Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Where is the Weight Difference coming from?

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Where is the Weight Difference coming from?

Old 11-13-23, 08:29 PM
  #51  
Senior Member
 
Join Date: Apr 2007
Posts: 6,715
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1070 Post(s)
Liked 1,167 Times in 741 Posts
Originally Posted by choddo
Could get 1kg of weight difference out of wheels, bars, seatpost, I reckon.
and tires, tubes and saddle. Can't really answer OP's question without a full build list - including the frame and fork.
Camilo is offline  
Old 11-14-23, 06:42 AM
  #52  
Senior Member
 
eduskator's Avatar
 
Join Date: Aug 2019
Location: Québec, Canada
Posts: 2,007

Bikes: SL8 Pro, TCR beater

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 927 Post(s)
Liked 549 Times in 414 Posts
Weight doesn't matter... That's a bold statement

Don't want to start (restart) a debate, and I agree that there is a lot more than weight when it comes to choosing a bicycle, but lighter is faster. Especially in hills. A 8kg bicycle will require more watts to maintain a certain velocity than a 7kg bicycle. It's physics. Now, is it significant? That is subjective.

Regarding the op's question, the endurance seems to have better and lighter components. Combined together on a full built, I have no problem believing that they shave over 1kg off.

Last edited by eduskator; 11-14-23 at 06:47 AM.
eduskator is offline  
Old 11-14-23, 06:51 AM
  #53  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by eduskator
Weight doesn't matter... That's a bold statement
Not as bold as claiming that 1 kg really matters on an endurance road bike.
PeteHski is offline  
Old 11-14-23, 06:59 AM
  #54  
Senior Member
 
Trakhak's Avatar
 
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 5,190
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 2340 Post(s)
Liked 2,763 Times in 1,580 Posts
Originally Posted by Eric F
An extra 1.5% would have been helpful on Saturday morning with a group of friends on a ride that included a lot of long, steady climbs (5000+' over 2+ hours). I could not quite maintain the pace of the rest of the guys and slowly got dropped between each of our re-group points.
Let me guess: the flyweight climbers waited at the re-group points until the stragglers arrived, at which point the flyweights, thoroughly rested, instantly took off again at blistering speed.

That's the way it worked back when I rode in "full Lycra," anyway (to borrow a term from a currently popular C&V thread).
Trakhak is offline  
Likes For Trakhak:
Old 11-14-23, 07:03 AM
  #55  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by eduskator

but lighter is faster. Especially in hills. A 8kg bicycle will require more watts to maintain a certain velocity than a 7kg bicycle. It's physics. Now, is it significant? That is subjective.
It’s better to simply state the objective facts. Most of my steady climbing is at between 2-4 W/kg. So that gives me a pretty good idea of how many more Watts I need per extra kg of weight. Going a step further I can simulate a specific course profile. Everything else is subjective.
PeteHski is offline  
Old 11-14-23, 07:22 AM
  #56  
Senior Member
 
Trakhak's Avatar
 
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 5,190
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 2340 Post(s)
Liked 2,763 Times in 1,580 Posts
Originally Posted by PeteHski
Not as bold as claiming that 1 kg really matters on an endurance road bike.
RChung would have the numbers, but I was surprised to see the results of calculations showing just how little difference bike weight made under any conditions other than extended steep climbs: "extended" here meaning Alps, Pyrenees, etc. Those calculations are what prompted the swing away from ultimate lightness and toward ultimate aero in high-end racing frames.

That said, the market swing toward endurance and gravel bikes, the successors to the sport touring bikes of the 1980's, has probably made a lot of manufacturers happy. Not only because they get to sell additional bikes but also because, with the focus shifting away from high performance and light weight and toward comfort and durability, they can expect the heavier bikes to hold up better, leading to fewer warranty claims, even from that part of the aging population of bike enthusiasts who tend to put on weight as they age.

