genejockey 

Horse. Water. Drink.

prj71

Yes.

PeteHski

38 mm at 60 psi would be a strange comparison to make when modern road race tyres run at that sort of pressure are typically 28-30 mm.

tomato coupe

It’s been done. I can’t find my copy of the results, but it’s in the same issue of Bicycle Universe where they measured the aerodynamic drag of top selling sombreros.

PDKL45

Re: Tire Testing

Not everyone adores Jan Heine, and he can be prickly at times (Welcome to the industry Reen Hers), but he has done good things with tires: https://www.renehersecycles.com/bq-tire-test-results/ People freak out and decry his methodology etc, but others have obtained similar results, and most of the criticisms, IMO, are coming from a place of overall Jan Heine skepticism--the anti-low trail fundamentalists for example--rather than any real evidence that he's falsifying results in service of his shadowy light casing agenda.

In my nutshell, the results are that wide tires run at lower pressures can be as fast as or faster than narrow tires run at high pressures, PROVIDED that that wide tires are supple. I.e. that they have a very flexible, light casing with a very high TPI and little rubber coverage. That's where the confusion comes from, where you get guys with hardcore crack pipe crunching urban puncture protection banded tires weighing in at a kilogram/2 lbs each innocently asking if their tires are faster than skinny tubulars because they're wide, and hey, they read it on the Internet.

So long story short, yes, studies have been done comparing tires of different widths at different pressures, see link above and Google "Tire Testing Bicycle Quarterly."

smd4

Fine. Study?

shelbyfv

I think the point is there won't be a study that includes 38mm tires at 60psi because it's beyond the range of what would be considered rational. When designing a comparison it doesn't make sense to include options that wouldn't be chosen. You won't see 23mm tires tested at 40psi either.

timtak

I have not read any (paper) cycling magazines, and have no idea bout rolling resistance, but I feel pretty sure that higher pressures lead to fewer flats, from my solitary subjective experience.

The surface area of my 23c at 100-110 Psi is lower than they would be at a lower pressure. It also seems ot me that softer tires allow the glass or whatever to embed in the tire whereas a higher pressure pings glass out to the side but I am not sure of the science of that. One could argue that a lower pressure would allow one go over the glass without picking it up whereas a harder pressure would force the glass into the tire.

This guy who claims to be a professional says lower pressures have lower rolling resistance on bumpy roads (I ride on smooooth roads)
and that lower pressures lead to flats (same video nearly 2 minutes later)
He says (agreeing with my subjective experience) "However you need to remember that the software you run your tires your chances of puncturing is much higher. It just picks up the glass and metal off the ground and obviously your chance of puncturing is much higher. "

I am not sure of the science behind "picking up glass" and why hard picks up less than soft, but that is my (and this "pros") experience.

timtak

I tried to correct the typo "software" to "softer" four times but each time I press save I am shown a black page with
ParseError: syntax error, unexpected string content "", expecting "-" or identifier or variable or number in ..../editpost.php(205) : eval()'d code on line 9

MaxKatt

I’m with you.

Atlas Shrugged

I have been a bit of a cantankerous dick on these forums lately so trying to play nice.

My theory is lower pressure tire folds over objects and much less likely to cause a larger cut or embed items. That said I run tubeless on my bikes so I am not aware of small leaks.

At the end of the day differences are extremely minor performance wise which leaves comfort and I much prefer wide low pressure especially for the riding I do.

timtak

I can appreciate the theory. It seems plausible as a theory. It doesn't match my experience though. It seems that I always get flats when I haven't pumped my tires, and rarely when they are rock hard!

I find my bikes comfortable. The only thing that was hurting was the soles on my feet after about 50 miles using carbon shoes, but now that I have swapped to glute centric (push pull) pedalling the soles of my feet too are fine.

timtak

I am not allowed to edit posts any more always getting that error (arseError: syntax error, unexpected string content "", expecting "-" or identifier or variable or number in ..../editpost.php(205) : eval()'d code on line 9__________________) message.Is there something strange about my account details?

