Newbie trying to understand rolling resistance tests, requesting assistance

ccand51997 wrote:
I"m running 19, 23, 25 and 29mm ID aluminum rims.  I'm not sure what you mean by you can't get that in aluminum.
I did not say aero wheels were important for gravel; in fact, I specifically said 'non-aero carbon rims."
How exactly does a carbon rim offer higher performance?  Please explain that.  I don't need stronger and stiffer than I already have and the weight difference might be 100-150 g max, for each wheel.  That is less than a pound for a set.  That means on a 3500 foot climb you would gain 10 seconds or so from the weight loss. That is not nothing, but it is a lot to pay for a wheelset that costs three times as much as I can build myself. 

Perhaps I was not clear enough:  you cannot get the same performance from a wheel with an aluminum rim at the same sizing.  The carbon rim is lighter, and it builds into a stiffer, stronger wheel.  Carbon rims with 25 mm internal width weigh about 350 grams.  When I say stiffer, I am talking laterally stiffer, which means you have a more precise handing wheel, which means you can ride faster through corners, and the wheel will behave better when putting out serious watts, and when you are out of the saddle.  Right now you can get a Roval Terra CL wheel set for about $1300.00(https://www.specialized.com/us/en/roval-terra-cl-wheelset/p/174204?color=278163-174204&searchText=30020-5200).  Carbon wheels have better performance, if you do not want that better performance, and would rather pay less for a heaver and flexier wheel set, that is fine with me.  Certainly no one has to have carbon wheels to ride a bike, but some folks want better performance than what an aluminum rim can offer, and are willing to pay a little bit more for it.  And your 3x more is just plain inaccurate, yes a good carbon wheel set will be a bit more expensive, usually something better is more expensive, but you do not have to pay 3x the price.  As to the weight difference, all this weight is at the rim, where it makes a much bigger difference than just to overall weight, acceleration is faster, handling is quicker and more precise.  A good carbon wheel set is one of the most impactful upgrades one can make to a bike.  It sounds like you may have never actually ridden a really good carbon wheel set, as the difference is immediately obvious.
If you like to build yourself, I would suggest We Are One rims, light, made in Canada, and high quality.  You can of course go cheaper with no name Chinese rims, and some of those rims are good, but if I was doing the build, I would go with We Are One for the quality.  Their 25 mm internal rims are 350 grams, and can be built into very strong gravel wheels with 24 spokes.

barrows wrote:

Perhaps I was not clear enough:  you cannot get the same performance from a wheel with an aluminum rim at the same sizing.  The carbon rim is lighter, and it builds into a stiffer, stronger wheel.  Carbon rims with 25 mm internal width weigh about 350 grams.  When I say stiffer, I am talking laterally stiffer, which means you have a more precise handing wheel, which means you can ride faster through corners, and the wheel will behave better when putting out serious watts, and when you are out of the saddle.  Right now you can get a Roval Terra CL wheel set for about $1300.00(https://www.specialized.com/us/en/roval-terra-cl-wheelset/p/174204?color=278163-174204&searchText=30020-5200).  Carbon wheels have better performance, if you do not want that better performance, and would rather pay less for a heaver and flexier wheel set, that is fine with me.  Certainly no one has to have carbon wheels to ride a bike, but some folks want better performance than what an aluminum rim can offer, and are willing to pay a little bit more for it.  And your 3x more is just plain inaccurate, yes a good carbon wheel set will be a bit more expensive, usually something better is more expensive, but you do not have to pay 3x the price.  As to the weight difference, all this weight is at the rim, where it makes a much bigger difference than just to overall weight, acceleration is faster, handling is quicker and more precise.  A good carbon wheel set is one of the most impactful upgrades one can make to a bike.  It sounds like you may have never actually ridden a really good carbon wheel set, as the difference is immediately obvious.
If you like to build yourself, I would suggest We Are One rims, light, made in Canada, and high quality.  You can of course go cheaper with no name Chinese rims, and some of those rims are good, but if I was doing the build, I would go with We Are One for the quality.  Their 25 mm internal rims are 350 grams, and can be built into very strong gravel wheels with 24 spokes.

