rbrides

Are there any known defects, or recalls, with Shimano 105 group set (series 5500, 5600, 5700 or 5800)? I bought a Specialized Diverge Comp 13 months ago and it has thrown the chain about every 200-300 miles. My bike shop has tuned it several times to attempt to fix it and they most recently replaced the front derailleur and the Praxis big ring with the same model/type as original but it still keeps throwing the chain. it is not confined to one specific shift direction; from big ring to small ring, from small to big, and "trim" on either ring have all done it. Some have suggested it is a "known" problem with the shifter not actuating fully/properly but I can not verify that.

My bike shop says its me peddling backwards. My response to that is; the Giant bike I purchased from them a few years ago NEVER threw the chain in 5000 miles. So I don't agree.

An additional thought (grasping for straws). How common is incorrect chain length of 1 or 2 links too long or too short a cause of "thrown chains"? It is the only thing that has not been modified to resolve this problem. I have replaced the KMC chain with identical as original as a routine maintenance item but made it the same length as the original. What is a proved way to determine correct chain length?

Lastly, I do not see any identification to tell me if it is 5500, 5600, 5700 or 5800 so I don't yet know what series it is. I've asked Specialized, awaiting their response, and I'm searching Google images to figure that out but have not found anything conclusive.

thanks.

trailangel

Javascript Bicycle Chain Length Calculator

ksryder

If it's a year-old bike then it's most likely 5800. But the sure way to tell is if it's 11-speed, then it's 5800.

You should be able to pedal backwards unless you're doing it while shifting.

My experience with dropped chains is it's usually a worn chainring, but could also be a worn cassette, or a worn chain. It could also be front or rear derailleur adjustment issues, or an incorrect chain length issue.

Check out Park Tool and Sheldon Brown and start inspecting/addressing each potential issue. Do one thing at a time so you eliminate variables.

Or, find a new shop.

Trakhak

Does the chain derail only when you backpedal? If so:

I would expect backpedaling to work fine with the chain in the middle of the cassette and on the middle chainring for any bike. I wouldn't expect it to work with the chain in some other combinations, e.g., small in front and small in back or large in front and large in back.

Even those combinations might work on a particular bike, but it's not guaranteed. In any event, derailleur systems are not designed with backpedaling in mind.

In short, best not to backpedal.

hokiefyd 

Many people advocate the "big, big, +1" method. That is, put a new straight length of chain (remove a pin or disconnect the quick connector) on the largest cassette sprocket, on the largest chain ring on the front, and through both derailleurs as it would typically route. Pull the two lengths of chain together in the middle, so that the derailleur cage pulls all the way forward (against its spring), and note the shortest possible chain length that would essentially create a straight path through the derailleur. Add one link to that and join the chain. That would be the shortest possible length of chain for your bike with the equipment you have right now.

As for the specific 105 series you have, you should find a part number on the inner cage plate of the front derailleur, and the inner parallelogram plate of the rear derailleur. It'll say something like "FD-5500" or "RD-5500", etc.

rccardr 

I always use the big/big method of chain sizing, but do not run the chain through the derailleur when doing so.
Has always worked for me.

rbrides

Thanksj Hokiefyd. I'll look again for the part number but did not find it before. Big big +1 is most common method I've heard of so thanks for helping verify that.

rbrides

Thanks! I like it.

rbrides

Thanks for the info. Yes, it is 11 speed. I have new cassette, big chain ring and am on second chain. I'm a fan of Park Tools and their videos and will look for more specific to these.

rbrides

Agreed. No back pedaling.

rbrides

Here is the response from Specialized.

"So that would have been the 5800 groupo. I haven't heard anything like what you are describing. Based on what you are describing, it sounds like an adjustment issue, but I wouldn't be able to say for sure. I know that style of front derailleur was tricky to set up, there were some specific steps that needed to be followed or it would not work.
There are plenty of videos out there that can go through the set up step by step."

