stephr1

I wanted to roll this out from my previous thread (https://www.bikeforums.net/bicycle-m...st-way-go.html) because I may be down to one specific thing (tho, it still doesn't make sense and people must be tired of that thread since I received no responses...boo!

As a quick update...I reinstalled my previous rear der (RD-M410) and problem still not solved

So, the one last thing it might possibly be may be related to the chain and a not-so-recent crank/chainrings replacement. The bike originally came with a 24/34/42 crank/chainring set and new chains were physically sized against the worn out chain...no problem. About 4 years ago I bought a Shimano FC-M361, 28/38/48T crank/chainring set but did not install it until at least a year or 2 later (less than 3,000 mi. ago) when the previous chainrings wore out.

I cannot remember if I resized my chain at that time. I may have believed the difference was minor enough so it wouldn't be an issue...and it wasn't. So the same chain and chainrings have been on the bike since then, yet the problem seems to have shown up only recently. And that leads me to my title question:

How critical is chain length when different (in my case, larger) chainrings are installed? If I am off by 1 link either way (it might be 1 link too short since the old chain would have been sized for the smaller chainrings) could that be causing the problem I am seeing? Again, I've been cycling this way for over 1000 mi. with no problems until recently.

I performed the visual tests of large-cog-to-large-chainring and small-cog-to-small-chainring and the rear der adjusts pretty much as expected. There appears to be no binding of the chain (if it were too short) other than the on-going issue of the chain taking a moment to "settle" onto the cog from the jockey wheel.

There may be 1 last possibility if this isn't it...the most recent replacement was the 7-speed shifter that I replaced a month or 2 ago. It's fairly low end Shimano and I wasn't all that happy about the shifting even after I thought I had it adjusted (mentioned that it my original thread on all this: https://www.bikeforums.net/bicycle-m...showed-up.html - Posting #7.7).

I am at your/the expert's mercy...and I am not worthy (and right now, neither is my mtb

Thanks in advance and cheers.....

Rolla

One link either way usually isn’t a problem unless it is. In your case, I doubt it’s the culprit. Rule of thumb: when something goes wrong, look at the last thing you did to the bike. Me, I’d check out that shifter before I started adding or subtracting links.

stephr1

I didn't think so either and, like I said, it's been running that way for quite some time. The shifter is on the list for tomorrow. I did the rear der today because I found it and it only took me ~15 mins. to do the replacement. The shifter means I have to take off the handgrips and brakes before I can remove it and then put it all back on in reverse Figure I'll have more motivation tomorrow.

This must be somehow related to the saying: "A lost item is always found in the last place you look." translated: "The problem is solved with the last thing you fix."

Thanks much...maybe good news tomorrow...I hope....cheers....

Retro Grouch 

Whenever I have a rear shifting problem that doesn't respond to shift cable tension adjustment, the first thing I do is to check derailleur hanger alignment. Most of the time that turns out to be the cause of the problem.

With a 7-speed cassette, I can usually eyeball the alignment adequately accurate. Shift your derailleur into a gear combination that makes your derailleur arm hang nearly straight down. Now prop your bike up against something and look at the derailleur arm from the back. If your derailleur arm seems to be leaning toward the rear wheel - that's it. Bend it back so that it points straight down and you'll be good to go.

stephr1

I appreciate the response. The difference here appears to be the noise I can't seem to resolve. Shifting is actually good...smooth and responsive (as much as is possible with a low end system). I did look at the der hanger (actually is part of the drop out section of the frame)..Der screws right into it. Can't see any distortion to that..but always willing to check it again at this point (can you tell I'm desperate I expect when I figure this out I will prob'ly do a face palming and exclaim "D'oh!!"

KCT1986

Is this noise happening on multiple cogs or a specific few?

Seems that it could be a mismatch between the amount of wear on the chain and cog(s). Pitch of each is not quite matching up and causing the chain to not settle in properly.

Russ Roth

Doubtful the shifter doesn't work right. I've assembled thousands of bikes with cheap low end shifters and if they were shimano shifters I never had one that failed to work. It can happen but it would be incredibly low on my list. Often if a shifter was replaced and the shifting was crap or a new build with the same problem, it was due to a small kink in the cable typically up near the shifter. They love to kink just inside the barrel of the shifter and while it might look like it should be nothing the internals of a 4mm housing is tight enough it can matter. Pull the cable completely out of the housing and look for a very slight bend, that's probably your culprit. Often it allowed for decent but not great upshifting and would feel like the shifter was a little tight to push but was more evident on the down shift with slow downshifting and noise.

stephr1

Initially, I thought it was just in the upper (5-7) cogs. On closer examination, it was happening on the lower ones, as well, even on the No. 1, a cog I barely, if ever, use (I typically start in No. 2). I've been using the same chain for a long time, SRAM 850/870. Both are designed for 6/7/8 speed setups. I've also worn down cassettes much worse than this one is and never had this problem.

