[Closed] Weight of bike vs weight of rider

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

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.

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?

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.

[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]

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!

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

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

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.

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...

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

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.

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.

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.

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

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

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

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!!!!

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)

- 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 ?

The

bladder half full nonsense

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

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?

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...

roverpig - Member

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

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

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.

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.

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

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.

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.

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?

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.

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

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?

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!

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.

[i]You'll get quicker by training to go quicker, not by buying stuff.[/i]

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

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

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.

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.

Haven't figured out quite how to explain it but I know if I went out for a hilly run and timed it as fast as I could and then lost 2kg and then went for another hilly run with a 2L (2kg) bottle of coke strapped to my back (theoretically, Ignore the fact this would be uncomfortable etc), I know it would be much slower and more knackering. I apply the same principles to my bike. The lighter weight I have to lug around it feels much more beneficial than loosing the same amount of weight from my body. There must be an explanation but I haven't thought of it yet.

My Carbon road bike weighs about 16lbs my steel training bike weighs about 25lbs i weigh about 240 lbs
So I'm 3% lighter overall but I go at least 10% faster when i do a 10 mile tt on my carbon bike

I put on 8lb in one week eating junk food whilst the wife was away and the following Sunday ride was noticeably more difficult. My balance was nowhere near the same and climbing was a little harder too.

Biscuit tin is now padlocked by the other half.

The only single determinant of how fast you go is how much work you put in to going fast.

I think most rational people would assume that....

Rider + bike = total mass that your engine has to propel. Adding 1kg to the bike has the same effect of adding 1kg to your body. The overall mass that your engine has to propel increases by 1kg either way. Anyone searching for an explanation to their own theory is attempting to dispel the commonly accepted laws of physics 🙂

Edit : assuming that the 1kg is fat and you maintain the same power output

crikey - Member

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

Kidding? Minimum weight limit. And ask Obree about aerodynamic advantages.

The TT carbon bike is more aerodynamic, and aerodynamics trumps weight, unless you're climbing at slow speed. If you lose body weight the reality is it will come with increased fitness, so losing a pound of body weight is always better than losing a pound of bike weight. A pound off your bike is dead weight. A pound off your body comes with additional benefits in fitness.

Upgrading bikes and kit is just nice. Full stop. Nothing to do with achieving tangible and noticeable benefits. No need to justify it. If you want it, and can afford it, and get it past your other half, fill yer boots!

The average person is carrying about 70,000 calories of lard, so plenty of poundage to be going at before you start chasing grams off your bike justifying that its better to lose weight off the bike. Unless you're sub 10% body fat that justification just doesn't stick!

neither bike are tt, just plain vanilla sit up an beg road bikes. in fact carbon has BIG tubes so probably lot less aero than 1" headtube steel bike.

Wheels do make a difference, lighter wheels definitely make it easier.

But generally i would agree an xtr rear mech is not going to make you faster unless you are <10% body fat
but some parts do count. In fact I'd say properly set up trail suspension is often heavier than XC parts and that would probably make the average rider faster

wobbliscott - Member

If you lose body weight the reality is it will come with increased fitness

What a ridiculous oversimplification. Lose muscle, lose weight.

"Don't buy upgrades; ride up grades". - Eddy Merckx

EAT LOADS OF PROTEIN, EAT LOADS OF VEG (NOT POTATOS, PASTA OR BREAD) STAY OFF THE BOOZE. DO THIS FOR 6 MONTHS AND YOU WILL BE A ****ING SLIM BORING HEALTHY MONK.

My totally non scientific research suggests that for every pound less of bike weight I can do a lap of Cannock a minute quicker. 5lbs saves 5 minutes. Not lost any body weight so maybe that's the way forward