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Ghost shifting?

Old 11-14-23, 07:27 PM
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Ghost shifting?

I rode my Roubaix for the first time in a while today. I noticed on some mild upslopes it was sounding like it was between gears then it would upshift then downshift on itís own.
Is this maybe just a cable that needs adjusting?
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Old 11-14-23, 07:46 PM
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I rode my Roubaix for the first time in a while today. I noticed on some mild upslopes it was sounding like it was between gears then it would upshift then downshift on it’s own.
Is this maybe just a cable that needs adjusting?
Yes so do a little research so you know enough to fix the problem
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Old 11-14-23, 07:50 PM
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Originally Posted by Rick
Yes so do a little research so you know enough to fix the problem
I used to work on Honda motorcycles. I should be able to work on my bicycle but they are 2 different worlds.
​​​​​​​ I really need a work stand.
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Old 11-14-23, 08:41 PM
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Originally Posted by pepperbelly
I used to work on Honda motorcycles. I should be able to work on my bicycle but they are 2 different worlds.
I really need a work stand.
My workstand:

Take note that it's outside. Still gets the job done on nice days and probably why my neighbors are always hitting me up to work on their bikes. If adjusting your cable tension doesn't sort your shifting then assume your cassette or chain is worn. Chain wear can be measured, cassettes are a little trickier to diagnose. Good luck
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Old 11-14-23, 08:41 PM
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The Park Tool repair guides are very good. They explain each step, with essentially no prior bike mechanic knowledge needed.

You might just need a simple barrel adjustment.

Other possibilities:
A slightly bent derailleur hanger, if the bike was tipped over or the derailleur banged into something.

A fraying cable! The cable usually frays inside the shifter, where it makes a bend. One strand at a time break. At first, it's "gears are noisy, I should adjust when I get home", then "I have to shift twice then back once to make a shift", then Snap -- the last few strands break.

There should be a window to see the cable in the shifter body where it makes the bend.

I once saw a Sram rear derailleur that had a sharp cable bend in the derailleur body, and it was fraying there.
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Old 11-14-23, 09:30 PM
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It only happened in the small front chainring and small rear gears. I thought it might be from cross chaining under higher pedal pressure.
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Old 11-14-23, 11:12 PM
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pepperbelly: I should have been a little less vague on the subject. When you post you should try to be a little more informative like you have been in your next two Comments. A stand does make it easier but until you have one. You can use a piece of rope or twine to raise up the rear or the whole bicycle. If you have a garage or even the limb of a tree. With at least the rear end off the ground you can shift through the gears and check the adjustment of the derailleurs. As suggested by another forum member and myself video guides on YouTube by Park Tool or others offer plenty of details. A simple barrel adjustment, Debre between the inner wire and housing or frayed inner wire causing friction and such can be a problem also. A simple barrel adjustment because of the inner wire stretching is quite common. As you gain experience from having to run down these things you will be able to share your knowledge with others. I awoke this morning just after 0300 with congestion and a sore throat. It has been a couple of decades since this has happened so my Poor communication skills are currently even worse.
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Old 11-15-23, 03:59 AM
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Originally Posted by pepperbelly
It only happened in the small front chainring and small rear gears. I thought it might be from cross chaining under higher pedal pressure.
best avoided anyway but I still wouldnít expect the symptoms you describe. Sounds like maybe the cable is sticking a bit (possibly in the shifter as described above but maybe elsewhere in the housing) and the mech spring isnít able to pull the chain across cleanly, which is more noticeable at the small cog end where the spring is a bit less loaded
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Old 11-15-23, 08:34 AM
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There are about a bazillion decent work stands on Craigslist and eBay. Building one is a waste of time IMO if you want something really versatile. I have two like this and they are just great

https://www.ebay.com/itm/174804678707?epid=25009753308&hash=item28b32bb833:g:WCsAAOSw1dJbXqfH&amdata=enc%3AAQAIAAAAwCuP2bJw7Y oSRTBGMSuhOoBxSvo6KVK8ysnU%2B5YdKfBlfc%2BLE3c6jyAJUjdEYSNS8s7v1l0o27SS3U7HhFh1C2kp1KiiXjgoaf5yi%2BRc MOhkhvD%2F6ExUUyoUlLDcEPcbSi%2FSK9YAOMQKg9h4w%2Ba1CESejFG3ju1naiCv6V4Cy9zGKZ9k%2FZCakaNUqSIXCqb7g7qc ULAeOstrG1Rq9YGs%2B8rTQpTwWCmguIHfib%2BlXFRAzgxGaSzM49I9glrencb09A%3D%3D%7Ctkp%3ABlBMUPy-xLb6Yg

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Old 11-15-23, 09:29 AM
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Pep, You Definitely Need a Workstand.

