Wide tyres - I just don't get it

First.Aspect

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

Why am I being absurd?

You’re choosing to misinterpret what I’m saying for no constructive reason.

The point is that I am not misinterpreting it, you are. But what do I know about science or engineering.

If you knew about science you’d know that the first stage in the process is informal observation, hypothesis generation and generally throwing ideas about in a constructive environment that encourages imaginative speculation. That’s what real scientists do. Formal testing comes afterwards. I can’t speak for engineers.

Sorry I had thought you had reached your conclusions already based on the data you have acquired. If not please see above for constructive criticism.

If you knew anything about science you'd know that it's not exactly a hotbed of constructive criticism. I hate to be the one to break this news to you.

pblakeney

Peter Sagan used to ride 28mm. He has now "downsized" to 26mm.
If it is good enough for a multiple world champion...

neeb

First Aspect wrote:

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

Why am I being absurd?

You’re choosing to misinterpret what I’m saying for no constructive reason.

The point is that I am not misinterpreting it, you are. But what do I know about science or engineering.

If you knew about science you’d know that the first stage in the process is informal observation, hypothesis generation and generally throwing ideas about in a constructive environment that encourages imaginative speculation. That’s what real scientists do. Formal testing comes afterwards. I can’t speak for engineers.

Sorry I had thought you had reached your conclusions already based on the data you have acquired. If not please see above for constructive criticism.

If you knew anything about science you'd know that it's not exactly a hotbed of constructive criticism. I hate to be the one to break this news to you.

I can pretty much assure you I know more about science than you do, although I’m not about to pull rank over something as trivial as an argument about tyre width on a cycling forum...

w00dster

Wow - sometimes this place amazes me.
Why does someone's own observations have to be backed up by hard science? Surely First Aspect you have a set of riding components that you feel are faster? I know what works for me for different situations. For me, I know what my riding preferences are for most conditions or riding situations. I haven't used any scientific protocols to measure it to prove that my observations are correct, I've just got my own view based on my own experience.
Neeb merely pointed out that in this day and age where certain people (with a conflicted interest) are saying wide tyres are just as fast or if not faster, Need has said he finds the opposite. He finds that 23mm tyres in his set up is the fastest more enjoyable ride. I don't think he needs science to back that up? The people saying that wider tyres are faster haven't got much science behind them either.
Its fine not to agree, but to request science to back it up is a bit unfair, we read plenty of reviews with zero science and we all generally have a laugh at the GCN Does Science video's, in part because we know that these things are so difficult to measure so accept its a bit of fun. Even when Emma Pooley does Science its still not exactly controlled experiments.

First.Aspect

w00dster wrote:

Wow - sometimes this place amazes me.
Why does someone's own observations have to be backed up by hard science? Surely First Aspect you have a set of riding components that you feel are faster?

Within reason. Such as knobbly tyres vs slicks, mtb vs road, wearing a rain jacket vs not, being cripplingly uncomfortable vs not etc
But the rest is just personal preference.

First.Aspect

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

Why am I being absurd?

You’re choosing to misinterpret what I’m saying for no constructive reason.

The point is that I am not misinterpreting it, you are. But what do I know about science or engineering.

If you knew about science you’d know that the first stage in the process is informal observation, hypothesis generation and generally throwing ideas about in a constructive environment that encourages imaginative speculation. That’s what real scientists do. Formal testing comes afterwards. I can’t speak for engineers.

Sorry I had thought you had reached your conclusions already based on the data you have acquired. If not please see above for constructive criticism.

If you knew anything about science you'd know that it's not exactly a hotbed of constructive criticism. I hate to be the one to break this news to you.

I can pretty much assure you I know more about science than you do, although I’m not about to pull rank over something as trivial as an argument about tyre width on a cycling forum...

Are you a scientist then?

cookeeemonster

PBlakeney wrote:

Peter Sagan used to ride 28mm. He has now "downsized" to 26mm.
If it is good enough for a multiple world champion...

