walnutz

Not gonna weigh in on what's faster. For me, wider tires are just more fun. Hopping curbs, riding dirt, taking single track spurs off the main road/trail, experiencing overall more comfort even on pavement, the list goes on. This all might not be relevant for you and that's fine. I just find myself enjoying the ride more and worrying less about road/surface conditions. That's enough for me.

Give 'em a shot. You may like them or may not, but they are different enough that they are worth trying. fwiw RH tires have pretty high resale value.

woodcraft

Yes, more than likely.


I think the point was to compare the performance of smooth and knobby tread tires, and showed little penalty using the knobby ones- all-road, right?

Sy Reene

I don't know. Did they test smooth tires on smooth vs rough surfaces or knobby tires on rough surfaces? Or only Knobbie + Smooth roads. FWIW, their conclusions are about the same anyway as Silca's from about 2 years ago (ie. chart below). I'd love to see something like the below with another 6 or 9 plotted lines for different tire types though.

aplcr0331

My tire scores well in a *test* - "Well, that's good data!" and "anyone riding these tires must be amazing and awesome, just like me"

Tires don't score well in a "test" - "but muh variables", "surface type", "dimensions" "tube, tubeless, tubular, foam roller?" too funny all of the sudden we're deeply rigorous...nerdvoice "I'd like to see the study controls and get a blood sample from all the researchers as well as a complete family history", also "what did they eat for breakfast on the day of the test".

No matter what tire I have I'm still me, unfortunately, so that means fat (you can actually hear me getting fatter) and slow.

But...we all have our tire preferences for sure. I assume if I like it then it's both uncool and does not actually perform very well in the "real world". Meaning when I'm dry humping my bike up some massive 3/4th's of a mile 3.7% climb, "rolling resistance" doesn't mean squat.

walnutz

Everything ok over there?

Sy Reene

Also, very possible I'm misreading this section below.. but isn't 9mph, well.. 9mph? ie. shouldn't the times all be pretty much the same?

Are Wider Tires Slower? Or Faster?

The answer is simple: ‘Neither.’ Above is one of many tests where we compared tires with the same casings (Rene Herse Extralights) in different widths – the numbers show the time it took to roll through the timed section of our 132 m-long test hill. The tiny differences between 28, 32, 35 and 44 mm-wide tires are not statistically significant – they are the inevitable ‘noise’ that you get with all tests. We tested at low speeds (15 km/h; 9 mph) to isolate rolling resistance and minimize the effect of aerodynamics on our results.

woodcraft

Yes, and they are saying that the times are all pretty much the same, but I think the pitch of the test hill is such that you coast approx. 9 mph.

ClydeClydeson

My experience has been that 'rolling resistance' is a very small fraction of your total drag when your speeds are around or above ~25 km/h. Above that, a wider tire (esp. a wider tire on a narrow rim) has more aerodynamic resistance. When I went from 28s to 35s on a set of narrow road rims a few years ago, on a descent I regularly rode I could feel the air trying to push my front wheel to and fro like I had not experienced with the 28s.

BUt below that speed, wider tires are generally faster in real-world applications. The rougher the road or softer the surface the bigger the advantage wider tires have.

I have only ridden tires up to 38mm on my all-rounder so perhaps your gains are negated by the aero and weight penalty some point above that.

A riding buddy that used to be about the same size as me (he gained some weight and I lost some) had 38mm tires with robust flat protection, and I had 35mm tires with no flat protection, and we coasted down hills at about the same speed.

One other point, as mentioned above, is that wider tires open up whole new roads for exploring that would not be possible on 25mm tires. Even if I have to work a little harder when taking a pull at the front of a fast group, I can take the gravel shortcut home or add a loop that the pure road bikes cannot follow.

Sy Reene

so you're thinking it's a downhill test hill? Starting from 0mph? Other tests of theirs are at other specific speeds though, eg. 18mph. How's that work?

Edit: nevermind, married the wrong graph to the wrong written description
And this first 131m test at 9mph shows a bunch of results a hair under 16 seconds. Makes sense.

Weirdly their other tests all seem to have values more than double this time (32+ seconds), meaning these tests were conducted at about 4mph?

