Does rotating weight really matter?
05-03-21, 11:06 AM
#51
climber has-been
Join Date: Dec 2004
Location: Palo Alto, CA
Posts: 5,431
Bikes: Scott Addict R1
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 1912 Post(s)
Liked 1,843 Times
in
965 Posts
From the usenet archives:
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, 26-Mar-2000
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, 26-Mar-2000
__________________
Ride, Rest, Repeat
Ride, Rest, Repeat
Likes For terrymorse:
05-03-21, 11:34 AM
#53
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 18880 Post(s)
Liked 10,640 Times
in
6,050 Posts
Originally Posted by bruce19
I'm not crazed about average speed. I do, however like it when what is advertised is what is delivered. And, at age 75 I know full well it''s the journey and not the destination.
05-03-21, 11:44 AM
#54
Senior Member
Thread Starter
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 8,247
Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1635 Post(s)
Liked 1,123 Times
in
657 Posts
Originally Posted by Seattle Forrest
Because this thread started off with you thought the benefits from light weight stuff wasn't enough to justify the price,
05-03-21, 11:50 AM
#55
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 18880 Post(s)
Liked 10,640 Times
in
6,050 Posts
Originally Posted by hubcyclist
but I think generally folks are looking for a tangible benefit when they decide to shell out cash on wheels and higher priced bikes. So its fair to temper peoples expectations. Ive seen videos where the time savings of nice carbon wheels vs basic aluminum wheels is about 1min per hour, I certainly cant justify spending that much.
I have the most basic of bikes, a base model allez with Claris and axis sport branded wheels and I get lots of enjoyment on the bike, the only limiter is me. And I go way faster than a lot of folks because Ive put in the work on myself. I think a lot of people buy into hype and then come up with nebulous things to justify spending way too much in absence of any tangible benefits they may have been looking for. Yeah its all about fun, but I think most folks have priorities outside of cycling and helping people make smart purchases is just as important as getting enjoyment.
I have the most basic of bikes, a base model allez with Claris and axis sport branded wheels and I get lots of enjoyment on the bike, the only limiter is me. And I go way faster than a lot of folks because Ive put in the work on myself. I think a lot of people buy into hype and then come up with nebulous things to justify spending way too much in absence of any tangible benefits they may have been looking for. Yeah its all about fun, but I think most folks have priorities outside of cycling and helping people make smart purchases is just as important as getting enjoyment.
It sounds like you're thinking the only thing any bike equipment can do for anybody is make you faster. But you've seen how disc brakes took over road cycling, the time savings is zero. Negative time savings if the wind is coming from the rotor side. A lot of people will never buy a rim brake road bike again and are happy about it. I've seen a lot of people complain that they can't get high end wheels anymore, I've never seen anybody complain that riders can't spend money on increased safety on the basis of minutes saved per hour.
I have not especially light, but deep, carbon hoops. The main benefit I get out of them is I enjoy riding more when I use them. Did they make me faster? Yes. Do I care? A little. Mainly I like the way the bike feels, looks, and sounds (when I'm going fast). Would I do it again? **** yeah!
Sometimes it's really fun to be fast, but there's so much more to cycling and the difference between 27.3 and 27.4 mph doesn't really affect my smiles per mile.
Likes For Seattle Forrest:
05-03-21, 11:51 AM
#56
Senior Member
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,208
Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 18880 Post(s)
Liked 10,640 Times
in
6,050 Posts
Originally Posted by bruce19
That's not accurate. I posted a video. I did not comment.
05-03-21, 03:12 PM
#57
Senior Member
Thread Starter
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 8,247
Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1635 Post(s)
Liked 1,123 Times
in
657 Posts
Originally Posted by Seattle Forrest
You just said it's upsetting that people aren't getting what's advertised. Can you elaborate?
Last edited by bruce19; 05-03-21 at 03:32 PM.
05-03-21, 03:19 PM
#58
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,330
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20611 Post(s)
Liked 9,283 Times
in
4,597 Posts
Originally Posted by bruce19
You said "Because this thread started off with you thought the benefits from light weight stuff wasn't enough to justify the price," That's not what I started off with. I will agree that the "benefit" real or imagined does not justify paying $2,000 or more for a CF wheel set. But, that's just me. If someone else does feel it's justified....go for it.
05-03-21, 03:40 PM
#59
Senior Member
Thread Starter
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 8,247
Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1635 Post(s)
Liked 1,123 Times
in
657 Posts
Originally Posted by WhyFi
Sooooooo what benefit is being advertised and unmet, with regard to rotating weight? Or is this not really a rotating weight thread and simply another "kvetch about products that cost more than I want to spend" thread?
05-03-21, 03:53 PM
#60
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,330
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20611 Post(s)
Liked 9,283 Times
in
4,597 Posts
Originally Posted by bruce19
It is a video. Take from it what you will.
Originally Posted by bruce19
My take away thus far is that there has been a lot of money spent for not much gain.