I guess we'll just have to agree to disagree. And maybe some of that is based off of my weight, which is only about 150 pounds.  I've never ridden a carbon rim--this is true--but I've also never said to myself, I need to go 10 seconds faster up this one hour climb and thus pay for that 200-300 gram weight loss.  
The rest of this is not really directed to you, since you have clearly made up your mind.  It is more for the newbie to provide a counterpoint to the argument that carbon rims are worth it.  
Yes, 300 is only 2.6 times more expensive, but that is on the low end for most of the carbon wheelsets I've seen for sale, and you did quote $1500 the first time.  
As for stiffer, well, I guess I'll just have to admit that I have no idea what you are talking about.--it sounds like a marketing speel to me-nor do I see how it would possibly effect my riding.    When I put my deep carbon rims on my tri bike (compared to my aluminum spoked training wheels), I can't tell one bit of difference by feel; I just know I go faster because of my average mph at the same wattage. I'm sure with a 60mm rim it is likely a much stiffer wheel, but so what?
Finally, the weight thing, other than absolute weight carried up a mountain, is a red herring.  Anything that accelerates faster also carries less kinetic energy and thus will slow down quicker than a slightly heavier wheel.  Zero sum game, Wheel inertia as a performance factor is a myth perpetuated by the bike industry in order to sell lighter, more expensive wheels.  Math does not back it up.  Anyone who understands how inertia works should understand that.
I'm going to reassert my original statement and agree to disagree.  Carbon rims and wheelsets will provide a nearly unmeasurable advantage, other than on a weight scale, over aluminum rims from a performance standpoint.  They may hold up to more abuse, but as I've never ruined an aluminum rim with a tire that was not flat, then that is a non-issue for me.
Tires, though, can  make a huge difference, which was how this thread began.

ccand51997 wrote:
I guess we'll just have to agree to disagree. And maybe some of that is based off of my weight, which is only about 150 pounds.  I've never ridden a carbon rim--this is true--but I've also never said to myself, I need to go 10 seconds faster up this one hour climb and thus pay for that 200-300 gram weight loss.  
The rest of this is not really directed to you, since you have clearly made up your mind.  It is more for the newbie to provide a counterpoint to the argument that carbon rims are worth it.  
Yes, 300 is only 2.6 times more expensive, but that is on the low end for most of the carbon wheelsets I've seen for sale, and you did quote $1500 the first time.  
As for stiffer, well, I guess I'll just have to admit that I have no idea what you are talking about.--it sounds like a marketing speel to me-nor do I see how it would possibly effect my riding.    When I put my deep carbon rims on my tri bike (compared to my aluminum spoked training wheels), I can't tell one bit of difference by feel; I just know I go faster because of my average mph at the same wattage. I'm sure with a 60mm rim it is likely a much stiffer wheel, but so what?
Finally, the weight thing, other than absolute weight carried up a mountain, is a red herring.  Anything that accelerates faster also carries less kinetic energy and thus will slow down quicker than a slightly heavier wheel.  Zero sum game, Wheel inertia as a performance factor is a myth perpetuated by the bike industry in order to sell lighter, more expensive wheels.  Math does not back it up.  Anyone who understands how inertia works should understand that.
I'm going to reassert my original statement and agree to disagree.  Carbon rims and wheelsets will provide a nearly unmeasurable advantage, other than on a weight scale, over aluminum rims from a performance standpoint.  They may hold up to more abuse, but as I've never ruined an aluminum rim with a tire that was not flat, then that is a non-issue for me.
Tires, though, can  make a huge difference, which was how this thread began.

You have a lot of opinions for someone with no experience riding a good carbon wheel set.  The overall weight savings are only a small part of the advantages of a good carbon wheel set.  If you had ever ridden one, you would probably understand this.  I would suggest to any "newbie": do not take the advice of persons who do not have any experience of the question at hand.  BTW, the the Roval Terra CL wheel set mentioned is ~$1500.00 at full price, right now on sale for ~$1300.00, if you had bothered to even click on the link provided you would have seen that.  There are even more affordable carbon wheel sets out there from direct Chinese suppliers which may offer similar performance.  Good aluminum wheel sets start around $800.00, most people are not building up wheels using "used" spokes, etc... so the price differential is much less than you keep saying...  In any case, better performance often, not always, costs more.  I am fine if you are not willing to pay a bit more for better performance, but as one with experience with carbon wheels, I would never ride an aluminum rim in situations where performance matters.

barrows wrote:

You have a lot of opinions for someone with no experience riding a good carbon wheel set.  The overall weight savings are only a small part of the advantages of a good carbon wheel set.  If you had ever ridden one, you would probably understand this.

In the interest of not sidetracking this thread any further, I'll end with this thought.  You have offered NOTHING BUT opinions when regarding performance.  It is your opinion that a carbon wheel is "more precise" "will behave better" and "Carbon rims offer higher performance."  You have not backed that up with any facts.  Everything you have said is subjective, it is not real or measurable.  The only fact presented is that a set of carbon rims can offer a 300 gram reductions in weight. Which is negligible.  You cannot say they are better except in your opinion, so let's not kid ourselves here.
You can continue to make assertions, but they are still OPINIONS and not everyone agrees with them.

I must congratulate wheelmonkey for a first post which generated so much comment!

I break and bend everything but have never had to bend a carbon rim back into shape. 

