"Experts"

[bicycletricycle]

The roads argument is interesting but some of these big tires are better results are on very smooth surfaces.

Originally Posted by benb

I find you can't really separate tires from where you ride.

Fact of the matter IMO is the roads where I live are not the same as they were 20 years ago. They have gotten dramatically worse.

Stuff gets repaved but it seems slow and the specific routes I like to ride due to avoiding car traffic sure seem to have gotten a lot worse, lots of places you need to stop pedaling, level the pedals, and almost get into "MTB attack position" if you don't have big tires.

Not potholes, 25-50' x 10' sections where the entire road is a minefield of 100 potholes that go down to different layers of the road and it feels a little sketchy to ride all the way out to the double yellow to go around it.

[bicycletricycle]

Originally Posted by EB

Most of the so-called replication crisis is in the social sciences, such as experimental psych.

Yes, but not all. So called hard sciences have problems as well.

More importantly, I would say that all the things that people actually care about are deep in the replication crisis.

Not technically part of the replication crisis but none the less interesting to me is the mystery of the changing standard KG weights (IPK). Some gain weight, some loose weight, we think we know some reasons but not all the reasons. In the end we gave up trying to figure it out and redifined the KG to avoid the unstable weight problem.

seems like a cop out solution to me.

https://en.wikipedia.org/wiki/Intern...f_the_Kilogram

[Waldo62]

Snip:

Originally Posted by bicycletricycle

So, how much of current trendy cycling expertise is also BS?

One man's BS is another's gospel. I am shorter than you and I ride 180 and 185mm cranks..................

[Mark McM]

Originally Posted by spoonrobot

The fact that brings us all back down to Earth: at what point in time would you be able to make this statement and have it be a broadly true statement?

I know it wasn't true in the recent past because I went out and bought the fastest 700cx35 tires I could find, and they were significantly slower than regular high-level 700cx23 tires.

So, it apparently wasn't true in 2014, or 2004, or 1994. So 2019? 2021?

Is it broadly true today?

It is often the case that a truth can not be summed up in a simple statement that covers all conditions, but instead a true statement has many conditions, presumptions, and assumptions for it to be true. In the case of the rolling resistance of 32mm tires vs. 23mm tires, it depends on many variables, including surface conditions. pressures, loads, construction and materials, etc.

So, if we hold the environment conditions constant, including a road that is representative of typical paved roads, and loads typical of single bicycles, and pressures typical to those used by the average cyclist, can we still say that a typical 32mm tire rolls faster than a typical 23mm tire? Maybe, maybe not. In the past, it was assumed that someone who bought a 23mm tire preferred low weight and rolling resistance over durability and robustness, and that they would be riding on smooth surfaces so needed little tread depth, so 23mm tires were typically built with flexible high thread count casings and thin treads. At the same time, it was assumed that someone who bought a 32mm tire preferred durability and longevity over weight and rolling resistance, and would be riding on looser surfaces, so 32mm tires were typically made with thick, stiff tread cords and deep high durometer treads with grooves and knobs for traction on loose surfaces. This meant that in the past, a typical 32mm tire did not roll as well as a 23m tire, as least on smooth pavement.

But what of today? With the acceptance of wider tires by people looking for performance, manufacturers are making 32mm tires with flexible high thread count casings and thin treads. And these tires can indeed roll with less resistance than otherwise similar 23mm tires in many cases.

[bicycletricycle]

I had some 185mm cranks for a while. Once I got used to them they were fine but then my other bikes felt funny so I decided to stay with 175. I had the same experience with 165 cranks.

Originally Posted by Waldo62

Snip:

One man's BS is another's gospel. I am shorter than you and I ride 180 and 185mm cranks..................

[bicycletricycle]

Amazing we can't say for sure on this. When I think about the ideal way to test this I start to get an idea of why this is actually hard to know, but still, if we knew anything about cycling I would have thought we knew this.

Will we know? I would love to see a max effort test on this.

Drum tests for the tires
Real world Aero with those pitot tube set ups
Computer CFD for theoretical aero
Real world roll down tests
Real world constant power tests
etc.

Would they correlate? Even F1 can have correlations problems with wind tunnel vs real world.

Originally Posted by Mark McM

So, if we hold the environment conditions constant, including a road that is representative of typical paved roads, and loads typical of single bicycles, and pressures typical to those used by the average cyclist, can we still say that a typical 32mm tire rolls faster than a typical 23mm tire? Maybe, maybe not.

[Mark McM]

Originally Posted by bicycletricycle

I had some 185mm cranks for a while. Once I got used to them they were fine but then my other bikes felt funny so I decided to stay with 175. I had the same experience with 165 cranks.

Power is applied by the legs through the cranks. So people have assumed that there must be some optimum crank length. Further, since people (and their legs) vary in size, people have assumed that the optimum crank length must somehow also vary with rider/leg size. I mean, this must obviously be the case, right?

Sometimes some ideas seem so obviously true, that people don't bother actually testing to affirm them. There are many cases of this cycling. Sometimes when somebody does actually get around to testing it, it turns out to actually be true. But just as often, the "obvious" ideas turn out to not be true.

