Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 12-29-10, 04:57 PM   #1
TomD77
Senior Member
Thread Starter
 
TomD77's Avatar
 
Join Date: Jul 2010
Location: Florida Panhandle
Bikes:
Posts: 572
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Noise coming from inside rear hub

Yesterday, I noticed for the first time a noise coming from the rear hub. When it first started (fairly abruptly), it sounded just like an out of true rim scrubbing on the brake once per revolution but with a gritty component to the sound. I put the bike on the car rack and found that the noise only happens in freewheel and goes away when there is drive pressure on the hub. The noise is loud enough to sometimes be heard over wind noise at 15-20 mph, especially with a little tail wind and seems to get worse with speed. There is definitely a coarse and gritty feel to the sound though it has to be on the rack to pick that up.

The owner and main mechanic at my LBS will be gone till next Monday and I tend to ride every day. First noticed it yesterday and rode today without noticeable change.

Shimano BTW

Is this something I need to stay off the bike for until repair?
TomD77 is offline   Reply With Quote
Old 12-29-10, 05:29 PM   #2
Alan@TreeFort
Senior Member
 
Join Date: Dec 2010
Location: Ann Arbor, MI
Bikes: 2010 Niner EMD, 2008 Surly Steamroller, 2007 Giant OCR.
Posts: 221
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hm, could be quite a few different things. My first instinct would be to check the spoke protector (aka pie plate), the plastic piece on the backside of the freewheel. These things are notorious for making horrendous noises. If thats what it is, I would just take it off and forget about it - as long as the derailleur is adjusted properly you don't need to worry about the chain getting thrown off the backside of the freewheel.

If thats not it, it is probably something within the freewheel or cassette body (depending on what kind of hub you have). The reason I suspect this is because you only hear the noise when the freewheeling mechanism is engaged (i.e. no drive pressure on the hub). If this is the case, its probably that you'll need to replace it.

I personally wouldn't suggest continuing to ride on it, if there is a problem within the pawls or the bearings it could produce more damage, like if the freewheel freezes causing damage to the chain and derailleur, and maybe worse. If its not the spoke protector, get it checked out.
Alan@TreeFort is offline   Reply With Quote
Old 12-30-10, 09:42 AM   #3
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 4,901
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
How old and how many miles on the bike?
davidad is offline   Reply With Quote
Old 12-30-10, 10:11 AM   #4
TomD77
Senior Member
Thread Starter
 
TomD77's Avatar
 
Join Date: Jul 2010
Location: Florida Panhandle
Bikes:
Posts: 572
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It's 5 months and close to 3500 miles.
TomD77 is offline   Reply With Quote
Old 12-30-10, 10:22 AM   #5
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,984
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Given the sudden onset and the more important fact that it only occurs when coasting, I'd bet that it's probably dirt in the freewheel/hub seal area. When pedaling they move together so no noise. - when coasting there's relative movement and noise. You'll want to have it serviced sooner rather than later, but I wouldn't be afraid ti ride it in the meantime.

BTW- if you have a cassette lockring tool, take off the cassette and see if it's simply a bit of string or other debris wound around the hub behind the cassette. This is common and easily remedied at home.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:28 AM.