The question then would be to define meaningful. In case you argue that meaningful would mean that there is a real world difference which is at least x% of perceived difference, maybe not so much. If meaningful would mean higher speed at any sustained power output, then on flat courses aero would be more beneficial than light weight. But the OP wasn’t asking if a weight difference would actually be faster on flats, just if a rider could reliably sense the difference in weight between bikes on a flat course.
Meaningful to me in this case would be a similar sense of the difference in equipment weight every time for similar changes therein.
I can’t tell personally. When I was younger I thought I could tell, but in retrospect I think I was picking up on differences in handling caused by trail and tire selection between bikes with otherwise similar riding positions. Now I “feel” differences in handling pretty easily — but not weight.
(My actual two most frequently-used bikes are a Term Short Haul — usually with a 40lb toddler and some bags on it — and a DeSalvo drop bar allrounder with nothing on it. You can definitely feel many differences between those )
It’s been quite a while, and while I’ve tried, I can’t find the original article, but…
it was either Jobst Brandt or Lennard Zinn who said in an article on the effects of rotating weight that it’s sort o silly to describe ‘acceleration’ on a bike. From an engineering perspective, bikes don’t accelerate, they speed up slowly. IOW, the rate at which we accelerate on a bike isn’t great enough for rotating mass to matter.
The article went on to describe tests that were done with what were at that time reasonable examples of a very heavy rim (MA40) vs a very light rim (GEL 280) , and measuring the force required to accelerate to speed from a standing start on a velodrome. The difference in power required to get to a set speed (I don’t recall the exact number, but it was roughly the top speeds attained by a top kilo rider on the track, roughly 45mph or so). The difference in wattage required was less than a couple of watts.
To the original question as to how much someone might notice extra weight on a bike when riding on the flats, I would say from my experience that it depends greatly on where the weight is located and what you’re doing at the time. For example, you can be cruising along with or without a saddle bag weighing a pound or so and not notice it at all. Stand up for a max sprint and you notice the difference in how the bike feels, swaying left and right underneath you, but it won’t affect the acceleration enough to matter. Put that same saddle bag below your waterbottle cages down at the BB and you won’t notice the weight no matter what you’re doing.
In addition, most of the “accelerations” (especially when racing) happen when the bike is already moving, so the wattage needed is even less than when accelerating from a dead stop.
Speeding up is accelerating. On a bike It’s just a low magnitude acceleration, and I think that’s prolly what they meant by “bikes don’t accelerate” I’m not sure why they chose to mistate things the way they did.
The second part of the comment says it all… speeding up slowly. Why would they say it that way? I dunno, maybe it’s having a background in motorsports that gives them a different perspective. Regardless, they were being humorous.
The real question this is what detectable/noticeable by a rider. A lot of folks claim they can or can’t. The problem with those claims is they don’t account for “sensor bias” and “sensor resolution”, with the latter meaning the ability of the human sensor to resolve all the inputs by cause and source. Sensor bias is hard to rule out if the human sensor knows what it’s about to test.
Of course, the actual research done into what cyclists perceive vs measured inputs is at best lacking. Sure, there’s a lot of anecdotal stuff, but anecdotal claims aren’t empirical data. Of course, while someone can’t prove that they sense what they claim, it’s also true that no one can prove that someone can’t sense what they claim…well, within limits anyway. If someone claims that their taste buds sense that chocolate ice cream is better than coffee ice cream, we’re allowed to immediately reject that claim since it violates not just the laws of physics but also the laws of taste.
My personal feeling is that weight, at least in the tiny margins most high-end cyclists think about, doesn’t matter. Yes, the pure physics will be such that there will be an effect, but it’s so small that it’s not worth paying attention to it.
Let’s suppose an average male recreational rider, together with their bike, weighs 160 pounds / 72.5 kg. Now let’s add 500 grams to either them or their bike. 500 grams is 0.69% of 72.5 kg - slightly more than half of one percent. Let’s say our rider has an FTP of 290 watts, or a w/kg ratio of 4 (again including their bike weight). If we add 500 grams to their total bike+rider weight, their weight goes up to 73 kg, and their w/kg ratio drops down to 3.97 (290 / 72.9 = 3.97). If they wanted to bring their w/kg ratio back up to 4, they would have to increase their power…by all of 2 watts. That’s only 0.69% of their total FTP.
One of the best power meters (Favero Assioma) has an accuracy of +/- 1%. Obviously 0.69% is within +/- 1%.
So the effect of 500 g might literally be undetectable.
Caleb, just back to my thread from awhile ago to say hello, and I appreciate your margin-of-error/sensitivity analysis.
But I doubt the average male recreational cyclist + bike weighs 160 lb. That’s only slightly above what the average pro weighs (plus the weight of the avg recreational cyclist’s bike). My 5’7” wife + road bike is about 160, albeit a (nice) 80s steel frame bike and after 2 kids.
On one of the Silca podcasts Josh was talking about Alex Dowsett’s hour record attempt that he consulted on and they worked out that up to 5kg wouldn’t affect the outcome, admittedly that’s a steady state effort round a velodrome but where an incline isn’t an issue, drag is the much bigger factor.
that’s a striking amount of weight that wouldn’t have made a difference! But fits with what I’d expect. As long as the weight isn’t adding aero drag, it would take a fair bit to influence other resistance (e.g., secondary effects on rolling resistance of tires)
There for sure have been tests done on cyclists to determine the “minimum perceivable difference” on their bikes for a lot of variables. Unfortunately, few if any are published. I’ve seen a couple from Cervelo when they did their “brainbike” dealer conferences. I’m sure they weren’t the only ones.
I’m not terribly convinced by manufacturer “research”. I’ve yet to see a manufacturer actually produce research that is written up as actual papers are in science. It seems like manufacturer research is only presented in white papers, and white papers definitely are not research papers.
Research on “minimal perceivable difference” would have to be very carefully done to actually measure what the study wants to measure, and that means accounting for a boatload of factors that bias the human sensor. It would also have to have a large sample set, not the typical tiny sample sets that manufacturers tend to use. Lastly they’d have to detail their setup, how the data was analyzed, etc. Even then it would take multiple studies by different groups to get some consensus on what that “minimal perceivable difference” is, how variable it is, etc.
I don’t think any of that will happen though, and even it did, I don’t think anyone trust manufacturer’s to be completely honest and open about their studies.
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