woodcraft

I noticed in the article linked by the OP on tire size, it was said that they found insignificant aerodynamic differences between 25mm and 32mm tires,

but also cited a study:
"The German magazine TOUR built a sophisticated setup with a motorized dummy rider and found that a 28 mm-wide tire had the same wind resistance as a 25 mm tire when the wind was coming from straight ahead. With a crosswind, the wider tire was very slightly less aerodynamic. Even then, the wider tires required only 5 watt more..."

Wind speed is not mentioned, but if this was at moderate speed, and the test was scaled up to larger tires at fast road speeds, the aero penalty would hardly be insignificant.

ofajen

His 700x35 also rated quite highly for low rolling resistance on bicyclerollingresistance.com though (unsurprisingly) poorly on the puncture tests.

I rode a set of RTPs on my 26er MTB until I had worn the rear tire to the point of having frequent flats. The other RTP is still on a front wheel and on my bike at present. That front tire has never flatted. They are really delightful on roads and crushed stone or gravel (until things get wet and soft).

I’m trying out a Contact Speed 26x2.0 for the rear now which is probably a couple of watts more than the RTP but hopefully a bit better protected against puncture. There aren’t many options for a wide roadish 26” tire that actually rate with a low rolling resistance.

Otto

tz250

that does not qualify one as a physicist.

njkayaker

Of course. But no one is saying it's supposed to take your preferences into account (since it's obvious that it can't).

You seem to think that his goal is to determine the "best in a universal sense".

I'm saying that it's obvious that it can't (so he can't be doing that).

elcruxio

Best in an universal sense is interesting also in the context of cornering. Wider tires on smaller rims don't necessarily corner as well in the loose as their thinner larger rimmed counterparts. It's a bit counter intuitive because of course the wider tire has more surface are and thus more grip. But in fact the wider tire has also more float meaning that it can float off the loose stuff while the thinner tire digs in the gravel and holds its course. This in turn means that to corner as well the wider tire may need studs whereas the thinner tire can be more slick.

It all depends on riding conditions, but I've found this to be the case on fine gravel roads when comparing 650x47 and 700x40 slickish tires.

njkayaker

???

He's designing those tires based on the results of his tests.

People are free to do their own tests.

Koyote

You really don’t have much going on in the way of reading comprehension, so I’m checking out of this conversation.

njkayaker

What you wrote doesn't make sense.

No one is really claiming that it does.

fietsbob

Not just wider but high thread-count thin , light tread 'supple ' casings.. @ $80 or so each..

Koyote

Except you, in post #26 .

njkayaker

Not really.

The idea here was to nudge you to describe what you thought the "scientific method" was supposed to do (rather than saying what it didn't do that no one was claiming anyway).

This is what I said the purpose if the investigation was.

You got my point and even agreed with it.

Then, you veered back into the weeds by arguing against a point no one really claimed. You are weirdly stuck on the "best" stuff.

tyrion

Jan Heine's science is pretty good. I know a person that sells tires should be suspect when he tests tires, but he does a good job. I'm always looking for someone that has personal interest in "x" and makes "scientific" claims about "x" - one of my hobbies - and Jan Heine has been a pretty solid player in that area. I think he makes a good faith effort to be a straight shooter.

njkayaker

It's OK to be somewhat skeptical but he's doing the tests to figure out how to make better tires. If he's doing that right (and honestly), his tires should rank fairly high.

He's showing the data he generates as part of this process. The sort of data which companies often keep a secret.

Ideally, some other independent concern would test tires (in a competent way) to produce "unbiased" results.

Nobody is stopping anybody from doing that.

burnthesheep

Use what you just posted to try to explain why I should run a GP5000 clincher latex instead of a CS TL in a time trial.

You can’t do it.

A test like the drum provides a consistent set of parameters so that you can compare data taken in those consistent conditions. It isnt going to tell you what pressure to run (which showing the truer pressure curve was the point of that article). It will give a lot larger data set than endless low controlled outdoor testing.

If someone cares so much anyway, you’ll pick the top contenders in a standardized data set then do your own real world conditions test.

