What is the truth behind bike weight? Does it really help THAT much?

Travis44

Carbon, titanium, grams and weight shaving: does it really make a difference? Will you really be able to tell the difference between a 16 lb bike and a 17 lb bike? I ride a 25 lb steel Scwhinn, so you can see that I am yet to experience this carbon obsession and such. I always hear people discussing how good a bike is just because of how much it weighs. My question: does it really matter? Does it effect riding on the flats as well as mountains? Or is it just a placebo, something that has a very minor effect but you "think" that your bike is lighter? Please respond, I want to get down to the bottom of this.

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wiredued

Using www.analyticcycling.com I found that on the mountain road I climb 10lbs extra weight requires about 24 watts more power to maintain the same speed. The steeper and longer the climb the more it matters in a race but I'm just doing it to calculate watts.

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dhk2

What matters is the total weight of bike and rider. Acceleration and vertical ascent rate on hills is almost proportional to total weight (at constant power). Total weight really doesn't matter on the flats at steady speed. EG, if you, your clothes, shoes, water and bike now weigh 200 lbs, saving 8 lbs on a new bike will leave your "system" at 192 lbs. That means you'll climb steep hills and accelerate ~4% faster. On a low-speed 10 minute climb, 4% is 24 seconds, which is a few bike lengths advantage.
"Does it really matter?" For most of us non-racers the answer is really no, but lots of us spend big money to get that small advantage. Guess it all depends how badly you want to beat up on your buddies.

Apart from the math, a lighter bike feels "quicker" and more responsive under you. When you step down on a stiff new 16-17 lb wonderbike, it will feel like it's a lot quicker to jump than your old lead sled. Despite what you hear about old-school steel, bet you'll like the ride feel on the lighter bike better too.

Try some test rides and see for yourself. It's been said many times that dieting is a lot cheaper way to save pounds than buying a new bike, but that's another topic

sogood

25lb to 16lb is 36% reduction in weight. Put on a 14lb bag on your present 25lb bike and ride it for a while, then take that weight off for a comparable percentage in weight reduction and ride it again. I think you'll be able to answer your own question in a factual way. One parameter you may not be able to discern is frame stiffness. Most of the CF frames these days have improved considerably in terms overall stiffness. You'll just have to imagine that one.

BTW, don't forget to come back and let us know what you've found and conclusion. And should you test downhills, then your heavily laden bike will go faster.

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Peter@vecchios

Do the arithmetic. Saving 2 pounds on a 200 pound package, rider and bike, is 1%. Not significant, not meaningful, not really anything of note. WAY to much emphasis on the bike and trying to lose grams, not pounds. 4 things make a SIGNIFICANT difference in cycling performance.
-Fit-does your bike fit ya
-Fitness-are you fit?
-Fat-lackthereof on you where you may be able to lose a SBW(standard bike weight-20 pounds)
-Finesse-riding and racing smart

Not the frame, not the wheels, not the machine really at all. Whether the bike is 18 pounds or 16 pounds, the bike only has a significant impact on riding performance is if something breaks, then it slows your ride down a lot.

But will somebody spec 32h wheels, even if they are .1 offa ton++? Just to save those 28 grams, yep. Will somebody buy a chain with holes in the plates and pins to save grams, yep.....so it goes, the daffy bike market.

Latest 'craze' is ceramic balls. Most engineers that have tested this say 1-2% more power..if it's worth the $400 or so for ceramics all the way thru-go ahead. I don't think so.

Peter@vecchios

Not really 36% of the bike and rider, of course. Plus 25 to 16 is 9 pounds, and on a 175 pound rider is 5%, not 36%.

Will the gent be 5% faster with a 16 pound bike?

TheDarkLord

That's highly misleading. It is the weight of bike plus rider that counts. The rider is moving along with the bike, and it is the entire mass that has to be accelerated. But there are other considerations when comparing a road bike and mountain bike, such as the effect of the knobby tires.

Coming to the OP's question, the weight savings probably makes a difference in pro-racing, but when it comes to typical riders, the placebo effect may contribute more than that of the weight savings itself.

sogood

Doesn't matter. The issue is whether a rider can feel a 36% reduction in the bike's weight. He'll just have to try it.

As for the math. 39lb (25+14) to 25lb is a 36% weight reduction, comparable to 25lb to 16lb. Of course, he can also try a 9lb variation (25lb to 16lb), but that's by absolute weight difference rather than by percentage.

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sogood

Not really. It may be the worst case scenario but it sure will tell the OP whether he can feel a difference (ride speed/time isn't everything). If he can't, then he can stay with his 25lb bike. If he can, then he may need to explore a bit more, possibly test ride a 16lb bike.

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Peter@vecchios

Well, not gonna wrestle over this but the energy to accelerate a bike is the mass of the bike and rider. So to 'feel' something you have to take into account the total, not just the bike weight. The only place weight of the bike makes a difference alone is when he's lifting it onto the roof of his car.

Also having everything be equal except 9-11 pounds is gonna be tough. I think a control would be add say 10 pounds to the package, like add weighted vest, then ride the same hill, to see but lots of variables.

So I think by isolating the weight of the bike increase is skewed a bit.

rudycyclist

Alienator can definitely answer this one for ya!!

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sogood

The OP needs to convince himself. So a simple experiment on his turf would allow him to "get to the bottom of it". So why not? All these physics probably doesn't mean very much for the OP.

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Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac

alienator

It's been answered here and in just about every other forum or whatever...er....elsewhere. The fact is that bike weight, be it on the frame, the wheels, the crank, or lodged in the crevices in the brakes or in your butt, it won't make much of a difference at all. A bike might feel a bit more spunky as you throw it backa and forth, but that doesn't equal quantum leaps in performance.

You can believe the facts or not.

JTE83

This is a bit unscientific because I was in different form for these top speeds, and I don't remember the exact weight of my bikes.

Top Speed in the flats no wind sprint & weight of bike -
2004 Cervelo Soloist Team 32.9 mph 17.4 lbs
2005 Kestrel Talon 31.1 mph 18.6 ? lbs
2002 Giant TCR Aero 2 30.2 mph 18.6 lbs
2005 Giant OCR 1 with 2 Jandd Commuter Panniers 29.8 mph 29? lbs

Haven't tried top speed on my best bike - 2006 CF Cervelo Soloist Team with Zipp 404s and Zero Gravitys!