Jim’s Tech Talk
By Jim Langley
My son-in-law Frankie has really taken to cycling. I introduced him to you a year ago when he asked for tips on shifting double-chainring road bikes to share with his riding group. Here’s that story in case you’re learning to shift or know someone who needs a quick primer: Beginners’ Guide to 2X Shifting.
Since last time, Frankie has added a mountain bike to his stable. Now that he’s got two rigs to keep running, he reached out to me for a lesson on derailleur adjustment. He only lives an hour away, so he came down to my house where we could put both bikes in a repair stand. With them off the ground, it’s both easy to pedal and to see how things are functioning because the bike is up high, close to you.
We worked on Frankie’s Felt first and that’s the one we’re concerned with for this article and contest. It’s a 2017 55x “gravel bike.”
Contest Rules
This is the first time for a contest in Tech Talk. Like a city limits sprint, the idea is to add a little fun. And the prize is a nice tool that is sure to see plenty of use in your home bike shop. Or, if you win it and already have one, you’ll now have one for your traveling toolbox and bench.
How this contest works is that I’m going to describe Frankie’s shifting problem and the steps we took to try to fix it. Keep in mind that this was a lesson on adjusting derailleurs for Frankie. Hopefully, if you’re learning, too, you’ll pick up some helpful tips.
To enter the contest, simply follow along reading everything we tried. At the end, there’s a cliffhanger of sorts because I don’t reveal what the problem was or how we fixed it. The first reader who posts a comment identifying the exact problem causing Frankie’s shifting issue will be the winner. We’re looking for a very specific problem and the fix for it.
The photos show the bike as it was when we worked on it. To give you a hint, the thing causing the issue is shown in the photos but that probably won’t help you come up with the prize-winning answer.
I will reveal the problem in next week’s Tech Talk. I will also tell who won the contest and prize unless that individual specifically requests anonymity (and reach out to learn where to ship the tool).
Frankie’s Shifting Problem
Ideally, to teach someone rear derailleur adjustment (the Felt is a single-chainring bike), the drivetrain actually needs something adjusted. So, I asked Frankie if he was having any shifting problems.
He said that he had recently changed to an 11-42 cassette for easier climbing. And now when he shifts, there is sometimes hesitation. And, also that the bike doesn’t always stay in gear. Instead it occasionally auto shifts into a harder gear.
“Perfect!” I told him, explaining that hesitation and shifting out of gear are often related, common problems and relatively easy to fix.
First Checks
I wasn’t certain that the SRAM Rival derailleur could handle such an oversize cassette (Frankie had bought it online). If not, that could cause the shifting glitches. But, a quick check of the derailleur specs online said it could.
Since it was a new cassette, I next checked to make sure it was properly installed and fully tightened. Because loose cassette cogs will move around, which can cause shifting issues like Frankie’s. The cassette was nice and tight.
Bikes can fall over and when it happens the rear derailleur often takes the hit and gets bent, messing up the shifting. I showed Frankie how to check for this by standing behind the bike and sighting to see if an imaginary vertical line would bisect the cassette sprocket the chain is on and both derailleur pulleys. It would.
Another quick check, I showed Frankie was to make sure his derailleur and its hanger on the frame were tight by checking with the right wrenches. Again, everything was fine.
Wanting to check the shifting, I quickly operated the lever to see if the bike would shift up and down the cassette and hit the gears with each click. It worked fairly well in the repair stand but did exhibit some slight hesitation shifting into the larger cogs.
Looking Deeper
Since this was a shifting lesson, I ran through basic system checks so Frankie could see how it’s done. I told him to always check the shift cable and shifter since cables can rust or fray and the housing they’re inside can get damaged over time. These things can cause shifting hesitation and worse, a broken cable.
I showed him how to pedal and push on the rear derailleur with his hand to shift up onto the largest cog. Then, by stopping pedaling and letting go of the derailleur, I showed him how slack is created in the shift cable and how you can free the housing from the frame shops. Once you’ve done that, you can slide the housing out of the way and visually check the cable for signs of rust or fraying. Also you can spot housing issues.
And, with the housing out of the way you can lube the cable. Frankie’s cable and housing sections were in near perfect shape and we just put a little grease on everything.