Yeah but he rode 28's for the 3 world titles then lost it on the 26's... :P

neeb

First Aspect wrote:

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

neeb wrote:

First Aspect wrote:

Why am I being absurd?

You’re choosing to misinterpret what I’m saying for no constructive reason.

The point is that I am not misinterpreting it, you are. But what do I know about science or engineering.

If you knew about science you’d know that the first stage in the process is informal observation, hypothesis generation and generally throwing ideas about in a constructive environment that encourages imaginative speculation. That’s what real scientists do. Formal testing comes afterwards. I can’t speak for engineers.

Sorry I had thought you had reached your conclusions already based on the data you have acquired. If not please see above for constructive criticism.

If you knew anything about science you'd know that it's not exactly a hotbed of constructive criticism. I hate to be the one to break this news to you.

I can pretty much assure you I know more about science than you do, although I’m not about to pull rank over something as trivial as an argument about tyre width on a cycling forum...

Are you a scientist then?

Yes - a biologist in a rather obscure area admittedly rather than a physicist or an engineer, but I do know a fair bit about the scientific process.. The point is that we’re not doing science here, we’re just waffling about certain well publicised claims by the cycling industry (that are certainly motivated more by marketing than by science) and how these correspond to our personal experience. That’s what I’m doing at least...

First.Aspect

Well I am glad we now agree that we aren't doing science here. I've always been quite persuasive.

pblakeney

CookeeeMonster wrote:

PBlakeney wrote:

Peter Sagan used to ride 28mm. He has now "downsized" to 26mm.
If it is good enough for a multiple world champion...

Yeah but he rode 28's for the 3 world titles then lost it on the 26's... :P

And there we have it...

cycleclinic

The difference i know is not big mean spirit rider. presenting the graph another way from zero would make little sense. I can see the numbers I know the error and it not huge the difference is there for big tyres on narrow rims. Thats what the results show. Dismising it as psuedo science is one way of saying you dont accept it. Trump does not aceept man made global warming but that does not change reality. the difference is drag between tyre widths is small but its there never the less.

anyway I will go back to one of my first statements in this thread. It is not clear that neeb was actually faster on narrower tyres. He may have just felt faster. We just went to on explain the only plausible reason no matter small and unlikey it is. However the evidence shows the narrow tyre may have made 2 W difference at most. I personally don't believe and know that cannot be noticed on a ride.

neeb

thecycleclinic wrote:

anyway I will go back to one of my first statements in this thread. It is not clear that neeb was actually faster on narrower tyres. He may have just felt faster. We just went to on explain the only plausible reason no matter small and unlikey it is. However the evidence shows the narrow tyre may have made 2 W difference at most. I personally don't believe and know that cannot be noticed on a ride.

Actually, I pretty much agree. As I've said, I think the narower tyre both feels faster and is faster, but the actual difference in speed (assuming I'm genuinely able to detect it by comparing variation in the power/speed relationship over multiple rides) might be in the order of 0.3 mph and I don't think that's something you can "feel" while you are actually riding.

So I think that 23mm tyres feel faster and probably are faster, but that might be for different reasons.

green_mark wrote:

From https://janheine.wordpress.com/2018/01/ ... re-slower/

The faster we ride, the higher the frequency at which our bike vibrates, because our tyres encounter road irregularities at a higher speed. However, narrower tyres also increase the frequency of the vibrations they transmit. Basically, a bike with narrow tyres feels faster even though it may actually be slower. Inflating your tyres harder is a simple way of tricking your brain into feeling that you are going faster

Without having read the article linked to, that's plausible - as are probably a number of other explanations for why a narrower tyre might feel faster. But I like feeling faster.. It means I enjoy riding more, ride more and probably end up riding faster for that reason too..

chippyk

w00dster wrote:

Wow - sometimes this place amazes me.
Why does someone's own observations have to be backed up by hard science? Surely First Aspect you have a set of riding components that you feel are faster? I know what works for me for different situations. For me, I know what my riding preferences are for most conditions or riding situations. I haven't used any scientific protocols to measure it to prove that my observations are correct, I've just got my own view based on my own experience.
Neeb merely pointed out that in this day and age where certain people (with a conflicted interest) are saying wide tyres are just as fast or if not faster, Need has said he finds the opposite. He finds that 23mm tyres in his set up is the fastest more enjoyable ride. I don't think he needs science to back that up? The people saying that wider tyres are faster haven't got much science behind them either.
Its fine not to agree, but to request science to back it up is a bit unfair, we read plenty of reviews with zero science and we all generally have a laugh at the GCN Does Science video's, in part because we know that these things are so difficult to measure so accept its a bit of fun. Even when Emma Pooley does Science its still not exactly controlled experiments.

Emma Pooley, where’s the emoji with love hearts for eyes?

First.Aspect

This isn't at all fair on MRS. He was merely pointing out the sort of thing that you have to teach undergraduates when it comes to interpreting experimental data and drawing conclusions from it. The problem people with a scientific background should have with subtantially everything that is published by the bike industry is that is wouldn't get past peer review. It probably wouldn't get past a decent PhD supervisor for presenting at a first year's internal talk. This is entirely different from saying "I don't believe it" and to draw analogy to climate change deniers merely demonstrates that you have no formal training in anything, I'm afraid Malcolm.

And Neeb, as someone who claims to work in biology (which is an ology after all) you have actually managed to take 2W at the outside (less than or equal to 1% in power, lets say, with error bounds considerably more and which is extremely generous as it is), but quoted data at more like 5%,which is exactly the same value in willymetres.

Woodster - we know that GCN does science is fun. It is like a busman's holiday for me. What suprises ME about this forum is how intractable people are and how little traction reasoned argument makes. Perhaps that's why I descend into poking people with a stick so quickly. This too is more fun than repeatedly banging my head on the keyboard.

svetty

thecycleclinic wrote:

mean spirit rider

Brilliant!

svetty

meanredspider wrote:

thecycleclinic wrote:

The difference in drag by using a narrow tyre is quite measureable. Here is just one set of data from hambini's blog.
What it clearly show is the difference in drag between a narrow and wide tyre is not just down to the width of the tyre but also the width difference between the tyre and rim. the difference may not be huge but if your buying aero wheels it is shame to squander half the gain by fitting a wide tyre.

Gotta love a bit of pseudoscience

The entire Enve data set is something like 183W +/- 1W

He’s used a charting technique that hides how small the difference is. I’d like to see that data with the confidence intervals plotted too. The accuracy of the PM must account for more than the difference let alone the other MSA influences.

I haven’t read the blog (I’m on a phone in Shanghai right now) so I can’t comment on the Shimano data set differences.

The graph is at a relatively modest 19mph and whilst the difference is small it is consistent. At higher speeds it will be more significant and for a serious tester will be worth exploiting as it's 'free speed' albeit small.

First.Aspect

Had another quick look at this article. The error is stated at +/- 2.5%, which is about +/-4.5W. The entire range of the plot is only 7W.

Comments on the statistical significance of differences within the margin of error are welcome.

cld531c

Narrow tyres look better. When my bike looks nice I am happy. When I am happy I ride better. That's my scientific input.

DeVlaeminck

First Aspect wrote:

Had another quick look at this article. The error is stated at +/- 2.5%, which is about +/-4.5W. The entire range of the plot is only 7W.

Comments on the statistical significance of differences within the margin of error are welcome.

Can someone link to this article please?

Edit

Found it

warrior4life

First Aspect wrote:

zefs wrote:

About comfort, I tested today between my bikes back to back.

Bike 1: Race geometry - 17c internal with 25mm tires (26mm actual) -> Hutchinson Performance Tubeless
Bike 2: Endurance geometry - 19c internal with 25mm tires (28mm actual) -> GP4000sii with butyl tubes

Bike 1 was more comfortable at same psi (80 - 90) despite Bike 2 being an endurance Giant Defy which is supposed to be more forgiving. I think tire casing plays a big role, GP4000sii is known as a more stiff/harsh tire.