The only way the sound goes away (or is just not as noticeable) is if I'm already moving and I don't stress (not accelerating) the drive-side crank (does not happen on the left-side crank). So this problem seems to be related to tensioning/untensioning the chain on strokes (pretty much at the bottom of a stroke on the right crank). It's something I've never seen before in the 20+ years I've owned the bike.

Appreciate the input...cheers....

stephr1

The shifter was next (and last?) on my list to "get up close and personal". Your suggestion about the cable makes sense and I'll check that before dealing with the shifter directly. That could explain why I never felt the shifter was quite right (it was close and it seemed like shifting was fairly consistent, as in no noise, but I sensed there was something off) and it was the most recently replaced. I have had a "sticky" shifter in the past due to gunk on the cable/in the housing but it was very obvious that something was happening. This is a much more subtle (both insidious and frustrating) symptom

Curious if you ever ran into a problem related to the cable guides (not housings). I have one mounted on the bottom of the bottom bracket housing that supports both the rear brake and rear der bare cables.

Thanks much for the insight. I can only hope

Cheers....

stephr1

OK. Checked out the cable...no kinks, hinks or skinks No fraying, nothing that would indicate some sort of cable restriction I did notice a slight bend near the middle of the cable length, but figured that was where the cable goes thru/over the cable guide mounted below the bottom bracket on the bottom of the frame (both rear der shift and rear brake cable go thru this). Since I had the cable out, even tho it didn't seem to need it, I dry lubed the cable anyway.

I did notice 1 thing odd, but am not sure if it was just a result of the problem or symptomatic of the root issue of all this. I reinstalled my previous rear der (not sure why I replaced it, seems to work just fine). Possibly of interest is that this old der uses the smaller pulley/jockey wheels (10 or 11T) and the one I just took off uses the 14/15T wheels). I noticed (on the old der) that when I rotate the crank, the lower pulley end of the der was moving back and forth (front to back) as if something was more oval than round, or maybe more like what happens when shifts occur, tho the movement was very slight, maybe 1/4" or less. I'll have to check it out more closely, but I believe the movement was sync'ed with the lowest position of the right crank rotation (which is when the ticking/clicking noise occurred). I hadn't noticed this on the newer rear der so I'll have to look at that, as well. Maybe later on today or tomorrow, for sure.

I did a ride this morning and while the ticking/clicking was not completely gone, it did seem to go away (at least, hidden by road noise) for short periods of time, even when accelerating. Did not see any specific patter on on this. Seems to be an improvement, but no idea why (maybe cable lube?). By the time I returned to my driveway, the ticking was back pretty consistently and loud enough to notice.

Onward...and hopefully, upward....cheers....

stephr1

UPDATE (9/6/21):

Yesterday was a couple of short tests up and down my street and, while the noise was gone, I wasn't completely satisfied with the bike's shifting. This morning was back to my regular riding. Made a few adjustments at the shifter end at the start of my ride and I was amazed at the difference: smooth, swift and solid shifting up and down. I cannot remember the last time I felt that way about the bike (maybe things have not felt that good for a while so any improvement seems like a great one I currently have the previous rear der installed (cannot remember why I replaced it since it now seems to be working just fine) so I'll have put the newer one back in and see if/how that changes my perception.

One other good thing that came out of this overly-long process I had been threatening to clean/regrease my hub bearings for a while. While I've had the rear hub apart, I did just that. Now I just have to do the front hub, much easier

UPDATE (9/5/21): (oops, had the wrong month

CONFIRMED! Found the previous set of pedals that I used to replaced the current ones and the problems is solved. I have new pedals on order but the olds ones should hold till I get the new ones. In the meantime, I can get back to doing my longer Wed. AM rides...weather and fires permitting....Yay!!!!!

So simple, yet I made it an expedition. I guess that would be so "engineer" of me



Couldn't find a face palm emoji so this was next best However, a big "D'oh!" is in order.

Think I found it this time. Someone in a previous thread of this suggested I check the bottom bracket and pedals. Bottom bracket is fine and I thought the pedals were, as well. Apparently I didn't do a thorough enough inspection I checked it out again earlier today, only much more carefully, and it looks as if the right pedal bearing is worn enough that it could be making the noise I've been hearing. The left pedal is also a bit loose, but it's the right one that is more obvious.

And it looks like the other things I found in this process were simply incidental and, most likely, typical of the low end stuff.

The good news is that I've been holding off on my longer rides because I was concerned about the drive train having a serious issue (I know. The pedals are part of that but I was referring more to potential of some kind of chain suck too far from home The bad news is now I have to find new pedals and wait until I can install them. The ones I have are not designed to be repaired (low-end again). Other good news is I learned to keep at it until I found the issue, even if it meant retracing my steps.

I want to believe this is it. I'll know for sure with the new stuff installed. I might still have the original pedals I replaced almost as soon as I got the bike. That should confirm or deny things for me.

Thanks again to all for helping out on this. Yet another trial of bike self-repair. That's OK. I've got the time

Cheers.....