2.25 pounds -- Noticeable?
 

My old bike weighed 24.25 pounds, my new bike weighs 22 pounds. I could swear that it feels lighter and easier going up the hills.

Do you think that is real, or am I imagining it?

Note that 2.25 pounds is also the weight of one Kryptolok 2 U-lock.

I'd venture it's real. When one gets fine-tuned as when playing a musical instrument small changes in the action or tone are noticable to the player almost immediately. 2.25 lbs is what, a kilo almost? That's a significant amount of weight in cycling terms. Especially when trying to climb a 25% grade. :p

Of course higher grade bearings, drivetrain, etc. contribute as well. And maybe you're in better shape than you were last year? :thumb:

Depends on where the 2.2 pounds came off. A lighter wheelset can make a big difference on hills

Likely too many variables to be able to say that the better climbing is entirely due to the weight loss.

It's 2.5 lbs you don't have to move. Percpetions of any difference would have multiple factors involved. For example what percentage is 2.5 lbs. of weight when considering the total weight of rider and bike? If the rider and bike weight 270 lbs. I'd venture that 2.5 lbs. doesn't make much difference. If however, the combined weight was 160 lbs. it might make a very big difference.

+1

The wheelsets of two of my bikes are very light, and within a few grams of each other. Both bikes--one just under 20 pounds and the other 28 pounds--climb about the same, which is to say goat-like.

My third bike, the Portland, goes from being a reasonable although not stellar climber in the three seasons, to having to granny up even modest grades with the studded snow tires on. The three-season tires are 250 grams each, and the studs are 875 grams each--or about 2.75 pounds total difference.

Would agree about the wheels being a factor on hills but I have two good bikes and I have interchanged the wheels. Both sets of wheels are within 50 grammes of each other and they have the same make and size of tyres and tubes. So I can intercahnge the wheels and should not feel a difference between the wheelsets and I don't. But one bike sails up hills and the other flies--no matter what wheels are fitted.

Boreas in ride trim is 16 1/2lbs and the TCR is 17 1/2. The TCR is CF and Boreas aluminium. Both bikes are stiff- in fact the TCR is too stiff with the wrong wheels fitted. But it is the TCR that flies up the hills.

But the OCR is 20 lbs in ride trim. It has climbed mountains successfully with lightweight wheels but it was harder than my current bikes. Not a fair test though due to different gearing and fit not being the same. Get the bike fitting perfectly and it will ride everywhere better.

Oh yeah--it does make a difference. Try riding a 16 pounder and you'll really be able to tell how much difference it makes.

Another vote for "yes, it is real". And the longer you ride and the more fatigued you get,the realer it gets.

I'm skeptical. It's not much more than the difference between a full and an empty water bottle. And weight on the wheels matters chiefly for acceleration and not significantly for climbing or other circumstances. http://en.wikipedia.org/wiki/Bicycle...f_light_wheels

The steeper the grade the more weight matters. If you're mainly riding the flats or shallow rollers, I'd say it matters very little unless you intend to out jump someone in a sprint. On the other hand, if your rides consistently climb, the longer and steeper the hill the more important weight will become. And even more so if you're power output is on the low side.

Al,

weight in the wheels makes more of a difference than any place else. As you climb you are carrying that weight up the hill, lighter is better. As you pedal you are constantly changing speed in the wheels, the lower mass will make the bike respond easier to the changes. This will give you the perception of more responsiveness in the bike and that will give you the mental push to go faster up the hill. Hill climbing has a huge mental aspect to it. When the bike responds faster, you feel rewarded for your effort and you put more effort in.

You guys are making it really difficult for me to avoid spending $$$ on a new wheelset. Is there anything definitive that says a lighter wheelset is a major factor in performance on hills?

I'll say it's real. When I carry my bike down the stairs before a ride, I notice the difference in weight with and without filled water bottles.

From Road Bike Action

From JObst Brandt, noted author of "The Bicycle Wheel"

http://yarchive.net/bike/rotating_mass.html

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: The weight question...
Date: 26 Mar 2000 02:30:27 GMT

Andre Charlebois writes:

> The most important weight is that which is at the periphery of a
> rotating mass. In other words, pedals, rims, tires, tubes are more
> important than cogs, BB's, hubs, etc.

This is an age old fable in bicycling and useful to cite when an
excuse for some new wheels is needed. If they are aerodynamic, then
that's easy to justify even though they are heavier, but just a bit
lighter ones are less so, so out comes the rotational inertia bit.
Inertia is important for acceleration but not at constant speed where
it is probably beneficial, although I don't know of any study that has
quantified this. Francesco Moser used a large flywheel rear wheel in
his last attempt at increasing his Hour Record but the flesh wouldn't
respond. I am sure they analyzed the effects however.

Although it may seem daunting, when another rider pulls away on a hill
or in a bike race on the flat, these accelerations, except in standing
starts, are so small as to make the rotating mass story a hoax. Sure,
the mass counts twice as much when accelerating but two times zero is
still zero, and how long does a rider accelerate. Weight of bicycle
components for climbing is the main consideration, not acceleration.
The rotating mass story is a fable that sounds good and has just
enough technical truth to be one that will probably sustain itself
indefinitely. Making equipment choices by it are a matter of faith,
not fact.

Jobst Brandt jbrandt@hpl.hp.com

AND:


From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: My proposed wheelset....opinions please.
Date: 5 Jan 2001 18:30:36 GMT

Mike Krueger writes:

>>> When one pushes down on the pedals, and the bike speeds up, that
>>> is acceleration.

