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

Rolling resistance in real world

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

Rolling resistance in real world

Old 10-14-19, 05:13 PM
  #1  
TiHabanero
Senior Member
Thread Starter
 
Join Date: Nov 2012
Posts: 3,899
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1471 Post(s)
Liked 939 Times in 493 Posts
Rolling resistance in real world

Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?

For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?

Last edited by TiHabanero; 10-14-19 at 05:19 PM.
TiHabanero is offline  
Old 10-14-19, 05:28 PM
  #2  
seau grateau
Senior Member
 
seau grateau's Avatar
 
Join Date: Sep 2009
Location: PHL
Posts: 9,948

Bikes: Litespeed Catalyst, IRO Rob Roy, All City Big Block

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1332 Post(s)
Liked 392 Times in 188 Posts
Real-world tests aren't controlled enough to really mean anything in most cases.
seau grateau is offline  
Likes For seau grateau:
Old 10-14-19, 05:32 PM
  #3  
asgelle
Senior Member
 
Join Date: Apr 2006
Location: Albuquerque, NM
Posts: 4,382
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 921 Post(s)
Liked 361 Times in 220 Posts
Originally Posted by seau grateau View Post
Real-world tests aren't controlled enough to really mean anything in most cases.
https://anonymous.coward.free.fr/watt...direct-cda.pdf read, understand, think
asgelle is offline  
Likes For asgelle:
Old 10-14-19, 05:35 PM
  #4  
seypat
Senior Member
 
Join Date: Oct 2010
Posts: 7,635
Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 2626 Post(s)
Liked 1,763 Times in 1,116 Posts
Originally Posted by TiHabanero View Post
Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?

For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?
Are we going to be graded on this?
seypat is online now  
Old 10-14-19, 06:08 PM
  #5  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,080

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 95 Post(s)
Tagged: 0 Thread(s)
Quoted: 3643 Post(s)
Liked 2,092 Times in 1,327 Posts
Originally Posted by TiHabanero View Post
Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?

For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?
First, we need to define terms. Are you asking about the rolling resistance of the tires themselves, or the total frictional losses with a human-shaped bag of meat on the saddle?
__________________
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 10-14-19, 08:04 PM
  #6  
RChung
Perceptual Dullard
 
Join Date: Sep 2009
Posts: 1,986
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 624 Post(s)
Liked 662 Times in 272 Posts
Originally Posted by TiHabanero View Post
Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?
Yes.
RChung is offline  
Likes For RChung:
Old 10-14-19, 08:27 PM
  #7  
MattTheHat 
Senior Member
 
MattTheHat's Avatar
 
Join Date: Aug 2018
Location: Allen, TX
Posts: 2,341

Bikes: 2021 S-Works Turbo Creo SL, 2020 Specialized Roubaix Expert

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 711 Post(s)
Liked 3,345 Times in 1,168 Posts
Originally Posted by TiHabanero View Post
Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?

For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?
Checkout bikecalculator.com. You can enter specifics for a given ride and it will display a very accurate estimate of power and speed. Change the power estimate and it will recalculate speed over the ride distance. Its quite interesting. Its cool to enter Strava segment details and find out how much difference a few extra watts will make. Or how little difference.
MattTheHat is offline  
Old 10-14-19, 11:21 PM
  #8  
znomit
Zoom zoom zoom zoom bonk
 
znomit's Avatar
 
Join Date: Sep 2006
Location: New Zealand
Posts: 4,506

Bikes: Giant Defy, Trek 1.7c, BMC GF02, Fuji Tahoe, Scott Sub 35

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 500 Post(s)
Liked 636 Times in 324 Posts
Originally Posted by TiHabanero View Post
For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?
By choosing the lower rolling resistance tyre in real world terms it means that your coefficient of flats has increased by a ratio of 1.5/1.2. The average moving speed improvements are more than offset by the increase in time spent fixing the extra flats. But you now have something else to brag about at the coffee shop.
znomit is offline  
Likes For znomit:
Old 10-15-19, 12:30 AM
  #9  
canklecat
Me duelen las nalgas
 
canklecat's Avatar
 
Join Date: Aug 2015
Location: Texas
Posts: 13,302

Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel

Mentioned: 196 Post(s)
Tagged: 0 Thread(s)
Quoted: 4423 Post(s)
Liked 2,505 Times in 1,624 Posts
One theory says the increased comfort from "softer" tires may translate to less fatigue and more efficiency over distance.

That's the only theory that seems to apply to my real world riding. Along with improved bike fit and physical conditioning.

Recently I've swapped my low profile wheels with 700x23 and 700x25 tires at reduced pressure (usually 70-85 psi front) to a semi-aero front wheel (30mm profile, flat blade spokes) with 700x20 tire at 120 psi or more. It's a bit harsher and more tiring over longer rides, but may be offset by slightly improved aerodyamics.

