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Resistance psi steel

Old 04-04-22, 03:04 PM
  #26  
tyrion
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Originally Posted by Sailboat Bob View Post
Ill look into what you suggested...

just seems unlikely the whole industry would ignore/not notice such a simple solution... For many decades. And suspicious that it come to light after the standard of construction changed.

but i really dont know thats why i asked.
The technology to accurately determine rolling resistance in the real world (power meters, bike mounted wind gauges, etc.) is fairly new. The idea that skinny, very high pressure tires were more efficient was mainly driven by intuition + seat of the pants feeling.

Josh Poertner is one of the pioneers of tire pressure optimization - he's made a very good case for lower-than-traditional tire pressures. You can search for his name and read all about it.

https://trstriathlon.com/talking-tir...shua-poertner/

Last edited by tyrion; 04-04-22 at 03:08 PM.
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Old 04-04-22, 04:16 PM
  #27  
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Originally Posted by davester View Post
I think not. The old school method was based on perception and prejudice (both notoriously unreliable), not science.
As is the idea that a carbon frame automatically has a higher stiffness as a lugged steel one - that is subject to the way the carbon frame is designed- and if it has, that would have any noticeable effect on how the bike rides in terms of vertical compliance. Under the load of an 80kg rider and hit with an ordinary road bump, a lugged steel.frame will give between 0.1 and 0.2mm. At the same time, the handlebars will give 10x that, the saddle 20x that, as does the fork. the tires too. the frames stiffness is just lost in the noise.

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Old 04-04-22, 05:56 PM
  #28  
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Check these dudes out.
Wide makes it glide.
Fat is where it's at.
Thick is quick.
Ironman on a Fatbike
Fat Bike Road Rig

Personally, I'm more of a skinny tire guy. For now.

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Old 04-04-22, 06:19 PM
  #29  
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the recent switch to 'wider' tyres on road bikes is semantics
I went from '25mm' gp4k to '28mm' gp5k and both measure 27mm on 19mm rims. Nothing changed.
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Old 04-04-22, 07:14 PM
  #30  
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Originally Posted by smd4 View Post
I am perfectly happy riding my 700x23s at 140 psi. I'm not looking for "comfort" in my racing bike, any more than I would be looking for comfort in a Ferrari. I want to feel every molecule of road surface.
first off , I ride racing bikes because of my build . I have long legs for my height and the shorter top tube and wheel base is quite comfy on long rides. Most of my ride, say 70% is nice smooth asphalt and 23cm tires are great . The other 30% or so is horrible and even though I only weigh 150lbs at 6’1” , quite scary. The racing bike for me is not for racing but for fit. So those bikes I own that will accommodate 28cm tires have them. My Medici seems like it may but right now it is running 25 RaceLites and is nice but I have to go slower through the rough areas. Seriously some of the roads in my area would “taco” a wheel if I am not careful and there is no other way out of town . In the end it is personal preference and , most importantly, riding conditions.

Last edited by Kabuki12; 04-04-22 at 07:19 PM.
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Old 04-04-22, 07:40 PM
  #31  
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I see in that Continental diagram... the inflation pressure, and contact area, are the same between the two tires, resulting in more deflection for the skinnier tire. Isn't part of the idea of running a wider tire is that you can run lower pressure? And if you run a 23 at 140 psi, its deflection will be less, and its contact patch will be smaller, vs a wider tire at 90 psi, which will have a larger contact patch. So there is a closing of the gap of "deflections", and thus rolling resistance?
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Old 04-04-22, 07:54 PM
  #32  
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Same thing SeaNaus was alluding to.

Last edited by WildRalph; 04-04-22 at 08:37 PM.
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Old 04-04-22, 08:59 PM
  #33  
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Originally Posted by bamboobike4 View Post

I no longer know any track racers, but I'd like to know what they think about the psi/tire width environment.
From what I saw last year, I seemed to be an oddity and I'm not certain the wider tires mattered compared to the fact I've just gotten slower. Bike came with a cheap wheels and I had some basic CX rims from my wife's c-dale cross laying about, 26mm deep, 19.2mm wide internal, dropped a touch of weight off. Supposedly they could run 23c but I went with 25c and honestly felt a touch faster but it might be more of a security feeling when it comes to sticking to the track and having that wider connection. I keep them inflated to 110psi but also weigh high 200s.