A bunch of them had already rolled back their frame warranties from lifetime to, e.g., five years, back when bikes were being built silly light, so the combination of heavier bikes plus limited warranty is all to the good from their point of view.
Trakhak is offline  
Old 11-14-23, 07:45 AM
  #57  
Senior Member
 
Join Date: Apr 2019
Location: UK
Posts: 1,195
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 576 Post(s)
Liked 379 Times in 287 Posts
Originally Posted by Trakhak
who tend to put on weight as they age.
Speak for yerself!
choddo is offline  
Old 11-14-23, 08:19 AM
  #58  
Senior Member
 
Trakhak's Avatar
 
Join Date: Jan 2005
Location: Baltimore, MD
Posts: 5,190
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 2340 Post(s)
Liked 2,763 Times in 1,580 Posts
Originally Posted by choddo
Speak for yerself!
I was usually around 136 lbs in my 30's---now I'm under 120! If I was a pet and had lost a proportional amount of weight, a vet would probably recommend that I be put down.
Trakhak is offline  
Old 11-14-23, 10:32 AM
  #59  
Senior Member
 
eduskator's Avatar
 
Join Date: Aug 2019
Location: Québec, Canada
Posts: 2,007

Bikes: SL8 Pro, TCR beater

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 927 Post(s)
Liked 549 Times in 414 Posts
Originally Posted by Trakhak
I was usually around 136 lbs in my 30's---now I'm under 120! If I was a pet and had lost a proportional amount of weight, a vet would probably recommend that I be put down.
Lightweight!! Must be a rocket on a bike. How tall are you?

At 6'1'', I was 200lbs in my mid 20s, I am now 165lbs in my mid 30s. Same body fat, just less muscle. Cycling really changes a body.
eduskator is offline  
Likes For eduskator:
Old 11-14-23, 10:46 AM
  #60  
Habitual User
 
Eric F's Avatar
 
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,569

Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4696 Post(s)
Liked 7,589 Times in 3,590 Posts
Originally Posted by Trakhak
Let me guess: the flyweight climbers waited at the re-group points until the stragglers arrived, at which point the flyweights, thoroughly rested, instantly took off again at blistering speed.

That's the way it worked back when I rode in "full Lycra," anyway (to borrow a term from a currently popular C&V thread).
20 years ago, that might have happened with this group. Now, we're actually friends, not just riding acquaintances, and it was a steady tempo on long climbs kind of day, with lots of chatting. I was just a little bit off (lingering fatigue, I think). All that said, MAMILs would be an accurate description of our group.
__________________
"Swedish fish. They're protein shaped." - livedarklions

Last edited by Eric F; 11-14-23 at 10:54 AM.
Eric F is offline  
Likes For Eric F:
Old 11-14-23, 10:54 AM
  #61  
Habitual User
 
Eric F's Avatar
 
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,569

Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4696 Post(s)
Liked 7,589 Times in 3,590 Posts
Originally Posted by Trakhak
I was usually around 136 lbs in my 30's---now I'm under 120! If I was a pet and had lost a proportional amount of weight, a vet would probably recommend that I be put down.
136...Ahh. One of THOSE guys. Race weight for me was 160-162, which served me just fine in the bunch sprint game that I much preferred over climbing.
__________________
"Swedish fish. They're protein shaped." - livedarklions
Eric F is offline  
Old 11-14-23, 03:34 PM
  #62  
Senior Member
 
Join Date: Aug 2015
Posts: 688
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked 72 Times in 46 Posts
The truth that we ignore most of the time is the following: we agree to pay more than 50% (maybe 75%) of a bike price for fancy elements above its utility, such as: brand, “aero”, WEIGHT, carbon fiber, etc. When reputable brands start to cut from the fancy elements (such as weight) for which we agreed to pay hard, but they keep the very high price, it looks like speculative practice to me.

Besides being fancy, a 1 kg lighter road bike feels a little better, as I tested, even on flat roads. There is a very subtle positive difference in acceleration and steering and… flat roads are never 100% flat; you will always have 100-300 m climbing over 50-60 km distance.
Redbullet is offline  
Old 11-14-23, 04:21 PM
  #63  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by Redbullet

Besides being fancy, a 1 kg lighter road bike feels a little better, as I tested, even on flat roads. There is a very subtle positive difference in acceleration and steering and… flat roads are never 100% flat; you will always have 100-300 m climbing over 50-60 km distance.
Again, objectively the difference in acceleration is negligible for 1 kg, even on a full bore sprint from low speed. It’s not that difficult to calculate. No need to be subjective in this regard. It’s pure physics.

