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FD won't shift

Old 11-23-22, 01:52 AM
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FD won't shift

I bought a used bike and didn't notice on my test ride that the cranks (not OEM) are not centered. Upon inspection, it appeared that the seller had put both 2.5mm spacers on the left side. I moved one spacer over to the drive side as per the crankset's instructions, but then the clamp-on Ultegra FD-6800 wouldn't shift into the big ring even with the limit screws backed off completely and the cable tightened until it barely grazes the inner chainring. What are my options?

FWIW it's an FSA Gossamer Pro Modular AGX+ crankset on a 2016 Diamondback Haanjo Trail.
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Old 11-23-22, 03:54 AM
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Just thinking out loud here: Assuming the 2.5mm spacers are to fit a 68mm BB to a crankset designed for frames with 73mm BB shells? Does your crank fit the BB if there were no spacers? Does the frame have a 73mm BB shell? Just because both spacers were stacked on the NDS, does that necessarily mean the crank isn't centered relative to the frame? Do some manufacturers advise the user to place the spacers that way when fitting cranks made for 73mm BB shells to frames with 68mm BB shells?
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Old 11-23-22, 08:03 AM
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Did the crank "offset" bother you besides aesthetics? Move the spacer back.
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Old 11-23-22, 09:56 AM
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"the cranks (not OEM) are not centered" with respect to what? A published chain line dimension?

It seems to me that the spacers placed on the non drive side was done to allow better ft shifting and/or chain line. If the spacer was to be relocated to the ND side again will there be small ring/chainstay clearance? If so than that is your likely solution.

For many decades bikes had their crank arms off set to the drive side on purpose and riders didn't die. Andy
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Old 11-23-22, 10:58 AM
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Take it to a shop where somebody who can understand the problem can actually see what the problem is. Or submit some photos.
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Old 11-23-22, 12:45 PM
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A quick search came up with specs from Bicycle Blue Book

Drivetrain
Bottom Bracket BB386
Cassette Shimano CS-5800 105 11spd (11-32t)
Chainrings 46/36T
Shifters Shimano ST-RS685 Dual Control 11spd
Crankset FSA Gossamer Pro Cross
Front Derailleur Shimano Ultegra
Rear Derailleur Shimano Ultegra
https://www.bicyclebluebook.com/valu...Haanjo%20Trail

So going only by those specs it should have had a 2 piece FSA crank in it. That probably had the correct spindle length. So maybe a previous owner put a different crank and BB in it and didn't quite get the right BB length.

Chain line on the GOSSAMER PRO MODULAR AGX+ is 47mm, I suspect that is different from the original crank which is more like a road cranks 43.5 mm chain line. But I didn't see FSA specs for that.

Last edited by Iride01; 11-23-22 at 12:54 PM.
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Old 11-23-22, 07:58 PM
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Originally Posted by Andrew R Stewart View Post
"the cranks (not OEM) are not centered" with respect to what? A published chain line dimension?

It seems to me that the spacers placed on the non drive side was done to allow better ft shifting and/or chain line. If the spacer was to be relocated to the ND side again will there be small ring/chainstay clearance? If so than that is your likely solution.

For many decades bikes had their crank arms off set to the drive side on purpose and riders didn't die. Andy
My Cannondale Synapse has a (proprietary) BB30a bottom bracket which is not centered on the center line of the bike frame. Are other bottom brackets necessarily centered? It seems theoretically possible to offset the bottom bracket to the left (or non-drive side) to make room for chain rings but still have a spindle that is centered. An unequal number of spacers on either side of the bottom bracket does not necessarily mean that the spindle is not centered. What matters is that both pedals are equidistant from the center line of the bike frame, right?
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Old 11-23-22, 09:32 PM
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Originally Posted by tFUnK View Post
Just thinking out loud here: Assuming the 2.5mm spacers are to fit a 68mm BB to a crankset designed for frames with 73mm BB shells?
Good question. The manual just shows them as being part of the assembly: one on each side plus a wave washer on the NDS.

Originally Posted by tFUnK View Post
Does your crank fit the BB if there were no spacers?
No, because the spindle (incorporated with the crank) is then too long and would have 5mm of play side-to-side.

Originally Posted by tFUnK View Post
Just because both spacers were stacked on the NDS, does that necessarily mean the crank isn't centered relative to the frame?
I guess not necessarily, but since it's put together a different way than the manual shows, I assume that's what it's doing.

Originally Posted by Andrew R Stewart View Post
"the cranks (not OEM) are not centered" with respect to what? A published chain line dimension?
Honestly, just because (A) it's put together differently than in the instructions, and (B) the cranks are a noticeably different distance from the seemingly symmetrical chain stays. I haven't done any string measurements or anything, but seems obvious to me given those two things.

