High Speed (+60 MPH) Pulsating Howl?

[Marklar]

Well shoot...went for a spin with Mrs. Quaid today and experienced what I can only describe as a high speed pulsing howl over 60. I run about 220 lbs., she’s about 115. Stock suspension, stock tires, bike has roughly 1200 miles on the clock, still under warranty. This was the first time I had a passenger on the back, and I didn’t adjust the suspension for the extra weight because, well, I’m a moron. The sound was not accompanied by a wobble, but it was very loud at times. It did not seem to correlate with engine rpm but with speed...came on right at 60 and continued up into low 70s. Makes it seem like it might be chassis/wheel/tire related? Seemed like it was coming from the front end but I can’t be sure. Inspection revealed nothing obvious. Never noticed this before when riding solo, without a passenger. Anyone else experience this? Any ideas what the issue could be?

[Landshark]

Wheel out of balance?  Pant leg hanging out and flapping in the wind? LOL.  Check for proper chain tension.  If non of that works,  buy her a bike!

[Matth]

Its the tyres. I had the same with err indoors on the back. Heavier the load worse it gets. Its the design of the tyres.

[Hibobb]

6 hours ago, Marklar said:

I run about 220 lbs., she’s about 115

You two are within the weight limits of the bike. I would first check the tire pressure  (32-F, 36-R). Maybe error to the higher side if anything. Perhaps the harmonic vibrations of the combined speed, weight, road surface, ect... caused Mrs. Quaid to start pulsating/howling!!

Edited April 18, 2021 by Hibobb

[Marklar]

1 hour ago, Hibobb said:

You two are within the weight limits of the bike. I would first check the tire pressure  (32-F, 36-R). Maybe error to the higher side if anything. Perhaps the harmonic vibrations of the combined speed, weight, road surface, ect... caused Mrs. Quaid to start pulsating/howling!!

Lol, that's hilarious, but I'm pretty sure it wasn't her! Also, tires were inflated exactly to spec - always check that before I ride.

[Marklar]

3 hours ago, Matth said:

Its the tyres. I had the same with err indoors on the back. Heavier the load worse it gets. Its the design of the tyres.

Interesting....I had heard the stock tires can cause a wobble, but not about this. Sorry though, what do you mean by "err indoors"? Whatever the case, thanks much, that would certainly be a load off (pun intended) if all it is are the tires! I'll be curious next time I ride to see if it goes away, at least in part. I should note, something I didn't say in my original post, that I do think the sound is there at all speeds, it's just barely perceptible below 60, where it really comes on. 

[Marklar]

5 hours ago, Landshark said:

Wheel out of balance?  Pant leg hanging out and flapping in the wind? LOL.  Check for proper chain tension.  If non of that works,  buy her a bike!

Could be out of balance I guess. Other things should be good - had just adjusted the chain @ 600 miles. Not a bad idea on a second bike thing - the T7 is great, but not the best for two-up!

[Canzvt]

Just to add food for thought. Have a Super Tenere also, and when I fitted Hidenau K60's to it (F&R) it made a weird resonation through the tank, highly audible at 80-120km/h. Fitted Mitas E-07's (almost the exact same tread pattern) the noise went away.

 

The stock Pirelli's have an interrupted centerline. An interrupted centerline will always create a resonance. Frequency and amplitude of the resonance is based upon (amoung other things) knob spacing, knob height and speed. You can't change the first 2 without changing tires, but the 3 one you already noticed.

 

My guess is that your ears are tuned to that frequency, and you are noticing it at the speeds you mentioned. I wouldn't worry about it.

[Marklar]

On 4/18/2021 at 6:47 PM, Canzvt said:

Just to add food for thought. Have a Super Tenere also, and when I fitted Hidenau K60's to it (F&R) it made a weird resonation through the tank, highly audible at 80-120km/h. Fitted Mitas E-07's (almost the exact same tread pattern) the noise went away.

 

The stock Pirelli's have an interrupted centerline. An interrupted centerline will always create a resonance. Frequency and amplitude of the resonance is based upon (amoung other things) knob spacing, knob height and speed. You can't change the first 2 without changing tires, but the 3 one you already noticed.

 

My guess is that your ears are tuned to that frequency, and you are noticing it at the speeds you mentioned. I wouldn't worry about it.

Thanks a ton for the insight Canzvt - that makes a lot of sense for sure! Haven't had a chance to ride solo again since this happened, but when I do, I'll report back here on whether the sound went away or not. It was so loud, I was contemplating a trip to the dealer since the bike is still under warranty, but I think I'll do some testing first because my dealer is two hours away and with my job, bringing it there would mean a couple weekends (Saturdays) burned up on just that. Thanks again!

[NvNick]

My HD did that when i put Metzelers on it and my pickup does it, noise chagrs with road surface changes.

[electric_monk]

"err Indoors" is an affectionate.??? term for the missus in the UK

[jdk2man]

I have the same thing. I can hear it.

I'm betting on the crappy oem tires. I replaced the front due to wobble. I assume the back has the same wobble but as a hum.

I have the tire to replace just not the time.

[Canzvt]

36 minutes ago, jdk2man said:

I have the same thing. I can hear it.

I'm betting on the crappy oem tires. I replaced the front due to wobble. I assume the back has the same wobble but as a hum.

I have the tire to replace just not the time.

So, just for clarity, this resonation (tire hum or lope) can happen regardless of the quality of the tire. It has to do with whether the center of the tire has continuous rubber in contact with the road at all times, or if not, the height and spacing of the knobs or tread blocks. The OEM tires both have an interrupted center contact patch, hence the resonance. Wobble is a different problem that COULD be caused by the same source. Tire harmonics is a very specific engineering science whereby tire manufacturers spend millions of dollars developing tire designs to combat this in the auto sector. Have a look at any reputable brand car tire and look at the tread spacing variability around the circumference. You will see it varies. This creates multiple resonance frequencies as the tire rolls, effectively damping out the amplitude (noise) of the tire. An open tire is more noisy than and closed tire. An open tire works better in mud than and closed tire. Always a compromise!

[NickQc]

I'm having this exact issue. A kind of howling noise from the front end that only appears at 100km/h+. I'm at 1500kms on the bike total, and it just started happening today out of the blue...no passengers or any changes. It definitely got worse the faster I went and was quite loud.

 

No wobble or anything fortunately, but makes me a little nervous.

[Canzvt]

Tires.

[AZJW]

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