Bike weights - the reality

markp2

There was a thread on here a little while ago about bike weight and effect.. How about building up a reference point for bikes in commuting trim?
Being at a bit of a loose end, I weighed my collection last night:

2008 Kinetic 1 roadie 8.0kg bare and 8.6kg as ridden with saddle bag, pump and computer.
1999 Cannondale jeckle full-sus MTB 13.3kg bare and 14.5kg with saddle bag, computer and crud catchers.
2009 Genesis Croix de Fer CX/commuter 12.4kg in 'summer' trim with 23mm tyres, saddle bag and alloy rack, 15.0kg in 'winter trim' with 28mm Randonneur tyres, mudguards, rack, lights, pump and saddle bag.

My favoured method of weighing is to lock the back brake on with an elastic band or tape and then balance the bike on digital bathroom scales. The results may not be 100% accurate but at least they will be consistant.

Maybe I need to get out more!!
Cheers,
Mark

kelsen

Can't you just weigh yourself whilst carrying the bike, then deduct your weight from that figure?

amnezia

kelsen wrote:

Can't you just weigh yourself whilst carrying the bike, then deduct your weight from that figure?

that would make more sense

markp2

That involves maths!

iPete

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

il_principe

iPete wrote:

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

Meh, that's discs for you!

always_tyred

Il Principe wrote:

iPete wrote:

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

Meh, that's discs for you!

How much do you imagine that the whole mechanical disc system weights? Now subtract the weight of some moderately low end calipers, and you'll probably still find that you have around 12kg of bicycle to account for.

Now, if you switched to £600 Mavic 29er wheels and replaced the kalloy everything with lightweight stuff, and popped a Zipp crank on there, and installed a Woundup fork, iit would probably come in more like 9kg.

But then it wouldn't be a £1k bike, would it?

Aidy

How much of that 12.4 kg is accounted for by the saddlebag?

Seems a lot heavier than I was expecting (I'd guessed at 23-24 lbs).

il_principe

Always Tyred wrote:

Il Principe wrote:

iPete wrote:

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

Meh, that's discs for you!

How much do you imagine that the whole mechanical disc system weights? Now subtract the weight of some moderately low end calipers, and you'll probably still find that you have around 12kg of bicycle to account for.

Now, if you switched to £600 Mavic 29er wheels and replaced the kalloy everything with lightweight stuff, and popped a Zipp crank on there, and installed a Woundup fork, iit would probably come in more like 9kg.

But then it wouldn't be a £1k bike, would it?

Sheesh, SOHF.

desweller

How does the Kinetic bike ride? Is that one of those custom Ti jobbies from Stroud way?

always_tyred

Il Principe wrote:

Always Tyred wrote:

Il Principe wrote:

iPete wrote:

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

Meh, that's discs for you!

How much do you imagine that the whole mechanical disc system weights? Now subtract the weight of some moderately low end calipers, and you'll probably still find that you have around 12kg of bicycle to account for.

Now, if you switched to £600 Mavic 29er wheels and replaced the kalloy everything with lightweight stuff, and popped a Zipp crank on there, and installed a Woundup fork, iit would probably come in more like 9kg.

But then it wouldn't be a £1k bike, would it?

Sheesh, SOHF.

I'm going to make up some acronyms.

I WIPO your UKIPO and if your PCT then QWERTY, okay?

markp2

Aidy - The saddlebag on the Croix weighs about 0.5kg with tube, multitool, CO2 cylinder X 2.

DesWeller - I think the Kinetic One rides brilliantly. It is indeed made/built in Stroud but mine is an all carbon jobbie. I haven't ridden many other road bikes but it seems as quick or quicker than all of the Giant/Trek/Specialized bikes that my mates use (I may just have bigger thighs of course!)
I chose the K1 because I was new to cycling, wanted a 'made to measure' bike on Cyclescheme which wasn't too far away to go for a fitting.

iPete

Always Tyred wrote:

Il Principe wrote:

iPete wrote:

Woah, didn't realise the Genesis Croix de Fer weighed so much. I mean it has dics but was expecting more 10-11kg.

But then it wouldn't be a £1k bike, would it?

So are there any sub 1k bikes that fit the description of, drop bars, disc brakes and can take a pannier rack, sub 11kgs?

I'm looking for an excuse to switch away from my Allez which does pannier/commute/tour duties but comes in at just over 9kgs stripped.

Zombie_donkey

You could tie a load of helium balloons to your bike to make it lighter.

Although the drag factor would more than negate any gains.

jedster

how much difference does weight make on a commuter, particularly around London?
Bugger all I reckon (but then I carry around rack, guards, dyno hub, pannier, tools, tubes, pump, a book, phone, blackberry, some papers, some clothes).

wgwarburton

jedster wrote:

how much difference does weight make on a commuter, particularly around London?
Bugger all I reckon (but then I carry around rack, guards, dyno hub, pannier, tools, tubes, pump, a book, phone, blackberry, some papers, some clothes).