I'll look for videos and specifics for the 5800. ksrider correctly said it was 5800 since its 11 speed. Touche'

rbrides

Here is a little something that points blame back to me. Shimano says " . . . lubricate all moving parts."

I've never lubricated a front derailleur.

I wash, and clean my bike very frequently and always use a chain scrubber then relubricate the chain after every wash. But I don't do anything special for the derailleur.

Who lubricates their derailleur and what do you use?

shelbyfv

As mentioned, the 5800 FD (as well as other first gen 11 speed) has some unique set up requirements. Best to go straight to the Shimano instructions. https://si.shimano.com/pdfs/dm/DM-FD0002-05-ENG.pdf

tomtomtom123

What is the jump in teeth between your small and big rings? I have a 20T jump so there is a big height for the chain to travel when shifting from big to small chainring, so there is a chance that the chain will drop towards the inside once every 2 hours if I don't have a chain catcher. To stop the chain from falling inside, you should use a chain catcher. SRAM chain catcher allows you to remove and reinstall it without affecting the alignment of the FD.



If the chain falls to the outside when you are shifting from small to large chainring, then one possibility is that your FD is moving too far out and pushing your chain off. If this is the cause, a simple tightening of the high limit screw to push the FD a little bit inward might fix this, plus a small loosening of the barrel adjuster if needed.

rbrides

The original Praxis 48/32 that Specialized put on the bike.

smashndash

Sorry, I’m still a bit unclear on how the chain is getting dropped. It seems like the chain gets dropped when shifting up front. Is your bike shop claiming that you are backpedaling mid-shift? I assume you’re not doing that. Bike shops really will find every possible way to blame the customer rather than taking responsibility.

I’ll be 100% honest here - toss the praxis junk. I know. It sucks to hear. But when I was using a praxis crank/chainrings (which everyone online seems to rave about), my shifting was garbage. Half the time, I couldn’t get the chain to shift from little ring to big. I had to shift into an easy gear out back to increase the amount of lateral force. I fought with my shop for about 6 months over this. They kept changing the story until eventually the head mechanic said that the Praxis cranks are the issue. Even swapping to an R8000 FD did nothing.

Obviously I wasn’t going to give that shop any more money, but I did the swap on my own. And guess what? Perfect shifting. Night and day. I have 5800 shifters/rear mech but I got an R7000 crank and R8000 FD. I highly recommend swapping to a next gen crank/FD.

I have dropped chains a couple times before but I think it only happens if I shift both front and rear at the same time. I’m not sure because it’s only happened a few times. I can backpedal in any gear combo and not have any issues.

I had an issue with my OE wheels as well, which made them practically unusable. It sounds cynical but unless you have deep pockets and can threaten to sue, bike shops are under no obligation to actually give you a functional bike. I learned this the expensive way. Good luck.

tomtomtom123

If your chain is dropping only when shifting the FD, then most likely the chain catcher, FD angle adjustment, and H limit screw adjustment like I mentioned previously could fix this. One other thing I forgot to mention for helping reduce chain drop to the inside is the L limit screw. When shifting from the large to the small ring, you want the FD to move only as close as necessary to force the chain off the big ring, plus a little chain clearance for no chain rub. But usually, most FD triggers have an inner trim position to give the extra clearance to stop chain rubbing when on the small ring and big cog. The reason why trim is on the inside (needing one more trigger pull after downshift to reach inner trim) is so that when you do downshift, it doesn't overshoot and push the chain so far in that it drops off.

Similarly, if the chain keeps dropping to the outside when you upshift from the small to large ring, then most likely it's because of the FD overshooting too far out and pushing the chain off to the outside. Adjusting the H limit screw, barrel adjuster, and FD angle may be able to fix this. On my shimano shifter and shimano FD, I don't know whether high trim is before or after the high shift position, because I can reach both clicks with 1 single trigger pull. I can either stop at the second to last index or the very last index when upshifting. But usually I have to go all the way to the last index to get the chain to move up to the big ring, so I set the H limit screw for this position so that it doesn't overshoot and push the chain off. In this position, if the chain is also on the big cogs, the chain is usually rubbing on the FD inner cage plate, so I have to press the down trigger for 1 click to get to the 2nd to last index which I guess would mean that it's the inner trim position for the high index.