The aero wheel and skinnier, harder tire is faster on a couple of 5 mile loops and over 30-50 mile rides but only on smoother roads -- mostly new or recently repaved access roads next to highways. Little traffic and few stops at night so it's easy to compare. But that same wheel and harder tire is a chore to ride long distances on chipseal and rougher roads, which eliminates the slight aero and rolling resistance advantage.

Too subjective to be useful to anyone else.
canklecat is offline  
Likes For canklecat:
Old 10-15-19, 04:17 AM
  #10  
jpescatore
Senior Member
 
Join Date: Oct 2017
Location: Ashton, MD USA
Posts: 1,218

Bikes: Trek Domane SL6 Disc, Jamis Renegade

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 338 Post(s)
Liked 263 Times in 192 Posts
Bicyclerollingresistance.com does rolling resistance tests on rollers with a bumpy surface, vs. the perfectly flat rollers that were long used. The theory is that this simulates a more typical riding surface for everyone except velodrome racers! They also do testing at various speeds, not just 25 mph racing speeds.

That type of testing has shown that for most non-racers narrower and higher pressure does not always mean lower rolling resistance. In fact, for the speeds I go at and the roads I ride on, narrow tires at high pressure make no sense. At 15 - 18 mph average, the aero factors are minimal - and my gigantic body width swamps the contribution of the wheels in wind resistance by a huge margin anyway.

I agree with the earlier poster about flats - I'll spend a watt or two to reduce flatting on the road to near zero. BicycleRollingResistance also does puncture resistance testing.
jpescatore is offline  
Old 10-15-19, 12:33 PM
  #11  
dalava
Senior Member
 
Join Date: Jun 2008
Location: Northern VA
Posts: 3,248

Bikes: Moots Vamoots, Colnago C60, Santa Cruz Stigmata CC, and too many other bikes I don't ride

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 152 Post(s)
Likes: 0
Liked 7 Times in 6 Posts
Originally Posted by asgelle View Post
This... give it a read and you will be informed.
dalava is offline  
Old 10-15-19, 12:47 PM
  #12  
burnthesheep
Newbie racer
 
Join Date: Feb 2018
Posts: 3,361

Bikes: Propel, red is faster

Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1562 Post(s)
Liked 1,526 Times in 947 Posts
It matters.

While the CRR and watts on BRR might not be absolute, the deltas are probably pretty good when doing comparisons.

I get tons of miles out of GP4000's, and assume 5000's would also. I wouldn't commute on them. But for training and racing, yeah.

It's not data, but I've put out power PR's on some personal segments by over 40w before only to still be slower overall......because I was on my "gravel/multisurface" setup with Gators on the bike. Wind those days being negligible.

Also, difference when I was TT'ing practice on a tubular Conti sprinter was dog crap CRR compared to a race tire. It can be shocking how much it matters.
burnthesheep is offline  
Old 10-15-19, 09:17 PM
  #13  
RChung
Perceptual Dullard
 
Join Date: Sep 2009
Posts: 1,986
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 624 Post(s)
Liked 662 Times in 272 Posts
Originally Posted by dalava View Post
This... give it a read and you will be informed.
The Bill of Rights bans cruel and unusual punishment.
RChung is offline  
Likes For RChung:
Old 10-15-19, 10:19 PM
  #14  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 23,153
Mentioned: 84 Post(s)
Tagged: 0 Thread(s)
Quoted: 18512 Post(s)
Liked 10,292 Times in 5,857 Posts
Originally Posted by znomit View Post
By choosing the lower rolling resistance tyre in real world terms it means that your coefficient of flats has increased by a ratio of 1.5/1.2. The average moving speed improvements are more than offset by the increase in time spent fixing the extra flats. But you now have something else to brag about at the coffee shop.
This is why I use wood instead of pneumatic tires. Makes me so much faster.

Let's not talk about tubeless.
Seattle Forrest is offline  
Likes For Seattle Forrest:
Old 10-15-19, 10:37 PM
  #15  
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Posts: 18,654

Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004

Mentioned: 113 Post(s)
Tagged: 0 Thread(s)
Quoted: 3472 Post(s)
Liked 1,466 Times in 1,066 Posts
Originally Posted by TiHabanero View Post
Reading another thread about tires and there was talk about rolling resistance. Got me thinking about it and has it been quantified over a real world course in terms of speed on a fixed course, time passed in a fixed distance, or distance traveled in time allotted?

