• This topic has 202 replies, 52 voices, and was last updated 12 years ago by hock.
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  • Saving circa 500g on wheels………
  • skywalker
    Free Member

    .sorry, forgot; changing wheel weight is very noticeable, in that we/you/me can all tell that it’s changed, but it doesn’t have the effect in terms of actual, measureable performance that we assume.

    http://en.wikipedia.org/wiki/Bicycle_performance#Advantages_of_light_wheels

    Read that, it explains it all, the contents in your link are just someones view.

    If we were on about road bikes then aerodynamics would play more of an important roll, but we are talking about mountain biking where you are constantly braking then accelerating. Aerodynamics will not help you climbing a hill, the speeds are too slow, whereas less weight will.

    Change of direction is also easier with lighter wheels due to less inertia, something you do a lot of in MTB’ing and not so much of on the road.

    crikey
    Free Member

    🙂 I’ll have to retire first!

    I suspect, and it’s only a suspicion, that the overall greater weight in mountain biking makes the change less significant.

    But.. It seems to be the case that the rougher the terrain, the more wheel weight is significant; not to any great extent, but you can calculate a difference.

    http://www.analyticcycling.com/ForcesLessWeight_Page.html

    and worth having a play if you are bored;

    http://www.analyticcycling.com/

    crikey
    Free Member

    skywalker, from your own quoted article;

    Thus increased rotating mass may slightly reduce speed variations, but it does not add energy requirement beyond that of the same non-rotating mass.

    Lighter bikes are easier to get up hills, but the cost of “rotating mass” is only an issue during a rapid acceleration, and it is small even then.

    So, rotating mass is not really all that.

    The miracle of light wheels (compared to saving weight anywhere else in the bike/rider system) is hard to see.

    Really not all that.

    Dickyboy
    Full Member

    Bigsi – it is possible to do the maths to show that 1g off the rims/tyres is worth 1.5g off elsewhere on the bike. However it can also be shown that the difference between an average weight rider & heavy bike (say 30lbs) & an average rider weight rider & light bike (say 20lbs) is only worth about 5% advantage & that is only on the ascents. Up to you if that makes a worthwhile difference & it also assumes all else is equal re feel of bike etc.

    Having done a couple of solo Mayhems I would say that weight is one of many factors to be considered but your psychology is paramount, if the 5% advantage above gives you an extra psychological advantage then it could well be worth every penny.

    radoggair
    Free Member

    well i enjoyed this 🙂

    crikey
    Free Member

    I’m giving up on this now, I’m feeling a bit one-issue-knobber about it.

    I’m still riding my ‘bought as climbing wheels’ Mavic Heliums from back in the day, and I do like light bikes, but even with a bike that weighed nothing, I’ll never be as fast as I was back in those days…

    …wanders off in ill fitting slippers and smelly dressing gown..

    skywalker
    Free Member

    skywalker, from your own quoted article;

    Thus increased rotating mass may slightly reduce speed variations, but it does not add energy requirement beyond that of the same non-rotating mass.

    Lighter bikes are easier to get up hills, but the cost of “rotating mass” is only an issue during a rapid acceleration, and it is small even then.

    So, rotating mass is not really all that.

    The miracle of light wheels (compared to saving weight anywhere else in the bike/rider system) is hard to see.

    Really not all that.

    Talk about selective reading…

    Read the whole thing 🙄

    crikey
    Free Member

    I have read it all, but I’m not carrying on because I’m boring even me. 😉

    cynic-al
    Free Member

    So , cynic-al did you read this as well and realised the biase of road riding

    Of curse there’s a bias, an so the aerodynamics matter much less, but it’s not like your speed varies that much on an mtb.

    hock
    Full Member

    EDIT deleted the stuff on off-road being more about acceleration and less about aerodynamics

    The other day I did my loop through the frosty local woods. One patch was half-thawed mud and it stuck like glue to my tyres -> man, could I tell that it makes a difference! While I can’t really tell if the bottle in my bottle cage is full or empty when riding.

    Just sayin’.

    bentudder
    Full Member

    Not sure about the science bit, but I quite like building wheels with not-massively-light-but-still-good hubs (XT is CHEAP these days) and nice light spokes and rims. Then – and this is the important bit – add some nice supple tyres set up as tubeless jobs. ie, XT / DT Comps / Stan’s 355s or Flows / Maxxis adVantages.

    Rotating weight is one thing, but tyre size, minimal rolling resistance and sidewall flexibility is another factor. Nice tyres at the right pressure make a lot of difference too, imho.

    radoggair
    Free Member

    but it’s not like your speed varies that much on an mtb.

    WHAT!! course it does. Maybe if you ride the pavements it doesn’t but on most trails it varies alot. On road, you could sit in the bunch and your speed will vary little but in mtb’ing, i dont recall sitting at the same speed for more than about 20 -30 seconds.