Originally Posted by bruce19
I do, however like it when what is advertised is what is delivered.
Likes For WhyFi:
05-03-21, 04:09 PM
#61
Senior Member
Originally Posted by bruce19
I do, however like it when what is advertised is what is delivered.
05-03-21, 04:10 PM
#62
Senior Member
Thread Starter
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 8,247
Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1635 Post(s)
Liked 1,123 Times
in
657 Posts
I have seen ads which tout the reduction in rotating weight as a significant advantage. Any search I've done says this is a myth or, at best, there is a minimal advantage in specific situations. IMO this does not justify a large expenditure of money. Especially when I could, and should, lose 10 lbs.
Likes For bruce19:
05-03-21, 04:15 PM
#63
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,330
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20611 Post(s)
Liked 9,283 Times
in
4,597 Posts
Originally Posted by bruce19
I have seen ads which tout the reduction in rotating weight as a significant advantage.
05-03-21, 04:28 PM
#64
Senior Member
Thread Starter
Join Date: Jul 2006
Location: Lebanon (Liberty Hill), CT
Posts: 8,247
Bikes: CAAD 12, MASI Gran Criterium S, Colnago World Cup CX & Guru steel
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 1635 Post(s)
Liked 1,123 Times
in
657 Posts
Originally Posted by WhyFi
Significant advantage in what way? By whom? Care to share some examples?
05-03-21, 04:35 PM
#65
Method to My Madness
Join Date: Nov 2020
Location: Orange County, California
Posts: 2,376
Bikes: Trek FX 2, Cannondale Synapse, Cannondale CAAD4, Santa Cruz Stigmata GRX
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 1203 Post(s)
Liked 789 Times
in
579 Posts
Yes, I think that Bike Forums is the perfect venue for us to be critical of each other's statements, semantics, and intent like we are all doing peer review of each other's posts.
05-03-21, 04:43 PM
#66
Senior Member
Join Date: Aug 2014
Posts: 2,430
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 739 Post(s)
Liked 410 Times
in
229 Posts
Originally Posted by bruce19
Do your own research. And stop being a kochleffel.
Last edited by colnago62; 05-03-21 at 04:46 PM.
05-03-21, 04:48 PM
#67
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,330
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20611 Post(s)
Liked 9,283 Times
in
4,597 Posts
Originally Posted by bruce19
Do your own research. And stop being a kochleffel.
Likes For WhyFi:
05-03-21, 05:02 PM
#68
Advocatus Diaboli
FWIW, there's a bunch of discussion here about not much. Typically from what I see here on BF, cyclists get a stock bike. Don't like the wheels -- they're heavy. Lighter wheels save weight -- that's not even a question. This topic seems should be about whether a gram saved on a wheel rim is how much better than a gram saved elsewhere -- is it worth 1.5x, 2x, 3x more than another option (per gram)?
Spending money on saving weight.. whatever -- do what you want to do and buy what you want to buy. I find it an interesting premise though that there's nothing that special about a wheel gram vs another type of gram. Aero however, is a completely different topic.
Boil it down.. if you could get a 1800 gram, awesome looking blingy wheel with a cool 28mm exterior width and 45mm depth for $750, or the same described wheel, at 1400 grams, for eg. $3k, would this be something you'd consider? What's your breakeven?
Spending money on saving weight.. whatever -- do what you want to do and buy what you want to buy. I find it an interesting premise though that there's nothing that special about a wheel gram vs another type of gram. Aero however, is a completely different topic.
Boil it down.. if you could get a 1800 gram, awesome looking blingy wheel with a cool 28mm exterior width and 45mm depth for $750, or the same described wheel, at 1400 grams, for eg. $3k, would this be something you'd consider? What's your breakeven?
Likes For Sy Reene:
05-03-21, 05:06 PM
#69
bike whisperer
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,480
Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1493 Post(s)
Liked 700 Times
in
495 Posts
Anyone who reads this thread will see a few pissing contests of no consequence, but in between is the clear point that lighter (and more aero) bikes are more fun.
And yeah, you notice rotating mass more. All the rotating mass, not just the wheels. Not so much the cranks, but consider that the whole bike rotates from side to side with the contact patches as the axis when you stand on it, so if you want your bike to feel light when you do that, start at the top - seat and bars matter like rims. Then you've got the front end rotating around the head tube; lighten all that and you'll notice that more too.
Save crank upgrades for last.
And yeah, you notice rotating mass more. All the rotating mass, not just the wheels. Not so much the cranks, but consider that the whole bike rotates from side to side with the contact patches as the axis when you stand on it, so if you want your bike to feel light when you do that, start at the top - seat and bars matter like rims. Then you've got the front end rotating around the head tube; lighten all that and you'll notice that more too.
Save crank upgrades for last.