>> sure. but no acceleration worth mentioning when talking about
>> inertia of rotating mass.

> OK, I'm not an engineer. Let's put this in layman's terms, so that I
> can understand it. Are you saying that it does not require more work
> to increase the rotating speed of a heavy wheel vs. a light wheel?
> (aerodynamics, tire rolling resistance, and all else being equal)

For bicyclists the main effort is overcoming wind resistance, the
second is raising weight up climbs (unless this is your specialty),
the two are distinctly different in human response as most of us
recognize. Way down the list for better bicycles lies tire rolling
resistance and friction in the chain. After that, at a great
distance, comes acceleration of changing speed... affected primarily
by the mass of the rider and bicycle. The difference of whether that
weight is at the periphery of the wheel or not is triflingly small as
was demonstrated by another writer. However, bicycles do not
accelerate at any perceptible rate from one speed to another, and when
they do, its at startup from the standing start. It has almost
nothing to do with riding once underway where change of speed occurs
at glacial accelerations (aka <1/20g).

Therefore, although one gram more or less on the tread (periphery) of
a tire is equivalent to two grams on the hub *for acceleration only*,
this is a greatly exaggerated physical effect that enables bicycle
shops to sell unnecessarily expensive wheels on the basis of this true
but irrelevant physics.

Jobst Brandt <jbrandt@hpl.hp.com>

The weight difference is both real and not real. Yes, the bike weighs less so you don't have to accelerate/maintain that extra mass. However, I suspect that the truth is that the new bike also has a different geometry than the old bike and that the geometry change is what is driving the improvement more than the 2.5 lbs weight loss. When combined the result is a notable difference in performance that neither individual change can support alone but the geometry change is a bigger alteration than the 2.5 lbs and less obvious.

Thanks. I don't think I've ever seen so much misinformation spread on a forum as much as here. It seems to be a lot of folks that are trying to cling to every variable possible except one: the rider.

Given the same rider, he will be faster on a climb on a lighter bike. That's not misinformation, it's physics.

Hi. We were talking about wheels and their proportional effect on weight/performance.

Lighter wheels effect the whole system weight too. I'll take lighter wheels any day. From my personal experience, they make a difference, especially when climbing. YMMV.

I upgraded the wheelset on my Roubaix in the middle of this past season. The new wheels were lighter and stiffer with better bearings. I immediately noticed a difference in climbing, accelerating and coasting. In my experience the wheels will make the most difference.

The lighter the wheels- the less rotational weight you have to turn. This can be as simple as putting lighter tyres and tubes onto a wheelset to notice a difference as that lighter weight would be at the extremity of the wheel. But I feel that more more important is the build quality of the wheel. Within a few hundred grammes- wheel weight would not be noticed for the "Average" rider.

But It is those original fitment wheels that I do not like. Bikes are made to a price and one of the Biggest cost savings on a bike would be made on the wheels. Cheap hubs onto a cheap rim with cheap spokes (And it does happen) do not make for a good wheel. Bearings do not run as free as they should- Rims can flex at the wrong time and spokes may not have the right quality to be able to flex ot stay stiff at the correct time. I have always said that the best thing you can do to improve a bike is to fit "Good" wheels but a good wheel builder can work wonders on a stock wheel to make it better.

The original wheels on the OCR were OK- they turned- and were always true. I noticed how poor they were when I fitted some handbuilts to it. Rolling speed on a downhill went up- it turned a few high speed corners into curves and at the end of a long ride I was not quite as fatigued.

I have never had Lightweight wheels- My handbuilts and Ultegras are around 1650 grammes a pair and I have Aksiums that are around 1800 and are good wheels but I don't notice any difference in speed or Climbing ability. But put those stock OCR wheels on and I do notice that the bike doesn't work as good as it should.

Your own body weight will fluctuate that much or more. A quart of water weighs about two pounds. Do you feel a difference according to how full your water bottle is? Do you feel a difference if you carry two water bottles? If you pick up a 20 lb bike versus a 30 lb bike, WOW!!! 33% lighter,you can really tell! But the total weight going up a hill is bike plus rider and the % change is much less.

Having picked up the 20 lb bike, there will be a strong psychological aspect going that it must be much faster.

With two different bikes you probably have two different gearsets, different geometry. These will most likely make a far bigger difference than 2.25 lbs.

Try carrying a second water bottle -- I doubt if it will make your new bike feel like your old one.

Don in Austin

I recall switching from a touring bike to a road (racing) bike years ago. The road bike was lighter and had a really short wheelbase. It accelerated much better and handled corners better. I also recall being in a short road race once and stripping the bike for the event - no frame pump, no rear pack with tools and tubes, no water bottle even. The loss of 3-4 lbs was noticeable.

So if you are reasonably fit and light, 2 lbs should be noticeable mainly in climbing, handling and acceleration. Also lighter bikes usually have higher end components, better shifting and better handling so that adds in too.

Now I recall, Diane nailed a friend of hers who had a new light bike by filling up the frame and handle bars with rice of all thing. He was at a light and the bar end was loose so he pulled it off and rice gushed out. He did not notice any difference by having a couple of extra lbs on rice on his high end bike. By the way, Diane is a mechanic so there was no damage.

The problem is that when we ride a bike with less weight we KNOW it. So it is hard to control for the placebo effect. That is the bike is lighter and therefore it will be better. It is hard to even figure a way to do it without going to some sort of outlandish lengths or having a bike mechanic friend with a warped sense of humor.