    Also, when you race, either road or mtb’ing , time lost can be out of corners where acceleration occurs

    cynic-al
    Free Member

    radoggair – Member
    but it’s not like your speed varies that much on an mtb.
    WHAT!! course it does. Maybe if you ride the pavements it doesn’t but on most trails it varies alot. On road, you could sit in the bunch and your speed will vary little but in mtb’ing, i dont recall sitting at the same speed for more than about 20 -30 seconds.

    Also, when you race, either road or mtb’ing , time lost can be out of corners where acceleration occurs

    🙄 are you goading me into a ride-off? I DARE YOU! 😡

    Of course your speed varies…I just don’t believe it’s enough to make the accelerational benefits significant (or even measurable).

    If you have proof, let’s see it, otherwise it’s just opinions.

    Light wheels fell light/fast because you get so tuned to your bike, also steering etc is lighter due the the reduced rotational momentum, but the actual effect is small (as per bike weight).

    skywalker
    Free Member

    If you have proof, let’s see it, otherwise it’s just opinions.

    There is plenty of proof in that link I gave, you two are just too narrow minded.

    but the actual effect is small (as per bike weight).

    If it wasn’t true, xc racers and road racers wouldn’t ride the lightest bikes possible, they would be happy to race 30 lbs Orange Fives and whatever the equivalent road bike is. Pretty obvious really.

    cynic-al
    Free Member

    skywalker – Member
    There is plenty of proof in that link I gave, you two are just too narrow minded.

    but the actual effect is small (as per bike weight).
    If it wasn’t true, xc racers and road racers wouldn’t ride the lightest bikes possible, they would be happy to race 30 lbs Orange Fives and whatever the equivalent road bike is. Pretty obvious really.

    Please quote the proof then, I didn’t see it.

    Of course people racing ride light bikes 🙄 they feel fast, no one is arguing otherwise. There is an effect on speed, but it’s nothing more than placebo + weight itself.

    bigsi
    Free Member

    cheers for the insightful replies to this thread guys. 🙂

    I’ve decided to go with the wheels because looking at where i can spend £200 elsewhere to save 500g its proving harder than i thought it would.

    It may end up being a placebo effect but I’m happy to take the chance although i will be looking at the tyre choice as well 8)

    skywalker
    Free Member

    Of course people racing ride light bikes they feel fast, no one is arguing otherwise. There is an effect on speed, but it’s nothing more than placebo + weight itself.

    LOL that is the funniest thing I have read today, nice one.

    cynic-al
    Free Member

    Easy to flame eh 🙄 lemme guess you are about 15?

    Shame you have nothing to back up your points, even your own article goes against them.

    crikey
    Free Member

    Still going?

    You’re not really covering yourself in glory here skywalker; even the article you quoted says exactly the opposite of what you are suggesting…

    🙄

    Northwind
    Full Member

    Crikey, the quotes you took from that article are taken completely out of context, and tbh I’d be astonished if you don’t realise that.

    For example:

    crikey – Member

    skywalker, from your own quoted article;

    Thus increased rotating mass may slightly reduce speed variations, but it does not add energy requirement beyond that of the same non-rotating mass.

    Is taken from a paragraph relating entirely to the miniscule speed variation caused when pedalling, not to overall speed variations.

    skywalker
    Free Member

    Like I said Northwind, selective reading.

    If they actually read the article they would have an understanding on the subject, but like I said on page one….

    I would make a contribution, but I think my time will be wasted explaining it. Clearly you two know better than the laws of physics.

    I don’t think they have the brain power between them to understand it.

    D0NK
    Full Member

    My riding seems to be,100% acceleration or decelerstion so I’d think lightweight is pretty important, lots of other stuff too tho, tyres pressure all that pales into insignificance compared to rider fitness and weight but same as every weight saving thread its about buying a tiny bit of an improvement , over 12hrs those little improvements build up into a lot I’d have thought

    crikey
    Free Member

    Believe all you like chaps; there is a large part of the bike industry that depends on you… 😉

    skywalker
    Free Member

    I give up.

    hock
    Full Member

    But thanks for trying, skywalker!
    Much appreciated!

    crikey
    Free Member

    Thanks.

    … the actual physics is quite simple to understand; rotating weight is the same as weight in terms of the performance of a bicycle. The idea that rotating weight is important is related to acceleration, which, in terms of the average STWer is a very small acceleration indeed. In addition, things that are very easy to accelerate are also very easy to deccellerate, so reducing weight at the wheel makes them slow down quicker too.

    People notice light wheels on bicycles, but that isn’t the same as a performance improvement, but some people can’t accept this, because they believe differently.

    Night!

    jivehoneyjive
    Free Member

    Lighter wheels accelerate better, deccelerate better and reduce unsprung weight; cry myth to the moon, but facts is facts, whatever bulbous brained streamlined roadies choose to claim this week.