__________________
Sheldon Brown's bike info ~~~ Park Tools repair help
Half-step triple, using double gear ~~~ 6400 STI rebuild walkthrough ~~~ Want 8/9/10s @126mm OLD? OCR. ~~~ Shimano cassette body overhaul ~~~ Ergopower Escape wear repair ~~~ PSA: drivetrain wear
List of US/Canada bike co-ops ~~~ Global list
Sheldon Brown's bike info ~~~ Park Tools repair help
Half-step triple, using double gear ~~~ 6400 STI rebuild walkthrough ~~~ Want 8/9/10s @126mm OLD? OCR. ~~~ Shimano cassette body overhaul ~~~ Ergopower Escape wear repair ~~~ PSA: drivetrain wear
List of US/Canada bike co-ops ~~~ Global list
05-03-21, 05:09 PM
#70
Advocatus Diaboli
Will people notice the faster accelerating or the faster deaccelerating first?
Likes For Sy Reene:
05-03-21, 06:15 PM
#71
bike whisperer
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 9,480
Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1493 Post(s)
Liked 700 Times
in
495 Posts
Originally Posted by Sy Reene
Will people notice the faster accelerating or the faster deaccelerating first?
__________________
Sheldon Brown's bike info ~~~ Park Tools repair help
Half-step triple, using double gear ~~~ 6400 STI rebuild walkthrough ~~~ Want 8/9/10s @126mm OLD? OCR. ~~~ Shimano cassette body overhaul ~~~ Ergopower Escape wear repair ~~~ PSA: drivetrain wear
List of US/Canada bike co-ops ~~~ Global list
Sheldon Brown's bike info ~~~ Park Tools repair help
Half-step triple, using double gear ~~~ 6400 STI rebuild walkthrough ~~~ Want 8/9/10s @126mm OLD? OCR. ~~~ Shimano cassette body overhaul ~~~ Ergopower Escape wear repair ~~~ PSA: drivetrain wear
List of US/Canada bike co-ops ~~~ Global list
Likes For Kimmo:
05-03-21, 07:13 PM
#72
Senior Member
Originally Posted by Sy Reene
FWIW, there's a bunch of discussion here about not much. Typically from what I see here on BF, cyclists get a stock bike. Don't like the wheels -- they're heavy. Lighter wheels save weight -- that's not even a question. This topic seems should be about whether a gram saved on a wheel rim is how much better than a gram saved elsewhere -- is it worth 1.5x, 2x, 3x more than another option (per gram)?
Spending money on saving weight.. whatever -- do what you want to do and buy what you want to buy. I find it an interesting premise though that there's nothing that special about a wheel gram vs another type of gram. Aero however, is a completely different topic.
Boil it down.. if you could get a 1800 gram, awesome looking blingy wheel with a cool 28mm exterior width and 45mm depth for $750, or the same described wheel, at 1400 grams, for eg. $3k, would this be something you'd consider? What's your breakeven?
Spending money on saving weight.. whatever -- do what you want to do and buy what you want to buy. I find it an interesting premise though that there's nothing that special about a wheel gram vs another type of gram. Aero however, is a completely different topic.
Boil it down.. if you could get a 1800 gram, awesome looking blingy wheel with a cool 28mm exterior width and 45mm depth for $750, or the same described wheel, at 1400 grams, for eg. $3k, would this be something you'd consider? What's your breakeven?
Likes For Racing Dan:
05-03-21, 07:45 PM
#73
Full Member
Originally Posted by Kimmo
Before either of those, how easy it is to carry up stairs.
When sprinting at speed in an important race, The aerodynamic advantage of a heavier wheel might outweigh the tiny loss in acceleration of the rotating mass.
Last edited by xroadcharlie; 05-04-21 at 02:04 AM.
05-04-21, 02:27 AM
#74
Method to My Madness
Join Date: Nov 2020
Location: Orange County, California
Posts: 2,376
Bikes: Trek FX 2, Cannondale Synapse, Cannondale CAAD4, Santa Cruz Stigmata GRX
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 1203 Post(s)
Liked 789 Times
in
579 Posts
Originally Posted by Racing Dan
So why doesn't anyone ever complain their heavy aero wheels flees heavy and sluggish, but heavy stock wheels do? :-)
05-04-21, 02:49 AM
#75
Senior Member
Join Date: Jul 2008
Location: Minas Ithil
Posts: 9,335
Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 2431 Post(s)
Liked 630 Times
in
389 Posts
I've never noticed a difference in speed when switching to a light wheelset. The biggest difference is the smoothness of the ride when going from wheels with stiff straight gauge spokes and light DB spokes. Straight gauge spokes, which the majority of stock wheels come with are my pet peeve.
I did buy a Swobo single speed bike than came new with 42mm tires, cheap and heavy ones (that were too wide for the narrow rims). I switched to 23mm Vittoria open tubulars and the difference was very noticeable.
I did buy a Swobo single speed bike than came new with 42mm tires, cheap and heavy ones (that were too wide for the narrow rims). I switched to 23mm Vittoria open tubulars and the difference was very noticeable.
