Could the “Chuffing” noise I hear be the ABS Tone Wheel?

[DaniBoy]

When going slow (10 MPH +/-) I hear a high pitched “chuffing”. For clarification, chuffing is that choppy sound like talking through fan blades. It slows when I slow. The only thing I can think of is air between the tone wheel and the speed sensors on the front. Like when then the teeth are going by the sensor. I notice it the most if I go slow and flip my modular helmet face up. Maybe I’m crazy, but it’s done it as long as I’ve had it. Does my possible explanation even sound plausible?

[DaniBoy]

When going slow (10 MPH +/-) I hear a high pitched “chuffing”. For clarification, chuffing is that choppy sound like talking through fan blades. It slows when I slow. The only thing I can think of is air between the tone wheel and the speed sensors on the front. Like when then the teeth are going by the sensor. I notice it the most if I go slow and flip my modular helmet face up. Maybe I’m crazy, but it’s done it as long as I’ve had it. Does my possible explanation even sound plausible?

[Peter Aawen]

When going slow (10 MPH +/-) I hear a high pitched “chuffing”. For clarification, chuffing is that choppy sound like talking through fan blades. It slows when I slow. The only thing I can think of is air between the tone wheel and the speed sensors on the front. Like when then the teeth are going by the sensor. I notice it the most if I go slow and flip my modular helmet face up. Maybe I’m crazy, but it’s done it as long as I’ve had it. Does my possible explanation even sound plausible?

I guess it might be vaguely possible, but unless you've got ears that still work as well or better than the ears on most Bats &/or Dolphins, then it's extremely unlikely that you're hearing the tone wheel 'chuffing'!

Apart from the fact that volume of noise they'd make would be so tiny and most likely impossible for the human ear to discriminate/detect in amongst all the other noises your Spyder makes, even at 10 mph - noises like the tires on the road; engine noises; belt noises; sprocket noises; et al -. the speed those teeth go past their sensors would make any noise they might produce blur into one continuous hum!! Have you seen how many teeth there are on each tone wheel? Or how close those tone wheel teeth are to each other & the sensors?!? Add to that, the fact that the tone wheels are mounted on a wheel that's rotating at what, 800 plus revs per mile, and it's even more improbable....

Bearing in mind that I haven't had my second coffee yet this morning let's just think about that for a bit - if the wheels are doing something like 800 plus revs per mile when you're travelling at 60mph or 1 mile per minute; then even if you're doing less than 1/3rd of that speed, ie 20mph, the road wheels & therefore the tone wheels themselves are STILL going to be doing more than 266 revs per minute at 20 mph; or a tad more than 133 revs per minute, or if you like, better than 2 revs per second at 10mph - and that's just the TONE WHEEL itself, not the teeth on the tone wheel!

So then you've gotta count all the gaps between the teeth on the tone wheel and multiply the result by 2 to work out how often a gap flicks by the sensor each second, or by 133+ if you still want to work in 'per minute' numbers!! Suffice to say that whatever way you look at it, the road wheel itself will be rotating probably a couple of times per second at just about any speed and because the tone wheel is mounted onto the road wheel, so will the tone wheel; only look at how many teeth there are on each tone wheel, teeth that're going to be whizzing past the sensor at some phenomenal rate!! So I'm pretty sure that even if you could hear that noise frequency and discriminate that sound amongst all the others going on, then simply because of the phenomenal rate those teeth'll be whizzing by, then unless you're related to Flipper, you AREN'T hearing any 'chuffing noise' from the tone wheel in the manner you describe!

However, if you look at the rear sprocket, and count the number of spokes on it, there's a much better chance that any 'rotating wheel type chuffing noise' you might be hearing is coming from that, but once again we run into the 'can you hear that small of a noise' in amongst all the other noises that'll be being made at the same time?? So for my 2 Bob's worth, I'd be looking at the exhaust & inspecting it for any leaks; maybe inspecting the belt & the sprocket teeth on both the front and rear sprockets for any damage; looking for any loose &/or flappy bits on the belts or sprockets; or maybe as a long shot, looking for a screw or nail etc embedded in the tread of a tire... Nah, that last one'd still be making a noise that's too fast to be called 'chuffing', even at 10 mph!

I'd suggest that any noise that you can hear as 'chuffing' at 10 mph or faster has GOT to be coming from something that's NOT rotating as fast as the road wheels &/or tone wheels rotate at that speed, or you simply won't be hearing it as a 'chuffing' noise at all!

Ps: OK, now that I've posted that last bit above, just some thoughties that might show that statement up - Have you tried raising each wheel off the ground in turn and rotating that wheel by hand as you listen closely for any untoward noises?? Any chance you're hearing a tire touching on something out of place in the wheel well, like an inner guard skirt or a fender bracket/wiring etc... or maybe you've got a slightly warped brake disc that's juuussst touching the brake pads as the disc rotates past?? Apart from an exhaust leak somewhere, I'm pretty much clutching for straws on possible causes of 'chuffing' noises.

[Navydad]

My guess would be the pads lightly rubbing on the brake disc. I often hear it on my RT at slow speeds. If that's the case, which I think it is, it isn't an issue.