Road Bike, Cycling Forums banner
1 - 7 of 7 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Thank you again to the guys who responded to me on the Felt section! I hopefully have moved to the proper section.

Background
My sister has taken her pre-owned Felt B16 to two bike shops and they don't have a good answer for us. It's a B16 converted from Tri to Road, by the previous owner or their shop. I have two issues and will post Symptom 1 here and then Symptom 2 just below.

Symptom 1
I can set the B Tension screw (Dura Ace RD-7800 GS) when the chain is on the large chainring 53T and large cog 28T and it works well. When I shift to the small chainring 39T the guide wheel rides (hits) on the large cassette cog.


If I turn in the B Tension screw so the small chainring works well with the large cog - then switching back to the large chainring results in a large gap between the guide wheel and large cog. Poorer shifting results this way also. And the position of the B screw plate is about 90 degrees to the hanger bracket. This angle cannot be correct and hard to achieve.

I've checked the chain length and it seems okay compared to what I've read online.

Picture 1 thru 4 is how I have it now:

Picture 1 - Large Chainring 53T, Large Cog 28T
Bicycle tire Wheel Bicycle wheel rim Mode of transport Bicycle part

Picture 2 - Small Chainring 39T, Small Cog 11T
Bicycle tire Bicycle wheel rim Wheel Mode of transport Bicycle part

Picture 3 - Small Chainring 39T, Large Cog 28T - Here is where the guide wheel seems to be too close to the cog and we are getting noise.
Bicycle tire Wheel Bicycle wheel rim Bicycle part Bicycle

Picture 4 - Large Chainring 53T, Small Cog 11T
Bicycle wheel rim Bicycle tire Bicycle part Spoke Bicycle

Picture 5 - Not related to above pictures! Here is where I need to put the B Screw (jacked up) to achieve any gap between the guide wheel and large cog when on the small chainring. Unfortunately the photo was taken while on the large chainring but you can see the large gap between sprockets. I'm sorry the photo rotated on me and I can't seem to correct it :(
Bicycle part Bicycle chain Bicycle drivetrain part Crankset Bicycle accessory

The derailleur pivots seem to be free and the springs rebound well.

What can I check next?

Felt B16 - 2009 I believe
Dura Ace 10 Speed RD-7800 GS, probably not original to the bike?
The rest of the drive is Dura Ace 10 Speed and matching I believe
Not sure of shifter condition or age but everything feels smooth.
53 + 39 Chainrings
28 thru 11 Cassette
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #2 ·
Symptom 2

I can get the derailleur to upshift with no hesitation or "non-shifts" - OR - I can get the derailleur to downshift with no hesitation or "non-shifts" - But not both, no matter how I adjust the derailleur cable tension???

I read online that this is usually a bent derailleur hanger condition?

So, I can get the tool to help see if this is the case, but I'm a little afraid to try and straighten it if it is bent. The hanger is molded into the frame and not a separate piece. I'd be afraid of breaking the carbon frame.

Is there anything else I should check first before ordering this tool?
Do I have a real concern with breaking something if I try and straighten the hanger, if it is bent?

Thanks again for any and all suggestions!
 

·
Los Barriles, BCS, Mexico
Joined
·
1,456 Posts
It appears that your chain is too short, lengthen it one link.
 

·
Registered
Joined
·
7,492 Posts
Yes the chain is at the short end of the range. Hence the larger gap in the big-big.

Is that a carbon frame and hanger? If it is then there's no straightening to be done.

The next cause of poor shifting would be a worn or frayed or dirty cable and housing. Not visible until you pull things apart.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #6 ·
Thanks for the replies guys. I didn't mention that I shortened the chain a total of 4 links (two inner and two outer plates) and the cog/guide wheel spacing got better. The result is what the above photos show. I will add one inner and outer link if you think I went too far?

bikerjulio-
The hanger is molded into the frame. All I know is that it has metal internal threads and I am unfamiliar with the actual construction. I wish I shot a picture of it with the derailleur off. Visually, it looks like the current derailleur is misaligned to the cassette by a fair amount. I'm going to order the hanger alignment tool just to see if it's a hanger/frame problem. Maybe it's a bent derailleur? I don't have another derailleur to check it against. Other suggestions?
 
1 - 7 of 7 Posts
Top