Steering feel is more subjective, but 1 kg isn’t going to change anything unless you strap it to the end of your bars. The bike geometry and your riding position is going to dominate steering feel and handling.

The only time you really notice a 1 kg difference is when lifting the bike above your head. Even then it’s pretty subtle.

I know a reality check isn’t going to change minds here.
PeteHski is offline  
Old 11-14-23, 04:40 PM
  #64  
Senior Member
 
Join Date: Aug 2015
Posts: 688
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked 72 Times in 46 Posts
Originally Posted by PeteHski
Again, objectively the difference in acceleration is negligible for 1 kg, even on a full bore sprint from low speed. It’s not that difficult to calculate. No need to be subjective in this regard. It’s pure physics.

Steering feel is more subjective, but 1 kg isn’t going to change anything unless you strap it to the end of your bars. The bike geometry and your riding position is going to dominate steering feel and handling.

The only time you really notice a 1 kg difference is when lifting the bike above your head. Even then it’s pretty subtle.

I know a reality check isn’t going to change minds here.
1 kg FEELS and rides different, this is from experience. The difference is, indeed, marginal - thus, it is fancy to pay for it. But this is what we want when we pay many thousands EUR/USD for a bike: fancy and marginal performance features.
I could buy a 1500 EUR bike with 22 speeds mechanical instead of 24 electronic, rim instead of disk brakes, AL instead of CF, durable and lighter than 9 kg, lifetime frame warranty. Very marginally faster and 3-4 times cheaper. But... that bike is not fancy brand and built.
My point was that if I agree to pay big money for fancy and marginally improved features, then I want to receive those features I paid for.
Redbullet is offline  
Old 11-14-23, 05:12 PM
  #65  
Habitual User
 
Eric F's Avatar
 
Join Date: Jan 2020
Location: Altadena, CA
Posts: 7,569

Bikes: 2023 Niner RLT 9 RDO, 2018 Trek Procaliber 9.9 RSL, 2018 Storck Fascenario.3 Platinum, 2003 Time VX Special Pro, 2001 Colnago VIP, 1999 Trek 9900 singlespeed, 1977 Nishiki ONP

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 4696 Post(s)
Liked 7,589 Times in 3,590 Posts
Originally Posted by PeteHski
Again, objectively the difference in acceleration is negligible for 1 kg, even on a full bore sprint from low speed. It’s not that difficult to calculate. No need to be subjective in this regard. It’s pure physics.

Steering feel is more subjective, but 1 kg isn’t going to change anything unless you strap it to the end of your bars. The bike geometry and your riding position is going to dominate steering feel and handling.

The only time you really notice a 1 kg difference is when lifting the bike above your head. Even then it’s pretty subtle.

I know a reality check isn’t going to change minds here.
Something that I've been pondering recently, inspired by other recent discussions about weight, flex, comfort, etc...

When it comes to the comparison of measured data vs. human perception, it seems to me that a possibly significant thing instrument data gathering misses out on is a human's ability to recognize a large combination of different factors simultaneously. What might seem like a very small difference when measured as a single factor, and concluded to be insignificant, could be perceived to be more significant when numerous other factors in a complex set of variables are also changing by "insignificant" amounts at the same time. The cumulative effect becomes something that the human recognizes as a variation from the response/reaction they expect in that situation. The more experienced that human is with a set of variables, the more likely they are to recognize cumulative differences, and maybe able to identify a smaller set of variables where they detect the difference occurring.

Stating that 1kg isn't going to be noticed unless you lift a bike over your head isn't a realistic judgement. Humans can teach themselves to know exactly the number of playing cards are in a stack, just by how the weight of the stack feels in their hand. I'm not saying that everyone has that kind of sensitivity, but it certainly seems within the realm of human perception that an experienced rider might be able to recognize a difference in how a lighter bike performs when they ride, or how a lighter set of wheels/tires respond differently under acceleration. I'm not making any conclusions about whether those differences result in a difference in speed/performance. This is about human perceptions.

