Weight of bike vs weight of rider

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  • Weight of bike vs weight of rider
  • thomthumb
    Member

    Could someone possibly please explain if/why losing weight from your bike is better than losing weight from yourself.

    it’s easier to get the credit card out than stop eating gregs.

    HTH

    cheers_drive
    Member

    You are correct to a point and what you say particularly holds true on a road bike where you are seated most of the time. On a MTB you move your body about – or at least you should be – to aid handling. A lighter bike is easier to move around under you although go to far and it’s easily knocked off line.
    I weigh 200lbs and yet can feel a big difference between a 25lbs bike and a 30lb one.

    5thElefant
    Member

    Assuming your carrying muscle not blubber it’s preferable to have a light bike. How else are you going to keep up with your mates who are made entirely of tendons and elbows?

    Premier Icon qtip
    Subscriber

    If you lighten your bike then it will still be lighter if you lose weight. There are benefits to losing weight from your bike no matter whether you can lose weight from yourself or not. Some that spring to mind:

    – lighter bike is easier to manoeuvre
    – suspension performs better if unsuspended weight is reduced
    – reduction in rotating weight is more noticeable

    If, like me, you are a lardy bastard then the biggest performance gains will come from losing body weight. I still enjoy riding a lighter bike more than a heavy one for the above reasons though.

    Premier Icon tomhoward
    Subscriber

    [silly example]

    Lose 30lbs.
    Once lost, add 30lbs of weight to your bike.

    Are your rides still the same? or have you noticed a difference?

    [/silly example]

    yorkshire89
    Member

    Losing weight on the wheels will help, but i agree that if your carrying a few extra pounds on your belly your better off losing that first!

    rocketman
    Member

    Could someone possibly please explain if/why losing weight from your bike is better than losing weight from yourself.

    You carry your weight all day – the bike is in addition and is being manipulated. A lighter bike is easier to ride and maneuver.

    Lose 10kg in body weight and add it to your bike and I guarantee it will feel awful

    Grizla
    Member

    I guess that I’m thinking in terms of overall percentage, a 2lb reduction in bike weight is still next to nothing.

    I do kinb of get the maneouvrability thing though, and if you say can notice the difference I guess I really am missing something.

    lol @tomthumb.

    Keva
    Member

    a lighter bike feels nicer to ride. It will accelerate quicker, be easier to manouver and will generally handle better, and be faster. Also, if like me you only weigh 60kg with around 10%bf there’s not a lot more to lose, so it comes off the bike. Saying that my bikes aren’t stupidly light at 23lbs, 24lbs and 26lbs but I certainly notice it if I’m heaving a 30lb anvil on wheels around the woods…

    Premier Icon nickc
    Subscriber

    Grizla. You’re more or less spot on, everyone else is pretty much justifying their credit card bills

    Grizla
    Member

    Thanks for the replies.

    I do understand that a 60lb bike might be tough to ride, probably more so than beight 2 stone overweight, so I guess I have an answer.

    BTW this isn’t a thinly veiled “I need to lose weight” plee. My ~210lb is fairly lightly spread over 6’5″ of body.

    Crag
    Member

    A lighter bike will get more nods of approval from your mates when they have a spin on it during the car park test.

    Unless of course they study your form quite closely and notice when you’ve dropped a pound or two.

    Premier Icon tomhoward
    Subscriber

    everyone else is pretty much justifying their credit card bills

    Riiiight…

    Your body is self propelled, it will propel itself regardless of its weight, as all that weight is being used to contibute to moving the body (assuming you arent a 500lb biffer).
    If you add weight to that, weight that does not contribute to the propulsion of said body, its dead weight so will slow you down much more than if you gained a kg or 2. so if you are going to add dead weight, best make it as low as possible.

    Solo
    Member

    Eco,nom,nom,ics:
    I’d say that depending on how wealthy one is. It may seem easier to ride the lightest weight bike you can afford, than to change the diet.

    Physics:
    I’d say a lighter weight rider would yield a greater effect as this will effect overall CoG, which should have an effect on ride and handling, etc.

    EDIT:
    as all that weight is being used to contibute to moving the body
    I’m not sure body fat contributes to the body’s efforts to move, other than in the sense of being an energy reserve.

    klumpy
    Member

    Assuming that to some extent you use your legs as suspension, then to some extent the bike is unsprung mass.

    Grizla
    Member

    Could someone possibly please explain if/why losing weight from your bike is better than losing weight from yourself.

    I reckon when I’m on my bike the combined weight is gonna be ~240lb, so losing half a pound off the bike seems neither here nor there, and that I could, for example, negate several hundred pounds worth of lightweight components just by riding with a half full bladder.

