bike weight: the numbers do not add up?

nvc

hello just bought a new bike a canonndale F4 Z , though I do not have a fat wallet.
I still love a light bike .

The thing is I weigh the bike on the scale , 13.6kg

but when I put the weight of all the parts together ( from each website)

things just did not add up I got 13kg

so that is 600g more

think got worse for my old bike weigh at 12.9 ,added together at 11.5kg 1.4kg different

what went wrong? thanks a lot


Model: 2008 Cannondale F4 Weight

Bottom Bracket:  • Bottom Bracket: Shimano BB-ES25 Octalink. 350 ?
Brake Levers:  • Brake Levers: Avid Juicy 3.
Rear Brakes:  • Rear Brake: Avid Juicy 3 (160mm Rotor). 404
Front Brakes:  • Front Brake: Avid Juicy 3 (160mm Rotors). 404
Cables: cannondale 150 ?
Cassette: • Freewheel: SRAM PG-950, 11-34. 420 ?
Chain:  • Chain: Shimano HG-53. 304
Crankset:  • Chainset: Shimano FC-M442, 22/32/44. 715
Derlr (Front) • Front Derailleur: Shimano Deore. 128
Derlr (Rear) • Rear Derailleur: SRAM X-7 Long cage. 270
Fork: • Forks: Rockshox Tora 302 Solo Air 100 with lockout. 2236
Frame:  Frame: CO2 Canti/Disc Aluminium. 1600 ?
Grips: • Grips: Cannondale V-tech grips.. 100 ?
Handlebar:  vHandlebars: Cannondale C3, 20mm rise. 250 ?
Headset:  • Headset: Cannondale Headshok Si. 300 ?
Pedals:  shimano M520 380
Quick Releases: Control Tech Ti 123
Seat:  • Saddle: Cannondale All Terrain. 317.4
Seatpost:  • Seatpost: Cannondale C4, 31.6 x 350mm. 329
Shifters:  • Shifters: SRAM X-7 Triggers. 262
Stem:  • Stem: Cannondale XC3 Headshok, 31.8mm. 250 ?
Tire (Front) 650 ?
Tire (Rear): 650 ?
Tubes: ? 200 ?
Wheelset:
--Rims:  • Rims: Mach 1 Sub Zero Disc, 32 hole. 940
--Spokes:  • Spokes: DT Swiss Champion, 1.8mm. 444
--Front Hub:  • Front Hub: Shimano M475 Disc. 245
--Rear Hub:  •rear Hub: Shimano M475 Disc. 449
mi reflector, chain protector 150
total 13020.4





for my old bike





items weight status
Brand X Frame 1700 new
spinner 1500 new
WTB Rocket V Comp Saddle 204 new
push seatpost 230 new
Shimano Chains HG 93 304 new
RaceFace Chain Stay Pad Protector 50 new
lx Rear Derailleur RD-M580-SGS 311 new
Shimano Deore 9sp HG50 358 new
Atomlab G.I. CNC Seat Clamp & Bolt 18 new
Shimano Deore Brake & Shifter Combo M510 450 new
Shimano Deore F-Mech Conventional M511 128 new
Shimano XT Gear and break Cable Set 200 new
rear break 0 old
Shimano Deore V-Brake M510 365 new

front wheel 1122 new
new
Front wheel net 1122

front sarencen 750
front quick release 58 old Front wheel 1781

rear wheel rim 520 new
rear wheel spokes 260 new
Shimano XT Disc Rear M765 369 new rear wheel net 1149
rear quick release 61 new
Michelin Tyres - rear 500 new
tube speculized 150 rear wheel 1860


wheel total 3790

peddle 380 new
answer carbon headbar 125 new
stem 300 old
AheadSet STS headset 141 new
Shimano LX UN53 Bottom Bracket 300 new
shimano Crankset Deore M510 700 new


total 11554

supersonic

with the dale there are a few guesses in there, and oe equipment is often a little heavier than aftermarket stuff. Need to add spacers for stem, seat bolt, grease even!

zero303

Manufacturer quoted weights are rarely correct. Truvativ bar and stem I just bought were about 10g a piece out...

Tyres I've weighed in the past have always been heavier than quoted.

switchback18

also, weights are usually quoted for 1 frame size, so if yours is larger, it will be heavier.

The general weight issue reminds me of old cars & horse power, they were always 'optimistic' with the figures.

I've found that design has a much bigger effect than weight. My DMR at about 28 pounds accelerates way faster than a Yates I had that weighed 23 pounds.

Geometry, tube profiles etc add up to a lot.

Stu 74

Have your scales been calibrated?! Seriously as well as the other possible explanations put forward inaccurate scales could well be a factor

Stu.

nicklouse

so the air in the tyres? that weighs.

supersonic

3g.

nicklouse

a bit more i think.

supersonic

Ah... 4g.

To be honest the weight weenies do weigh it, and glue and grease and stuff. Not sure what it actually all works out out,a few dozen g maybe.

SDK2007

Some quick observations from me

Inner tubes weigh more than 200g each and you have 2 of them
Your handle bar probably weighs bit more

xtreem

Spoke nipples?

Chris`I

Xtreem wrote:

Spoke nipples?

Dont forget rim tape

BlackSpur

To be honest it really isn't worth worrying about.

dav1

alsopossible forany grime to add up weight, water that hasnt been removed and is lingering in a hard to reach spot. The possiblilities for an extra 500g are endless.

RichMTB

nicklouse wrote:

so the air in the tyres? that weighs.

According to Avogadro's Law 22.4 litres of gas at STP is one molar weight, The molar weight of air is about 29g (Nitrogen is 28g and Oxygen is 32g)

BUT

The air in tyres isn't STP it about three time denser (eg 45psi) so 22.4 litre of tyre air weighs about 87g or put another way every litre of air in your tyres weighs roughly 4grams

icedmind

u weight the star nut, bolt n top cap?
also the cables and outers

Splasher

^^ Good stuff on the weight of air in tyres.