Originally Posted by Andrew R Stewart View Post
It seems to me that the spacers placed on the non drive side was done to allow better ft shifting and/or chain line. If the spacer was to be relocated to the ND side again will there be small ring/chainstay clearance? If so than that is your likely solution.

For many decades bikes had their crank arms off set to the drive side on purpose and riders didn't die. Andy
Yes, the chainrings clear and the bike works fine that way. My left hip was a little sore after that ride, but that may or may not be related.

Originally Posted by Iride01 View Post
So going only by those specs it should have had a 2 piece FSA crank in it. That probably had the correct spindle length. So maybe a previous owner put a different crank and BB in it and didn't quite get the right BB length.

Chain line on the GOSSAMER PRO MODULAR AGX+ is 47mm, I suspect that is different from the original crank which is more like a road cranks 43.5 mm chain line. But I didn't see FSA specs for that.
Yeah, that's what I suspect. Just wasn't sure if there was a way to correct it.
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Old 11-23-22, 10:09 PM
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Originally Posted by SoSmellyAir View Post
My Cannondale Synapse has a (proprietary) BB30a bottom bracket which is not centered on the center line of the bike frame. Are other bottom brackets necessarily centered? It seems theoretically possible to offset the bottom bracket to the left (or non-drive side) to make room for chain rings but still have a spindle that is centered. An unequal number of spacers on either side of the bottom bracket does not necessarily mean that the spindle is not centered. What matters is that both pedals are equidistant from the center line of the bike frame, right?
I don't care too much about the BB's being centered as it's the rings and crank arms that my body interfaces with. The BB only get those parts where the rest of the bike and my body can deal with them. I recently had one of my Phil BBs rebuilt (old/worn bearings) with a 1.5mm axle off set to better balance the BB shell and BB unit centering and retain the ring/chain stay clearances.

Some of us are especially sensitive fitting issues. If a hip continues to be problematic find the fix (which likely what's happening right now), even if it means a different set up. Fitting solutions are not easily done via long distance. Andy
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Old 11-23-22, 10:54 PM
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Presumably, this is a road bike. Yes or no? FSA Gossamer came in two spindle configurations, 24 mm and 30 mm. Which one is it? Bearings for these spindles can be either press-fit or outboard threaded. If it's outboard threaded, is it an FSA bearing or Shimano, because the widths are different.

The purpose of chain line is to establish a kind of neutrality over gear combinations. The innermost and outermost rear cogs need to be equally accessible from the inner and outer front chainrings. The most straightforward way to check this is to lay a yardstick over the space between the chainrings (presuming it's a double) and cog #6 (presuming it's an 11-speed). The point is, you want midpoints. The yardstick should be parallel to the center line of the bike. If it isn't, you have to fiddle with the shims. On a 130 mm axle, the 11-speed cassette moves the chain line about 0.95 mm inboard from 10-speed. It might just be possible that this crank wasn't meant to be used with 11-speed systems. I can't tell because you haven't told us about the bike or shown us photos. But establish the chain line first.

Also be aware that Shimano 11-speed front derailleurs use virtually no slack in the cable, unlike previous 8-, 9-, and 10-speed generations. Then there is the matter of the converter pin, whose position is determined by the pull angle of the cable as it emerges behind the bottom bracket.

Last edited by oldbobcat; 11-23-22 at 11:01 PM.
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Old 11-24-22, 01:05 AM
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Originally Posted by oldbobcat View Post
Presumably, this is a road bike. Yes or no? FSA Gossamer came in two spindle configurations, 24 mm and 30 mm. Which one is it? Bearings for these spindles can be either press-fit or outboard threaded. If it's outboard threaded, is it an FSA bearing or Shimano, because the widths are different.
It's a gravel bike, the first I have ever owned so I don't know much about how they are configured. 30mm spindle with FSA outboard bearings.

Originally Posted by oldbobcat View Post
The purpose of chain line is to establish a kind of neutrality over gear combinations. The innermost and outermost rear cogs need to be equally accessible from the inner and outer front chainrings. The most straightforward way to check this is to lay a yardstick over the space between the chainrings (presuming it's a double) and cog #6 (presuming it's an 11-speed). The point is, you want midpoints. The yardstick should be parallel to the center line of the bike. If it isn't, you have to fiddle with the shims. On a 130 mm axle, the 11-speed cassette moves the chain line about 0.95 mm inboard from 10-speed. It might just be possible that this crank wasn't meant to be used with 11-speed systems. I can't tell because you haven't told us about the bike or shown us photos. But establish the chain line first.
The shifting works very well with the stacked spacers on the NDS, but you may be on to something here. It's a 135mm rear spacing, and maybe the aftermarket crank is meant for 142mm?