    I’d sooner get lighter wheels and feel an appreciable performance advantage than debate over what shape tyre knobs are suited to the trail conditions over the coming hour/week/month.

    cynic-al
    Free Member

    Don’t give up skywalker…I mean all you’ve done is link to one wiki article, claim it’s fact, flame crikey and me but fail to quote anything to support your point.

    I’m still not actually sure what your point is – is there anything more to it than crikey and me being wrong?

    My points are 1. losing weight doesn’t make you significantly faster than the proportion of weight loss to overall weight on the climbs only…2. weight loss to wheels may make a little more difference, but not the 3x referred to in 1 touted in magazine articles…despite 3. your bike “feeling way faster” etc.

    Happy to hear any EVIDENCE that’s relevant.

    crikey
    Free Member

    Lighter wheels accelerate better, deccelerate better and reduce unsprung weight; cry myth to the moon, but facts is facts.

    Zzzzz.

    Better than what?
    How much better?
    A wee bit of proof would enhance your suggestion immeasurabley…

    marting
    Free Member

    Good debate this.

    If you care about the facts, rather than the argument, read the wikipedia article – it’s worthwhile. FWIW, I just did the maths myself and got to the same answer. Reduced rotating mass does make a difference in accelerating and stopping, but it’s small.

    And for £200 to save 500g? Eat better/less and/or exercise more, and lose 1kg of non-rotating mass in the spare tyre. Might even save money too!

    DuggieStyle
    Free Member
    D0NK
    Full Member

    do you all have to get so defensive and bicker about it? Seems even the naysayers admit there’s a minor difference even if it’s only a teeny tiny difference. So what we are basically arguing about is specifics, you want a clearly defined measurable reproduceable figure. OK 42, that’s about as good as you are going to get, real world testing of MTBing I’d have thought would be nigh on impossible.

    Can’t we just agree there’s an unquantifiable difference and the crikey and Al can call the weight weenies “marketing dupes” and the skywalker et al can call the luddites….well whatever.

    That OK? After all we don’t have to justify our purchases except maybe to our OHs or bank managers neither of whom are going to be swayed by “performance benefits” anyway quantifiable or not. And hell “lightweight feels better” isn’t a good enough reason?! The whole point of riding my bike its to feel better (sorry sounding like I’m trying to justify my position too much now so I’ll shut up – not much of a WW anyway, too clumsy for uber light stuff)

    seosamh77
    Free Member

    A wee bit of proof would enhance your suggestion immeasurabley…

    quite easy to test, get the same bike, one set of light wheels, one set of heavy wheels. same rider, time the acceleration.

    lighter wheels do make a bike feel better imo. whether that translates into being actually faster, well i don’t know, neither do I really care, i’m just concerned about how feel of the bike.

    skywalker
    Free Member

    Poor trolling Al

    LOL excellent

    honourablegeorge
    Full Member

    D0NK – Member

    do you all have to get so defensive

    Can’t we just agree

    First day on the internet? You’ll figure it out.

    njee20
    Free Member

    Wow. Well done gents!

    To the OP: I’m surprised you’ve managed to build a bike with X0 and yet some £200 wheels will save 500g! I’d sooner have Deore and light wheels than X0 and heavy ones!

    anto164
    Free Member

    Not bothering with reading the bumf above me, but this is my 2c.

    Lighter wheels definately transform a bike.

    I have a Giant reign X, and had some pro2s on ex729s. Went from them to Mavic Crossmax SX wheels, and lost about 600g. Also went from dual ply minions to single ply folding ardents (saving of approx 1kg)

    Makes a MASSIVE difference. All of a sudden the bike accellerates really well, climbs much better, and also much stiffer (Which is suprising)

    If you want to spend money, best way to spend it is on wheels. Otherwise, wear lighter clothing.

    BTW, whoever is talking about how aero the bike.wheels are, this only comes into play at 20mph+

    D0NK
    Full Member

    Lighter wheels definately transform a bike.

    but don’t actualy make it betterer, or maybe they do, or maybe it’s all a troll for Als amusement.

    WTF am I still doing here in my own time anyway?

    cynic-al
    Free Member

    Sorry, but how is my buying lightweight wheels inconsistent with my position on this thread?

    They feel great, I’ve not said otherwise, just that the difference the weight makes to times is as I’ve said above.

    or are you trolling?

    Or thick.

    skywalker
    Free Member

    Not bothering with reading the bumf above me, but this is my 2c.

    Lighter wheels definately transform a bike.

    I have a Giant reign X, and had some pro2s on ex729s. Went from them to Mavic Crossmax SX wheels, and lost about 600g. Also went from dual ply minions to single ply folding ardents (saving of approx 1kg)

    Makes a MASSIVE difference. All of a sudden the bike accellerates really well, climbs much better, and also much stiffer (Which is suprising)

    If you want to spend money, best way to spend it is on wheels. Otherwise, wear lighter clothing.

    BTW, whoever is talking about how aero the bike.wheels are, this only comes into play at 20mph+

    At last, someone with a brain cell.

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