Next, since the cable was slack, I showed Frankie how you can test the shifter function by pulling on the cable with your left hand (holding onto it right next to the frame) and operating the lever through its entire range of clicks. That way, you feel the shifter itself through the cable because there’s no derailleur spring pulling on it.
Frankie’s shifter operated perfectly. No issues.
Rear Derailleur Adjustment Checks
Moving on to the rear derailleur, I went over the functions of the 3 adjusting screws so that Frankie would understand. First, I showed him the top screw for getting the clearance between the top derailleur pulley and the largest cog just right. Too close and the derailleur can jam instead of make the shift onto the big cog.
After that, I showed him the low and high gear limit screws that define how far the derailleur moves in and out when shifting. I explained that once correctly set, those screws usually stay in place and don’t need adjusting. But, so that he could learn how they’re used, I changed the screws and let him put them back in the right place.
I also taught him how to operate the derailleur by hand, pushing to shift onto the larger cogs and letting go to shift back down. Testing shifting like this is the best way to tell if the limit screws are functioning correctly because you can feel the stops. NOTE: this is for cable systems only, not electronic shifting.
Finally, the Cable Tension Adjustment
Yes, I could have started with this adjustment, however remember that this was a lesson to teach adjusting shifting. So, I took the long way to get here in order to teach Frankie other important checks first.
To do this final tuning, I had Frankie connect the shift cable again as it was before we started. I told him to make sure all the housing sections that we’d pulled out of the frame stops were fully seated again. I also reviewed with him that we had verified that the shifter, cable and housing were A-OK. That the rear derailleur was adjusted correctly and that there was no issue with the cassette.
At this point, I jinxed myself by telling Frankie we only had one easy last adjustment to make to get his bike shifting perfectly again. I then proceeded to show him the cable tension adjustment barrel on the rear derailleur and told him how it works. That counterclockwise turns make the cable tighter. And that shifting hesitation like his and a bike coming out of gear after a shift are frequently the result of a slightly loose cable.
But, when we made this “easy last adjustment,” it did not fix the shifting hesitation.
Can you identify the issue and win our contest?
Those are all the clues in Frankie’s lesson – that turned into a mechanical mystery. Now it’s your turn to try to solve it. Again, we’re looking for a specific answer in order to win the contest and prize. If no one comes up with the exact answer we have in mind, the winner will be the roadie who comes closest. Good luck!
Ride total: 9,772
went to 11-42 cassette from something smaller. 1. a longer rear derailleur cage may be needed and 2. a longer chain to accommodate the larger rear cog (42)
I agree with William Wiesand – lengthen the chain. The photo also suggests that the chain is not wrapping properly, which results in compromised shifting.
Adjust the B screw. Probably needs to be tightened.
I was always taught to change out the chain when you put on a new cog set or chain rings. The new cogs and old chain aren’t playing well with each other.
This is a weird guess, but is the quick release somehow interfering with shifting? I’ve never see the lever on the drive side of the rear wheel; it’s always on the non-drive side. It looks like it might not be closed all of the way, as it’s hitting the frame. Didn’t want to guess chain length, as two others already said that!!
Good catch on the QR.
Hi Tony, since you were first to mention the QR being on the right side – and then several others mentioned it, I’ll reply to you and hope the other folks see this.
No, the issue with the shifting doesn’t have to do with the QR lever being on the right side of the bike.
And, what might surprise you – and the others who mentioned it, is that it’s actually recommended by component manufacturers to place the QR levers on the right hand side (drive side) of the bike when a bike has disc brakes. This is how Frankie’s bike was correctly set up by the shop that built it.
I will explain the reasons for this in next week’s column. Thank you!
Jim
Needs either a longer chain or working with the angle adjustment screw. The derailleur should be wrapping more chain on the bigger cogs.
A long-time riding buddy was continually cursing his Huret DuoPar for lousy and slow shifting. A quick look showed the chain almost vertical and connecting to very few teeth on the lower part of the cogs. That fix took seconds to resolve!
Replace the chain. The derailler is at max extension on the 2nd picture. A longer chain will allow the derailer to move to the last two cogs.