Originally Posted by oldbobcat View Post
Also be aware that Shimano 11-speed front derailleurs use virtually no slack in the cable, unlike previous 8-, 9-, and 10-speed generations. Then there is the matter of the converter pin, whose position is determined by the pull angle of the cable as it emerges behind the bottom bracket.
Now that is something I was unaware of and need to read up on.
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Old 11-24-22, 09:25 AM
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"Also be aware that Shimano 11-speed front derailleurs use virtually no slack in the cable, unlike previous 8-, 9-, and 10-speed generations. Then there is the matter of the converter pin, whose position is determined by the pull angle of the cable as it emerges behind the bottom bracket."

This! When this design series of ft ders is set up well they do shift really fast and with "authority". But that set up window is complex and narrow. Even after a few dozen examples crossing my repair stand I find myself doing far more fiddling with them than more traditionally designed ders. I would personally not run one if I could help it, (wait I can help it and I don't use these. The big reason is that I stopped my gearing count grail at 9x3 and these ders don't work on a triple or the wider 9 spd chain.) Andy
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Old 11-24-22, 09:51 AM
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Originally Posted by urbanknight View Post
Originally Posted by Iride01 View Post
So going only by those specs it should have had a 2 piece FSA crank in it. That probably had the correct spindle length. So maybe a previous owner put a different crank and BB in it and didn't quite get the right BB length.

Chain line on the GOSSAMER PRO MODULAR AGX+ is 47mm, I suspect that is different from the original crank which is more like a road cranks 43.5 mm chain line. But I didn't see FSA specs for that.

Yeah, that's what I suspect. Just wasn't sure if there was a way to correct it.
Well it seems a previous owner corrected the chain line somewhat by putting the spacers on the left side of the BB shell. The Ultegra front DR is for a road crank and expects a road chain line. So weren't the spacers on the left side giving that crank made for a wider chain line about the correct chain line for that bike, what ever that is.

When you stand behind the bike and look from the center of the rear stack of cogs then when do they appear to be lined up more with the center of the front stack? When where the previous owner had it or when you made your adjustment?

Happy T-Day!

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Old 11-24-22, 10:36 AM
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Originally Posted by Iride01 View Post
Well it seems a previous owner corrected the chain line somewhat by putting the spacers on the left side of the BB shell. The Ultegra front DR is for a road crank and expects a road chain line. So weren't the spacers on the left side giving that crank made for a wider chain line about the correct chain line for that bike, what ever that is.

When you stand behind the bike and look from the center of the rear stack of cogs then when do they appear to be lined up more with the center of the front stack? When where the previous owner had it or when you made your adjustment?

Happy T-Day!
That's what made me wonder if a simple fix would be getting a MTB derailleur, or even a different crankset since I prefer a different length anyway. But I also hate doing bottom brackets, so I'd want to get one compatible with the one that's installed already

I'll have to look at it when I get back to it.
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Old 11-24-22, 11:00 AM
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Originally Posted by urbanknight View Post
That's what made me wonder if a simple fix would be getting a MTB derailleur, or even a different crankset since I prefer a different length anyway. But I also hate doing bottom brackets, so I'd want to get one compatible with the one that's installed already

I'll have to look at it when I get back to it.
A mountain bike derailer doesnít usually play nice with road shifters. Iíve moved spacers on lots of bikes to use mountain bike cranks with road derailers. It works and it doesnít cause problems, so why not? As an added benefit, it drives the OCD crowd crazy, so thatís a plus.

The solution to your problem is to swap the spacer back. It worked, why not just live with it?
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Old 11-24-22, 11:22 AM
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Originally Posted by cyccommute View Post
It worked, why not just live with it?
Because Iím part of the OCD crowd!
seriously though, I already moved the spacer back and will just use my OCD angst to pedal harder or something.
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Old 11-24-22, 11:31 AM
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Originally Posted by urbanknight View Post
That's what made me wonder if a simple fix would be getting a MTB derailleur, or even a different crankset since I prefer a different length anyway. But I also hate doing bottom brackets, so I'd want to get one compatible with the one that's installed already

I'll have to look at it when I get back to it.
You don't want to open another can of worms with MTB derailleur compatibility with your STI levers. I'd recommend chucking the whole 6800/FSA mix and buy a full GRX kit before you go throwing in MTB components.

Going back to your original post, it seems you had a bike that shifted properly but you didn't like the asymmetry of two spacers on the non-drive side, so you made it symmetrical and now the bike won't shift. So it seems that the guy who installed the crankset knew what he was doing. And If you want the bike to shift again, all you have to do is move the spacer back. Look, the purpose of the spacers is to resolve the chain line, not change your pedaling dynamics. If the chain line doesn't work, the bike doesn't work.

