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#1
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How silent is your bike?
I didn't invent this experiment; I rode across it by accident. I made
the test with a Rohloff hub gearbox but it works for any drivetrain, including derailleurs and other hub gearboxes. Most towns and cities have a constant hum of background noise which makes it difficult to distinguish other low-level noises about you. But last Sunday morning I was riding just at dawn and on the busiest road in town at that, a fast stretch out of town, which at this time of the morning was totally empty except for me and my bike. Every time comparisons are made, it is claimed that a Rohloff gearbox is noisier than a set of derailleurs. My own opinion has always been that the Rohloff makes some noise in all gears but that it is low in the top seven and more irritating because of the psychological impact of its sighing quality in the bottom seven than actually loud. This turns out to be half wrong. Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. Now, put your Rohloff box in 11th gear (or 14th, any from 8-14 will do) and ride along that stippled yellow line that marks the hard shoulder. Eh, what's this? The sound switches on and off! Check that it's safe, then ride in the middle of the road on the solid white line. Now the sound is gone! My bike rides on monstrous 622-60mm Big Apple Liteskins at pressures normally under 2 bar. Even on apparently smooth roads they are not silent tyres, though they're not very loud. The white line of smooth paint silenced them altogether. Whatever sound remains must be the sound of the mechanicals, including the Rohloff. My chainline is straight to within fractions of a millimetre and I use KMC's excellently overbuilt longlife X8 chain with Rohloff's own oil inside a fully enclosing chaincase; the chain is effectively silent. That leaves the Rohloff. I had always assumed that the low noise I heard in the top seven gears was the Rohloff doing its thing. It wasn't. It was the tyres. The Rohloff in the top seven gears is silent. Period. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Andre Jute Da Phantom |
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#2
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How silent is your bike?
On 14/06/10 05:47, Andre Jute wrote:
I didn't invent this experiment; I rode across it by accident. I made the test with a Rohloff hub gearbox but it works for any drivetrain, including derailleurs and other hub gearboxes. Most towns and cities have a constant hum of background noise which makes it difficult to distinguish other low-level noises about you. But last Sunday morning I was riding just at dawn and on the busiest road in town at that, a fast stretch out of town, which at this time of the morning was totally empty except for me and my bike. Every time comparisons are made, it is claimed that a Rohloff gearbox is noisier than a set of derailleurs. My own opinion has always been that the Rohloff makes some noise in all gears but that it is low in the top seven and more irritating because of the psychological impact of its sighing quality in the bottom seven than actually loud. This turns out to be half wrong. Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. Now, put your Rohloff box in 11th gear (or 14th, any from 8-14 will do) and ride along that stippled yellow line that marks the hard shoulder. Eh, what's this? The sound switches on and off! Check that it's safe, then ride in the middle of the road on the solid white line. Now the sound is gone! My bike rides on monstrous 622-60mm Big Apple Liteskins at pressures normally under 2 bar. Even on apparently smooth roads they are not silent tyres, though they're not very loud. The white line of smooth paint silenced them altogether. Whatever sound remains must be the sound of the mechanicals, including the Rohloff. My chainline is straight to within fractions of a millimetre and I use KMC's excellently overbuilt longlife X8 chain with Rohloff's own oil inside a fully enclosing chaincase; the chain is effectively silent. That leaves the Rohloff. I had always assumed that the low noise I heard in the top seven gears was the Rohloff doing its thing. It wasn't. It was the tyres. The Rohloff in the top seven gears is silent. Period. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Hub gear noise would change with shifts and be easy to isoloate, and as you found, tyre noise changes with surface[1]. Fwiw, my Alfine setup is far quieter than my Rohloff, that is I can't hear it, but the gear spacing of the Alfine sucks goats. I really like the linear spacing of the Rohloff. [1] Hands up those that have experienced the eery silence of black ice, just before the... |
#3
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How silent is your bike?
