fatdad

All the recent threads about body weight/BMI/etc not to mention my forum username has me wondering if there is a difference between bike weight and body weight. My 2005 Trek 5200 weighs around 18 lbs and I read about all of these 15-16 lb. bikes out there now.

Is there some correlation between losing bike weight and body weight, in other words, is losing 2 lbs of bike weight the same as dropping 2 lbs of body weight with regards to performance? Or does one have to lose more off the body to achieve similar results as dropping bike weight?

ericm979

Most riders want to bring both their bike and their body to the top of climbs. That's more conveient for riding back down. So bike weight and body weight are equivalent.

It's cheaper to lose body weight than bike weight. All you have to do is eat less.

Getting a lighter bike costs more but doesn't require willpower. And of course if you have already got your body fat low, then getting a lighter bike is the only way left to cut the amount of weight you are dragging up climbs.

uke

If you weigh 200lbs and ride a 15lb bike, you're pulling the same weight as someone who weighs 180lbs on a 35lb bike. It's far better to lose weight on the body before trying to buy it off the bike.

datlas 

I don't think it makes a difference whether you lose 2 pounds off your bike vs. your body, but I am sure you will get lots of opinions!

If it is any consolation, MY road bike is 25 pounds and works just fine for me.

Creakyknees

dropping body weight is way more important, IMO, especially in the case of someone who's heavier than a pro:
- it usually means you're getting fitter - not only lighter, but better aerobic system, stronger etc.
- it reduces the load / abuse on the bike
- it's free - all you gotta do is eat right and ride

dropping weight on the bike is ok within reason / practical limits, too:
- it usually costs money
- can cut into the durability / reliability of your bike / parts

Hermes

Body weight and bike weight are equal when climbing. At greater speeds, losing body weight may reduce drag and be more aero and worth more than bike weight.

jesspal

Being a clyde myself, I think that losing 5lbs+ of body weight would be a lot cheaper than losing 5lbs+ of bike weight. It would obviously be much more healthy as well.

This will probably not be the same for an individual that has a low bmi and weighs 135lb. They may not want to lose body weight and their only way of cutting weight is lighter bike.

Coyote2

For some of the reasons stated, losing 2lbs of body weight will enhance your performance more than losing 2lbs of bike weight, with the possible exception of folks whose body fat is already so incredibly low that losing more causes a reduction in power output.

Losing 2lbs of bike weight is often easier, though, as it only takes a credit card.

umd

As others have said, as a pure distribution of weight issue, it doesn't matter where the weight comes from. However, from a health and fitness issue, if you are unfit and unhealthy, dieting and/or exercising to lose the weight will likely result in better performance. I.e. if you take a fatty and give him a 2 pound lighter bike, it will make whatever % reduction in [total bike+rider] weight difference given a steep enough climb. However, make him exercise the 2 pounds off and he will gain fitness as well as lose the 2 pounds and the improvement will be more than the weight alone.

Most of us I'm sure are carrying around an extra 2 pounds we could lose, but for those of us that are relatively thin, it becomes significantly more difficult to do so.

fatdad

Thanks for replies...my wife especially thanks you for the replies...and given the current economy, my wallet is truly humbled and gratified by your replies.


Losing 2lbs of bike weight is often easier, though, as it only takes a credit card.

So true...maybe the belt-tightening needs to apply to more than our budget...

umd

Ironically, one step in losing weight is buying better food. So although you may be eating less overall, it is likely to still be more expensive (than buying more cheap food)

merlinextraligh

Wait, don't you guys know that Bicycling says that 1lb off the bike is equal to 3lbs of body weight, and we haven't even got to rotating weight yet.

JamisVE

Exactly, that's just what I was going to reply about. Rotating weight. What are the thoughts on that?

Hammertoe

I thought I read somewhere that the UCI bike weight regulation penalized lighter riders because they must push a larger percent of their bodyweight up hills as compared to a heavier rider...

I don't think I said that right but get the picture...

Is this correct...



But it should be all about power/wt ratio...

Hermes

I always defer to Bicycling. And of course, rotating weight.

umd

power/weight doesn't include the bike. Lighter guys have less power than a heavier guys with the same power/weight. If rider A is 60kg and rider B is 70kg and they are both at 6 W/kg, then rider A has an FTP of 360 and rider B has an FTP of 420. If they both have 7kg bikes, then that is 10% of rider B's weight, but 11.7% of rider A's, so an extra 1.7% of rider A's power, or roughly 6W has to pushing the extra (proportionally) weight. If both riders had bikes proportional to their weight, rider A would need a 6kg bike to match rider B's 7kg bike.

recursive

The fastest rotating part of a bike are the wheels, and the energy stored in a 30mph spinning wheel is no more than a static non-spinning wheel moving in a straight line at 30mph. So I don't see how the multiplier could possibly be more than 2x. And that's an upper bound. So taking a pound off your wheels is theoretically possible of being close to equivalent of 2 pounds of static weight. But given wheel prices, the returns diminish very quickly.

If you had enough fitness, you could drop all the weenies in this thread on a 20 pound bike. My race bike is probably 18 or 19, but I don't exactly know, because I don't obsess about it. Focus on fitness.

coldass

Pick up a weight.
Now start lifting it up and down and/or walk up an endless flight of stairs with it.
You will have to stop at some point.

Now pick up a lighter weight.
Lift it up and down and/or walk up the stairs.
You will go longer.

At any weight a lighter bike will be an advantage - in particular if the weight saved is rotational.

And being lighter yourself does not mean you'll move an object further. But I'll guarantee that at a your weight and fitness now you'll move a lighter object further.

You should get a lighter bike. You'll like it better regardless of body weight and likely ride it more and further and higher and longer...

fatdad

Sigh...we are card carrying members of Whole Foods/Trader Joes...wifey likes the miserable rotten 6 yr old to learn good eating habits...

JamisVE

I do actually, everyday. These are just questions we have about weight (rotating, etc), not obsessions. My obsession is making spring arrive faster.

tntyz

Having a few extra lbs to mash on the pedals during a climb might be an argument to keep some weight on your body

At some point during my weight loss it's going to be easier to lose bike weight than body weight. My current Trek hybrid weighs in at 36 lbs. I have 10 more lbs of body weight to go before I hit my goal and my reward will be a much lighter bike.

umd

Another one of the most overused phrases on bikeforums. One can focus on fitness but still care about the weight of their bike without obsessing over it. I don't get why people think it has to be an either or situation.

recursive

It may not seem like it, but I agree with you 100%.

JamisVE

+1

umd

It may seem like obsession hanging out on bikeforums all the time, but honestly I built my bike to be light from the get go, and I haven't changed anything on it except for fit (stupid Toupe saddle) or training (power meter).