By the way, is your front derailleur band-mount or direct-mount?

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Old 11-24-22, 12:22 PM
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just a couple weeks ago did a quick scan for some GRX stuff (including 810 crank) on the QBP site and saw a lot of zeroes ... out of stock
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Old 11-24-22, 01:02 PM
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When I did a quick glance at the FSA Gossamer Pro Modular AGX+ crank, I thought it was a three piece crank. But now I realize it too is a 2 piece crank. But it's made for wider BB shells and chain lines of what gravel bikes of late have been going to.

GRX cranks have that same 47 mm chain line. So going to GRX isn't necessarily going to do anything for you if your rear expects a chain line more typical of a road bike. So while a GRX FDR might give you the swing you need to reach the rings with the symmetrically spaced crankarm on both sides, then you still might have less than great shifting in some combos.

Seems the bigger issue is going to require you change the crank to something that want's that narrower chain line.

https://shop.fullspeedahead.com/en/f...ab79e2de27645/

https://shop.fullspeedahead.com/en/f...c298e69684883/

https://shop.fullspeedahead.com/en/f...847f3c9e4e882/
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Old 11-24-22, 02:48 PM
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Originally Posted by oldbobcat View Post
You don't want to open another can of worms with MTB derailleur compatibility with your STI levers. I'd recommend chucking the whole 6800/FSA mix and buy a full GRX kit before you go throwing in MTB components.
Good point with the FD. I consider this entry level into gravel biking for me, so I'm not going to spend too much on an outdated, budget brand, aluminum bike with quick release.

Originally Posted by oldbobcat View Post
So it seems that they guy who installed the crankset knew what he was doing.
Actually, he (or whoever worked on the bike for him) neglected to install the wave washer, but I fixed that easily and didn't bother to mention it here because it was relevant.

Originally Posted by oldbobcat View Post
By the way, is your front derailleur band-mount or direct-mount?
Band

I will do as many of you suggested and run it with both spacers on the NDS. I didn't even notice it until I felt the play from the missing wave washer and went to inspect the problem.
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Old 11-24-22, 03:01 PM
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Originally Posted by Iride01 View Post
When I did a quick glance at the FSA Gossamer Pro Modular AGX+ crank, I thought it was a three piece crank. But now I realize it too is a 2 piece crank. But it's made for wider BB shells and chain lines of what gravel bikes of late have been going to.

GRX cranks have that same 47 mm chain line. So going to GRX isn't necessarily going to do anything for you if your rear expects a chain line more typical of a road bike. So while a GRX FDR might give you the swing you need to reach the rings with the symmetrically spaced crankarm on both sides, then you still might have less than great shifting in some combos.

Seems the bigger issue is going to require you change the crank to something that want's that narrower chain line.
Yeah, and most road cranks won't have the lower gears I want. That is apparently the reason the seller bought the crankset, to get that 30t inner ring, but it's strange that I think the crank that came on the bike would also have accepted a 30t. Could have been parts availability I guess.

It looks like the Omega AGX might have what I need, but can't seem to find a manual or documents to support it.
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Old 11-24-22, 09:14 PM
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Originally Posted by urbanknight View Post

Band
On another forum I found some concern that the band mount unit doesn't reach as far as the direct mount. But I don't know if there's anything you can do about it. Anyway, good on you for figuring out the wavy washer.
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Old 11-24-22, 09:19 PM
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Originally Posted by oldbobcat View Post
On another forum I found some concern that the band mount unit doesn't reach as far as the direct mount. But I don't know if there's anything you can do about it. Anyway, good on you for figuring out the wavy washer.
Guess I could get a direct mount FD and an adapter, but I really should just ride it and see if it even bothers me beyond vanity.
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Old 11-24-22, 10:25 PM
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Originally Posted by urbanknight View Post
Guess I could get a direct mount FD and an adapter, but I really should just ride it and see if it even bothers me beyond vanity.
Yeah, Shimano makes banded direct-mount adapters, but you'd still have to buy a new 6800 or 8000 direct mount front derailleur. And even if it does reach, if the chainline is wrong, it will never be right. Fix the chainline first.

Case in point. Years ago I did some work on a Cervelo with FSA cranks with a 24mm spindle. The owner had replaced the threaded outboard BB bearings with Shimano, a deceptively smart move because Shimano are less expensive and more durable. But the Shimano bearings were about 1-2 mm wider than FSA. While the spindle was long enough to clamp the left crank properly, the drivetrain was never happy cross-chaining from the big ring. Big-big was impossible, and shifting to the big ring from cogs 2-3 in back was hit-or-miss.
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