#1
|
|||
|
|||
Tire puzzle
Frankie left us with a formidable conundrum.
When you make a choice of equipment to obtain improvement, it is likely that its effects are negligible and that the negative effects associated with it will outweigh and overcome any minuscule advantage predicted. So .............. If you mount a narrow tire to achieve a better aerodynamic factor, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] increased rolling resistance. Take another look from the other side - If you mount a wide tire to achieve a decreased rolling resistance, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] a poorer aerodynamic factor. So I am paralyzed. At least I put on new tires and can't afford to spend on replacements to test out any theory. Maybe by the time they wear out, Frankie will have returned to explain it all. The tires, should anyone care, are the Force & Attack pair that I picked up for 20€ together. I do have my preferences, but I fear to note them here. -- Bonne route ! Sandy Verneuil-sur-Seine |
Ads |
#2
|
|||
|
|||
Tire puzzle
"Sandy" wrote: (clip) If you mount a narrow tire to achieve a better aerodynamic factor, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] increased rolling resistance. (clip) ^^^^^^^^^^^^^^^^^^ Your information is incorrect. A wider tire will have *increased* rolling resistance. That makes this the easiest puzzle I ever worked on. |
#3
|
|||
|
|||
Tire puzzle
On Tue, 10 Mar 2009 10:25:43 -0700, Leo Lichtman wrote:
"Sandy" wrote: (clip) If you mount a narrow tire to achieve a better aerodynamic factor, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] increased rolling resistance. (clip) ^^^^^^^^^^^^^^^^^^ Your information is incorrect. A wider tire will have *increased* rolling resistance. That makes this the easiest puzzle I ever worked on. haha. Agreed. As Sheldon points out, narrow tyres have higher rolling resistance when at the same pressure as a wider one but such a tyre would be grossly under inflated (or the wider one massive over) and unsuitable for riding. |
#4
|
|||
|
|||
Tire puzzle
Leo Lichtman wrote:
Your information is incorrect. *A wider tire will have *increased* rolling resistance. * Is that true? I always thought that everything else being equal (including pressure), a wider tire would have less rolling resistance. Art Harris |
#5
|
|||
|
|||
Tire puzzle
On Tue, 10 Mar 2009 11:30:58 -0700, Art Harris wrote:
Leo Lichtman wrote: Your information is incorrect. Â*A wider tire will have *increased* rolling resistance. Is that true? I always thought that everything else being equal (including pressure), a wider tire would have less rolling resistance. Art Harris It will but at an appropriate pressure, not an equal one (I think??) From Sheldons page: "...A common debate among cyclists centers on the issue of whether a wider tire has more or less rolling resistance at the same pressure. The constant pressure is proposed because it appears more scientific to eliminate this as a variable, but this is not realistic in practice. The short answer to this question is that, yes, a wider tire of similar construction will have lower rolling resistance than a narrower one at the same pressure. This fact is, however, of no practical value. If you are comparing two tires of similar construction, with the same load, and the same pressure, either the wider tire is overinflated, or the narrower tire is underinflated!..." |
#6
|
|||
|
|||
Tire puzzle
On Tue, 10 Mar 2009 19:27:55 +0000, Keiron wrote:
On Tue, 10 Mar 2009 11:30:58 -0700, Art Harris wrote: Leo Lichtman wrote: Your information is incorrect. Â*A wider tire will have *increased* rolling resistance. Is that true? I always thought that everything else being equal (including pressure), a wider tire would have less rolling resistance. Art Harris It will but at an appropriate pressure, not an equal one (I think??) Scratch that and reverse it. At it's recommended (higher) pressure a narrow tyre will have less rolling resistance than a wider tyre at its recommended (lower) pressure. |
#7
|
|||
|
|||
Tire puzzle
Keiron wrote:
Is that true? I always thought that everything else being equal (including pressure), a wider tire would have less rolling resistance. Art Harris It will but at an appropriate pressure, not an equal one (I think??) Scratch that and reverse it. At it's recommended (higher) pressure a narrow tyre will have less rolling resistance than a wider tyre at its recommended (lower) pressure. Sheldon's article doesn't exactly say that. He says that it's not fair to compare wide and narrow tires at the same pressure. But he says that if you did, the wider tire would have lower RR. http://sheldonbrown.com/tires.html#rolling That still leaves the possibility that a slightly wider tire at a slightly lower pressure might have the same RR as a narrower one at higher pressure. Or maybe even a bit lower. And this all assumes similar construction (casing, tread, etc.). Art Harris |