I recently changed to a SRAM YAW FD and kept using my Shimano trigger (long pull version, for double chainring, with 4 index positions). The SRAM YAW is designed not to use trim because of the "yaw" action which pivots the cage so that the front of the FD cage moves further than the tail of the cage, along with a very wide cage. With the SRAM YAW FD, the cage angle and L and H limit screws are very important because the wide cage makes overshooting and dropped chains more likely if you don't adjust it well. Using the Shimano long pull trigger was fine, since the first 2 index gave complete cable slack anyway, and I set the H limit screw to the 2nd to last position, so both the inner High trim and high index position gave the same cage position. The FD spring simply picked up the extra cable pull when shifting to the very last index.

79pmooney

Something I've been doing since the dark ages (the very first days of better shifting chains circa 1977; narrowing down the FD shifting with the limit screws. I would set the limits screws (usually) so the chainrubbed the FD cage in the small-big (low) ear and also the large-small (high) gear. If I still had your issues I'd take it a step further. I'd keep tightening the limit screws until either I could no longer shift well onto that chainring or the chain dropping stops.

A firm believer that the only place you can really fine tune your FD is out on the road. A mechanic's ride around the block doesn't always cut it. Especially to troubleshoot problems that happen every 200 miles.

Ben

rbrides

Thanks for input Ben and voice of experience.

rbrides

The chain is dropping while shift the FD; in any direction. Never drops while shifting rear. Maybe it is the Praxis. That's an expensive upgrade but maybe necessary

tomtomtom123

I think it would be best to try adjusting the FD before changing the chainrings. Limit the FD movement by the L and H screws to only the amount necessary to shift the chain in either direction. Then adjust the screws 1/8 or 1/4 turns and the barrel nut 1/2 turns at a time until the chain no longer rubs. Optimal FD angle is more difficult to determine. I have a very thick seat tube so the FD is touching the seatpost in the low position, so then I only have to adjust the swing of the tail to clear the chain on the small/big combo, so I don't have to worry about the position of the front of the cage in relation to the swing of the tail.

For your bike, the optimal front of cage when on low index would be just enough for the chain to shift down, then for the low trim index swing the tail to clear the chain rub at the tail. For the front of cage high index and high trim index, the front of the cage should positioned for the chain to not rub on the front of the cage. You repeat the adjusting and checking several times, alternating between adjusting the H and L screw and tail swing until you get good shifting and no more chain drop.

Swinging the tail inward will move the front of the cage outward. Swinging the tail outward will move the front of the cage inward. The tail is more important for chain rub when on the small chainring, and also upshifting. The front of the cage is more important for the chain rub when on the big chainring, and also downshifting.

trailflow1

Have a different mechanic at a different shop look at it. or try to fix it yourself

Some things to check for

Chainring orientation on the spider. The shift ramps need to be in the correct position

Warped big chainring

Bent or missing chainring teeth

Loose chainring bolts

Crank side to side play/loose crank bolt. Incorrect bb spacers/dust covers installed

Twisted chain

Are you a heavy rider ? The crank and rings might be flexing under load.

Homebrew01

Nonsense, if we're talking about the front chainring.
Try a different shop, or at least a different mechanic.

"...My bike shop says its me peddling backwards. ..."

Racing Dan

5800 .. Is it?

How many non-Shimano parts are on there. Its throwing a KMC chain form a set of Praxis rings with only the FD being Shimano, - Either the 5800, 5801 or R7000.

Imo its hard to fault Shimano here.

That said, my Fuji has a similar setup. Praxis buzz rings, a KMC chain, FD4700 and ST4700. Works fine, for now. I do tend to reduce crank torque when changing the rings, to prevent the chain from slipping.

My other bike is all Tiaga 4700. None of them have ever thrown the chain.

Racing Dan

Shimano has proper instructions on how to size the chain.