How many times do you accelerate away from a set of lights on your commute?

Cheers,
W.

asprilla

Surely it's only weight of the tyres and wheels that affects your acceleration. Overall weight only affects climbing hills, or have I comletely missed the mark with that statement?

jonginge

ye kannae break the laws of fizzix

davis

Asprilla wrote:

Surely it's only weight of the tyres and wheels that affects your acceleration. Overall weight only affects climbing hills, or have I comletely missed the mark with that statement?

I'm afraid you have. Newton's Second Law is "Acceleration = Force/Mass". If you increase the mass, then you'll decrease the acceleration for a given force (i.e. it'll accelerate more slowly unless you push harder).

asprilla

davis wrote:

Asprilla wrote:

Surely it's only weight of the tyres and wheels that affects your acceleration. Overall weight only affects climbing hills, or have I comletely missed the mark with that statement?

I'm afraid you have. Newton's Second Law is "Acceleration = Force/Mass". If you increase the mass, then you'll decrease the acceleration for a given force (i.e. it'll accelerate more slowly unless you push harder).

/facepalm.

I guess pointing out I've got a degree in cosmology would just embarrass me further......

However, maybe I can redeem myself a little by pointing out that the rotational mass of the wheels / tyres is worth about 1.5x that of the non-rotating mass of the bike frame, so if you want to save weight then the theels and tyres is the place to do it.

davis

Asprilla wrote:

davis wrote:

Asprilla wrote:

Surely it's only weight of the tyres and wheels that affects your acceleration. Overall weight only affects climbing hills, or have I comletely missed the mark with that statement?

I'm afraid you have. Newton's Second Law is "Acceleration = Force/Mass". If you increase the mass, then you'll decrease the acceleration for a given force (i.e. it'll accelerate more slowly unless you push harder).

/facepalm.

I guess pointing out I've got a degree in cosmology would just embarrass me further......

However, maybe I can redeem myself a little by pointing out that the rotational mass of the wheels / tyres is worth about 1.5x that of the non-rotating mass of the bike frame, so if you want to save weight then the theels and tyres is the place to do it.

Hmmm.... Let's see... Yep, I'm afraid it does ;-)

Now you get to redeem yourself: why 1.5x? Does it not depend on the rotational velocity (i.e. how fast you're going)?

asprilla

Kinetic energy of an object in motion is half mv squared whereas kinetic energy of a rotating wheel (sassuming all the mass is at the outer edge) mv squared.

Since all the mass isn't at the outer edge though it's not double.

Here, as usual, wikipedia does a better job than me:

http://en.wikipedia.org/wiki/Bicycle_pe ... t_vs_power

davis

That answers that, then.
Pride redeemed. Carry on.

The Rookie

Back on topic, my Carrera tourer based home built (to suite me) commuter (in avatar) comes in at 11.5Kg bare, 13Kg with rack and panniers (suitable for laptop bag, lunch and 'bike bits - tools/tube/waterproof etc)

Rack is a cheap steel one and well overweight, wheels are MTB and could do with shedding a bit as well when I have the money!

Simon

jedster

How many times do you accelerate away from a set of lights on your commute?

a fair bit - I agree. The thing is that we're talking at saving what 2-3% of total bike/rider/luggage weight. May be important in a competitive situation or if you are pushing yourself over a very long ride but for the commute? Meh...

I reckon convenience, ease of use, low maintenance, reliability are much more valuable than light as features of commuting kit

J

londonbairn

I definately felt improvement from changing weight, moving from Mirage/Racing 7s to Ultegra SL/Racing 5s on my commuter was felt for sure.

Getting rid of my backpack on somedays makes a hell of a difference too.

Though shedding 1lb off your body weight is a way cheaper process than trying to shed 1lb off an already light roadbike...

jimmypippa

Just weighed my commuing kit:

Bike +rack etc (inc waterbottle) 32lbs
loaded pannier (excluding usual packed lunch) 12lbs

about 19kg in total.

meanredspider

Just been and weighed my two bikes

Cube Reaction RX 20" pretty much "out of the box" but with SPD 520 - 11.2kg (24.6lbs)

Focus Variado Compact (105) in commuter trim (saddle bag incl tool, pump, 2x inner, rear plastic mudguard, Bontrager hardcase tyres, SPD 520 etc) - 11.2kg (24.6lbs)

The "advertised" weight of the Cube is 10.7kg and the Variado something in excess of 10kg sans pedals

ketsbaia

Just weighed my racing steed. 10kg exactly, with pedals.

For a 14-year-old aluminium plodder, that's really not bad.

iPete

I take back my previous comments regarding weight and don't suddenly feel the need for a carbon racer!

Took my Allez out in fully loaded touring mode, must have been carrying 10-12kgs, 2 full pannier bags, 2 full water bottles for 42 miles and hell, it was only the climbs where I felt it, had a hoot through some county lanes, averaged about 16mph, not my fastest but enough to change my mind on being a weight weeny for my commute!