#8
|
|||
|
|||
Tire puzzle
Keiron wrote:
Leo Lichtman wrote: "Sandy" wrote: * (clip) If you mount a narrow tire to achieve a better aerodynamic factor, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] increased rolling resistance. (clip) ^^^^^^^^^^^^^^^^^^ Your information is incorrect. *A wider tire will have *increased* rolling resistance. *That makes this the easiest puzzle I ever worked on. haha. Agreed. As Sheldon points out, narrow tyres have higher rolling resistance when at the same pressure as a wider one but such a tyre would be grossly under inflated (or the wider one massive over) and unsuitable for riding. Solar racer tires, which have similar per-tire loadings and for which minimum rolling resistance and aerodynamic profile are the highest priorities, are quite a bit wider than racing bike tires. Do you think Michelin, GM, and MIT are mistaken about this? Wider bike tires with lower pressure often go faster on less than totally smooth surfaces, because they do not use up as much of the bike's kinetic energy into jarring the rider (who is a highly damped system). Otherwise track racers and road racers and cyclocrossers and MTB racers could all succeed with the same sort of tires. Chalo |
#9
|
|||
|
|||
Tire puzzle
On Tue, 10 Mar 2009 13:03:27 -0700, Chalo wrote:
Keiron wrote: Leo Lichtman wrote: "Sandy" wrote: (clip) If you mount a narrow tire to achieve a better aerodynamic factor, that factor is negligible and will in fact bring with it a slowing factor due to [one of many] increased rolling resistance. (clip) ^^^^^^^^^^^^^^^^^^ Your information is incorrect. Â*A wider tire will have *increased* rolling resistance. Â*That makes this the easiest puzzle I ever worked on. haha. Agreed. As Sheldon points out, narrow tyres have higher rolling resistance when at the same pressure as a wider one but such a tyre would be grossly under inflated (or the wider one massive over) and unsuitable for riding. Solar racer tires, which have similar per-tire loadings and for which minimum rolling resistance and aerodynamic profile are the highest priorities, are quite a bit wider than racing bike tires. Do you think Michelin, GM, and MIT are mistaken about this? Alas I know not about solar racer tyres and can neither dispute those company's claims but I don't know that you can compare these like for like. I don't know that solar racer and bicycle tyres are meant to perform in any similar manner. Do they cover the same type of surfaces, how wide are they? What are they made from? Wider bike tires with lower pressure often go faster on less than totally smooth surfaces, because they do not use up as much of the bike's kinetic energy into jarring the rider (who is a highly damped system). Otherwise track racers and road racers and cyclocrossers and MTB racers could all succeed with the same sort of tires. Chalo I don't dispute what you say but I don't feel that this is a like for like comparison. I'm definitely no engineer, was just reiterating what I saw as commonly accepted. Cheers |
#10
|
|||
|
|||
Tire puzzle
On Tue, 10 Mar 2009 12:55:56 -0700, Art Harris wrote:
Keiron wrote: Is that true? I always thought that everything else being equal (including pressure), a wider tire would have less rolling resistance. Art Harris It will but at an appropriate pressure, not an equal one (I think??) Scratch that and reverse it. At it's recommended (higher) pressure a narrow tyre will have less rolling resistance than a wider tyre at its recommended (lower) pressure. Sheldon's article doesn't exactly say that. He says that it's not fair to compare wide and narrow tires at the same pressure. But he says that if you did, the wider tire would have lower RR. http://sheldonbrown.com/tires.html#rolling That still leaves the possibility that a slightly wider tire at a slightly lower pressure might have the same RR as a narrower one at higher pressure. Or maybe even a bit lower. And this all assumes similar construction (casing, tread, etc.). Art Harris Yep, can't argue with that logic but what Sheldon then says, as i see it, a wider tyre at a lower than recommended pressure (or any tyre at a pressure for which it's not ideally suited) likely wouldn't perform in the way it was intended. Again that's not to say that there's not a wide (enough) tyre at a low enough pressure that doesn't have a lesser rolling resistance by design that narrow tyres. I'd just imagine the instances of that are less? To be fair i hold my hands up and admit i'm just guessing. Cheers |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
The Saddle Puzzle | PopeSamXVI | Unicycling | 1 | September 24th 06 09:22 PM |
What is this? Crufts? (+ a puzzle) | Mikefule | Unicycling | 14 | May 23rd 06 10:54 AM |
4 hills and a puzzle | Mikefule | Unicycling | 21 | May 11th 06 11:55 PM |
Old puzzle | Richard | UK | 8 | June 8th 05 12:20 PM |
Here's a puzzle | Tilly | UK | 42 | March 20th 05 01:26 PM |