In 2001, Jim Martin at the University of Utah tested a group of trained cyclists of various heights with cranks ranging from 120mm to 220mm. Over most of the range of crank lengths there were only small variations in power output, with only the shortest (120mm) cranks having a modest drop-off in power output (4%). Interestingly, even the riders with the shortest legs were able to produce power with the longer cranks, and the riders with the longest legs were able to produce power even with the shortest cranks.

So why the push toward short cranks today? As usual, it's probably a matter of over-extrapolation. Racing cyclists are interested in going faster, which means either increasing power or lowering drag. Shorter cranks may allow a cyclist to ride in a more deeply crouched position, reducing frontal area and drag. At the same time, they can produce the same amount of power with shorter cranks, so shorter cranks may produce a net boost in performance for racing cyclists.

But what about the rest of cyclists? For cyclists who are interested in riding in extremely bent over positions, shorter cranks may have less benefit. Other cyclists should select crank length based on personal preferences and their own physiology, and now what a small population of racing cyclists are doing.

Over extrapolation is a problem with many scientific studies. The conclusions of a scientific study may indeed be true - for the specific population in the specific conditions tested. However, the conclusions may not apply outside of the population and conditions tested - none-the-less people will always be tempted to apply those conclusions far more broadly than they really should.

[benb]

IME there is a significant learning curve to dramatically changing your tire sizes.

When I just came off 23s right to a bike that could take 42c and came stock with 35c I had no idea *** pressures I should be running and I significantly overinflated those and they were both slow and horrifically uncomfortable.

You also have a learning curve of figuring out what model tire in that size is going to work for you on your roads and your weather.

[Bob Ross]

Originally Posted by bicycletricycle

everyone on 165's now.

Originally Posted by reuben

Well, your statement that everyone is on 165s now is BS.

Yeah, I guess I never got that memo.

Crap, does this mean the fashion police are going come confiscate my Hipster Cyclist cred?!?!? Or just my oversized crank arms? Oh, the horror...

[bicycletricycle]

Over extrapolation is a big problem.

I also think the simplification required to do precise testing is a big part of the problem. In a sort of strange way the better the experiment the more removed it is from reality. I know why we must try to remove variables but it isn't always that helpful when the real world (that we actually have to make decisions in) always presents us with more variables than we are even usually aware of.

Hence the replication crisis being especially in the social sciences when cases or the most complex because the tend to involve humans which are a huge can of worms.

We can get close to knowing very simple things but we are very far from understanding complex real world problems and when people try to apply the reliable results from experiments the always end up over extrapolating.

Originally Posted by Mark McM

Over extrapolation is a problem with many scientific studies. The conclusions of a scientific study may indeed be true - for the specific population in the specific conditions tested. However, the conclusions may not apply outside of the population and conditions tested - none-the-less people will always be tempted to apply those conclusions far more broadly than they really should.

[bicycletricycle]

Just don't go get a bike fit and you will be fine.

Originally Posted by Bob Ross

Yeah, I guess I never got that memo.

Crap, does this mean the fashion police are going come confiscate my Hipster Cyclist cred?!?!? Or just my oversized crank arms? Oh, the horror...

[dcama5]

[QUOTE=bicycletricycle;3368819 Hour record is being set on 27's now so maybe even on the track 23's aren't king, even on the track.

I am not prescribing nihilism, just that we should all be a lot more humble about what we know and much more accommodating with those we disagree with.[/QUOTE]

You cannot make that statement about the hour record, because the variables were not controlled. Would this record holder done the same on 23s, or 21s, or 32s? That's why, in a scientific study, variables are controlled.

[weisan]

Accept everything blindly without questioning - not advisable.

Question everything and tag them all as conspiracy theory - not advisable.

It's a balance.

If there's no risk taking, hypothesis, ideation, experimentation, not afraid to work with unknowns - human civilization wouldn't exist.

I like to tease the skeptics among my pals:

"Fine, if you truly believe what you believe, prove it! Go ahead and take off all your clothes and be completely naked, give up everything you have in possession, forget everything you know... because none of these would have existed if not because someone somewhere at some point in time questioned, "why not?!"... and more importantly, they didn't just stop there, they get to work instead of just talking like most of us do.

[bicycletricycle]

I can't say what?

I am not sure what a scientific study of optimal tire size for the hour record would look like but I think the person who has done the most work in this area may be Dan Bigham and he is pushing for bigger tires. He does pretty rigorous real world testing with a bunch of different equipment so I think I would actually trust his opinion on this much more than anyone else on the planet right now.

Doesn't mean he is right in any ultimate way though

Originally Posted by dcama5

You cannot make that statement about the hour record, because the variables were not controlled. Would this record holder done the same on 23s, or 21s, or 32s? That's why, in a scientific study, variables are controlled.

[dcama5]

Originally Posted by bicycletricycle

I can't say what?

I am not sure what a scientific study of optimal tire size for the hour record would look like but I think the person who has done the most work in this area may be Dan Bigham and he is pushing for bigger tires. He does pretty rigorous real world testing with a bunch of different equipment so I think I would actually trust his opinion on this much more than anyone else on the planet right now.

Doesn't mean he is right in any ultimate way though

Our daughter has published 13 studies in peer-reviewed journals, I published one (I'm retired now, but I was more clinical). What I am saying is - the current hour record may have been set on 27s, but that proves nothing about the comparison with 23s. That is because all the other variables that could have led to that result were not controlled.