No doubt, a lighter bike may feel faster. But in actual real-world performance, especially in the non-racing world, the difference is more perception than reality. Weight can make a difference, but one needs to be talking about pounds, not grams. And there are other factors that make a much bigger difference than weight.
I have two bikes that are very similar in many ways, but have a large difference in weight. Both are made by the fine folks at Mercian, with frames made of the same Reynolds 725 heat-treated chrome-moly. Both are equipped with recent-era Campagnolo components and similar wheels. One has a longer wheelbase and slightly more relaxed frame angles. Stripped down, the bikes are very similar, but one of them is fully loaded up for touring and commuting, with front and rear racks, fenders, multiple bags, and lights. Heading out the door on the way to work, the loaded bike carries roughly 15 - 18 pounds more than the stripped down version.
|Fully loaded up, with full bags, ready for the commute to work, this bike pushes nearly 40 pounds|
|Similar frame and componentry, but essentially "stripped down," this bike weighs around 22 pounds or so.|
My commute to work is just over 13 miles and typically takes me about 50 minutes. The ride home is a bit over 15 miles and takes me an hour. It varies a little from day to day, but rarely by more than a minute or two plus or minus.
One morning when the weather was good, and the afternoon forecast was looking even better, and I had very little that I needed to carry with me to work, I chose to ride the lighter, stripped down bike. Dropping roughly 15 pounds, I have to say, I felt fast. The bike surged forward with every pedal stroke. On the long, slow slog of a climb I encounter every morning, I felt like I was flying. The bike felt weightless rocking side-to-side beneath me as I climbed out of the saddle (with prose like that, I could review bikes for Bicycling. All I need to add is "laterally stiff and vertically compliant"). When I pulled into the parking lot at work, I found I had made it in 45 minutes. Five minutes faster! My fastest commute ever.
Before any weight-weenies start rejoicing (do weight-weenies even read this blog?) I should point out something else that I failed to mention. There are over 30 traffic lights along my route between home and work -- more than two lights per mile! On the morning of my personal-record-best ride, I had the nearly miraculous luck to hit every green light for more than 13 miles. Every single one was green. At no point did I have to stop for the whole commute. So, was my 5-minutes-faster time because I was on a lighter bike, or because of my unbelievable luck with the lights? No question, luck had something to do with it. But how much?
About a month later, I got my answer. Riding my regular commuting bike, loaded up with my usual bags and gear, I had an unexpected repeat of my luck with the traffic lights: once again, I had managed to hit every light green all the way from home to work. No stopping and starting. No lost momentum. I did not feel the bike surge forward with every pedal stroke. I could feel the extra pounds shift side-to-side beneath me as I climbed the long, slow incline. But I arrived at work in 46 minutes; a minute off my best time. It's true that far less time than that would be the difference between winning and losing in a race -- but this was no race. In any other situation, such a small difference is totally inconsequential.
I've read that studies show there is a difference of 1 mph in average speed for every 12 pounds added to or subtracted from a bike. Although hardly exact or scientific, my little informal experience above seems fairly consistent with that result. Clearly, there are other factors that can potentially make a bigger difference than weight. Traffic lights obviously make a difference. Wind direction makes a difference. I've found that riding to work into a strong headwind can add a good 5 minutes to my usual time. My own personal physical state makes a difference, too. Some days I just feel faster -- I get into a rhythm, my lungs and legs feel great, and everything just comes together. Other days . . . well, not.
I guess what I'm getting at here is that the quest for ever lighter bikes and components isn't really transforming the experience of bicycling in any meaningful way. The over-sized, swollen-looking frames and components rendered in carbon fiber might be bringing the weight of bicycles into sub-16-pound territory, but what's the point? If they are visually atrocious, less durable, less reliable, less practical (can they accept fenders and racks?), while simultaneously more complicated and more expensive, then what do we gain?