That said for simple tarmac I think 25mm tires are still optimal.

So you changed 4 variable there. Tyre brand, bike, inner tube, internal width. #gcndoesscience

On a similar note

Ihad two pairs or Cero AR30 wheels, one with 25mm tyres and one with 23mm. Ar30's at the time were 19mm wide.
I went out on the 23mm tyres, got two miles out and got a flat.
I walked back and switched to the 25's.
This was in 2012. pre wide tyres really.
I remember at the thinking 25mm are so much comfier and roll better, its just a shame they're slower.
Knowing what I know now I'd say on anything but a perfect surface 25's feel better. Super smooth 23's roack hard.
Aero wise its barely noticable.

Currently I'm riding 28's, once I got my head around the lower PSi they feel great also.

zefs

There is a sweet spot depending on surface, bad roads with bumps vs smoother tarmac.
Thing is some people also confuse the "optimized for 28c tires" of wheel manufacturers and put a 28mm tire on such rim, which then measures 30-31mm which isn't optimal for their setup. Add that you need to use less air pressure for wider tires the difference is noticeable on speed (it's slower) but the comfort/handling improves which is great if that's what you are after.

Wider tires don't give better puncture protection though and depending on how low you go with air pressure, the opposite is true since the contact patch increases.

trek_dan

The width of tub rims don't make any difference to the tyre, unlike clinchers or tubeless. 23c will have less contract patch.

First.Aspect

trek_dan wrote:

The width of tub rims don't make any difference to the tyre, unlike clinchers or tubeless. 23c will have less contract patch.

Contact patch depends on the pressure in the tyre and on the bike. My understanding would be that if the pressure in two tyres of differing widths is the same the size of the contact patch is the same, albeit of different shape. Hence all the stuff you hear about rolling resistance. Which is not something that article considered anyway.

zefs

Not the air pressure, but air volume must be the same and also the carcass material would make a difference in contact patch.

First.Aspect

zefs wrote:

Not the air pressure, but air volume must be the same and also the carcass material would make a difference in contact patch.

Yes I'm sure tyre construction is a factor, but if you inflate a 25c gp4000 to 60 psi, and inflate a conti gp4000 space hopper to 60psi and put the same load on each, the contact patch will be the same size. The clue is in the "i".

sungod

thegreatdivide wrote:

sungod wrote:

thegreatdivide wrote:

To be fair, a Lightweight Obermayer is a wheel with ancient aerodynamic qualities. It's an overpriced, side wind catching vanity purchase that'll send you into ditch every time a bus overtakes.

if you'd ridden them for years you'd know that with the correct width tyres they don't catch the sidewind any more than other wheels, less in fact than much shallower rims such ambrosio nemesis (though the higher spoke count on those may be a factor there)

in spite of being overtaken by many buses and other large vehicles they show no propensity to send me into ditches, nor off mountain roads, so you are provably wrong there too

obermayers also have great lateral stiffness, astonishing strength, and are light, so very light, no other wheel comes close

but as you are clearly speaking from ignorance, you wouldn't know any of that

sounds more like you are just bitter that you can't afford them

EDIT - I actually couldn't give a flying f*ck.

i was spot on then

neeb

First Aspect wrote:

And Neeb, as someone who claims to work in biology (which is an ology after all) you have actually managed to take 2W at the outside (less than or equal to 1% in power, lets say, with error bounds considerably more and which is extremely generous as it is), but quoted data at more like 5%,which is exactly the same value in willymetres.

FA, if you look back at what I actually posted you will see that the only "data" I "quoted" was an entirely hypothetical example designed to illustrate how one might notice a consistent trend in the relationship between power and speed over multiple rides on the same route. At no point did I say that 23mm vs. 25mm tyres caused me to ride 0.5mph faster (I assume you were referring to the 19.7-20.7mph vs. 19.2-20.2mph example and are equating a +/- 2.5% average speed difference with a +/- 5% power difference at around 20mph, who knows.. I'll give you the benefit of assuming that you didn't think my example equated to a 5% speed difference!).