On Jun 13, 9:56 pm, Tosspot wrote:
On 14/06/10 05:47, Andre Jute wrote: I didn't invent this experiment; I rode across it by accident. I made the test with a Rohloff hub gearbox but it works for any drivetrain, including derailleurs and other hub gearboxes. Most towns and cities have a constant hum of background noise which makes it difficult to distinguish other low-level noises about you. But last Sunday morning I was riding just at dawn and on the busiest road in town at that, a fast stretch out of town, which at this time of the morning was totally empty except for me and my bike. Every time comparisons are made, it is claimed that a Rohloff gearbox is noisier than a set of derailleurs. My own opinion has always been that the Rohloff makes some noise in all gears but that it is low in the top seven and more irritating because of the psychological impact of its sighing quality in the bottom seven than actually loud. This turns out to be half wrong. Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. Now, put your Rohloff box in 11th gear (or 14th, any from 8-14 will do) and ride along that stippled yellow line that marks the hard shoulder. Eh, what's this? The sound switches on and off! Check that it's safe, then ride in the middle of the road on the solid white line. Now the sound is gone! My bike rides on monstrous 622-60mm Big Apple Liteskins at pressures normally under 2 bar. Even on apparently smooth roads they are not silent tyres, though they're not very loud. The white line of smooth paint silenced them altogether. Whatever sound remains must be the sound of the mechanicals, including the Rohloff. My chainline is straight to within fractions of a millimetre and I use KMC's excellently overbuilt longlife X8 chain with Rohloff's own oil inside a fully enclosing chaincase; the chain is effectively silent. That leaves the Rohloff. I had always assumed that the low noise I heard in the top seven gears was the Rohloff doing its thing. It wasn't. It was the tyres. The Rohloff in the top seven gears is silent. Period. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Hub gear noise would change with shifts and be easy to isoloate, and as you found, tyre noise changes with surface[1]. Fwiw, my Alfine setup is far quieter than my Rohloff, that is I can't hear it, but the gear spacing of the Alfine sucks goats. I really like the linear spacing of the Rohloff. [1] Hands up those that have experienced the eery silence of black ice, just before the... [hand raised] |
#4
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Energy loss in the tyre tread and road interface by air pumping.
On 14 June, 05:47, Andre Jute wrote:
Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. That creaking will be my knees ;-) Now, put your Rohloff box in 11th gear (or 14th, any from 8-14 will do) and ride along that stippled yellow line that marks the hard shoulder. Eh, what's this? The sound switches on and off! Check that it's safe, then ride in the middle of the road on the solid white line. Now the sound is gone! The sound was the smooth tread pumping air through the road surface. I guess the rubber is soft in comparison to a real tread with a profile. A harder ttread will ride higher on the profile of the road surface and sometimes the pattern itself will reduce the amount of air pumping at the road. The simple fact is that patterned treads require harder rubber so will tend to stand off the road surface and reduce pumping effects. My bike rides on monstrous 622-60mm Big Apple Liteskins at pressures normally under 2 bar. Even on apparently smooth roads they are not silent tyres, though they're not very loud. The white line of smooth paint silenced them altogether. Smooth on smooth will tend to do that. Get a microphone down there for better feedback. Whatever sound remains must be the sound of the mechanicals, including the Rohloff. My chainline is straight to within fractions of a millimetre and I use KMC's excellently overbuilt longlife X8 chain with Rohloff's own oil inside a fully enclosing chaincase; the chain is effectively silent. That leaves the Rohloff. I had always assumed that the low noise I heard in the top seven gears was the Rohloff doing its thing. It wasn't. It was the tyres. Specifically, the tread. The Rohloff in the top seven gears is silent. Period. But it could have improved efficiency with a different lubrication, which may mean it is not actually silent. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Suggesting it was the wrong choice on economic grounds. |
#5
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How silent is your bike?
