely.

    To ride at that level I think the top riders are all fairly equal (I’m thinking top 20 in a World Cup for example.) Even when you get one rider dominating, he’s still only fractionally better than the rest of the field (and all are way better than your average rider.)

    When you see some of the “tests” claiming that one wheel size is over a minute quicker over some 20 minute course than another wheel size, about 5% quicker. If that really was all consistently down to wheel size then you would get two (or three) speed races as that is a massive step, bigger I think than the gap between riders abilities.

    woodsman
    Free Member

    Sponsored riders ride what they have to. I know of some female sponsored riders, 5’3″-5’4″ and they were given 29ers because that’s what the brand were marketing.

    schmiken
    Full Member

    Just to play devils advocate (I’m a 650 fanboy) Nino rides a 29er for marathon racing, and Emily Batty rides for Trek (who don’t do 650). Top riders tend to ride what they are paid to ride/whatever their sponsors are pushing that year.

    And Emily looks shoehorned onto a 29er, she rides a -17 stem with no headset topcap. Its daft.

    mrblobby
    Free Member

    … and whatever they end up riding, they are still competitive against their peers.

    woodsman
    Free Member

    It’s good to have a choice, remember those “lamp-post” seat posts that taller riders used to have on their 26ers. But I don’t think wheel size should become a universal standard.

    Like head tubes, how many variants do we have, do we need bigger, how many busted head tubes have you seen on xc/cx/road bikes for example! ?

    scruff
    Free Member

    Even on her tippy toes its too big for her.

    woodsman
    Free Member

    She’ll need some pipe lagging on the top tube to prevent minge strike

    [did I really say that]

    brooess
    Free Member

    It’s impossible – too many variables and anyone who says they can prove wheelsize makes a definitive difference to how fast you can ride is basically lying. You can believe it if you want, but it’s impossible to prove it.

    How quick a bike goes down a given trail has more to do with rider skill than anything else… some days I’ll ride a trail faster than other days – depends how fit I am and how smoothly I’m riding…

    BruceWee
    Full Member

    One thing that stands out for me is that there is never any mention of comparing wheel sizes but with the same contact patch area. For example, I’ve not seen any test where they’ve said,

    “We compared a 29er with a 2.1″ tyre, a 650b with a 2.3″ tyre, and a 26″ with a 2.5” tyre. These sizes allowed us to run the tyres at the same pressures and maintain the same contact patch area.”*

    Seems to me that if you don’t even bother to maintain the contact patch size then any like with like test is going to be completely meaningless.

    *I know these sizes probably won’t result in the same contact patch size, if you can be bothered doing the maths to get the right numbers then knock yourself out 🙂

    Edit: My experimentation with a 3″ tyre on a 24″ rim on the back of my Nomad continues. The only conclusion I can draw so far is I’m having fun 🙂

    RamseyNeil
    Free Member

    For many of us although speed is a factor there are other things that come into play too . It’s great if you can ride up , down , through or over stuff that your riding buddies can’t . For me , who is by no means a riding God , I find that I can do all these things better on a 29″ bike . I have never ridden a 650B but having gone from 26 to 29 and noticed big improvements I can’t see how going back down to 650b , which is pretty close to 26″ could possibly be better .

    mrblobby
    Free Member

    One thing that stands out for me is that there is never any mention of comparing wheel sizes but with the same contact patch area. For example, I’ve not seen any test where they’ve said,

    Think like for like test is pretty pointless as far as most are concerned. If the bike isn’t set up how it’s actually be ridden then what’s the point? Compromising performance for some like for like setting doesn’t tell you much if you want to know which is quicker out on the trails.

    If we want to eliminate variables then maybe we should look to the world of unicycling as wheel size is a bigger factor there 🙂 and bigger is definitely better for trail riding!

    Northwind
    Full Member

    mrblobby – Member

    To ride at that level I think the top riders are all fairly equal (I’m thinking top 20 in a World Cup for example.) Even when you get one rider dominating, he’s still only fractionally better than the rest of the field (and all are way better than your average rider.)

