Do deep section carbon rims create irritating noise?
ai_1
Posts: 3,060
I'm planning to buy a new bike at some point in the next few months and in the price range I'm considering, some of the bikes available are offered with deep section carbon rims (typically Mavic Cosmic Carbone SL). I've only ever used shallow rim aluminium clinchers to date.
During sportives on a couple of occassions I've noticed wheels with deep carbon rims creating a bit of a racket and I'm wondering if this is typical of deep section carbon rims in general and Cosmic Carbone SLs in particular?
I reckon noisy wheels would drive me nuts after a while - like a rattling drive train.
Any opinions?
During sportives on a couple of occassions I've noticed wheels with deep carbon rims creating a bit of a racket and I'm wondering if this is typical of deep section carbon rims in general and Cosmic Carbone SLs in particular?
I reckon noisy wheels would drive me nuts after a while - like a rattling drive train.
Any opinions?
0
Comments
-
Ai_1 wrote:I'm planning to buy a new bike at some point in the next few months and in the price range I'm considering, some of the bikes available are offered with deep section carbon rims (typically Mavic Cosmic Carbone SL). I've only ever used shallow rim aluminium clinchers to date.
During sportives on a couple of occassions I've noticed wheels with deep carbon rims creating a bit of a racket and I'm wondering if this is typical of deep section carbon rims in general and Cosmic Carbone SLs in particular?
I reckon noisy wheels would drive me nuts after a while - like a rattling drive train.
Any opinions?
Sorry but no sympathy from me, I love the sound of them( I have a set myself). Even better if they have a carbon disc rear wheel. 8)Norfolk, who nicked all the hills?
http://farm4.static.flickr.com/3013/243 ... 8d.jpg?v=0
http://img362.imageshack.us/my.php?imag ... 076tl5.jpg
http://img216.imageshack.us/img216/3407 ... e001af.jpg0 -
If you're all about quiet then deep carbon rims aren't for you. Might I suggest DA hubs(quiet as a mouse) and aluminum rims.0
-
Deep section equals noisy the end.
However Noise is subjective and can be defined as 'unwanted sound' - so you might actually like them in which case not noisy at all :-)Yellow is the new Black.0 -
Buy the bike and I'll do you a free swap - your new Mavic deep section carbons, for my Bontrager Race Lite wheels
Summer - Canyon Ultimate CF SLX 9.0 Team
Winter - Trek Madone 3.5 2012 with UDi2 upgrade.
For getting dirty - Moda Canon0 -
I have Cosmic Carbone SLs, they're only noisy when under power, going uphill for instance. Even then, not really that noisy, just a kind of vroom vroom sound, which I quite like
0 -
absolutely love the noise of carbon rims 0
-
Just think ... all that sound they create ... takes energy to do that ... that energy isn't being used to propel you up the hill! ... wasted!0
-
So I guess a plane breaking the sound barrier is going slow then????Yellow is the new Black.0
-
Do you mean the whir noise? Or perhaps they had rattly valves and that's what you're referring to? Rattly valves are easily sorted with a bit of tape, the whirring noise is avoidable if you only ever ride very, very slowly.More problems but still living....0
-
My Corima disk makes an awesome noise, love it when there are buildings both sides the sound just echoes from them. One TT course has a tunnel and im always tempted to slow down so I can enjoy the noise for that little bit longer :P10 mile TT pb - 20:56 R10/17
25 - 53:07 R25/7
Now using strava http://app.strava.com/athletes/1551520 -
only irritating to all the people you go flying past....Your Past is Not Your Potential...0
-
Rattle valves are sorted with nuts and dust caps!amaferanga wrote:Do you mean the whir noise? Or perhaps they had rattly valves and that's what you're referring to? Rattly valves are easily sorted with a bit of tape, the whirring noise is avoidable if you only ever ride very, very slowly.0 -
amaferanga wrote:..... the whirring noise is avoidable if you only ever ride very, very slowly.
I wondered why I always heard that whirrin' sound.0 -
Slowbike wrote:
Rattle valves are sorted with nuts and dust caps!amaferanga wrote:Do you mean the whir noise? Or perhaps they had rattly valves and that's what you're referring to? Rattly valves are easily sorted with a bit of tape, the whirring noise is avoidable if you only ever ride very, very slowly.
What? And what if you have unthreaded valves or valve extenders? Then you need tape.
And what difference do dust caps make exactly? Why would the valve end be rattling?More problems but still living....0 -
amaferanga wrote:Slowbike wrote:
Rattle valves are sorted with nuts and dust caps!amaferanga wrote:Do you mean the whir noise? Or perhaps they had rattly valves and that's what you're referring to? Rattly valves are easily sorted with a bit of tape, the whirring noise is avoidable if you only ever ride very, very slowly.
What? And what if you have unthreaded valves or valve extenders? Then you need tape.
And what difference do dust caps make exactly? Why would the valve end be rattling?
You can turn a spiral into the dust caps - it's helps with vortex shedding - everyone who is anyone is doing it these days ...0 -
Thanks for the feedback guys.
Like I said, I've never ridden on deep section carbon rims and was only aware of the noise from hearing other peoples bikes during sportives etc. It wasn't clear to me what was making the noise as it seemed to vary a lot. I assumed it was largely down to the rim creating a soundbox that was amplifying road noise and drive train noise.
