Jhon

Just bought a 2022 Trek Sport Dual 1 hybrid bike. When ridden there is this constant low hum or whoosh noise. It increases with speed. Not present when just spinning the tire. I haven't heard this on any of our other bikes. I can only think of the tires or the hollow frame as the source, maybe more so the latter (it also has a few small holes where the cables run through it). Tires pressure is 40psi. Any similar experience or ideas what may be causing this? Thank you.

PBC peugeot

could be tire noise
due to no center rib

cxwrench

Hold your bike up to your computer, can't hear it yet.

Rolla

All frames are "hollow," so I doubt it's the frame or the internal cables. Sounds more like tires -- do you have similarly knobby ones on your other bikes? Are the tires properly inflated? Is the noise more from the front, the rear, or both? Does it happen when you pedal, when you coast, or all the time? Are your brake rotors true and centered between the calipers? Can you "feel" the noise, or do you only hear it? Get someone to ride alongside you to find the location of the source.

Iride01 

If it particularly happens when you are at faster speed, then it might just be a quartering crosswind blowing through your wheels.

spelger

When I rented a CF bike in FL last year I heard a similar sound. I've now replaced the old alloy wheels with new alloy wheels on my alloy frame. I hear the same sound. I'm chalking it up to spokes or rim profile.

Kedosto

I’ve heard new knobbies that howled so loud they almost had a ring to them. If the noise you’re hearing is from the tires, it’ll get a little quieter as they wear in, and you’ll get used to the hum at the same time.

Jhon

Thanks all for your comments. What I gather from them is that the tires / wheels seem to be the primary suspects. To some of your questions - the sound is present all the time, pedaling or coasting, starting at medium slow speed. The tires, brand new, have lots of very small knobs, I think because this is a hybrid model and not a mountain one. I expect they will wear out pretty fast.
Could be the tires, could be the wheel/spokes. The noise is mildly distracting and as I'm not planning to change the wheels any time soon I guess I just have to get used to it.
Thanks again.

Iride01 

Looking back at your OP and seeing you said 40 psi in the tires then I'm guessing fairly wide knobbie tires. I'll lean toward it being the tire tread on the particular surface you ride. Probably fairly smooth asphalt with very small aggregate.

You might just pump them up more to see if that changes the sound. You can always put them back at your proper inflation afterwards. Then you might can get an idea if getting some smoother tread tires might help. If you are riding paved roads you absolutely do not need knobbies. If you ride a lot on paved road, those knobs will be worn down soon enough.

GamblerGORD53

It's the tires for sure. Could be the new tire extrusion hairs adding to the noise.
My tour bike actually does have a weird hum at about 23 to 32 mph, maybe fork resonance? I noticed it going down my favorite speed hill on the highway.
36 mm Schwalbe Marathon Plus tires.
========== EDIT
I just looked at my old video of that hill run. The bike and fork were way different. But the hum happened then also, but maybe the speed was different.

c0urt

dont forget bladed spokes, surprised that question made it through

BlazingPedals

Knobbie tires will always make noise, regardless of whether or not they have a center ridge or the flashing is still on the knobs.

Jhon

I am sorry if I posted in the wrong forum or missed some rules on acceptable topics.

c0urt

your post was perfect, I meant I am surprised no one asked what kind of spokes you have

KerryIrons

FYI tire treads are molded, not extruded. And those "hairs" are called sprues. Just so you know

Jhon

Checked the spokes - not bladed. Inflated the tires to max (50psi vs the 40 I had before) - makes no difference.
Given the fact that the rest of the bikes in the family have knobbies (new word I learned here, thank you) and don't make the same noise, I am after all inclined to think that the hollow nature of the frame has something to do with it. I understand that all frames are hollow but the cavity of this one seems pretty large and who knows may be picking up and amplifying some vibrations or something. I tried to "silence" it by grabbing it with my hand and I think it muted the sound slightly. Of course there's a very good chance I am just being delusional.
Thanks for all the comments again.

MattTheHat 

I thought from the title this thread might be about a lost follow-up album from Traffic.

pdlamb

I'm still sticking with knobbies on the tire as the reason for the hum. It may be the pattern, or the wear on the rest of the family's tires, that makes your different from theirs. Keep riding, and see if the hum diminishes after a couple hundred miles.