Doge

I was part of some long tread a few years ago here and had hashed this out to death. I agree the casing matters. Below are coated ones at the same PSI. The Red tire is a Veloflex and known to be pretty supple. The top is a FMB silk 25 and it just deforms around the Veloflex. I had François MARIE (FMB) make me silks without any coating on the side for rolling resistance (Parent of a racer). Those we so fast.

ofajen

If you have 60 minutes to spare (sorry, I initially thought it was shorter) this podcast has an excellent discussion on the topic that features Jan Heine and Josh Poertner who developed wheels and tires for Zipp for their race teams. It’s more complex than some have described, and some may find it interesting:

https://cyclingtips.com/2016/08/cycl...and-pressures/

Otto

RChung

Ugh. Jan's popular and he says counter-intuitive things so I'm sure I'm going to get criticized for this.

I use wider tires at lower pressures than I used to but I don't currently have a bike that would allow me to use 35 or 44mm tires, so I don't have a dog in this fight. If you want to use wider tires and you like them, that's what you should do.

However, if you read Jan's test procedures (and you know something about field tests and how to perform them) you'd see that some of his claims are based on tests that are not very precise. For example, he claims that there is no rolling resistance difference between narrow and wide tires; but if you read his test protocols you'd understand that this is, at least in part, because his procedures are kind of crude so wouldn't be able to detect small differences. Maybe there's a RR difference, maybe there isn't, but he can't detect one with his crude experiments so he claims they aren't there.

Which is not to say that the benefit he claims, or the mechanism he claims, might not actually exist. Just that his test procedures as he's described them aren't sensitive enough to know for sure.

As an aside, he recently had a blog post about aerodynamic drag of handlebar bags. His test for that was also a little crude.

RChung

Actually, I think Jan has said that he doubts the tests that Josh and Tom Anhalt and others have done. Jan doesn't believe there's an impedance breakpoint, for example. He thinks the impedance breakpoint that others see is evidence that they're doing their tests incorrectly.

asgelle

Sigh.

HTupolev

How do you mean? He definitely thinks that resistance can increase when a tire is pumped beyond a certain point due to the tire's performance as suspension diminishing. The only way in which his view on this matter seems significantly different from others' is that he claims that resistance can start to decrease again once a tire is pumped really stiff, which he thinks is due to the impedance topping out while hysteresis continues to decline. And I'm not sure if this is even much of a "difference", since few tire testers seem to care what happens in that part of the range.

RChung

He appears not to believe in the "V" shape. He appears to believe that RR is flat, or nearly so, and then increases. Because he doesn't think there's a "V," he doesn't believe that the slope of the left part of the V is shallower and that the right part of the V is steeper. And I *think* his claim that resistance can decrease again is because that's what he's seen from his (poorly executed) tests. He doesn't believe in roller tests, and he doesn't believe in pendulum tests. [Edited to add:] He only believes in certain kinds of tests using power meters. He thinks that power meters introduce another layer of error that's uncontrolled so they make tests less reliable, not more. On those occasions when he's used power meters (such as laps he takes on the flat apron of a track) he tries to hold power and speed constant. I, of course, told him that since he has a power meter and speedometer and a way to record the data, he doesn't have to hold those things constant -- all he has to do is account for them in his calculations. He thinks that adds too much error.

So, he's been doing his tests based on roll downs but his measurement is based on a single data point, i.e., elapsed time. I haven't gotten him to explain how he's getting hundredths of seconds on his timing, while trying to control entry speed. I asked him once if he were using electric eyes triggered by the passing of his wheel. He never replied. I told him that (if he wasn't going to use a power meter) a better way to do his tests was instead of putting all of his analytical weight on a single measurement of elapsed time, to record speed at each second (so for a 15 second elapsed time test, he'd have 15 observations of speed). That way, he could spot anomalies both with the speed and with the accelerations. I also suggested that since he would have second-by-second data, he could improve his tests by starting at two (or more) different entry speeds. Then he could use the accelerations and he wouldn't have to control the speed. He said that would introduce the uncontrollable variable of CdA, and wind. I told him that measuring Crr and CdA was a feature, not a bug and the additional data would help him improve the sensitivity and robustness of his tests by helping to identify when the wind tainted his results. He asked me about the std error on my tests, and didn't believe me when I told him. I suggested he try a couple of different protocols but he has collected a lot of data and considers that part of his testing closed. So I've given up.

wphamilton

For a precise measurement I take it with a grain of salt. But from the perspective of "will it make a practical difference for most people, under these conditions" it looks valid enough.