On Jun 14, 5:56*am, Tosspot wrote:
On 14/06/10 05:47, Andre Jute wrote: I didn't invent this experiment; I rode across it by accident. I made the test with a Rohloff hub gearbox but it works for any drivetrain, including derailleurs and other hub gearboxes. Most towns and cities have a constant hum of background noise which makes it difficult *to distinguish other low-level noises about you. But last Sunday morning I was riding just at dawn and on the busiest road in town at that, a fast stretch out of town, which at this time of the morning was totally empty except for me and my bike. Every time comparisons are made, it is claimed that a Rohloff gearbox is noisier than a set of derailleurs. My own opinion has always been that the Rohloff makes some noise in all gears but that it is low in the top seven and more irritating because of the psychological impact of its sighing quality in the bottom seven than actually loud. This turns out to be half wrong. Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. Now, put your Rohloff box in 11th gear (or 14th, any from 8-14 will do) and ride along that stippled yellow line that marks the hard shoulder. Eh, what's this? The sound switches on and off! Check that it's safe, then ride in the middle of the road on the solid white line. Now the sound is gone! My bike rides on monstrous 622-60mm Big Apple Liteskins at pressures normally under 2 bar. Even on apparently smooth roads they are not silent tyres, though they're not very loud. The white line of smooth paint silenced them altogether. Whatever sound remains must be the sound of the mechanicals, including the Rohloff. My chainline is straight to within fractions of a millimetre and I use KMC's excellently overbuilt longlife X8 chain with Rohloff's own oil inside a fully enclosing chaincase; the chain is effectively silent. That leaves the Rohloff. I had always assumed that the low noise I heard in the top seven gears was the Rohloff doing its thing. It wasn't. It was the tyres. The Rohloff in the top seven gears is silent. Period. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Hub gear noise would change with shifts and be easy to isoloate, and as you found, tyre noise changes with surface[1]. Fwiw, my Alfine setup is far quieter than my Rohloff, that is I can't hear it, but the gear spacing of the Alfine sucks goats. *I really like the linear spacing of the Rohloff. [1] Hands up those that have experienced the eery silence of black ice, just before the... +1 But I wasn't on the black ice long enough to take SPL readings... In fact, I was on it, on an uphill section, just long enough to lose traction, put both feet on the road on the black ice (the advantage of a mixte frame!) and slide back gently and upright of course (only lesser cyclists fall) to firmer footing, where I turned and headed for home, stopping every motorist I met and warning them to take the other road. One ignored me and not long afterwards I heard and saw the police drive slowly to the scene of his accident. Blustering idiots are everywhere. -- AJ |
#6
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How silent is your bike?
On Jun 14, 6:17*am, thirty-six wrote:
On 14 June, 05:47, Andre Jute wrote: The Rohloff in the top seven gears is silent. Period. But it could have improved efficiency with a different lubrication, which may mean it is not actually silent. You should check you facts before you shoot off at the mouth, Trevor. The official standard all-seasons lubrication in a Rohloff is actually thin oil. The only officially permitted alternative is an even thinner oil, the cleaning oil, which doubles as lubrication for positively arctic conditions. A thicker grease, the only remaining possibility and therefore by elimination what you seem to be suggesting, would act as a sound dampener and not make the hub less silent as you claim but even more silent. A thicker grease would also make the Rohloff less efficient, rather than more efficient as you claim. It is the other manufactures of internal hub gears who use grease and can increase their efficiency by using thinner lubrication. That will also make their hubs noisier even as they make them more efficient. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Suggesting it was the wrong choice on economic grounds. Who says that the only economic justification for any hub, or a Rohloff, is huge mileage? That's patent crap. Economic justification exists only in the light of the purchaser's requirements and circumstances. AJ |
#7
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How silent is your bike?
On 14 June, 10:48, Andre Jute wrote:
On Jun 14, 6:17*am, thirty-six wrote: On 14 June, 05:47, Andre Jute wrote: The Rohloff in the top seven gears is silent. Period. But it could have improved efficiency with a different lubrication, which may mean it is not actually silent. You should check you facts before you shoot off at the mouth, Trevor. Huh, I said 'different' lubrication, not a different viscosity oil. I was thinking of something like molybdenum disulphide but did not go into it further because I'm not certain it could be used without an oil carrier. If the hub will run dry, then the use of molybdenum I think would be worth exploring. The official standard all-seasons lubrication in a Rohloff is actually thin oil. The only officially permitted alternative is an even thinner oil, the cleaning oil, which doubles as lubrication for positively arctic conditions. A thicker grease, the only remaining possibility and therefore by elimination what you seem to be suggesting, would act as a sound dampener and not make the hub less silent as you claim but even more silent. A thicker grease would also make the Rohloff less efficient, rather than more efficient as you claim. Consider why you had to make two guesses and still get it wrong. It is the other manufactures of internal hub gears who use grease and can increase their efficiency by using thinner lubrication. That will also make their hubs noisier even as they make them more efficient. My Rohloff, incidentally, hasn't done the thousands of miles that's commonly said to be required to run it in; it's only done just over 3000km. Suggesting it was the wrong choice on economic grounds. Who says that the only economic justification for any hub, or a Rohloff, is huge mileage? That's patent crap. Economic justification exists only in the light of the purchaser's requirements and circumstances. Go and take your tablets. |
#8
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How silent is your bike?