    I feel like I must be missing something though, with all the fuss that’s made over stuff being light…

    Sorry if this is obvious or has been covered elsewhere.

    Premier Icon Onzadog
    Subscriber

    I want a heavier bike and a lighter me. It will lower my centre of gravity and help keep me upright!

    ndthornton
    Member

    all that weight is being used to contribute to moving the body

    Erm – is it? – 1kg of flab is sod all help in moving your body. 1kg of leg muscle will help a bit of course but probably not enough to cover the increase in mass since bigger engines require more fuel.

    Also what’s all this bladder half full nonsense… As far as I know buying light weight components and emptying your bladder are not mutually exclusive – Top Tip…..you can do both!!!!

    Premier Icon ahwiles
    Subscriber

    qtip – Member

    If you lighten your bike then it will still be lighter if you lose weight. There are benefits to losing weight from your bike no matter whether you can lose weight from yourself or not. Some that spring to mind:

    – lighter bike is easier to manoeuvre
    – suspension performs better if unsuspended weight is reduced…

    suspension also performs better* is the ‘suspended’ weight is increased.

    ‘s why heavy cars are more comfy.

    (*isolating the suspended weight from input forces)

    Premier Icon roverpig
    Subscriber

    – lighter bike is easier to manoeuvre

    I suspect the difference is marginal and a bike that is easier for you to move around also gets knocked around more by the trail. So it’s not clear that it’s actually better.

    – suspension performs better if unsuspended weight is reduced

    On a full suss bike is unsuspended weight just the wheels?

    – reduction in rotating weight is more noticeable

    Hasn’t that “myth” been debunked recently ?

    Grizla
    Member

    The

    bladder half full nonsense

    was a light hearted example, for demonstration purposes.

    Although I’m sure we’ve all been glad to reach a pee stop at least once in our lives.

    Premier Icon tomhoward
    Subscriber

    1kg of flab is sod all help in moving your body.

    The 1 kg of flab is (very basically) stored energy, so is (potentially) doing more to help move you than the inanimate hunk of metal you are trying to lump around the moors…

    1kg of leg muscle will help a bit of course but probably not enough to cover the increase in mass since bigger engines require more fuel.

    Thats more to do with efficiency though isn’t it?

    Premier Icon weeksy
    Subscriber

    I’ve been having a simillar discussion with myself trying to justify the purchase of a lightweight 29er HT for commuting. I’ve started and am trying to commute a lot more at the moment. At a 22mile each way commute it’s a decent jaunt, taking in some of the hills over by me means it’s taking 1hr 15. This is all on a 29Spearfish.

    I was thinking “maybe a lightweight HT would be easier”…. but i carry things like my water on the bike, a small toolkit/tube/etc on seat bag and a laptop, lunch and clothing in a rucksack…

    I don’t NEED it to be easier/quicker… but might be nice…

    Premier Icon ahwiles
    Subscriber

    roverpig – Member

    On a full suss bike is unsuspended weight just the wheels?

    fork legs, brake calipers, rear mech, cassette, etc.

    Premier Icon composite
    Subscriber

    I’m currently trying to build a light-ish 29er for marathon type racing next year. I justify the cost because I am also losing weight from myself. Done 15lbs over the last few months and I’m in the 15% body fat region now. Imagine how your bike would feel if it lost that much! Already feeling the benefits even when trying to push up hill on my P7. One of the heavy post cern ones.

    avdave2
    Member

    I’m 55 KG, the only place I can lose weight is off the bike! And being light means I get more benefit for every gram I lose off the bike and more of a disadvantage for every gram it goes up. My off road commuter built with no regard to weight saving is I would estimate over a quarter of my weight. I have a lighter bike for longer rides though.

    – suspension performs better if unsuspended weight is reduced

    I’d buy that on a motorbike swapping from a steel swingarm, steel sprocket, drum brakes and wire wheel with steel rim to a cast aluminium swingarm, renthal sprocket, disk brake and mag wheel. But I don’t think there’s enough weight on a mountianbike to make a difference.

    As for the other arguments, why is is one or the other, why not get the credit card out and go on a diet, not this “lose 10kg of blubber then add it to the bike”, even without the spending spree you’ve still got the same bike!

    My tuppence would be get rid of non-usefull weight. If there’s excess fat, diet. If there’s Domains on your XC bike, buy some SID’s. Loseing muscle is rarely going to help, ditto drilling holes in your frame.

    ndthornton
    Member

    Thats more to do with efficiency though isn’t it?