I wonder if axle/qr was not fully seated in the dropouts
Does SRAM have a B adjustment like Shimano? A larger cog would require the jockey wheels be adjusted farther back of they may hit (or come too close to) the cassette.
Needs a longer chain. The chain gets too tight, too short to be able shift to the larger gears.
Chain is too short.
My first guess was B-screw, but you covered that, second was chain length, but I’m at least third to guess that one. I’m going to go with “the barrel adjuster was already completely wound out and couldn’t tighten the cable.”
Frankie needs a better mechanic. One who will correctly install the QR. ; )
Each photo shows the rust on the chain, but there is no comment about lubing the chain in the diagnostic progression. Stiff chains shift poorly.
Answers so far makes sense, but could it be incorrect routing of cable in derailleur?
First thing I thought when I saw the top picture- QR is interfering with the cable? What is the lever doing on that side?
The cable loop is too long causing sloppy unreliable performanced. Shorten it.
The issue which I suspect has already been addressed. So, reaching further….Sometimes the lube in the shifter gets gunky. The solution is to degrease the shifter and re-lube.
Another potential issue could be that the cable housing to the RD is not the correct length and/or is causing friction on the shifter cable.
I can’t see the photos, but I would go with a stiff chain link. Or a loose cone/bearing on the rear wheel allowing the wheel and hence the cassette to move out of alignment with the chain and derailleur.
I would question the condition and length of the chain both.
The change in size could result in a chain that is slightly too tight, but I think that would only inhibit shifting to the largest chain ring.
A worn chain that has its links slightly misplaced, put on a new rear cog would result in skipped shifts and wonky shifting.
Jim, I win with one word – SRAM. That’s the main problem. haha
Cable housing is getting “caught/wedged” between the frame and the the qr lever, just enough to hold
the derailleur in place between shifts. Put the lever on the non-derailleur side
When Frankie changed the cassette, he put the quick release skewer in backwards. The lever is now catching the cable housing when he shifts to a smaller cog which then restricts the flow of the cable and prevents proper positioning of the rear derailleur.
It’s now 9 a.m. here in Santa Cruz, CA and there have been some great guesses. But no one has won the contest with the correct guess yet, so please keep trying. Thanks!
Jim Langley
Gunk or something wrapped around the bottom derailleur idler pulley causing it to seize up and the chain to hop over its teeth?
Chain too long by just a link or two?
Go get the big blue book from park tool and read the whole book enough said.
Go get the big blue book by park tool read the whole book enough said..
Not sure you understood the contest, Kevin. I will give the answer next week. So YOU have plenty of time to read the Park book if you want – and then try to answer the puzzle and win the contest 😉
Jim
Next off-the-wall guess…did he buy the right speed cassette for his bike? E.g., put an 11 speed cassette on 10 speed shifters?
There may be a spacer needed behind the cassette.
That bike was set up as an 11 speed and now has a 10 speed cassette on it so the derailleur won’t align properly with the cog spacing.
Also, turn the QR skewer around to the other side.
Bent Deraileur Hanger
That bike was set up as an 11 speed and now has a 10 speed cassette on it so the indexing on the shift lever won’t move the derailleur far enough to align properly with the new cog spacing.
Also, turn the QR skewer around to the other side.
Here was my thought as well – especially when you mentioned the answer is in the photo.
Bent tooth on DR or issue with pulley wheels (need lube, loose, bent or defective).
Chain ring loose, bent or defective or not positioned correctly vs the cassette..
BB loose or installed with incorrect spacer or incorrect spindle length.
Frame bent
Frankie chews gum when he rides?
I have run out of other options
Bent QR or QR springs missing or caught?
Frayed cable in the brifter. Just had the same issue.
The rear derailleur is too short and cannot handel the 42 cassette.
Is the 1.8mm spacer missing from behind the cassette? An 11 speed MTB cassette uses a 10 speed free hub spacing. This looks like an xt cassette and it would have come with an 11 speed cassette that would have not needed the spacer.
Wild guess but perhaps the clutch or the locking pin on the Rival derailleur are interfering with the cable tension. I’ve never had or worked on a clutched derailleur but this seems like a tension issue and logically the clutch might affect that.