Tosspot wrote:
[1] Hands up those that have experienced the eery silence of black ice, just before the... Not in memory since I've been using studded tires for a decade or so, which are hardly silent. They make a distinct crackle noise. |
#9
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How silent is your bike?
On Jun 14, 12:47*am, Andre Jute wrote:
I didn't invent this experiment; I rode across it by accident. I made the test with a Rohloff hub gearbox but it works for any drivetrain, including derailleurs and other hub gearboxes. Most towns and cities have a constant hum of background noise which makes it difficult *to distinguish other low-level noises about you. But last Sunday morning I was riding just at dawn and on the busiest road in town at that, a fast stretch out of town, which at this time of the morning was totally empty except for me and my bike. Every time comparisons are made, it is claimed that a Rohloff gearbox is noisier than a set of derailleurs. My own opinion has always been that the Rohloff makes some noise in all gears but that it is low in the top seven and more irritating because of the psychological impact of its sighing quality in the bottom seven than actually loud. This turns out to be half wrong. Here's the experiment. Ride out on a Sunday morning around dawn or before. Stop. Wait. Observe the special quality of the ambient silence. Observe that there is still a very low level of background hum. Find the smoothest road you can. That will normally be a main road. Ride along it at whatever speed you like. Observe the sound your bike makes. Ask yourself what it consists of. I've found that my bike is far from silent... I'm running a SRAM 9- speed cassette, don't remember what brand chain, Ultegra long cage derailleur, all on a Shimano 105 hub. Oddly, and in contrast to bikes I had years ago, the drivetrain makes more noise under power than it does when coasting - the 105 hub is quite quiet in overrun but something is making a heck of a racket when the chain is actually moving! One needs to be in a quiet location and/or next to a wall to detect this however, simply because of the high levels of background noise... Nothing seems to be nonfunctional, however, so I have not worried about it. Certainly it is quieter than other people's rear hubs while coasting... (seems to be the ones with "racey" prebuilt wheelsets that are the loudest; not sure whose freehubs I'm hearing - Mavic maybe?) nate |
#10
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How silent is your bike?
On Jun 14, 12:01 pm, thirty-six wrote:
On 14 June, 10:48, Andre Jute wrote: On Jun 14, 6:17 am, thirty-six wrote: On 14 June, 05:47, Andre Jute wrote: The Rohloff in the top seven gears is silent. Period. But it could have improved efficiency with a different lubrication, which may mean it is not actually silent. You should check you facts before you shoot off at the mouth, Trevor. Huh, I said 'different' lubrication, not a different viscosity oil. I was thinking of something like molybdenum disulphide but did not go into it further because I'm not certain it could be used without an oil carrier. If the hub will run dry, then the use of molybdenum I think would be worth exploring. I'm happy with my hub gearbox just the way it is. Perhaps you should write to Herr Rohloff and explain to him that you know better about his gearbox than he does. The official standard all-seasons lubrication in a Rohloff is actually thin oil. The only officially permitted alternative is an even thinner oil, the cleaning oil, which doubles as lubrication for positively arctic conditions. A thicker grease, the only remaining possibility and therefore by elimination what you seem to be suggesting, would act as a sound dampener and not make the hub less silent as you claim but even more silent. A thicker grease would also make the Rohloff less efficient, rather than more efficient as you claim. Consider why you had to make two guesses and still get it wrong. No, I didn't get it wrong. You had a halfbaked idea about molybdenum disulphide, which you threw it out onto an engineering conference a) without checking that it can even be applied except in a thin oil base and b) without knowing that Rohloff boxes already use thin oil and c) without actually explaining what it your halfbaked idea was and d) expecting people to divine from the rattling in your head what your halfbaked idea was. Now you get your knickers in a knot when I point out that your flash of inspiration is half-baked and its presentation quarter-witted, both estimations being on the generous side. It is the other manufactures of internal hub gears who use grease and can increase their efficiency by using thinner lubrication. That will also make their hubs noisier even as they make them more efficient. Andre Jute Never more brutal than he has to be -- Nelson Mandela |
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