Bicycle Mechanics - Are aluminum bikes more noisy?

Just an observation, but to my believe lightweight aluminium bikes make more noise on hot days than cooler days. For that matter, a lot more noise than any other steel bike, on any given day. I ride amongst bikes a black GIANT TCR ZERO, which on a really hot day "pings" when I stand out of the saddle. I've had it serviced and tuned, the whole works (wheels included) yet the little "ping" remains.
On the other hand, my trusty steel horse an OLMO, is quiet as can be.
Does steel frames absorb more "background" noise than a thin walled lightweight aluminium frames?

Yes

I second that yes

not a ton of sample, but i personally have only owned 2 steel bikes and 3 aluminum bike (and the aluminum ones are newer and more expensive)...

but i have had the same experience --- the seat post loose/squaking, the bottom bracket rattling and just other odd ticks and rattles.

i never noticed any differences with temperature (and never considered it)

but it does seem like steel seems to absorb and/or cushion the little squeaks and rattles much better than aluminum. anyone know why? if it just that aluminum is more stiff, so tolerances are more easily exceeded? or that steel absorbs vibration (noise) better?

Yup! My Cannondale road bike used to 'ping' as well.

pink! pink! tink! tink! creak! tick!

yep... noisier...

pink! pink! tink! tink! creak! tick!

And to think, they make aircraft out of the stuff as well! Thankfully, we never hear that at 11,000m.

Does anyone know the real reason why this happens though. Your insights are welcomed

YES!. I can every creak/rock/arg EVERYTHING. Took me a month of riding to realize nothing is broken.

Aluminum resonates sound clearer that steel. I don't know about carbon but I assume that is doesn't resonate sound very well either.

Originally posted by Maelstrom
I don't know about carbon but I assume that is doesn't resonate sound very well either.

Don't bet on that. I have a CF MTB and RB and both could rival JBL speakers in terms of resonance characteristics. Creaks are comonplace. I was bugged by a rattling noise which sounded like it was coming from my BB the other day and I was vainly trying to isolate the source... tightened cranks and chainring bolts, regreased pedals... etc... As it turns out, it was my minitool in my seatpack (little allen wrenches rattling against each other) that was the culprit. The sound was transmitted to my frame through my seatpost and the area around the BB acted like a nice big loudspeaker.

The same experience here - my Al framed bike makes more noise than the steel framed one (both are road machines). I believe that one reason for this is that aluminium (aluminum)* is softer than steel, and also has the tendancy to stick where there is friction or a fretting motion between two parts. This is known as "graunching" in elevated technical circles... The creaking is most likely the making and breaking of these small adhesions in the places where two parts are supposedly fixed together e.g. seatpost and seat tube. Of course, no two parts are ever really fixed together on a bicycle!


With regard to carbon fiber, they make loudspeaker cones from the stuff, no wonder its noisy ;)

Hope that is of interest

Ed

* Element number 13, atomic weight 26.98. Discovered by English scientist Humphrey Davy in 1808 and originally named (by him) aluminum. Big slice of humble pie to us Brits!