Also regarding aero benefits of wider tires, specialized has a wind tunnel youtube video proving that it still matters (40 sec over 40 km).  When extrapolated for gravel speeds and distances it means tens of minutes.  Or if you ride socially with friends, the same amount of time but for less work.

Volsung wrote:I break and bend everything but have never had to bend a carbon rim back into shape. 

Also regarding aero benefits of wider tires, specialized has a wind tunnel youtube video proving that it still matters (40 sec over 40 km).  When extrapolated for gravel speeds and distances it means tens of minutes.  Or if you ride socially with friends, the same amount of time but for less work.

Indeed....This is one of the benefits of carbon wheels that don’t get a lot of attention. The rims aways will go back to true. Unless they’re broken, which happens very very rarely, always.
And for deeper ones on gravel, yes, there are some aero benefits however small, that add up in a a 10 or 12 hour race.

Volsung wrote:I break and bend everything but have never had to bend a carbon rim back into shape. 

Also regarding aero benefits of wider tires, specialized has a wind tunnel youtube video proving that it still matters (40 sec over 40 km).  When extrapolated for gravel speeds and distances it means tens of minutes.  Or if you ride socially with friends, the same amount of time but for less work.

40 seconds, under "cross wind" conditions, but only 12 seconds under "head wind" conditions.  And the extrapolation details are not specified (speed).

To say that tens of minutes for gravel speeds and distances is unsubstantiated.  A 1-2 minutes over 100 miles, yes, tens of minutes, absolutely not.

wheelmonkey wrote:

@thumper88 respectfully I am not convinced. I don't think that only outlier tires beat the Pathfinder Pro at BRR. For instance, the Pathfinder Pro is beaten by 40mm Gravelking SS TLC and 40mm Gravelking TLC in BRR's testing. I think Gravelkings are real tires, not outliers. At velonews, the pathfinder pro beat every gravel king tire on test, including gravelkings at the same tire width. 

I think I'm going to have to end up doing my own testing. Only one lab can be right, and I'm really curious who it is.

The GK SS 38 (as far as I know there is no 40), Pathfinder Pro, and S-Works Pathfinder Pro are the only tires I've used over the past few years. So I can save you a test:   

The GK SS will be a bit faster than the Pathfinder on pavement and very, very smooth gravel. 

When the gravel gets rougher the Pathfinder pro will be faster. Significantly so if things get rocky, especially when going downhill. 

And near the end of a 100-ish mile gravel ride, the added suspension from the larger Pathfinder Pro will have you feeling better/riding faster than had you used the GK SS 38. 

All of which kind of highlights the futility of any sort of lab test for gravel tires. Our use cases are so varied I def wouldn't buy tires based on those alone. 

Also, after ~1,000 miles the center tread on the GK SS 38 will be gone and you'll start thinking about replacing them. After 1,000 miles the Pathfinder Pro (both versions) will still look mostly brand new.

mtgrvl wrote:

The GK SS 38 (as far as I know there is no 40), Pathfinder Pro, and S-Works Pathfinder Pro are the only tires I've used over the past few years. So I can save you a test:   

The GK SS will be a bit faster than the Pathfinder on pavement and very, very smooth gravel. 

When the gravel gets rougher the Pathfinder pro will be faster. Significantly so if things get rocky, especially when going downhill. 

And near the end of a 100-ish mile gravel ride, the added suspension from the larger Pathfinder Pro will have you feeling better/riding faster than had you used the GK SS 38. 

All of which kind of highlights the futility of any sort of lab test for gravel tires. Our use cases are so varied I def wouldn't buy tires based on those alone. 

Also, after ~1,000 miles the center tread on the GK SS 38 will be gone and you'll start thinking about replacing them. After 1,000 miles the Pathfinder Pro (both versions) will still look mostly brand new.

This all sounds spot on. I tried the S-works but didn’t see any advantage except weight... they were a LOT lighter. If you were doing a super vertical course it might be worth it. But otherwise, lot more cost, likely less flat protection and tread and apparently same RR.

John wrote:

40 seconds, under "cross wind" conditions, but only 12 seconds under "head wind" conditions.  And the extrapolation details are not specified (speed).

To say that tens of minutes for gravel speeds and distances is unsubstantiated.  A 1-2 minutes over 100 miles, yes, tens of minutes, absolutely not.

Most of my gravel routes are a squarish loop, so there's at least 50% crosswind and you're vastly overestimating my party pace.

Hey OP... dont forget the quarq pressure meters that screw onto your valve stems. Sounds like you’re prob gonna need a set to compare with your pumps.

thumper88 wrote:Hey OP... dont forget the quarq pressure meters that screw onto your valve stems. Sounds like you’re prob gonna need a set to compare with your pumps.