As I said, these is just something I've been pondering. I do not have links to scientific research to support any of it, and haven't made an effort to try to find any These are unfounded opinions, and not intended to be a personal attack on you, or your comments, PeteHski. In all likelihood, you probably know more about the subject than I do.
__________________
"Swedish fish. They're protein shaped." - livedarklions
Eric F is offline  
Old 11-14-23, 05:53 PM
  #66  
Junior Member
 
frdfandc's Avatar
 
Join Date: Mar 2008
Location: Cecil County, Maryland
Posts: 154

Bikes: 2013 Jamis Dragon Race

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 58 Post(s)
Liked 37 Times in 30 Posts
I dropped just over 1 lb on my bike via wheelset and noticed the huge difference when climbing. But also dropped about 1 lb with a weight weenie approach. Ti bolts everywhere, lightweight stainless steel cages, carbon seat and post. Didn't notice any change in the bike.
frdfandc is offline  
Old 11-14-23, 06:31 PM
  #67  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by Eric F
Something that I've been pondering recently, inspired by other recent discussions about weight, flex, comfort, etc...

When it comes to the comparison of measured data vs. human perception, it seems to me that a possibly significant thing instrument data gathering misses out on is a human's ability to recognize a large combination of different factors simultaneously. What might seem like a very small difference when measured as a single factor, and concluded to be insignificant, could be perceived to be more significant when numerous other factors in a complex set of variables are also changing by "insignificant" amounts at the same time. The cumulative effect becomes something that the human recognizes as a variation from the response/reaction they expect in that situation. The more experienced that human is with a set of variables, the more likely they are to recognize cumulative differences, and maybe able to identify a smaller set of variables where they detect the difference occurring.

Stating that 1kg isn't going to be noticed unless you lift a bike over your head isn't a realistic judgement. Humans can teach themselves to know exactly the number of playing cards are in a stack, just by how the weight of the stack feels in their hand. I'm not saying that everyone has that kind of sensitivity, but it certainly seems within the realm of human perception that an experienced rider might be able to recognize a difference in how a lighter bike performs when they ride, or how a lighter set of wheels/tires respond differently under acceleration. I'm not making any conclusions about whether those differences result in a difference in speed/performance. This is about human perceptions.

As I said, these is just something I've been pondering. I do not have links to scientific research to support any of it, and haven't made an effort to try to find any These are unfounded opinions, and not intended to be a personal attack on you, or your comments, PeteHski. In all likelihood, you probably know more about the subject than I do.
It’s an interesting subject for sure. I worked directly with top professional race drivers for 20 years (mainly F1 across several different teams) and one important thing I learnt was that driver perception of changes in performance is actually pretty unreliable. Data is King when it comes to performance analysis. Subjective driver feedback is a distant second, but still psychologically important.

Steering “feel” is a good example of a parameter that appears subjectively important to the driver, but has no real effect on objective performance. If you ride a bike with a full 1 litre bottle of water, you can certainly “feel” a slight difference in the way it responds to steering inputs, but it makes no significant difference to your ability to actually steer.

A rider might also claim to feel increased acceleration from a lighter set of wheels. Typical comments like “these 500g lighter wheels spin up so much quicker” are just a mind game. You are still accelerating a total mass of around 80 kg and your rate of acceleration will be in the order of 0.1g for a few seconds at best. 500g lighter wheels don’t suddenly spin up ahead of the other 79.500g they are hauling. But they somehow feel lighter and faster to the rider and that’s a psychological gain. But the thing is, the psychology only works if the rider believes there is a real significant gain. It’s effectively a placebo.
PeteHski is offline  
Likes For PeteHski:
Old 11-14-23, 06:54 PM
  #68  
Advocatus Diaboli
Thread Starter
 