Provided there are no red flags in the methodology that we don't see in the write-up. I had some questions when reading it, and I'm presuming they'd been handled.

trailangel

Riding while high

Hiro11

A lot of what Jan Heine says jibes with my experience and I happen to absolutely love Rene Herse tires... but I still tend to take what he says with a grain of salt. Who knows what the testing "proves", there are so many variables and the results seem to me to fall within the margin of error for any testing. I might be wrong, but that's what I believe. Given that prejudice, I tend to go by my experience.

In the 90s, I used to run tubed clincher 21s with 115 psi on my road bike. I now run tubeless 28s (GP5000TLs) at 75-80 psi on my road bike. I weigh about 165, the same now as I did then (thank you cycling). In my experience, I'm not feeling appreciable more drag on the 28s. I AM definitely feeling far, far more comfortable and having far fewer flats (knock wood, I have never flatted this setup on my road bike). My modern carbon road bike with these tires gives a hovercraft-like ride, I would have killed for this while slamming over every little bump back in the 90s. This additional comfort and lack of road shock makes a huge difference in my fatigue levels, especially on longer rides. I also have significantly more grip on the lower pressure tubeless tires. Rubber compounds are better now, that combined with the larger contact patch and more compliant tire really allows you to carve corners at speed.

So, setting aside any imperceptible (to me) rolling resistance issues, I'll take a modern tubeless road setup any day.

cbrstar

When I looked at the Continental GP 5000 I noticed that there is a 85g difference between the 24 and the 32. So I've been wondering how much does this amount of weight difference effect the moment of inertia? I imagine that bitd smaller tires also meant smaller lighter rims. But looking at some catalogues online there didn't seem to be any weight differences stated on the wider rims.

JayKay3000

Tires are as much a personal choice for the roads you ride than what internet experts claim to be the truth. There are lots of options, try a few and see what works for you or just keep riding what you had till they wear out or they can't seem to handle the terrain you're riding them through.

RChung

Jan appears to think that, too, so he disbelieves that any method of testing could have a smaller margin of error to any other method of testing, which is why he doubts that any other method could be superior to his. So he sticks with his. [Edited to add:] That sounded meaner than I meant it to be. If he really believes this way then what he's doing makes perfect sense. I think there are differences among testing methods, so I try to use more robust protocols and procedures -- but maybe I'm the one who's wrong.

kingston 

Jan pays for his testing with the marketing budget not the R&D budget so it doesn't have to be all that precise.

mstateglfr 

If you showed 100 random people a Rene Herse tire, they would say its a tire company. I get it, its a components brand and not exclusively a tire brand, but does that really make a difference with regard to the post you responded to? The other poster doesnt trust Compass/RH to produce unbiased results. Regardless of if they are a tire company, a components brand, or just a boutique marketing company- the important part is the other poster thinks there is a vested interest to produce testing results that show Compass/RH in a good light.
This is especially applicable since Compass/RH so heavily advertises that their tires are unique due to their proprietary designing.
They design tires, market those tires, and sell those tires- whether you call that a tire company or a company that sells its own tires- really no difference either way.

PatW

I have no data to provide... just my impressions.

I ride road bikes and performance ones at that. I have ridden tire sizes from 23 mm, 25 mm, 28 mm and 32 mm. Now I am older now and I have slowed down but with luck, I can cruise around 19 or 20 for awhile.

Some of the roads on the course I ride have gotten rougher in the last couple years. And on 25 mm, it was tiresome to ride. My bike did ride better with 28 mm tires. I have recently gotten a new bike and it has 32 mm tires. The bike is about the same quality as the old one. The 32 mm tires give a noticeably better ride on rough pavement. There are sections of the road that made me wonder why I was doing this. With the 32 mm tires, the sections still are not really pleasant but they are not nasty anymore. The ride on the 32 is noticeably easier. As far as speed, I have not noticed any effect either. There might be but I have not noticed.

Now if I were young and still doing performance riding, I might wonder a bit about weight differences and acceleration. But even then, I might have stuck gone with the 32 mm just for the comfort. Even as a performance rider, the extra comfort might have had a bigger effect on speed in a positive sense than any loss of speed from weight.

I have noticed that when I am by myself or with a group and we hit a section of really smooth pavement, the cruising speed of the group jumps up at least an MPH.