But shouldn't that be mass, not weight. And you've neglected to consider that the bike is not being weighed in a vacuum so you have the bouyancy effect of the air around the tyre. So the actual contribution to the bikes mass is the relative density of the pressurised air compared to atmospheric pessure air, not the absolute density. :?

As for bike weights, most published numbers are optomistic at best, lies at worst. Hang it on a well calibrated scale and that's what it weighs.

When I added up the published weights of the parts on my bike and it came to 29 lbs, weighed it on the scales and it's 30.5 - it's an all too familiar story. But look at it this way, everyone's in the same boat so if your bikes covered in XT and your mates it covered in Deore, your's is still lighter.

nvc

thanks everyone.


the tora 302 solo air 100mm quoted as 2236g

I measured as 2344g after cutted off about 43 grams .there must have some really heavy air in it.
:oops:
I have a big and very accurate scale max out at 43999.99 g. and sometimes I weigh stuff for fun :oops: but I guess I am not going to strip down the bike this time.

nvc

Splasher wrote:

^^ Good stuff on the weight of air in tyres.

But shouldn't that be mass, not weight. And you've neglected to consider that the bike is not being weighed in a vacuum so you have the bouyancy effect of the air around the tyre. So the actual contribution to the bikes mass is the relative density of the pressurised air compared to atmospheric pessure air, not the absolute density. :?

As for bike weights, most published numbers are optomistic at best, lies at worst. Hang it on a well calibrated scale and that's what it weighs.

When I added up the published weights of the parts on my bike and it came to 29 lbs, weighed it on the scales and it's 30.5 - it's an all too familiar story. But look at it this way, everyone's in the same boat so if your bikes covered in XT and your mates it covered in Deore, your's is still lighter.

hello the air is condensed in the tyre , 4bar? 60psi? so it is heavier. wondering wether the tour de france riders pump H2 into the tyres

seems I am not the only one did the sums.

btw the C dale use larger headset that must weight like 100g more

xtreem

[b]nvc[/b] wrote:

hello the air is condensed in the tyre , 4bar? 60psi? so it is heavier. wondering wether the tour de france riders pump H2 into the tyres

I've heard from a comentator that the bikes for Tour de France can't weight less than 6800g.
They can make them lighter but then that's a fragile peace of metal.

BlackSpur

nvc wrote:

Splasher wrote:

^^ Good stuff on the weight of air in tyres.

But shouldn't that be mass, not weight. And you've neglected to consider that the bike is not being weighed in a vacuum so you have the bouyancy effect of the air around the tyre. So the actual contribution to the bikes mass is the relative density of the pressurised air compared to atmospheric pessure air, not the absolute density. :?

As for bike weights, most published numbers are optomistic at best, lies at worst. Hang it on a well calibrated scale and that's what it weighs.

When I added up the published weights of the parts on my bike and it came to 29 lbs, weighed it on the scales and it's 30.5 - it's an all too familiar story. But look at it this way, everyone's in the same boat so if your bikes covered in XT and your mates it covered in Deore, your's is still lighter.

hello the air is condensed in the tyre , 4bar? 60psi? so it is heavier. wondering wether the tour de france riders pump H2 into the tyres

seems I am not the only one did the sums.

btw the C dale use larger headset that must weight like 100g more

Great idea. Ever see that film of the Hindenburg blowing up?

RichMTB

Splasher wrote:

^^ Good stuff on the weight of air in tyres.

But shouldn't that be mass, not weight. And you've neglected to consider that the bike is not being weighed in a vacuum so you have the bouyancy effect of the air around the tyre. So the actual contribution to the bikes mass is the relative density of the pressurised air compared to atmospheric pessure air, not the absolute density. :?

Splasher, you are indeed correct It should be mass of air in tyres but the bouyancy effect wouldn't change the weight (or the mass) but would possibly have a very small effect on the measured weight (depending on whether scales or a balance was used)

xtremedash

These sort's of weights are insignificant to the great big one sat on the bike! As others have said the published weight's will be optimistic.

Anonymous

who cares? :roll:

howsmyriding27

well said - if you're that worried about weight, you won't enjoy the ride as much! (constantly grumbling about the extra gram of toast you had that morning)

The Spiderman

I have found this too.With bikes its all the little incidental,seemingly insignificant bits,when added together,which add to more than you think.
Individually little bits like rim strips,cables,top cap,water bottle, cage and bolts,headset spacers,seat clamp,qr skewers,etc,don`t sound like much but often add up to 500g or so.
XC racers use ti bolts ,because all those seemingly insignificant 8g bolts add up when multiplied several times.Its quite normal to be able to save 300g or more,on bolts alone.
For real as opposed to quoted weights,have a look on www.weightweenies.com
I used to obsess about these things,but soon came to realise that I was always going to be lighter and faster on my hardtail than my 17 stone mate on his 6" travel full susser.

nvc

howsmyriding27 wrote:

well said - if you're that worried about weight, you won't enjoy the ride as much! (constantly grumbling about the extra gram of toast you had that morning)

then you miss a different kind of fun.

FSR_XC

What about oils & grease etc.

There is going to be a bit of difference between 'dry' weight & 'ride ready' weight.

Are you including all of the bolts?

grantway

Same has race bikes normaly the Manufacture will wheigh the small bike
and submit that as the weight of the bike.

Unless if the bike is reviewed and frame size is stated in a test bike
in a magazine

But in saying that when I rang Orange they told me the exact wheight
of the bikes I was intrested in, and this was a medium to large size frames.