Ghost shifting - New cables and housing is always a good thing. For me, ghost shifting has been due to the rear derailleur hangar. The RD hangar alignment tool is about $50, and I do not recommend the cheaper aluminium types..
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Old 11-15-23, 09:46 AM
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Is there a particular direction that the RD was being shifted that seems to cause it to happen or is it occurring no matter which direction the last shift was?

If the last shift was to a cog with less teeth, then I'd suspect a frayed cable in the STI or shift lever housing or binding somewhere. But not a given that that is the issue. The other possibilities as well as this have already been mentioned. Or it might be just a 1/8 to 1/4 turn of a barrel or inline adjuster.

I suppose this isn't a very old Roubaix that you put a new chain on just before you took a recess from riding it. If it is, then perhaps a cog is worn, but that's a stretch. Only once in my life have I worn out a cog on the rear or a front ring.
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Old 11-15-23, 09:50 AM
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Originally Posted by pepperbelly
I used to work on Honda motorcycles. I should be able to work on my bicycle but they are 2 different worlds.
​​​​​​​ I really need a work stand.
A rope hanging down with a loop for the seat works is all you need. I use a second one with a hook for the stem occasionally.
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Old 11-15-23, 10:04 AM
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Originally Posted by Iride01
Is there a particular direction that the RD was being shifted that seems to cause it to happen or is it occurring no matter which direction the last shift was?

If the last shift was to a cog with less teeth, then I'd suspect a frayed cable in the STI or shift lever housing or binding somewhere. But not a given that that is the issue. The other possibilities as well as this have already been mentioned. Or it might be just a 1/8 to 1/4 turn of a barrel or inline adjuster.

I suppose this isn't a very old Roubaix that you put a new chain on just before you took a recess from riding it. If it is, then perhaps a cog is worn, but that's a stretch. Only once in my life have I worn out a cog on the rear or a front ring.
It is a 2013 that I bought used in 2020. I put a new chain on it then and have only ridden a few hundred miles since. I use White Lightning wax chain lube.
Riding around town I tend to stay in the small front ring. I was in a smaller gear in the rear but not the smallest.
I am going to check the cable and shifter and derailleur. When I get out later I will put it in the large front ring and see if the problem is still there.
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Old 11-15-23, 10:06 AM
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Originally Posted by 79pmooney
A rope hanging down with a loop for the seat works is all you need. I use a second one with a hook for the stem occasionally.
I really prefer it to be held steady. It would swing too much on a rope.
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Old 11-15-23, 10:16 AM
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I tend to stay in the small front ring. I was in a smaller gear in the rear but not the smallest.
A quick solution might be to just shift to the big ring on the front and two cogs bigger teeth on the back. Unless you have unusual gear combos on your bike that will put you in almost the same gear ratio or gear inches for pedaling effort. It's possible that the angle the chain is making from the small ring to the smaller cogs that it is just too much angle for the bike at the moment. Perhaps when the bike was used regularly that you didn't have this because everything was limbered up. Sitting for awhile the lube and gunk everywhere is just not letting things fall into place as quick as they should.

If you don't have the problem going to the two smaller cogs when in the big ring, then I might just say you either need to ride more or just clean the cassette and lube everything well. Or do both!

Your chain will probably last longer if you wouldn't x-chain. As much as I hate to sound like those that swear your bike will explode the moment you x-chain, I will agree that avoiding the small/small or big/big will be better for chain and cog longevity. You'll almost always have a combo that is or is close to that ratio/gear inches in the other ring.

