FD problem



rparedes

New Member
Jul 21, 2007
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Set up: shimano 105; 10 speed; triple. When chain is on first 3 cogs (largest) and middle chain ring, it suddenly shifts to the small chain ring. This happens mainly when going uphill. I've tried adjusting the FD but still happens; not every time but always at an inconvenient time. :mad: Is it chain line problem? Or is the frame flexing too much? Or is the chain too short? Any insight will help Thanks
 
FWIW. I believe the problem IS, as you suspect, due to the chainline & may be exacerbated by frame flex OR the size of the actual cogs ...

[*] Who knows?!? The problem might even exist on YOUR bike even if you were to switch to Campagnolo shifters!?!

To state the obvious (presuming that you would like to resolve the problem without unnecessarily spending money), EITHER shift down to the Granny + appropriate cog before starting the climb OR if you don't need the Granny then lock it out by adjusting the front derailleur's inner stop ...

OR, if you are resigned to spending money, then swap the Triple for a "Compact" Double + a Cassette whose largest cog gives you the low gearing which you need for the roadways you ride on ...

OR, if you need a Triple AND you don't want to change your habit of shifting to the larger cogs before uphill inclines when you have a Granny AND you are willing to spend money THEN a Shimano 6503 crankset (Ultegra Octalink Triple ... or, the 105 Octalink equivalent, of course) mounted on a 112.5mm XTR Octalink BB will give you a better chainline which may-or-may-not resolve the problem by moving your crankset ~3mm inboard ... you will need a 2.5mm BB 'spacer' for the driveside since the XTR BBs are designed for 73mm BB shells (the BB spacers come with new BBs but may be absent if you buy the BB used from someone else).

N.B. Depending on YOUR frame, chainring clearance may be tight, but it shouldn't be since I presume your bike can typically handle a normal Double crankset with a 52t-or-53t chainring.
 
rparedes said:
Set up: shimano 105; 10 speed; triple. When chain is on first 3 cogs (largest) and middle chain ring, it suddenly shifts to the small chain ring. This happens mainly when going uphill. I've tried adjusting the FD but still happens; not every time but always at an inconvenient time. :mad: Is it chain line problem? Or is the frame flexing too much? Or is the chain too short? Any insight will help Thanks
I'd suggest you go to the Park Tools repair tutorial page and read their tutorial on front derailleur adjustment. Hell, bookmark the page because their repair tutorials cover virtually anything you could want to do to your bike. Likewise, you can find loads of videos on YouTube for just about any bike repair or maintenance procedure that you might need to do in the future. Lastly, all of the component group makers (Shimano, Campagnolo, and SRAM--not sure about MicroShift) have, on their websites, pdf's of their installation and adjustment procedures for all of their products.
 
Alfeng Thanks for the input. I have a compact double on my other bike. This bike though, is used for long rides 60-100 miles, so I always depend on the triple, specially if I'm not familiar with the terrain. I think there is a chain line issue 'cause when the chain is on the largest cog, it really skips and wants to jump to the small chain ring. I don't think it's a FD adjustment; I'm pretty good and have been doing my own wrench work for about 10 years. This bike is a new frame I got a couple of months ago and I moved all the parts from an old al frame... The chainstay is shorter than the old frame, so that may be the problem. I'm gona try lengthening the chain to see if less tension might work. If that doesn't; I'll just have to shift to the small ring :rolleyes:
 
alienator said:
I'd suggest you go to the Park Tools repair tutorial page and read their tutorial on front derailleur adjustment. Hell, bookmark the page because their repair tutorials cover virtually anything you could want to do to your bike. Likewise, you can find loads of videos on YouTube for just about any bike repair or maintenance procedure that you might need to do in the future. Lastly, all of the component group makers (Shimano, Campagnolo, and SRAM--not sure about MicroShift) have, on their websites, pdf's of their installation and adjustment procedures for all of their products.
Thanks . I'm very familiar with park tools; I have their blue book and have been doing a lot of derailleur adjustments for a long time. Have built several bike over the years . I think, like alfeng suggests, that this is a chainline issue, so I'll work on solving it.. Thanks for the input.
 
Originally Posted by alfeng .

FWIW. I believe the problem IS, as you suspect, due to the chainline & may be exacerbated by frame flex OR the size of the actual cogs ...

  • Who knows?!? The problem might even exist on YOUR bike even if you were to switch to Campagnolo shifters!?!
  • To state the obvious (presuming that you would like to resolve the problem without unnecessarily spending money), EITHER shift down to the Granny + appropriate cog before starting the climb OR if you don't need the Granny then lock it out by adjusting the front derailleur's inner stop ...