For example if tire A has rolling resistance of 1.2 and tire B has rolling resistance of 1.5 (being of greater resistance) how does that translate to real world use as described above?
Answer to first question is simply Yes, with the proviso that the verb would be "can" rather than "has." See asgelle's post above. Answer to question 2 is more complicated because of the interaction between tire and surface. For each exact surface condition, there will be a fastest tire. Can you figure out which? Yes, given unlimited funds and time. Is it worth the trouble? Well, if you're a pro it might be worth it to pay someone to find the perfect tire/wheel combo for a particular course, but only if you plan on winning enough prize money and have the ability for that to be possible. You hope your team will take care of all that. Talented amateurs will also go to quite a bit of trouble with it. And remember, it's the fastest tire/wheel combo, not only the tire.

If you're an ordinary bloke, you look at power/speed on different surfaces with different tires and pressures. I don't think it's possible to make really fine judgements in ordinary riding, but I think it's pretty easy to tell a high CRR tire from a low one.

I haven't found low CRR tires to necessarily incur more flats. It's more complicated that that, and also more complicated than the BRR puncture coefficient.
__________________
Results matter
Carbonfiberboy is offline  
Old 10-15-19, 11:40 PM
  #16  
canklecat
Me duelen las nalgas
 
canklecat's Avatar
 
Join Date: Aug 2015
Location: Texas
Posts: 13,302

Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel

Mentioned: 196 Post(s)
Tagged: 0 Thread(s)
Quoted: 4423 Post(s)
Liked 2,505 Times in 1,624 Posts
Yeah, regarding punctures, I haven't experienced any more punctures at lower pressure than high or max pressure. But I weigh 150 now, which may help. I weighed 175 when I resumed cycling in 2015 after a 30 year hiatus.

Now I tend to split the difference between the max pressure on the sidewalls and the various formulas for low pressure. Usually with 700x23 that works out to 100 psi rear, 85 front, and for 700x25 around 90 rear, 75 front. I could go lower but that feels about right in handling and comfort. I go by the feel over some familiar rough road patches. If it feels a bit harsh I'll stop and tap the valve a few spurts.

So far my only pinch flat occurred when I was pinched between a couple of trucks and couldn't avoid a brick in the road. No pinch flats on normal rough road spots.
canklecat is offline  
Old 10-16-19, 08:59 AM
  #17  
RChung
Perceptual Dullard
 
Join Date: Sep 2009
Posts: 1,986
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 624 Post(s)
Liked 662 Times in 272 Posts
Originally Posted by Carbonfiberboy View Post
Answer to first question is simply Yes, with the proviso that the verb would be "can" rather than "has."
I'm pretty sure I ride in the real world, on real courses on real roads.
RChung is offline  
Old 10-16-19, 09:16 AM
  #18  
Cypress
Globo Gym lifetime member
 
Cypress's Avatar
 
Join Date: Jan 2006
Location: Salem, Oregon
Posts: 5,204

Bikes: Fast ones

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 410 Post(s)
Liked 612 Times in 305 Posts
Watts are watts. Run a Hard Case tire with butyl tubes, then switch to a GP5K with latex tubes and tell me you didn't pick up 2+ mph at the same wattage.
Cypress is offline  
Likes For Cypress:
Old 10-16-19, 09:20 AM
  #19  
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Posts: 18,654

Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004

Mentioned: 113 Post(s)
Tagged: 0 Thread(s)
Quoted: 3472 Post(s)
Liked 1,466 Times in 1,066 Posts
Originally Posted by RChung View Post
I'm pretty sure I ride in the real world, on real courses on real roads.
The subject of my post is that "real roads" RR will vary with road surface characteristics and equipment. There's not one number for one tire at one pressure on any rim on every road, nor can your results be extrapolated to another's conditions and equipment. I would hope you'd agree with that.

Edit: all that's necessary is for the tester to follow the procedure in your document.
__________________
Results matter

Last edited by Carbonfiberboy; 10-16-19 at 09:43 AM.
Carbonfiberboy is offline  
Likes For Carbonfiberboy:
Old 10-16-19, 09:28 AM
  #20  
wphamilton
Senior Member
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 15,280

Bikes: Nashbar Road

Mentioned: 71 Post(s)
Tagged: 0 Thread(s)
Quoted: 2933 Post(s)
Liked 339 Times in 226 Posts
Originally Posted by ThermionicScott View Post
First, we need to define terms. Are you asking about the rolling resistance of the tires themselves, or the total frictional losses with a human-shaped bag of meat on the saddle?
This makes me wonder if there is a "kitchen table science" way to measure physiological energy produced, since you'd need to know that instead of/addition to power meter measurements.

With C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water) for aerobic effort, anyone know precisely where all the water goes? I'm thinking respiration mostly, or a definable percentage of it to define a relation with energy. Then are there enough of the "6H2O" respired to be able to measure? Any biologists out there that have done the math?