    Yup, but they’re not the same- by which I mean, one rider might be a stronger climber, another a better technician. So that’ll all still play to the strengths and weaknesses of different bikes. And then, add in the personal taste factor, like in downhill your Leovs and Beaumonts liking harder suspension than most and you’ve got some massive skews. The human element’s overriding here I reckon.

    scaredypants
    Full Member

    Somebody (like, say, stw ?) could organise a semi-objective test, maybe at one of the 24hr race sites or their own weekender thing.

    Chainless race from a standing start down a couple of different routes (one fairly smooth but needing cornering speed and the other nice and rough). Take a selection of “largely” comparable bikes with different wheelsizes and let anyone do timed runs, as many as they like, offering a small prize for fastest 26, 650 and 29 down each run. At the end, make everyone vote for the bikes they liked best as well, to cover the subjective fun bit

    You could repeat the same format back up the hill on the next day if you wanted (err, with chains on, I guess)

    The aggregated data could be posted on here for a stw excel-off afterwards 😀

    andyrm
    Free Member

    Robin at Enduro Mag recently did a test of 3 wheel size variants of the same bike:

    Biketest: Commencal Meta – 3 wheel sizes compared

    Review came back that each was a bit faster in certain situations, but overall, he felt the 650B version was the best all rounder of the 3 variants, when speed, control, fun factor were all considered. But essentially, it’s not that clear cut.

    As far as I know, this is the only test of it’s type I have seen in the press.

    🙂

    DanW
    Free Member

    … and whatever they end up riding, they are still competitive against their peers.

    It is almost as though differences in training and physiology play a bigger role in racing than the differences between high end tools provided by sponsors from different brands 😕 😆

    A minute gained on a 20 minute lap might sound great (who wouldn’t take that!) but 5% error is within the measurement error of devices used to try and measure comparative differences of wheel sizes (power output for example) not to mention variation is all the other factors already discussed.

    Still, I’d love to see the results of a 29er vs a placebo 29er (26er in disguise!) 😀

    andytherocketeer
    Full Member

    As far as I know, this is the only test of it’s type I have seen in the press.

    No. Seen another with 3 guys all testing 3 variants of the same bike.
    One preferred 26, one preferred 29, one preferred 650b.

    It’s the only review (note “review”, not “test”, cos there’s nothing testing about it in a scientific way), where one of the reviewers dared to say that 650b inherits the compromises of 26+29. Of course 99.9999999% of all 650b BS will only ever mention that you get the best of both worlds.

    Except in MBR where they’ve already decided the outcome before even stepping on the bike, based entirely on wheel size and whether the brakes are Avid Elixir,and whether the tyres are Nobby Nic.

    scaredypants
    Full Member

    whether the tyres are Nobby Nic

    To be fair, they’re right on that. Any bike with NNs on is a bike set up for a long walk, IME

    andytherocketeer
    Full Member

    not IME

    Oh forgot bar width. Knock off 1 point out of 10 for every 1cm shorter than the longest bar width they’ve ever had in to review.

    Northwind
    Full Member

    You forgot to mention the performance-enhancement of an Orange headtube badge 😉

    kimbers
    Full Member

    heres another
    http://www.mbaction.com/Main/News/Shootout-Wheel-Wars-29-vs-275-vs-26-5159.aspx

    I saw this in their mag in 2012 back when stw didnt have a weekly 3-way wheelsize smackdown I think it was the first proper mention id heard of 650b

    chiefgrooveguru
    Full Member

    “We compared a 29er with a 2.1″ tyre, a 650b with a 2.3″ tyre, and a 26″ with a 2.5” tyre. These sizes allowed us to run the tyres at the same pressures and maintain the same contact patch area.”*

    The difference really isn’t that big:

    http://bansheebikes.blogspot.co.uk/2013/11/wheel-size-facts-part-3-contact-patch.html

Viewing 36 posts - 41 through 76 (of 76 total)

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