I'm also finding this interesting. The Michelin ad suggests just going higher at a certain weight but the mavic CXP pro carbon rims that I'm building up tonight have a maximum inflation rating of 87psi, which will work fine under a 93lb 11yo but I doubt would be faster under my butt. Was surprised when they arrived to discover they have an internal width of 21mm making them quite wide in my view but the sticker on the rim clearly says they're fine for 25c tires. When I started doing mechanic work 25 years ago I first heard the rumblings of the wider is better but would have looked at someone funny if they wanted to put a 25c tire on a 21mm wide rim which was, at the time wide for a mtb. I've got a set of Mavic 217 and velocity aeroheads, both mtb rims from back then and both are marginally narrower than the velocity aileron or the cross rim on my track bike and significantly narrower than the CXP pro. Far cry from the 19c tires I raced on at the time on 13mm internal rims.
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Old 04-04-22, 09:04 PM
  #34  
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Originally Posted by vespasianus View Post
I always assumed it came from the MTB world, which quickly realized that 2.4" tires were faster and more comfortable than 1.95" tires. Now, I will say that under certain conditions, those skinny tires were fast - but not over the long haul on a good MTB track.
It could have come from several places, and I'm not a first hand witness to any of it, how it REALLY started. I can talk about how it first appeared in BQ, which was not an MTB magazine. So I can talk about what BQ said, but not what happened.
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Old 04-04-22, 10:32 PM
  #35  
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Originally Posted by WildRalph View Post

I see in that Continental diagram... the inflation pressure, and contact area, are the same between the two tires, resulting in more deflection for the skinnier tire. Isn't part of the idea of running a wider tire is that you can run lower pressure? And if you run a 23 at 140 psi, its deflection will be less, and its contact patch will be smaller, vs a wider tire at 90 psi, which will have a larger contact patch. So there is a closing of the gap of "deflections", and thus rolling resistance?
Exactly.

But...some people would rather stick to their cognitive bias than read - and correctly interpret - the small print

A hard-blown, skinny tire is going to have a smaller contact patch and therefore lower rolling resistance than that of a softer, fatter tire. The argument, however, always seems to come down to what is more comfortable - and that of course varies from individual to individual. As far as rolling resistance goes, however, facts are still facts!

FWIW, I'm firmly in the narrow tire/high pressure camp.

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Old 04-04-22, 10:51 PM
  #36  
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Originally Posted by Drillium Dude View Post
FWIW, I'm firmly in the narrow tire/high pressure camp.
Same here, and it's got nothing to do with my frames allowing nothing bigger than a 25c. Nup...nothing.
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Old 04-05-22, 06:54 AM
  #37  
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It still gets down to the surface of the roads that you are riding on . Personal preference is , for me and my riding habits , dictated by the roads I frequent. At my shop in Ventura there is only one small(maybe half a block) area that is bad . The rest of my lunch ride out to the harbor and back is nice, smooth asphalt . I frequently ride my Raleigh Comp. GS which has 700 x 23 Kevlar thread tires pumped to 120psi on this ride and I love the feel and agility of the bike with those tires, but I’m only doing a lunch ride of less than ten miles. I have done half day rides of 3-4 hours on that bike and , with those tires and inevitably bad roads, I feel fatigue.
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Old 04-05-22, 07:20 AM
  #38  
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Tom Anhalt and Josh Posner were the first to publish testing results or summaries of testing results showing the advantages of lower pressure tires on rough roads. Michelin was the first company to commercialize such a product.....in the 1890's

Who woulda thunk tire casings could return more energy than my fat ass on 20 mm tubulars at 170 psi.

The very fastest tires in the 80/90's from my experience were the supple and wide Avocet tires (without the kevlar). They were made by Panaracer. The casings looked like the Compass ones but the treads were slick. I used to get snickered at riding them (32 mm rear and 28 mm front) in criteriums until I took most the Primes.

Most riders on most roads should be on wide tires but at speed, the aerodynamics take over and narrow is faster.
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Old 04-05-22, 09:47 AM
  #39  
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I'm going to say it. You're not going to like it. Nonetheless, in my experience, that marketing material "stuff" posted by Verktyg is all a bunch of quasi-scientific BS. I will explain why I say that.

First graphic shows same pressure in the narrow and wide tires - it isn't done that way. That's not the point, no one is making or suggesting that. The issue is a narrow, high pressure tire versus a wide low pressure tire.

When I pump my wide tires (Schwalbe Kojak) to higher pressures they are ridiculously bouncy and very uncomfortable. This totally negates why I have wide tires on that bike.

I rode my road bike for two years in goat head country and not once, not even once, did I get a goat head flat. May be this is because I rode my rode bike on the roads. Those who off-road said Stan's was essential because nothing would stop goat heads. If you did not want flats, you had to have a sealant.

If I ride at the Michelin recommended pressures, I would not get through a single ride without a flat. For me, 87 psi is tantamount to a flat, certainly an impending flat, either from glass or a pinch flat.

Every time I go low, I get a flat. I've tried it from laziness. I've also experimented with it after reading articles/info like the above.

I ride narrow tires at high pressure. Front: 25 mm at 100 psi. Rear: 28 mm at 110 psi. Are there any wide tires that hold 110-120 psi? My Kojaks go pretty high but not 110 psi.

I am a big guy but am not fat. I am way off the Michelin chart for rider weight, not even close. Maybe it works for you guys, if you are smaller (most are smaller than me) but I can tell you with certainty, it does not work at all for me.