You'd have to account for perspiration also but surely you could collect it and weigh it, for a few rides anyway.
wphamilton is offline  
Old 10-16-19, 09:49 AM
  #21  
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Posts: 18,654

Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004

Mentioned: 113 Post(s)
Tagged: 0 Thread(s)
Quoted: 3472 Post(s)
Liked 1,466 Times in 1,066 Posts
Originally Posted by wphamilton View Post
This makes me wonder if there is a "kitchen table science" way to measure physiological energy produced, since you'd need to know that instead of/addition to power meter measurements.

With C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water) for aerobic effort, anyone know precisely where all the water goes? I'm thinking respiration mostly, or a definable percentage of it to define a relation with energy. Then are there enough of the "6H2O" respired to be able to measure? Any biologists out there that have done the math?

You'd have to account for perspiration also but surely you could collect it and weigh it, for a few rides anyway.
IME blood volume and tissue H2O storage increases, and then you pee it out over the next day or two if there's been enough riding and effort time to accumulate a serious amount of H2O. And of course the sweat and respiration losses, as you say. That's not precise of course, just IME. There's also the water released by glycogen breakdown, which I think accounts for a lot of that pee.
__________________
Results matter
Carbonfiberboy is offline  
Old 10-16-19, 10:14 AM
  #22  
Notso_fastLane
Senior Member
 
Notso_fastLane's Avatar
 
Join Date: Dec 2011
Location: Layton, UT
Posts: 1,600

Bikes: 2011 Bent TW Elegance 2014 Carbon Strada Velomobile

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 624 Post(s)
Liked 692 Times in 414 Posts
Originally Posted by znomit View Post
By choosing the lower rolling resistance tyre in real world terms it means that your coefficient of flats has increased by a ratio of 1.5/1.2. The average moving speed improvements are more than offset by the increase in time spent fixing the extra flats. But you now have something else to brag about at the coffee shop.
He did ask about the "real" world.

I ride on practically bulletproof tires that are on the heavy side, plus have liners in them. But I commute and need to get to work reliably. They still roll reasonably well. I don't feel the difference as much on the velo, because it's already 70 lbs, but it's more noticeable on the (recumbent) bike.

Once I get the velo up to speed though, aerodynamics becomes more important, and that's where it really shines. I had some Kojaks on my bent when I was in Tucson, and on the smooth bike trails around town, they were nice and fast, but it seems like on the surface streets, which were much rougher on average, my 'slow' commuting tires were slightly faster (and way more comfortable).
Notso_fastLane is offline  
Old 10-16-19, 11:30 AM
  #23  
wphamilton
Senior Member
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 15,280

Bikes: Nashbar Road

Mentioned: 71 Post(s)
Tagged: 0 Thread(s)
Quoted: 2933 Post(s)
Liked 339 Times in 226 Posts
Originally Posted by Carbonfiberboy View Post
IME blood volume and tissue H2O storage increases, and then you pee it out over the next day or two if there's been enough riding and effort time to accumulate a serious amount of H2O. And of course the sweat and respiration losses, as you say. That's not precise of course, just IME. There's also the water released by glycogen breakdown, which I think accounts for a lot of that pee.
This is all about measuring the glycogen breakdown as I see it. I figured there'd be a blood volume increase and some would make its way to the bladder, amounts which you couldn't really measure very easily. But if say 10% of it exits in respiration, and you could weigh the difference, then those other accumulations wouldn't change the before/after weight and you could multiply by 10. Or whatever the formula might be. We breathe out water vapor for sure, but I don't know if there is a reliable curve relating water produced and water respired.
wphamilton is offline  
Old 10-18-19, 11:01 AM
  #24  
tomato coupe
Senior Member
 
Join Date: Jul 2009
Posts: 3,785

Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 2405 Post(s)
Liked 4,213 Times in 1,712 Posts
Originally Posted by canklecat View Post
So far my only pinch flat occurred when I was pinched between a couple of trucks ...
I don't think tire pressure is going to help in that situation.
tomato coupe is offline  
Old 10-18-19, 03:13 PM
  #25  
canklecat
Me duelen las nalgas
 
canklecat's Avatar
 
Join Date: Aug 2015
Location: Texas
Posts: 13,302

Bikes: Centurion Ironman, Trek 5900, Univega Via Carisma, Globe Carmel

Mentioned: 196 Post(s)
Tagged: 0 Thread(s)
Quoted: 4423 Post(s)
Liked 2,505 Times in 1,624 Posts
Originally Posted by canklecat So far my only pinch flat occurred when I was pinched between a couple of trucks ...
Originally Posted by tomato coupe View Post
I don't think tire pressure is going to help in that situation.
Yeah, I'd need wider tires. About 6 feet wide.
canklecat is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.