I've no idea what the exact aerodynamic advantage of 23mm vs. 25mm tyres is (on optimal rims or otherwise), I never claimed to. So I didn't "take" 2W from anywhere. I was describing my observations and explicitly stated from the outset that they would not be statistically signifcant:

"Yes - I have multiple average speeds and average power figures for a couple of 30-40 mile routes - not controlled conditions obviously and doubtless not enough repetitions to be statistically robust given the other significant variables (basically wind and 2 or 3 traffic lights), but strongly indicative."

To which you replied:

strongly indicative eh? On a good day in the summer I'm about 5 to 7% faster on the same bike over the same route than on a bad day. How much faster are you on 23c tyres than 25's exactly, because I'm sure as hell buying a set of your 23c tyres if you can really tell the difference over that much scatter in your data

In the process not only being unnecessarily confrontational but completely inappropriately equating the variation in your own absolute speeds with what I was talking about, which was variation in the relationship between power and speed.

Obviously the extent to which such variation due to a single cause would be statistically significant would depend on its magnitude, the sample size and variation due to other factors. But even if 23mm tyres only equated to a 2W difference, if this was completely consistent it would be detectable given a large enough sample size, even if other factors caused speed from one ride to the next to vary by considerably more than a figure equating to 2W power.

But this isn't the point of course - I wasn't claiming to be demonstrating anything, I was stating what my impressions were, which I am quite entitled to do at less than 95% confidence intervals, thank-you-very-much!!

First Aspect wrote:

Woodster - we know that GCN does science is fun. It is like a busman's holiday for me. What suprises ME about this forum is how intractable people are and how little traction reasoned argument makes. Perhaps that's why I descend into poking people with a stick so quickly. This too is more fun than repeatedly banging my head on the keyboard.

And why do you think reasoned argument makes so little traction on forums? Has it occured to you that it's because there is always someone like you around who is determined to polarise the debate by being confrontational, thus forcing people into defensive positions that they can't easily back down from - quite often positions that they didn't even advocate in the first place?

First.Aspect

So the data you quoted in response to me asking for some has now been downgraded to hypothetical. Okay. I think where we are as a consequence is that you think 23c tyres "feel" faster, yes? Jolly good.

It wasn't *my* rational argument I was referring to by the way. I just went straight in at ascerbic this time because someone else's rational arguments were already being scoffed at.

I'm interested to know why you think you know more about science than I do. Don't you need a set of rexel coloured pencils to study biology?

neeb

First Aspect wrote:

So the data you quoted in response to me asking for some has now been downgraded to hypothetical. Okay. I think where we are as a consequence is that you think 23c tyres "feel" faster, yes? Jolly good.

It wasn't *my* rational argument I was referring to by the way. I just went straight in at ascerbic this time because someone else's rational arguments were already being scoffed at.

I'm interested to know why you think you know more about science than I do. Don't you need a set of rexel coloured pencils to study biology?

No - you didn't ask me for data, you asked me if I had measured speed. I said that I had. Later on I provided a hypothetical example of how a small but consistent variation in the power / speed relationship might be detected over multiple rides, using hyothetical data. This was not actual data provided in response to your imaginary request for it.

As I said in response to cycleclinic's post above I think 23mm tyres both feel faster and are faster. I do not have statistically robust evidence for the latter however, nor am I intending to submit a paper to Nature on it.

I suspect that I know more about (at least many aspects of) science than you because your attitude as dispalyed here is more like that of an embittered technician than a scientist. If you are actually a phycisist or an engineer and this is your idea of public outreach there are probably courses you could go on.. I would never dream about being that arrogant and insulting to laypeople on a public forum devoted to my own subject area.

First.Aspect

I'm sorry for polarizing the debate and forcing you into an entrenched position you are finding it hard to back down from.

You got it in one. My job is cleaning test tubes that scientists do stuff with.