Last edited by Iride01; 11-15-23 at 10:19 AM.
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Old 11-15-23, 10:56 AM
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Originally Posted by Iride01
A quick solution might be to just shift to the big ring on the front and two cogs bigger teeth on the back. Unless you have unusual gear combos on your bike that will put you in almost the same gear ratio or gear inches for pedaling effort. It's possible that the angle the chain is making from the small ring to the smaller cogs that it is just too much angle for the bike at the moment. Perhaps when the bike was used regularly that you didn't have this because everything was limbered up. Sitting for awhile the lube and gunk everywhere is just not letting things fall into place as quick as they should.

If you don't have the problem going to the two smaller cogs when in the big ring, then I might just say you either need to ride more or just clean the cassette and lube everything well. Or do both!

Your chain will probably last longer if you wouldn't x-chain. As much as I hate to sound like those that swear your bike will explode the moment you x-chain, I will agree that avoiding the small/small or big/big will be better for chain and cog longevity. You'll almost always have a combo that is or is close to that ratio/gear inches in the other ring.
Would WD-40 at the shifter and derailleur help?
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Old 11-15-23, 11:04 AM
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Originally Posted by pepperbelly
Would WD-40 at the shifter and derailleur help?
WD-40 is a great cleaner but short-lived on the lubing side of things. I'll use it to clean up the derailleurs and shifters and then use lithium grease for lubing.
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Old 11-15-23, 11:21 AM
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Originally Posted by pepperbelly
Would WD-40 at the shifter and derailleur help?
I'd try it. Whether it will or won't help will depend on why you are having the issues.

WD 40 is a better cleaner than it is a lubricant with longevity. Cleaner cogs might let things slip in place better. But if the problem is for the many other reasons mentioned, it's unlikely to help or solve the issue for very long.
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Old 11-15-23, 02:19 PM
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Originally Posted by pepperbelly
Would WD-40 at the shifter and derailleur help?
NO! WD 40 would be a poor choice at either but especially at the shifter. WD40 has a lot of uses, bikes is not one of them. Any lube applied to the shifter is likely to attract dust, dirt or sand increasing wear and making things stick.
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Old 11-15-23, 03:01 PM
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I took it out for a ride using the big ring.
It did ok but there is a sort of noise.
I cut the ride short after 4 miles because it sounded like something was in the spokes and it felt like it was slipping gears.
I will take it my a lbs tomorrow and have them see if something broke.
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Old 11-15-23, 03:45 PM
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Originally Posted by pepperbelly
It is a 2013 that I bought used in 2020. I put a new chain on it then and have only ridden a few hundred miles since. I use White Lightning wax chain lube.
Riding around town I tend to stay in the small front ring. I was in a smaller gear in the rear but not the smallest.
I am going to check the cable and shifter and derailleur. When I get out later I will put it in the large front ring and see if the problem is still there.

My last road bike was a 13 Roubaix Expert. I know the ins and outs of the Roubaix.
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Old 11-15-23, 04:59 PM
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Originally Posted by frdfandc
My last road bike was a 13 Roubaix Expert. I know the ins and outs of the Roubaix.
Mine is a Ď13 Roubaix Comp.
I just went out to check it. The rear wheel spins easily. I lifted the bike by the seat stem and hand cranked the pedals. In big ring or small ring there is a grinding feeling. I think the bottom bearings are bad.
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Old 11-15-23, 05:53 PM
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If the bottom bearings are bad, instead of simply replacing them what are the upgrade options?
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Old 11-15-23, 05:55 PM
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Originally Posted by pepperbelly
If the bottom bearings are bad, instead of simply replacing them what are the upgrade options?
Not much. They are fairly standard. You can get better bearings with tighter tolerances etc but theyíre probably too good for most bike frames.

Unless the ones you have are only sealed on one side. I vaguely recall I had a bike with a pressfit shimano BB that was supplied with those. Got fully sealed bearings the next time which lasted longer. But also didnít go through a flood.

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Old 11-15-23, 06:05 PM
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Originally Posted by choddo
Not much. They are fairly standard. You can get better bearings with tighter tolerances etc but theyíre probably too good for most bike frames.

Unless the ones you have are only sealed on one side. I vaguely recall I had a bike with a pressfit shimano BB that was supplied with those. Got fully sealed bearings the next time which lasted longer. But also didnít go through a flood.
I am not sure which bottom bracket/bearing mine has. I came across an abec 3 set that screws together rather than having a press fit. I think it was for a PF 30. My Roubaix has a carbon frame. Apparently that makes finding which bb it takes complicated.
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