    On flat – yes as your working against drag which is virtually the same for different weight riders and absolute power is king.

    up a hill – Def not as your working against gravity, strength-to-weight ratio is king

    Thats why there is such a difference in body shape between the sprinters and the climbers on the tour de France.

    The 1 kg of flab is (very basically) stored energy, so is (potentially) doing more to help move you

    …If you ride for a week without eating

    sicklilpuppy
    Member

    A lighter bike is easier to ride, so you ride it more often, and you get lighter. Unless there is a good chippy/bun shop on your regular route. Put lighter wheels and/or tyres for a quick noticable difference, then lighten things as they need replacing or cash flow alows.

    wilko1999
    Member

    1 lb of flab on your stomach takes the same amount of effort to move as 1 lb of metal on your bike if the power source is constant, surely!? Lose 1 lb of flab and you have one less lb to propel with the same engine! Power to weight ratio increases of the complete moving package. I’m not saying don’t buy light bits for your bikes, I am always thinking of ways to make my bike lighter, but I’m not going to kid myself – if I lost some weight, the same engine I was using before would have less work to do.

    Premier Icon Northwind
    Subscriber

    Basically mechanical advantage isn’t it? I weigh 60kg, my lightest bike weighs about 9.25kg, my heaviest about 17kg, so I’ve got a 6-to-1 advantage over the light one but less than a 4-to-1 advantage over the heaviest one. When I move my bikes, they move me too, equal and opposite reactions, right?

    wilko1999
    Member

    A lighter bike definitely means less work done by your engine. A corresponding drop in body mass (assuming you maintain the same strength and fitness) will yield the same results when using the same engine.

    fuzzhead
    Member

    A lighter bike definitely means less work done by your engine. A corresponding drop in body mass (assuming you maintain the same strength and fitness) will yield the same results when using the same engine.

    I’d go along with this – obviously weight dropped from wheels needs to be multiplied by a ratio to cater for rotational forces

    ollie51
    Member

    Aren’t we all forgetting the two key determinants of how fast you go?

    When going up hill/accelerating = Power / weight
    When on the flat = Power / Coefficient of Drag

    If I lose a kilo from the bike I improve my power to weight ratio do I not? Thus going uphill faster. Unless I’ve bought some aero wheels or whatever, i’ve not changed the coefficient of drag to any significant extent. Indeed it’s debatable if the wheels make more than a negligible difference at the kind of speeds most people ride at anyway…

    Equally if I lose a kilo from me it has the exact same effect as above, however it is likely if I lose a kilo that my surface area will reduce (you get smaller don’t you?) this will reduce my coefficient of drag. This makes me faster of the flat too.

    Ergo, losing weight from the body > losing weight from the bike, no?

    Premier Icon ononeorange
    Subscriber

    I have often thought about this. All I can offer though is my experience. I am a fat biffa and recently decided to lose a few spare pies. 3/4 stone in, and I am knackered and have buggered both ankles by going mad on a military fitness thing. So I reckon lose the weight off the bike!

    crikey
    Member

    Aren’t we all forgetting the two key determinants of how fast you go?

    The only single determinant of how fast you go is how much work you put in to going fast. The problem these days is that people assume that they can buy their way quicker, which is super for the deep section light weight aero sellers, but has very little influence on the actual speeds that people ride at.

    Even the speed merchants from here will suggest that such and such an upgrade has ‘massive’ benefits, with very little in the way of quantifiable evidence to support their assumption.

    One would assume that with all the aero and weight advantages available these days, that TT records would be tumbling every week…

    http://www.cyclingtimetrials.org.uk/Competition/CompetitionRecords/Men/tabid/210/Default.aspx

    You’ll get quicker by training to go quicker, not by buying stuff.

    vdubber67
    Member

    You’ll get quicker by training to go quicker, not by buying stuff.

    That sort of common sense thinking will get you into trouble round these parts ;D

    juan
    Member

    I weight around 61kg, bike weight around 14.7kg, so it’s around 25%.
    Until I had my kit 🙁

    Premier Icon mattjg
    Subscriber

    I have a light bike, at its best it’s like riding a cloud, the way it moves beneath me.

    Light bike is a handling benefit IMO, light(er) me is a pace/fitness benefit.

    Premier Icon ads678
    Subscriber

    I’m about 100kilos of pure rippling muscle (apart from the fat bits), and I ride an Orange Five and an On One Inbred 29er. I reckon I match my bikes quite well. 😀

    I’d still like a lighter FS cos carrying the 5 up hike-a-bike bits is a killer sometimes.

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