I'll probably need to try and get a test ride on something with carbon rims and see what I think.
smidsy - I missed your point too. Noise generation doesn't take place without energy loss but any link between this in relation to bikes and talk of supersonic aircraft seems pretty tenuous. Care to explain?0 -
smidsy wrote:
You said that the energy needed to create the noise wasn't going into getting you up the hill so is wasted. My supersonic plane retort was added to underline that noise is sometimes a by-product of going fast. The plane does not lose speed when it creates the sonic boom - the sonic boom only happens because the plane has already generated sufficient velocity in the first place.
Tenous maybe - but you still both missed it
Yellow is the new Black.0 -
smidsy wrote:smidsy wrote:
You said that the energy needed to create the noise wasn't going into getting you up the hill so is wasted. My supersonic plane retort was added to underline that noise is sometimes a by-product of going fast. The plane does not lose speed when it creates the sonic boom - the sonic boom only happens because the plane has already generated sufficient velocity in the first place.
Tenous maybe - but you still both missed it
Um it still requires energy to generate that noise though so what's your point?More problems but still living....0 -
I don't think the guy was seriously implying noisy wheels represent an energy loss... Pretty sure that is the point being missed here 0
-
Ec0 wrote:I don't think the guy was seriously implying noisy wheels represent an energy loss... Pretty sure that is the point being missed here
It's an insignificant amount of energy, but it's still an energy loss. I think the guy was just trying to sound smart....More problems but still living....0 -
amaferanga wrote:Ec0 wrote:I don't think the guy was seriously implying noisy wheels represent an energy loss... Pretty sure that is the point being missed here
It's an insignificant amount of energy, but it's still an energy loss. I think the guy was just trying to sound smart....
No - I was just doing a leg pull ...
Of course creating sound takes energy - any fool knows that - the amount lost in the creation of sound from carbon wheels is not going to be significant though .. 0 -
These systems aren't somehow sequential but rather aspects of the same thing. If the sole aim of a vehicle is to move then noise & heat production are evidence of inefficency.smidsy wrote:smidsy wrote:
You said that the energy needed to create the noise wasn't going into getting you up the hill so is wasted. My supersonic plane retort was added to underline that noise is sometimes a by-product of going fast. The plane does not lose speed when it creates the sonic boom - the sonic boom only happens because the plane has already generated sufficient velocity in the first place.
Tenous maybe - but you still both missed it
I think I see what you were getting at with your sonic boom point but it's incorrect which is why I didn't understand what you were trying to say. If anything a aircraft generating a sonic boom is the ideal example of how much power can be lost through noise generation and how it's NOT just a by-product.
Air resistance at low speed is mostly due to resistance of air particles to moving past each other (viscosity). This is what prevents us from cycling much faster. As you gain speed and start approaching the speed of sound things change and "compressibility" becomes the main component of drag. Compression waves = sound. So it's incorrect to say that a sonic boom only happens because the plane has already generated sufficient velocity in the first place and imply that somehow that makes sound separate and less relevant. Sound isn't just the result of speed it's actually a limiting factor on speed in an atmosphere and is where most of the losses are.
So.... Obviously this doesn't apply usefully to bikes but also your point wasn't missed. It wasn't there.
I've gone way too far off topic so I'll stop typing now...0 -
5 star thread, would read again.When the going gets weird, the weird turn pro0
-
smidsy wrote:smidsy wrote:
You said that the energy needed to create the noise wasn't going into getting you up the hill so is wasted. My supersonic plane retort was added to underline that noise is sometimes a by-product of going fast. The plane does not lose speed when it creates the sonic boom - the sonic boom only happens because the plane has already generated sufficient velocity in the first place.
Tenous maybe - but you still both missed it
"You said" <-- Did I? Where?0 -
FWIW I find the "noise as inefficiency" idea very interesting. If true it sort of puts a damper on the constant barrage of hype we get from wheel makers about their deep dish stuff being the best thing since sliced bread. Am hoping a few more knowledgable people will put in their 2 cents worth. Anyone??? :?0
-
Dodgy - seems the 'quote' missed off the actual person who said it.
dennisn - I still believe that the noise is a by-product of speed rather than a negative of power output. Noise (or more accurately sound) is a pressure wave which obviously does move the air but I can not see how that translates to wasted energy. The energy is already generated and the noise then emits due to the air movement against the deep rim. I do not see how this equals lost speed.
Obviously air resistance is the enemy and the faster you go the more power you need to push against the pressure to increase the speed (any aerodynamics folk about?) - but this applies always and not specifically to deep rims. Frontal area and smooth surfaces help but I do not see how deep rims negatively affect this,
I remain to be convinced but also accept that i may be wrong (just do not see how yet).Yellow is the new Black.0 -
smidsy wrote:Dodgy - seems the 'quote' missed off the actual person who said it.
dennisn - I still believe that the noise is a by-product of speed rather than a negative of power output. Noise (or more accurately sound) is a pressure wave which obviously does move the air but I can not see how that translates to wasted energy. The energy is already generated and the noise then emits due to the air movement against the deep rim. I do not see how this equals lost speed.
Obviously air resistance is the enemy and the faster you go the more power you need to push against the pressure to increase the speed (any aerodynamics folk about?) - but this applies always and not specifically to deep rims. Frontal area and smooth surfaces help but I do not see how deep rims negatively affect this,
I remain to be convinced but also accept that i may be wrong (just do not see how yet).
Interesting to say the least. Intially, when I first saw the topic I thought the OP was referring
to the somewhat "crunching" sound that full disc wheels seem to give off, along with a sort of "whoosh". I always chaulked it up to sort of an echo effect that they created within the wheel itself. Are echos a form of ampliefied sound or just sound bouncing around?0