Last edited by Bad Lag; 04-05-22 at 10:08 AM.
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Old 04-05-22, 09:54 AM
  #40  
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What the heck is "Gravitational Resistance"? It is just friction and wind resistance. That you need to use the brakes and that increased speed down hill means higher wind resistance,... how is that a differentiator? It's friction, book it as such or normalize it out of the study.

IMO, this is the "weight weenie" for the new millenium - much ado about nothing.

Last edited by Bad Lag; 04-05-22 at 10:03 AM.
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Old 04-05-22, 12:06 PM
  #41  
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Originally Posted by Drillium Dude View Post
FWIW, I'm firmly in the narrow tire/high pressure camp.
DD
How about your motorcycle?

Merely curious, as that arena, tire-wise, has undergone many, many changes in tire approach.
Of note, though, is that suspensions and motorcycle weight have also changed just as much.

Road bikes, not so much. I pretty much forget about tire width and psi after about 200 yards.
Unless I have a flat.
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Old 04-05-22, 12:32 PM
  #42  
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Originally Posted by bamboobike4 View Post

How about your motorcycle?
Does not compute.

For a bicycle tire argument, let's leave out comparisons to those used on motorized vehicles such as motorcycles or automobiles - the dynamics involved are almost completely unrelated.

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Old 04-05-22, 01:41 PM
  #43  
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Originally Posted by Drillium Dude View Post
Does not compute.
For a bicycle tire argument, let's leave out comparisons to those used on motorized vehicles such as motorcycles or automobiles - the dynamics involved are almost completely unrelated.
DD
Agreed.
Only reason I asked is the explanation Continental's rep gave me at NAHBS, that they were developing F1 M/C tires and realized lower rolling resistance with wider tires, and they utilized this approach to bicycle tires.

My reality is that if I convince myself something is better, and it's even close, it's better.

Once again, I think a bell curve applies. Too thin and too much psi, I don't like, same as too wide and too little psi. My riding tastes only require the narrower band from about 22mm to 28mm, and I use about the same psi in all. All that is subject to one caveat: whatever's on sale.

As I start in on gravel, I've been told that my 650B's will need much less air, but I'm starting at 100psi and working my way down.
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Old 04-05-22, 06:14 PM
  #44  
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Originally Posted by Bad Lag View Post
What the heck is "Gravitational Resistance"?
Scientific term to describe a rider with too much mass
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Old 04-05-22, 06:22 PM
  #45  
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I am enjoying this thread as it affects everyone who rides . Interesting to hear the different types of riders and their experience. I think whether narrow with high pressure or wider and lower pressure , good points have been made. Some of you have a different take than I do but I can see that your riding style or environment is different as well. I guess that is why there are so many options available to us. My conclusion is that tires are very important to all of us. I once bought a set of lower priced tires , Kenda I think. I lived to regret it soon after I purchased them . I was on a trip up north shortly after buying my Raleigh Comp. and got a blow out on a hot day. The closest bike shop that I could find welcomed me and recommended the 700 x 23 tires I mentioned earlier with the Kevlar. These were younger guys that also knew about C&V bikes ( wow! , Campagnolo!)and they were racers. The tires weren’t super expensive but still more than I was used to paying. They are not my favorite tires for my type of riding , but that bike behaves completely different after they were installed and not in a bad way! When I want to feel the road and the response that bike can deliver , I pump them babies up to 120 psi and head out. I feel like I am younger again …. for a while.
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Old 04-05-22, 08:14 PM
  #46  
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Originally Posted by Kabuki12 View Post

When I want to feel the road and the response that bike can deliver , I pump them babies up to 120 psi and head out. I feel like I am younger again . for a while.
Oh, yeah - I get it. And this is what I want (for myself, mind you) every single ride. Until I can't handle it no more - but high-quality, foldable clinchers with supple casings should ensure I can handle it for another 5 to 10 years. I hope

One other thing I've found: if I get a slow puncture and lose 20psi or more, but then it equalizes enough to get me home, I notice it's more fatiguing to ride because the rolling resistance has increased along with the size of the contact patch. Bummer

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Old 04-05-22, 08:15 PM
  #47  
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Originally Posted by Bad Lag View Post
I am a big guy but am not fat
'Gravitationally resistant'
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Old 04-06-22, 12:02 AM
  #48  
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Originally Posted by P!N20 View Post
'Gravitationally resistant'
Let's just say, on race day, you want to draft me.
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Old 04-06-22, 12:06 AM
  #49  
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P.S. - Nowhere in my post (or is it a rant?) above do I mention rolling resistance as a criteria for my tires or my pressures or it having anything to do with my riding.
P.P.S. - Verktyg, no offense meant to you, your posts are great!
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Old 04-06-22, 12:22 PM
  #50  
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Originally Posted by Bad Lag View Post
What the heck is "Gravitational Resistance"?
Originally Posted by Seanaus View Post
Scientific term to describe a rider with too much mass
I think I need to join the Resistance"... pretty sure I qualify.
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