Sy Reene's Avatar
 
Join Date: Feb 2015
Location: Wherever I am
Posts: 8,556

Bikes: Merlin Cyrene, Nashbar steel CX

Mentioned: 14 Post(s)
Tagged: 1 Thread(s)
Quoted: 4675 Post(s)
Liked 1,508 Times in 983 Posts
Ok, so boil this down to the essentials. On one hand a bike with some more alloy parts and a light system; however local bike shop availability, vs. a bike almost 3lbs lighter but also has a power meter, though mail order. Same price. Which do you go with?
Sy Reene is offline  
Old 11-14-23, 07:18 PM
  #69  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by Redbullet
1 kg FEELS and rides different, this is from experience. The difference is, indeed, marginal - thus, it is fancy to pay for it. But this is what we want when we pay many thousands EUR/USD for a bike: fancy and marginal performance features.
I could buy a 1500 EUR bike with 22 speeds mechanical instead of 24 electronic, rim instead of disk brakes, AL instead of CF, durable and lighter than 9 kg, lifetime frame warranty. Very marginally faster and 3-4 times cheaper. But... that bike is not fancy brand and built.
My point was that if I agree to pay big money for fancy and marginally improved features, then I want to receive those features I paid for.
You can pick and choose which of the “fancy” marginal performance features you like. If weight is your main priority then you could buy something like an Aethos and compromise on aero efficiency. But most people have realised that weight is not actually the most important factor in a high-end bike unless they are competing in hill climbs.
PeteHski is offline  
Old 11-14-23, 07:26 PM
  #70  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by Sy Reene
Ok, so boil this down to the essentials. On one hand a bike with some more alloy parts and a light system; however local bike shop availability, vs. a bike almost 3lbs lighter but also has a power meter, though mail order. Same price. Which do you go with?
If they both fit you equally well I would get the Canyon. In fact I did exactly that when I was considering the previous gen versions of both these bikes. I just thought the Canyon was better value for money and my LBS sucks anyway!

Edit: The integrated lights on the Synapse would be a deal breaker for me.

Last edited by PeteHski; 11-14-23 at 07:30 PM.
PeteHski is offline  
Old 11-14-23, 07:33 PM
  #71  
climber has-been
 
terrymorse's Avatar
 
Join Date: Dec 2004
Location: Palo Alto, CA
Posts: 6,825

Bikes: Scott Addict R1, Felt Z1

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 3196 Post(s)
Liked 3,285 Times in 1,654 Posts
Originally Posted by PeteHski
Again, objectively the difference in acceleration is negligible for 1 kg, even on a full bore sprint from low speed. It’s not that difficult to calculate. No need to be subjective in this regard. It’s pure physics.
Hmm.

Speaking pure physics, acceleration varies with the reciprocal of mass (A = F/M), so the difference in acceleration ought to be similar to the difference in power-to-mass ratio.

Unless I am missing something obvious.
__________________
Ride, Rest, Repeat

Zwift: Terry Morse [OldAF]
ROUVY: terrymorse





terrymorse is offline  
Old 11-14-23, 08:09 PM
  #72  
I am potato.
 
base2's Avatar
 
Join Date: Jun 2015
Location: Pacific Northwest
Posts: 3,022

Bikes: Only precision built, custom high performance elitist machines of the highest caliber. 🍆

Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1727 Post(s)
Liked 1,541 Times in 889 Posts
PeteHski We've been through this before. It isn't so much the rate at which the "gyroscope"s come up to speed (acceleration) as much as it is the response of the gyroscope to rider input that makes light bicycle wheels desirable.

The output of a gyroscope is perpendicular and at a right angle to the input. So, when in motion, a left/right turn of the handlebars results in a force at the top and bottom of the wheel whose effect is to lever the frame over about the wheels axis of rotation.

Lighter gyroscopes require less steering input to change orientation at a given speed. This high rate of response to rider input tends to be considered a desirable quality. "Nimble" and "lively" are appropriate terms.

Conversely heavy gyroscopes require "gobs" of effort to change the gyroscopes orientation. The higher rider steering effort required to cause the lever effect that moves the frame about the axle into the desired lean angles necessary for travel upon a bicycle leads to what many consider a "sluggish" feel. This slow rate of response is often (but not always) considered a less than desirable quality.

The compromise of light responsive steering input and steering stability will continue to be the subject of armchair quarterbacks for many years to come.