Real world you can buy a few sets among teammates and use Chung VE testing by holding aero constant instead of CRR and see the delta in CRR for your personal setup. Not actual CRR, but delta.

I do this. I did a test showing a 19mm track tub to have lower CRR than another normal TT tire in 23mm (if you want to risk not finishing the race by using a track tire).

Point being, there are people who talk crap and post articles, then there are folks who actually use the data sets to apply them in the real world to themselves. Then go race.

I’m a hobbyist TT rider. Not very strong. No money for tunnel testing or a $10k bike. I’m all-in on all TT kit I own under $1500. Despite paltry power and a low budget, I’m pretty freaking quick.

How am I that quick on low power and budget? Hopes and dreams and fairy dust? No, some of us do know WTF we’re talking about.

tomato coupe

By that logic, tires by every manufacturer should rank high in their own tests, since they're all trying to figure out how to make better tires.

njkayaker

No, they might not care that much. Or they are making different trade-offs. Or they are using a (arguably) insufficient test (like the smooth roller). Or they did the test a long while ago and haven't kept improving.

If they don't show their data, we don't know.

That the company's tires rank higher doesn't necessarily mean they are cheating either (it's possible).

tyrion

I have no interest in doing it.

tomato coupe

You don't think Continental, Michelin, Schwalbe, or Vittoria care that much about making better tires? I think they probably care a great deal about it.

njkayaker

Read the rest of what I wrote.

Are all of these likely to rank exactly the same?

It's possible that people are cherry-picking the tires being compared but it might not be just Heine doing that.

One issue is that these companies might be optimizing narrower tires. It seems that wider tires tended be more focused on durability than performance.

I said it was reasonable to be skeptical.

At this point, you really need to run your own unbiased test. I'll wait.
​

Miele Man

The problem with the drum test is that the drum does NOT mimic real road surface conditions. In over 60 years of bicycling I've never come across a road shaped like a steel drum. ;<)

Cheers

Kapusta

Real world testing yields messy, less-than consistent and somewhat subjective data, but it is describing the EXACT thing we are most interested in.

Roller Drum tests yield precise, quantifiable, reproducible, and consistent data.... but.... its relationship to what we really care about is unclear..

The former is an example of measuring what you value.

The latter is an example of valuing what you can measure.

Unfortunately people are too often seduced by the latter. They are essentially mistaking precision for accuracy.

Bill in VA

But is it FEELS great, you tend to ride more. Disclaimer: I am a Rene Herse tire fan, and I do not compete.

When I bought my current bike, it came with Vittoria Randenneur 28mm tires. A dreadful, heavy, sluggish, but very durable tire many like for touring or commuting. Switching to Continental GP4000SII 28mm tires (wonderful) and then to the Rene Herse (Compass) 28mm tires (even more wonderful with tan sidewalls) and then to Rene Herse 32s, I was hooked on the feel like I remembered feeling with Clement Seta tubulars and Clement hand made cotton clinchers. They were responsive and rolled very well, and good in damp, especially the GP4000SII. (Damp means damp as is a wet, but not raining road.)

I have yet to have a flat with any of those tires.

So to paraphrase what they said in the '60s, if it feels good, I will use it.

70sSanO

I would think every tire mfg can make an equally flexible paper thin tire that will ace rolling resistance tests no matter where they are performed.

I didn’t care enough to read the article close enough to find out if he was running his Extralights for the tests. If he was then I would believe they roll fast. I’m not sure they are truly any faster in repairing a flat.

People talk real world, well real world is buying a tire that rolls fast enough with the least headaches. After the fighting over testing criteria is done, they go buy Gatorskins.

John

79pmooney

Significant typo. (He found that the rougher the surface, the bigger the optimum wheel diameter. Interestingly, he found that on smooth pavement, 29" 27" was optimum.) i"ll go back and correct the original.

Cyclist0108

I'm not saying everything needs to be a Karl Popper crucial test of two competing hypotheses, but there are some common factors that most sane people agree with, like the need for a complete set of competently-designed, and hopefully exhaustive, experimental controls. If you don't think he did the proper controls, that is fair enough, but it doesn't mean he has no idea how to do an experiment. All experiments can be improved, usually by inclusion of more and better controls.