Thanks for all the great ideas/guesses. It’s now about 12:30 here and no one has won the prize. A lot of same answers/guesses. So, you can go through all the tries and rule out those quickly and then try to think of other issues that could solve Frankie’s issue.
Good luck!
Jim
It could be a bad barrel adjuster, possibly sheared or stripped.
Cable routed on wrong side of the fixing bolt.
Cable guide on bb gunked up
End cap on cable housing crimped or hole too small restricting cable?
Might there be some damage to the derailleur just below the hinge and just left of the “Sram” printing? I don’t know how that would affect shifting, but it looks like perhaps part of the mechanism may have broken off in a fall on to the right side.
It looks like the shift cable end is somehow improperly going through the derailleur and might be interfering with its motion.
Multiple suggestions of a chain issue, which Jim has pointed out is not the answer. However, I think everyone should go put their bike in a stand and run through the gears. They’re saying it should be a longer chain when in fact it appears to need a shorter one. The picture shows the chain on the almost largest cog and the big ring with the derailleur almost full vertical, when on these gear positions it should be pointing about 20 degrees forward. It would be vertical on the smallest cog.
Shimano 1.2mm gear cable, when SRAM specs 1.1mm?
Cable clamped on the wrong side of the fixing bolt on the SRAM rear derailleur?
The derailleur cable is clamped on the wrong side of the anchor bolt. It should run to the outside side of the bolt, clockwise when viewed from the rear. Switch the cable over to the correct side of the anchor bolt. SRAM designed those extra cable lever arms to both change the cable travel ratio and to reduce the effect of incorrect anchoring, but they don’t work throughout the range.
That derailleur just looks wrong. On all my bikes, the upper (guide) pulley sits well ahead of the axle but here we see the upper pulley way back behind the axle. The parallelogram would normally be more horizontal, rather than pointing down at the ground. There’s much less chain wrap around the cassette cogs than I usually see, and effectively the derailleur is trying to do its work at the back of the cassette rather than the bottom. Jim does say that they confirmed the derailleur is the long cage version that can handle 42 teeth, and they adjusted the top screw for getting the clearance between the top derailleur pulley and the largest cog just right. So I’m not sure that’s the problem, but it’s very noticeable. .
Looking at it some more, it’s almost like the Cage Lock is in the locked position and needs to be released.
The chain looks a little wide. Is it correct width? Don’t like the rust either which would point to lack of lube and maintenance.
Hey Jim!
Have you tried checking the bottom bracket cable guide? Might need to put some grease on it and make sure the cable is not seizing on it,
Or, could it be that the SRAM master link is installed backwards (since it is unidirectional)?
Based on your comment that the problem is visible from the picture, it looks to me like the change is too long. On the gear the chain is on, I would expect the derailleur to be further forward. The top of the chain and the bottom should be almost parallel. To accomplish that, the chain needs to be shorter.
Maybe it’s not the derailleur. Since it’s a 1x, maybe the chainring isn’t properly aligned?
Bent derailleur hanger?
First, Jim, as you know I am old school, but I was a good mechanic in my days at the shop. I very rarely have opportunity to work on this newer equipment. But since you said the problem is visible in the pics, I figured that I have as good of a chance as anyone at figuring this out. So I copied the pics into my computer so I could zoom in on the details. I see two potential problems. First, I think there appears to be a piece of string or thread hanging from something near the lower pulley. Might that string be wrapped around something, or hung up on something, causing the shifting hesitation? The other thing I see is a very short end of the cable with the gold cap on it. I am wondering if it catches on part of the derailleur and causes it to hesitate until the cable comes free of whatever it is caught on? These are both guesses, but I bet I could find the problem if I had my hands on the bike.
I also see what I think looks like a tight link in the chain, but you said it isn’t the chain.
Well he should clean his idler wheels for sure but is that a crack in the body of the rear changer? I’m not familiar with that product so it is hard to tell.
Boy, some great thoughts from all of you. I really appreciate the comments and ideas. Nice to see so many friends, too. No one has identified the problem yet, though.
