Strange noise from rear of bike
 

This may be covered somewhere, but frankly I can't even figure out where to start looking.

I have a 1998 Bianchi San Remo road bike, with original components (component details can be seen here: 1998 Bianchi San Remo - BikePedia - gearset, shifters, breaks, wheels, are all original). The bike is very low mileage - when I bought it a few years ago it still had manufacturer's grease on some sprocket wheels, and I've only put a few hundred miles on it. Only changes to the bike were seat, post, bars, stem, pedals, and tires/tubes.

This year was a late start on my biking season, so I took the bike to a local shop for an annual cleanup/tuneup, they that there were no issues. Wheels were inflated to 90psi before the ride.

When I took it out for the first time, there were funny noises from the rear of the bike. For all the world it sounded like a dragging brake (this bike has cantilever brakes), so I pulled over to check, but the brakes were aligned correctly, and I could not reproduce the noise off the bike. I stopped and checked several times - with no load both wheels spun completely freely.

I noticed the following: The noise is worse when I'm coasting than when I'm pedaling (pedaling mostly but not completely eliminates the noise). The noise is much worse if I deliberately shift my weight back. I'm heavy (~300lbs), but never had issues with this bike reacting poorly to my weight before.

Once I got home, I put the bike on a stand, but no matter what I did, I couldn't get the noise to come back.

Any ideas? I can't even figure out where to start looking for a problem...

Really? Another noise in a written venue?

Here's a short list:
https://www.google.com/search?client...est&gws_rd=ssl

Thanks. I have searched for it. I have not found anything resembling this. Hence my question - I don't even know where to start looking.

From the fact that it happens only when you're on the bike and gets worse when you shift your weight over the rear, together with the fact that you're a big rider, I'd be looking at tire clearance—How close the rear tire comes to the top of the brake calipers and bottom bracket.

That makes sense. I'll look at it.

Did the shop true the wheels or in any way turn any spoke nipples? Did they clean/grease the axle bearings or freewheel?

The best clue is the nature of the sound, but given that you only hear it when riding, and your weight, my best guess -- only a guess on such limited info -- is a hub bearing problem, or possibly a broken axle.

Remove the rear wheel and rotate the axle to feel for roughness. Most likely, opening it up, cleaning and greasing will solve it.

One diagnostic test, if there's a shallow grade handy, is to install the rear wheel reversed (cassette on left), with the chain passing under so it doesn't rub, and hung to the chain stay do it doesn't drag, then sit on the bike and coast down the hill. If you hear the same noise, it's in the hub.

I asked them to check the wheels and true them if needed, and was told they didn't need it. Not sure about the greasing.

Keep in mind that bike mechanics in shops have no simple way to check a bearing under load. Many a bearing will seem fine unloaded, and manifest issues when spun loaded. This is why I suggested isolating the problem by reversing the wheel and coasting down hill.

Yup. I will do so, probably tomorrow or this weekend.

Thanks.

i doubt they did