How heavy is yours?

[gavintc]

looks like my 23kg (48 pound) Kettler is the heaviest...

You are supposed to take it off the turbo trainer to weigh it

 

[mac1]

turbo trainer - wassat? I do my shopping on it and lift it over the back door frame with 2 full panniers - shudder to think what it weighs then...gotta be 60+

 

[asterix]

In the summer I'll be doing a Raid Pyrenean in a group of about 20 and will use my steel audax bike with mudguards. It weighs c.11kg (c.24lbs) and it's a certainty that many other riders will have significantly lighter bikes.

Had I not done the touring version in 2007 with the full kit, I'd be worried the bike would be too heavy but in fact I know that won't be a problem if I am fit enough.

 

[mossy]

Dimante (old race bike now a winter bike) 25lb
Orbea Aspin 21lb

Now its me that needs to lose weight not the bikes.

 

[addictfreak]

Scott addict R4 2008 15.86lbs 7.2kgs

Scott scale 35 2009 23.35lbs 10.6kg

 

[addictfreak]

Forgot my winter roadie

Focus Varido Expert 2008 8.7kg 19.2lbs

 

[zacklaws]

Trek 1.2 18lb
Trek 4.5 Madone 19lb

I cannot understand why my Madone, carbon frame weighs more than my aluminium 1.2

 

[bike_the_planet]

But the $64,000 question is: how much does bike weight really matter?

Weight is only of significant consequence when you are a) accelerating, or cycling uphill.

If you're doing the latter, then the amount of power you need to apply to the pedals depends on a) the speed of ascent and the weight of you + your bike + your luggage.

Say you weigh 75 kg, your panniers weigh 15kg and the bike weighs 10kg and it takes you 10 minutes to climb a particular hill. If you then repeated the exercise using a 12kg bike, then you would need to apply 2% more power to get up the same hill in 10 minutes.

Or, if you apply the same power as before, it'll take you 2% longer - ie 10 minutes 12 seconds.

So, does weight matter?

If you're riding in a competition, then yes.

If you're touring, then the slower you go, the longer you'll be on your bike and the more you'll see...

Hmmm...

 

[youngoldbloke]

What really matters is the responsiveness of the bike - the feeling that energy put in is being efficiently translated into movement. This must be affected by many factors other than weight - spoke tension, tyre pressure, bearing efficiency, drive train, frame material and geometry etc etc etc.

 

[bike_the_planet]

What really matters is the responsiveness of the bike - the feeling that energy put in is being efficiently translated into movement. This must be affected by many factors other than weight - spoke tension, tyre pressure, bearing efficiency, drive train, frame material and geometry etc etc etc.

I would suggest that all of the above are still secondary compared to the main limit on efficiency - air resistance.

Power required to overcome air resistance rises exponentially with speed. If you double your top speed from, say, 15km/h to 30km/h then you need four times the effort.

At 40 km/h 95% of your effort will be overcoming air resistance.

Unless your bike's in a really neglected state, nearly all your energy is successfully transfered to the rear wheel.

Cheers,

 

[kyuss]

Kinesis KiC2: around 17.5lbs/8kg (it's hard to be specific when all you have is bathroom scales).

Giant Bowery with a carbon fork: Not weighed it yet, but it feels lighter than the Kinesis. I'm guessing in the region of 17lbs/7.7kg or so.

I'll need to weigh them both properly. It would be interesting to know.

 

[youngoldbloke]

I would suggest that all of the above are still secondary compared to the main limit on efficiency - air resistance.

Power required to overcome air resistance rises exponentially with speed. If you double your top speed from, say, 15km/h to 30km/h then you need four times the effort.

At 40 km/h 95% of your effort will be overcoming air resistance.

Unless your bike's in a really neglected state, nearly all your energy is successfully transfered to the rear wheel.

Cheers,

That is pretty much a given - the bicycle chain drive is highly efficient. So what is it that makes one bike feel like riding a slug, and another one like a cheetah, if it's not weight, responsiveness etc.

 

[bike_the_planet]

That is pretty much a given - the bicycle chain drive is highly efficient. So what is it that makes one bike feel like riding a slug, and another one like a cheetah, if it's not weight, responsiveness etc.

Yes, and given that most of us (on the flat at any rate) will be cycling at 20km/h +, then air resistance will swamp out any small changes due to geometry, bearing resistance etc.

If you're going uphill, then you'll probably be going slower, so weight, rather than air resistance will be the deciding factor.

But it's the weight of you + the bike that's significant. For example a 500ml water bottle will weigh 1/2 kg and have only 1% effect on your speed at the very most.

So, once again, I stake my claim that small changes due to bearing efficiency, tyre resistance and geometry will be way down the list (unless your bike is in a very poor state of repair)

'ave a good day.

Tony

 

[youngoldbloke]

Must be 'all the mind' then. IME some bikes are responsive, easy running, have a 'get up and go' feel. Others not. Not great weight difference necessarily, but generally the lighter the bike, the better. Air resistance does not explain the difference.

 

[asterix]

For me it's important to have a frame that's laterally stiff.

My old 531 bike (60cm frame) was a too bendy through the BB and not nearly as good up the hills as its Chas Roberts custom built replacement (compact audax) that was specced to be a good hill climber.

The difference is that every hill-climbing pedal stroke is more rewarding on the newer bike especially when getting up out of the saddle and giving it welly.

Can't wait to get into them Pyrennees..