Wild guess, brake cable housing instead of shifter cable housing. Sorta think that’s it too simple. I’d also would guess it might be the Bb cable guide loose, it’s one thing you didn’t mention but it’s not really part of the pictures. I’m probably gonna kick myself when you reveal it.
My wife says it is rider’s error, either shifting under a load and/or not completely shifting thru the index.
derailleur pulleys are worn creating lateral slack causing shift hesitation
10 sp RD vs 11 sp?
Hey Jim (and John!),
Sorry to be MIA for so long! This is a fun challenge that has generated a lot of feedback.
When I’ve had mystery shifting issues in the past that were not fixed by cable, rear derailleur, of hanger adjustments, I look to the drive train.
I’ve seen stripped out rear der sprockets that prevent shifting altogether. The ones on his bike look like-new, but I would also check the bearings to ensure they are free.
The chain ring can also cause jumping in the rear when it is excessively worn. The wear on the shark-tooth teeth cause an effectively longer chain. However, this slack in the chain might make the chain jump momentarily to a lower/larger cog, which I’m not sure is what you are seeing here. It is hard to tell in the photo because this wear starts at the power stroke point on the chain ring, which is covered by the chain.
This is a tough one you’ve found for us, Jim!
Jim
Quick follow-up:
I’d love to see a photo from the back side but it almost looks like the chain isn’t routed around the top jockey wheel. It’s probably a perspective issue and it would make a ton of noise, so I’m sure that’s not it.
It also looks like something is fouling the lower jockey wheel that could cause some issues.
Alan
Directional chain installed backward.
I’m wondering why the quick release is on the wrong side, although I don’t think it would effect shifting.
There are a couple of rusty links on the chain that could cause decreased flexibility in the chain and difficulty with shifting.
B screw slipped off of the step on the derailleur hanger
Cable housing too short.
Derailleur Cable housing is too long and needs to be shorter for crisper shifting.
Due to inadequate vertical clearance, it appears that the upper derailleur pulley will shift into the larger cassette cogs.
Due to inadequate vertical clearance, it appears that the upper pulley will shift into the larger cassette cogs.
Loose derailleur hangar bolt.
Hesitation too easier gears and ease to harder gears is generally solved with a backing out of the cable adjuster. I have also seen chains pop out of the largest cog to the next one down if the inner limit screw is too “limiting”. But these have been mentioned.
Maybe we are all focusing on the rear too much. The issue may be a slightly bent chain ring.
Chain is not the correct length, If he changed the cassette and didn’t change the chain then that is the problem.
Loose / worn out free hub body. Or loose axle creating a little wobble.
I’m wondering if front deraileur changer cable is not tense enough. I had this happen on a cold day, which kept me from shifting, so had to finish the ride in one gear!
Thanks for all the tries and thoughts. It’s now a day later and no one has correctly identified what was wrong with Frankie’s bike. So we don’t have a winner yet.
Please let me know if you’d like me to start giving some hints. My concern is that not everyone will likely check back to see the hints.
But, if enough of you ask, I’ll give a hint, maybe a couple,
Keep trying! Thanks!
Jim Langley
The photos do not show the rear derailer in position on the largest gear. I suspect that if it were you would see that the chain is too short because in the photos it does not appear to have enough chain wrapped around the gear. Adjust the distance from the upper derailleur pulley to the cassette with the proper length of chain. This derailleur might not work with the 42t cassette.
Cable routing? Is the derailleur cable end pinch bolt pinching the cable the correct way? If not, this will affect the leverage (a loss), of the shifting action when going to larger cogs.
Rick
I notice the shifter cable and housing coming from the right (rear) shifter is routed to the left side, or opposite side of the down tube, and not the right side ,or adjacent side of the down tube as is the norm. The shifter cable could be impacting something internal to the frame as it crosses back to the right side opening under the bottom bracket which is shortening the cable throw, most noticeably when trying to shift onto the bigger dogs. That could play havoc with rear derailleur adjustment. Since there is no front shifting, it isn’t the likely culprit of both shifter cables looped around the other in an internally routed frame.