I have a 950 gram wheel set. I actually think they are too light. If ever such a thing were possible. Any bike they are installed on does exactly what you asked before you realize you asked it. They are anything but "relaxing" to ride.

Last edited by base2; 11-14-23 at 09:29 PM.
base2 is offline  
Old 11-15-23, 03:58 AM
  #73  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by terrymorse
Hmm.

Speaking pure physics, acceleration varies with the reciprocal of mass (A = F/M), so the difference in acceleration ought to be similar to the difference in power-to-mass ratio.

Unless I am missing something obvious.
It’s the very low values of “A” involved with a bicycle that make it insignificant. I made a very simple spreadsheet to calculate the power required to accelerate a mass and it was trivial for a 1 kg mass at 0.1g acceleration, which requires somewhere in the order of 500W to accelerate the total mass at that rate (excluding power required to overcome air and rolling resistance). I might dig it out later if you are interested.

SwissSide developed a simulation tool for comparing aero, weight and rotational inertia for all kinds of specific course profiles. Even they were surprised how little weight and wheel rotational inertia affects performance on a crit course, where accelerations are most brutal.
PeteHski is offline  
Old 11-15-23, 04:05 AM
  #74  
Senior Member
 
PeteHski's Avatar
 
Join Date: May 2021
Posts: 7,823
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 4079 Post(s)
Liked 4,459 Times in 2,774 Posts
Originally Posted by base2
PeteHski We've been through this before. It isn't so much the rate at which the "gyroscope"s come up to speed (acceleration) as much as it is the response of the gyroscope to rider input that makes light bicycle wheels desirable.

The output of a gyroscope is perpendicular and at a right angle to the input. So, when in motion, a left/right turn of the handlebars results in a force at the top and bottom of the wheel whose effect is to lever the frame over about the wheels axis of rotation.

Lighter gyroscopes require less steering input to change orientation at a given speed. This high rate of response to rider input tends to be considered a desirable quality. "Nimble" and "lively" are appropriate terms.

Conversely heavy gyroscopes require "gobs" of effort to change the gyroscopes orientation. The higher rider steering effort required to cause the lever effect that moves the frame about the axle into the desired lean angles necessary for travel upon a bicycle leads to what many consider a "sluggish" feel. This slow rate of response is often (but not always) considered a less than desirable quality.

The compromise of light responsive steering input and steering stability will continue to be the subject of armchair quarterbacks for many years to come.

I have a 950 gram wheel set. I actually think they are too light. If ever such a thing were possible. Any bike they are installed on does exactly what you asked before you realize you asked it. They are anything but "relaxing" to ride.
I am totally unconvinced about the significance of gyroscopic effects on bicycle handling. Especially not within the range of typical 1-2 kg wheel sets. It might well change the steering “feel” but not the performance. But this is getting way OT for this thread.
PeteHski is offline  
Old 11-15-23, 04:27 AM
  #75  
Senior Member
 
Join Date: Aug 2015
Posts: 688
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked 72 Times in 46 Posts
Originally Posted by PeteHski
You can pick and choose which of the “fancy” marginal performance features you like. If weight is your main priority then you could buy something like an Aethos and compromise on aero efficiency. But most people have realised that weight is not actually the most important factor in a high-end bike unless they are competing in hill climbs.
We don't need to run in circles because we agreed this: 1 kg lighter bike can only give marginal gains (0.2-0.5 km/h on flat / climb, maybe?). My point is that 5000 EUR/USD is already a very high price that should offer you the fancy light weight as well. I could buy a 6.6 kg bike with 2300 eur 6-7 years ago. Now a 5000 EUR / USD bike is 2-2.5 kg heavier and part of this difference comes from lower grade (cheaper) carbon fiber used, compared with 6-7 years ago.
If you put it the other way around, once they reduced costs on carbon fiber and increased the weight, the reasonable price would be below 4000 EUR/USD (the extra of almost 75% vs the old bike price being inflation, disk vs rim brakes and electronic vs mechanical shifting). But still, there is a premium price of 5000 vs max 4000, which is not justified in any other way than greedy...
Redbullet is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.