Drive chain problem
#1
Thread Starter
Senior Member
Joined: Apr 2008
Posts: 346
Likes: 0
From: Morro Bay, CA
Drive chain problem
I'm having problems with:
DRIVETRAIN:
Shimano 105, 30-speed Shifters and Derailleurs
FSA Vero 3-Piece Aluminum Crankset with 50/39/30T CNC 7075/T6 Aluminum Chainrings
and am pretty much a noob at this. I'm sure the bike shop will fix it for me, but I'd really like to become more self-reliant.
The middle gear of the front gearset is losing the chain every rotation. The chain isn't hitting the derailer at all... it's just that every cycle of the gear the chain loses its seating and starts riding on top of the teeth rather than set down between them. This causes one of two things to happen... either the chain clicks back into place with a small jerk, or the petals simply spin under the chain causing a grinding sound and difficulty pedalling. It seems to be worse when the rear gear is set to the middle gears rather than the very large or very small.... pretty much right when you should be using that gear. The larger and smaller front gear are not having this problem.
Any hints before I take it to the shop?
DRIVETRAIN:
Shimano 105, 30-speed Shifters and Derailleurs
FSA Vero 3-Piece Aluminum Crankset with 50/39/30T CNC 7075/T6 Aluminum Chainrings
and am pretty much a noob at this. I'm sure the bike shop will fix it for me, but I'd really like to become more self-reliant.
The middle gear of the front gearset is losing the chain every rotation. The chain isn't hitting the derailer at all... it's just that every cycle of the gear the chain loses its seating and starts riding on top of the teeth rather than set down between them. This causes one of two things to happen... either the chain clicks back into place with a small jerk, or the petals simply spin under the chain causing a grinding sound and difficulty pedalling. It seems to be worse when the rear gear is set to the middle gears rather than the very large or very small.... pretty much right when you should be using that gear. The larger and smaller front gear are not having this problem.
Any hints before I take it to the shop?
Last edited by JMRobertson; 05-26-08 at 08:15 AM.
#3
Thread Starter
Senior Member
Joined: Apr 2008
Posts: 346
Likes: 0
From: Morro Bay, CA
The cable to the front derailer? It's not the derailer hitting the chain... it's just the chain slipping off the gear. Again... I've had my bike about a month... so all this stuff is pretty new to me.
#4
Thread Starter
Senior Member
Joined: Apr 2008
Posts: 346
Likes: 0
From: Morro Bay, CA
Further info... one of the teeth in the middle gear is noticably bent in towards the smaller gear... probably a 15 degree bend. The chain will not go on this tooth, but rides on top of it. Is that normal?
#5
Administrator

Joined: Feb 2005
Posts: 13,651
Likes: 2,694
From: Delaware shore
Bikes: Cervelo C5, Guru Photon, Waterford, Specialized CX
The derailleur moves the chain to set points - over the chainring. There are stops that limit the inner and outer movement and those are set with screw adjustment. Cables stretch from use, usually when new. That tends to have the largest impact on the middle chainring of a triple set up. You can check it out and make adjustmenst per here:
https://www.parktool.com/repair/readhowto.asp?id=75
https://www.parktool.com/repair/readhowto.asp?id=75
#6
Senior Member
Joined: Feb 2005
Posts: 9,438
Likes: 9
From: Oklahoma
Bikes: Trek 5500, Colnago C-50
Al
Last edited by Al1943; 05-27-08 at 03:13 PM.
#7
Senior Member
Joined: Aug 2007
Posts: 166
Likes: 0
From: Delaware, OH
Bikes: Giant OCR2, Puegeot Altitude 21 MTB
, which uses this exact same FSA setup you describe. After the first time, it was replaced with a brand new middle ring of the same type. (Both times , I was in the middle of 200K brevet which made it a lot more interesting to finish with only two working rings...
)The fact that it happened twice makes me believe that there is some kind of design problem with the setup in general. After the second time, I got my LBS to put on a Shimano crankset and rings, and they managed to get it warrantied through Giant. I have about 450 miles on this setup with no signs of trouble.
(Side Note: The new Shimano is 52-42-30, which seems to require a lot less shifting in the front rings then the original 50-39-30 setup did)