I would check to ensure that the rear derailleur has been installed correctly. If the spring loaded plate between the B-knuckle and the derailleur hanger has not be rotated back to catch against the derailleur hanger B-screw tab when bolting the derailleur to the hanger, there will not be enough tension on the spring. The B-screw appears to be set really low, suggesting it is either floating or pressing off the derailleur hanger directly and not the correct spring loaded plate.
A hint or two would be appreciated as we all can’t see the forest because of all the trees.
CONTEST UPDATE – AND A HINT! There are no correct answers yet (thanks for all the “entries”!). It’s awesome to see so many tries!
HERE IS A PRETTY BIG HINT:
At the end of the story, I tell you that using the adjusting barrel to try to fix the shifting hesitation did NOT work. I describe how I told Frankie it would be easy to finish the job by turning the barrel to slightly tighten the cable.
But when I did that, it did NOT fix the shifting hesitation. That’s a clue to use to figure this out.
KEEP in mind that a few people guessed that something might be wrong with the adjusting barrel. That’s a good guess, but it’s not the problem. Other folks said that something’s wrong with the cable itself. Not that, either. Then, people thought that the shifter or the routing or the housing was the problem. No. They’re all fine. Some asked about the routing of the cable around the anchor bolt. No, that’s fine, too.. And it has nothing to do with the chain, frame, chainring, cassette, etc.
The problem is something else. What is it? Think like a mechanic. The issue is something that you might hear from your boss, the head mechanic on your first day on the job. It’s basic stuff. (That’s not to say it’s easy or obvious.)
First person to figure it out wins. Good luck! More hints if there isn’t a winner by later today. Thank you!
Jim Langley
Maybe Frankie didn’t tighten the anchor bolt enough so that the cable was slipping.
Nice job David!! YOU ARE THE WINNER!
Well done. Please scroll down and see my comment telling everyone you won and about getting you the prize. CONGRATS!!
Was there enough tension in the cable? It sounds simple, and I assume you would have checked it after he played with it. But it’s a guess!
Thanks for the guess, Tony, that’s not what we’re looking for. Keep trying 😉
My guess is the chain is worn out and not engaging correctly with a brand new rear cassette or the chain is not compatible with the new rear cassette. no details on model number or manufacture, in the description above. I would change the chain out with a new one that is compatible with the rear cassette.
Jim: You said that the cable needed to be tightened to fix the problem but that turning (or trying to turn) the barrel adjustor did not work. Could it be that the adjustor was already maxed out? If so, the solution would to be to turn the adjustor all the way in, loosen the cable bolt and take the slack out of the cable, tighten the bolt and then use the adjustor as needed?
After reading your hint, all I’ve got is that you were turning the barrel adjuster and it was not engaging with the underlying existing screw, or you were turning it the wrong way.
I’m with Walt’s guess. Barrel adjuster out of travel, unhook cable, reset adjuster etc.?
Awe, just read your hint. Is the barrel adjuster, for some reason left hand thread vs right hand thread and you need to adjust it clockwise to tighten the cable?
Jim: You said that the cable needed to be tightened to fix the problem but that turning (or trying to turn) the barrel adjustor did not work. If you were able to turn the adjustor but nothing happened (cable did not tighten), then the cable is hung up somewhere. In that case, replacing the cable and housing should fix the problem.
When Frankie connected the shift cable, he failed to ensure the housings were fully seated.
Or, the cable is frayed or otherwise hung up in the rear DR or adjustor…just make sure they freely pass through the adjustor and DR opening freely (or lube or replace them).
Could it be that the shifter is not working properly or it got damaged and needs to be replaced?
Lube evrything!
Lube e cable and housing.
Lube the cable and housing.
Is the barrel adjust completely loosened already and has no travel left to adjust the cable tension? If so, dial the barrel adjust all the way in, loosen the cable fixing bolt and pull the slack out and then re-tighten the bolt. Then adjust the shifting as needed with the barrel adjuster.
WE HAVE A WINNER!!!
It’s David Zak
See his answer above.
Congrats David!! Thanks everyone for participating!!
David- please email me your address at [email protected] so I can send your prize. Well done!
Is the bolt tight?
Done. Thank you for the brain teaser today. I think we all got a kick out of it.
One of the chain links is broken , still held together by the pin and one side , but the link facing the inside could be broken and it’s hard to see.