A bored at work ramble

[weisan]

As I support and argue against the "other side", I thought it's also important that I come clean with some personal anecdotes and speak the truth...

I was maybe 4-5 miles into a group ride when the ride leader who is right behind me commented..."Er...weisan, I didn't see that you have your water bottles on the bike..." That's when I looked down and..."Oh M$hit". So I had to turn back and go back to the car and chase for like an hour + before I catch the group. During that hour + of chasing, I had ample time to ponder over the fact that prior to discovering my water bottles were not with me, I truly felt that my bike was behaving a bit differently from usual...it was more lively and responsive when I stood up and sprinted up a hill or accelerate...I don't think that's placebo effect. It truly made a difference without those additional full water bottles on the bike. Now if only I can figure out how to hire a support crew everytime I head out for a ride who will hand me water or fix my flat.....

Also, I ransacked my whole garage just to make sure I am not hiding any weight weenie part before the UCI inspectors show up....well, I did find one that I brought back from the co-op a while ago hiding in the corner but rest assured the evidence was promptly destroyed so we should be good now.

[rustychisel]

Originally Posted by weisan

Ouch.

Was that for scooping out the excess weight by the pound or by the gram?

[oldpotatoe]

Originally Posted by nmrt

I absolutely do not subscribe to this x% of the total weight line of thought.
You can be 500 lbs but a bike that is 19 lb will feel much different than a bike that is 14.5 lb.

End of story.

Not at all the end..the 19 pound bike may 'feel' better than the 14.5 pound bike. Lighter isn't always 'better', it's just lighter..too many other variables BUT if the 'goal' is lighter, spend that $ and get it lighter..

And for above..go ahead and forget those heavy water bottles..just think how light you will be when you get dehydrated and start to cramp..then weight won't matter at all cuz you won't be riding any more that day..

[AngryScientist]

my butt meter tells me that light wheels matter more than a light bike.

i have way too many wheelsets and regularly ride anything from 2000+g beater wheels to 1300 g tubulars. these make a huge difference to the ride and feel of the bike IMO.

for example: if i were going to ride a big day with a lot of climbing, and i had two choices:

a) steel frame/fork with no weight weenie parts, but 1300g carbon tubulars

b) carbon wonderbike with all weight weenie parts, but 2100g 36 spoke box section wheels

i would pick (a), even though total weight of (b) is lighter overall.

[dancinkozmo]

climbing tip : keep the bike light by carrying water bottles in your jersey pockets

[zap]

Swishing a light bicycle out of the saddle in the drops (or hoods) for some distance at speed on a climb is........sufferingfun.

[Mark McM]

Originally Posted by 93KgBike

Even cargo-bikes have a gram-saver category if you can believe it; while there may be cargo-bike races, I don't think cargo-bike racer is a label that can exist; the sponsor would have to be chaos itself.

But given the same 'motor' power, doesn't removing weight off a cargo bike increase the cargo capacity of the bike (and also possibly increase its speed, saving time)? Bikes aren't the only transport vehicle where weight matters. Airliners and cargo planes only carry enough fuel to get to their destination (even if their total flight range is much longer), because carrying the extra weight of unneeded fuel increases the cost and time of moving the passengers and freight.

[Mark McM]

Originally Posted by dancinkozmo

climbing tip : keep the bike light by carrying water bottles in your jersey pockets

You forgot to add the smiley face to indicate sarcasm

[oldpotatoe]

Originally Posted by Mark McM

But given the same 'motor' power, doesn't removing weight off a cargo bike increase the cargo capacity of the bike (and also possibly increase its speed, saving time)? Bikes aren't the only transport vehicle where weight matters. Airliners and cargo planes only carry enough fuel to get to their destination (even if their total flight range is much longer), because carrying the extra weight of unneeded fuel increases the cost and time of moving the passengers and freight.

Not sure it increases the time. The aircraft don't fly slower cuz they are heavier but the same cruise speed which is more expensive for sure because higher power setting for set cruise mach if they are heavier..Maybe SAAB will chime in.

[Mark McM]

Originally Posted by oldpotatoe

Not sure it increases the time. The aircraft don't fly slower cuz they are heavier but the same cruise speed which is more expensive for sure because higher power setting for set cruise mach if they are heavier..Maybe SAAB will chime in.

All else the same, for the same power setting, a heavier aircraft definitely flies slower. (The extra lift required generates more induced drag.)

Minimizing time (maximizing speed) and minimizing fuel consumption are always a trade-off. At a heavier weight, an aircraft must either flow slower at the same fuel consumption, or consume more fuel at the same speed. Since fuel costs money (and is a major component of airliner costs), you can believe that air transport operators don't fly their aircraft heavier than they have to, and that means only loading as much fuel as is required (the maximum fuel load of a transport aircraft may be up to half of its maximum take off weight).

[oldpotatoe]

Originally Posted by Mark McM

All else the same, for the same power setting, a heavier aircraft definitely flies slower. (The extra lift required generates more induced drag.)

Minimizing time (maximizing speed) and minimizing fuel consumption are always a trade-off. At a heavier weight, an aircraft must either flow slower at the same fuel consumption, or consume more fuel at the same speed. Since fuel costs money (and is a major component of airliner costs), you can believe that air transport operators don't fly their aircraft heavier than they have to, and that means only loading as much fuel as is required (the maximum fuel load of a transport aircraft may be up to half of its maximum take off weight).

I’m agreeing with you. Yes they light load and ‘at same power setting’, it is slower speed for a heavier aircraft but these guys are constrained by cruise Mach, to ensure the very crowded airways don’t get gooned up by an aircraft flying too slowly. If for some reason they were heavier, they would fly at higher power setting, not fly slower.

[Mark McM]

Originally Posted by oldpotatoe

I’m agreeing with you. Yes they light load and ‘at same power setting’, it is slower speed for a heavier aircraft but these guys are constrained by cruise Mach, to ensure the very crowded airways don’t get gooned up by an aircraft flying too slowly. If for some reason they were heavier, they would fly at higher power setting, not fly slower.

https://alum.mit.edu/slice/why-hasnt...y-faster-1960s

In an era when everything else is accelerating, airplanes are actually flying at slower speeds than they used to…

Specified cruising speeds for commercial airliners today range between about 480 and 510 knots, compared to 525 knots for the Boeing 707, a mainstay of 1960s jet travel. Why? “The main issue is fuel economy,” says Aeronautics and Astronautics professor Mark Drela. “Going faster eats more fuel per passenger-mile.