    OR, if you are resigned to spending money, then swap the Triple for a "Compact" Double + a Cassette whose largest cog gives you the low gearing which you need for the roadways you ride on ...

    OR, if you need a Triple AND you don't want to change your habit of shifting to the larger cogs before uphill inclines when you have a Granny AND you are willing to spend money THEN a Shimano 6503 crankset (Ultegra Octalink Triple ... or, the 105 Octalink equivalent, of course) mounted on a 112.5mm XTR Octalink BB will give you a better chainline which may-or-may-not resolve the problem by moving your crankset ~3mm inboard ... you will need a 2.5mm BB 'spacer' for the driveside since the XTR BBs are designed for 73mm BB shells (the BB spacers come with new BBs but may be absent if you buy the BB used from someone else).

  • N.B. Depending on YOUR frame, chainring clearance may be tight, but it shouldn't be since I presume your bike can typically handle a normal Double crankset with a 52t-or-53t chainring.
Alfeng,
I have an older Shimano deore MTB 9 speed RD laying around; I also have a 10 speed shifter Ultegra double and an older FSA 50/34 compact crank somewhere... will a Shimano 10 speed MTB Cassette work OK? it should; right?
 
Quote:Originally Posted by rparedes .I have an older Shimano deore MTB 9 speed RD laying around; I also have a 10 speed shifter Ultegra double and an older FSA 50/34 compact crank somewhere... will a Shimano 10 speed MTB Cassette work OK? it should; right?


Yes ...

Your configuration of a 9-speed Shimano MTB rear derailleur + 10-speed Ultegra shifter + 50/34 FSA crank + a 10-speed MTB Cassette (presuming a 10-speed Shimano chain + 10-speed Shimano front derailleur) should work with the caveat that although almost everyone else thinks-and-says that the geometry of the 9-speed & 10-speed Shimano rear derailleurs is the same, I think otherwise AND that you may find that you will need to hubbub the rear derailleur cable anchoring by attaching the cable at 3 o'clock to make a 9-speed Shimano rear derailleur respond the same way as a 10-speed Shimano rear derailleur ...

So, if you try the initial setup with your 9-speed Deore rear derailleur's cable anchored in the normal 6 o'clock position & it results in dodgy indexing, then hubbub the cable anchoring.

BTW. Although you may have to adjust the B-screw, it might be possible to use an 11-36; otherwise, an 11-32/11-34/12-34 should be otherwise good-to-go (I'm currently setting up a bike whose chain includes a few extra links cannibalized from another new chain to allow for the possibility of installing an 11-36 Cassette).

Also, although some people say it is a bit tedious, I have previously noted that 'I' prefer to adjust a rear derailleur's STOPS when the chain is not threaded through the pulleys. I think that it can be faster.
 
Originally Posted by alfeng .


Yes ...

Your configuration of a 9-speed Shimano MTB rear derailleur + 10-speed Ultegra shifter + 50/34 FSA crank + a 10-speed MTB Cassette (presuming a 10-speed Shimano chain + 10-speed Shimano front derailleur) should work with the caveat that although almost everyone else thinks-and-says that the geometry of the 9-speed & 10-speed Shimano rear derailleurs is the same, I think otherwise AND that you may find that you will need to hubbub the rear derailleur cable anchoring by attaching the cable at 3 o'clock to make a 9-speed Shimano rear derailleur respond the same way as a 10-speed Shimano rear derailleur ...

So, if you try the initial setup with your 9-speed Deore rear derailleur's cable anchored in the normal 6 o'clock position & it results in dodgy indexing, then hubbub the cable anchoring.

BTW. Although you may have to adjust the B-screw, it might be possible to use an 11-36; otherwise, an 11-32/11-34/12-34 should be otherwise good-to-go (I'm currently setting up a bike whose chain includes a few extra links cannibalized from another new chain to allow for the possibility of installing an 11-36 Cassette).

Also, although some people say it is a bit tedious, I have previously noted that 'I' prefer to adjust a rear derailleur's STOPS when the chain is not threaded through the pulleys. I think that it can be faster.
Thanks!
BTW, I also think it's easier and faster to adjust the RD stops without the chain; I can see much better from the back, so the pulley teeth align perfectly with the large and small cogs...
 
Originally Posted by rparedes .

Thanks!
BTW, I also think it's easier and faster to adjust the RD stops without the chain; I can see much better from the back, so the pulley teeth align perfectly with the large and small cogs...
Sometimes it's necessary to adjust the outer limit screw so the pulley is a hair outboard of the small cog. That allows the spring to pull the cage down with a bit more "enthusiasm."