I was going to add the following to my last post.
The pros in Dubai (good roads) a few years ago were variable but generally using high pressures.

tomato coupe

I've never heard anyone accuse JH of falsifying results. But, there are many people with solid science backgrounds that point out problems with his methodology and his unwillingness to discuss experimental details. When you sprinkle in bizarre and demonstrably false statements like the recent "Swept the podium" article, any "JH skepticism" that exists is well earned.

PDKL45

Didn't he just go out onto some hill with a bike and some tires with a mate and a stopwatch? Of course it's earned, when you present that type of testing as rigorous "science."

Do I think he has a point regarding tires? Yes, I do.

Do I agree with him on everything else he says? No, not even close. See planing, for example.

Do I think that JH skepticism arises from factors other than his testing methodology, though? Undoubtedly. He's said too many things that others disagree with too loudly and too publicly for too long for JH skepticism to only come into play when he tests tires.

PDKL45

I'm getting a parse error in trying to edit. The point about no one accusing JH of falsifying results is reasonable and that was hyperbole on my part.

smd4

Sounds like increased friction to me.

PeteHski

2016 was a long time ago in terms of tyre development and pressure. The pros are now running wider tyres at much lower pressures. For example Geraint Thomas quoted 4.5 bar (65 psi) for his 28 mm Conti tubeless tyres recently (in a 2022 podcast).

PeteHski

Some of the tyre manufacturers disagree with you, but I'm not sure how much it has been studied. I do know I haven't had a single flat in the last 3 years on tubeless tyres in the 28-32C width at lower pressures around 60-65 psi. So for me it doesn't really matter either way.

PeteHski

Why do I need to find a study?

PeteHski

What it "sounds" like to you doesn't matter.

PeteHski

It's hard not to be when people talk complete shyte

smd4

Same as how a higher pressure tire feels to me, too.

Atlas Shrugged

Problem is I head over to C&V and it becomes like arguing with a drunk. It’s a Luddite religion for a few of them and like a moth to a flame I can’t help myself.

timtak

Would it be okay to say then that we are both being subjective? I am fine with that (rather than my being a 1970's magazine reader, or speaking complete shyte)

I wonder why our experience is different.

You mention that tubeless are strong against flats. I presume that this is because (instead of a tube) they contain sealant. An inner tube can easily weight 100g so that allows for quite a lot of sealant. But I tried tubular tires for a while and filled them with a variety of off the shelf and home made (e.g. latex and glitter) but it did not work out too well. Sometimes it worked but sometimes it did not whereas a patch and a spare tube has almost always worked.

There is a good chance that I am very wrong but I generally feel that cycling "development," of hardware such as frames, and software such pedalling styles and positions is somewhat over-rated.

I am guessing that the additional money available to cycling now as oppose to 1970 has more effected
1) The number of cyclists (there are more now, so the pros now are the best of a bigger pool of athletes)
2) The size and strength of cyclists (the pay to cyclists compares well with any other sport so tall strong athletic people from all over the world are doing it)
3) The teamwork of cyclists. Bigger teams with bigger funding means that it is not a case of mano a mano but one conglomerate against another.

It seems to me that the aerodynamic benefits of team cycling make teams vastly faster than individuals.

And it is the increase in teamwork, due to funding, thus larger teams, that are more coordinated due to radios and information relaying support staff, including analysis of breakaways and the peloton's ability to bring them back in, as well as expensive performance enhancing drugs resulting a more level (superhuman) playing field, that has resulted in the faster cycling times that we are now seeing rather than development that might matter to an individual amateur cyclist.

I am wondering about tubeless tires. I can imagine how they are beneficial for cyclists with team cars carrying spare wheels, who are never going to repair a flat nor change a tube, even if they are riding clinchers.