$214 each.  😱

John wrote:

$214 each.  😱

Heh heh heh. No price is too high for precision! no more worries about that tiny sip of air you lose when detaching pump from valve stem!

I actually had a set of the first generation ones and they actually saved the one race is used them on for me. But... really impractical in long term. didn’t play well with sealant, at least for me.

thumper88 wrote:

Heh heh heh. No price is too high for precision! no more worries about that tiny sip of air you lose when detaching pump from valve stem!

I actually had a set of the first generation ones and they actually saved the one race is used them on for me. But... really impractical in long term. didn’t play well with sealant, at least for me.

I was wondering about the sealant potential issue.  I find the Blackburn Tubeless pump's analog dial gauge reasonably accurate, but use a digital gauge (SKS Airchecker) to set the exact pressure.

John wrote:

I was wondering about the sealant potential issue.  I find the Blackburn Tubeless pump's analog dial gauge reasonably accurate, but use a digital gauge (SKS Airchecker) to set the exact pressure.

The Accu Gage has worked well for me. Very industrial. And, more important.... $12.95 and free shipping on amazon.

Many years ago I got a McDaniel Controls Model K gauge.  It's all stainless steel, liquid filled, 0-60 psi, and specified accurate to 1%.  I spliced it into the hose on my floor pump and it's worked flawlessly.  I don't remember what I paid but that model is going for around $100 now.  Probably more accurate and longer lived than I am.

wheelmonkey wrote:

It's important to remember that we were racing on 120-200 psi on the road FOR YEARS because no one was doing the real world testing. We looked at drum resistance, that test said "more PSI is faster", and so everyone, including the pros, raced on high pressures that were much slower. The incredible work done to find the "break point" phenomenon, and the discoveries from the big-volume/low-PSI people (Rene Herse, Tom Anhalt, Josh Poertner) on pressure breakpoints has absolutely changed cycling. As someone who did hundreds (!!) of crits on 150+ psi and has suffered terrible crashes during those years, I like to question the thinking of the day because I've seen it change. I've been in criterium parking lots listening to racers say that 200 PSI was faster than 150 PSI. I would love to go back in time and show up with "fat" tires at 90 PSI and absolutely smoke corners from a place of grip safety.

Now we have this emerging sport of gravel racing with new ideas everywhere and very little data. We have many manufacturers of aero gravel wheels while Rene Herse is asserting publicly that above 32mm you can't get aero gains on big tires (and Enve agrees!?). We have Cannondale shipping full-suspension gravel race bikes. Which matters more, suspension or aero? Neither? And finally we have the divided church of rolling resistance, fighting about test methodologies and getting very different answers. I am invested because I've seen so much change since I first pulled up to a race line in 2002. So many times we've gone from "everyone does it" to "nobody does it". Look at an old downhill race bike with 26" tires and its steep head angle and try not to laugh! Gravel feels very early days and I expect we'll look back at this time and laugh as well. The way forward is always science. 

 

Really?  Who was running 120-200 psi?  I started racing triathlon in 1989, some crits and road races in 2000s, cyclocross in 2006, and gravel three years ago.  I have relatively minimal road race racing experience, but in all those years, with most of my riding on the road, I think 110 psi is max that I've ever pumped my tires (23mm).

I always thought that the talk of pumping tires to 150 psi was kind of a practical joke of roadies.  Maybe I was a lucky idiot, but I seem to recall even in 90s, that 100-110 was recommended in the literature as max pressure.

I'm not expecting science to provide an absolute answer in terms of gravel tire or pressure choice.  Terrain varies too much for a precise scientific approach.  Look at, for example, cyclocross.  Some pretty big names contesting Worlds recently.  Yet tire choice for a course, and tire pressure, remains an art in that sport.  And when it doesn't "feel" right to the pros, they'll pit and get a bike with different tires or pressures.  There are no pits in gravel races, so you gotta take your best guess and ride it.

Thanks for starting the tread.  Some folks that appear very wise and informative have taken the time to post here and I've appreciated greatly their input.

I struggle with the differences in RR methodology and don’t hold much faith in the tests at BRR except to be directionally correct. A great example is that the Tufo Thundero and Speedero had almost exactly the same RR, even though the Thundero had bigger knobs and a different tread pattern. Is one to believe that is actually true? If so- why would anyone buy the Speedero?

phrantic09 wrote:I struggle with the differences in RR methodology and don’t hold much faith in the tests at BRR except to be directionally correct. A great example is that the Tufo Thundero and Speedero had almost exactly the same RR, even though the Thundero had bigger knobs and a different tread pattern. Is one to believe that is actually true? If so- why would anyone buy the Speedero?

I have the exact opposite opinion of BRR and I am a premium member.  Regarding the Tufos, that is a Tufo question, not a BRR one.