or a bent hanger
So, this might have happened... NBD - 2016 Fuji Touring workhorse
- Thread starter wafter
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or a bent hanger
Thanks both.
As I think I've posted elsewhere I've done my best to check hanger alignment, although this was hampered by a couple of factors - the fact that the paint on the hanger has chipped across the majority of the hanger (so no longer provides a flat / square register face for the tool) and potentially the cheap tool itself.
I'm tempted to take all the paint off that area to give a flat face, but am very much aware that this would mean running it unprotected as anything I apply is just going to get crushed / chipped by the RD.
I guess it's also possible that something more fundamental is at fault (the bike has had a new rear rim in the past - potentially due to accident damage) although I've not spotted anything glaringly obvious in the bike's behaviour / fitment of parts / whilst working on it that would suggest this.
Finally just to summarise the situation regarding relevant components and what's been done (with no longstanding difference apparent after any of the changes):
Cable outers: Replaced with new in areas of tightest rads (under bar tape from bar end shifters)
Cable inners: Replaced with new; hanging up / creep seems unlikely since ghost shifts happen in both directions
Shifters: Original; Creep seems unlikely since ghost shifts happen in both directions
Rear derailleur: Replaced with new
Cassette: Original, doesn't appear excessively worn, assume that if it was it'd be skipping as well..
Chain: Replaced, same behaviour with both half-worn (apparently) original and new replacement
Perhaps somewhat oddly the replacement derailleur (Shimano FD-M592-SGS from a reputable UK supplier) feels similar to the original (Shimano FD-M591-SGS) in terms of component movement - with a bit of slop in the parallelogram and maybe a couple of mm lateral float in the top jockey wheel. By contrast the GRX 810 item on my Genesis seems to have none of this movement...
Finally this isn't "just something that non-indexed shifters do", is it? I can understand a late / delayed shift if it's not quite aligned, ticks for a bit and finally makes the jump... however it's not right that it just shifts of it's own accord potentially minutes after the lever's been operated is it?
bikingdad90
Guru
It isn’t something stupid like the cable routing on the frame itself like the incorrect bottom bracket cable guide or when you flex the frame under load it is crimping/catching the cable?
Depending on the hub speed, it isn’t missing a spacer on the cassette and the cassette is moving under load?
Depending on the hub speed, it isn’t missing a spacer on the cassette and the cassette is moving under load?
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Thanks - feck knows tbh but I appreciate the suggestions!
AFAIK the BB guide is original with no obvious points of restriction; while I don't think it's related to frame-flex as it does it both under load and when just wafting along with little force at the pedal.
I did suspect the cassette; although there appears to be zero float / play present. The problem has been consistant in the near-4k miles I've put on the bike - which I think rules out sprocket wear as I'd imagine it'd be unuseable due to skipping by now.. on top of that I think it's all pretty low-mileage (original tyres when I bought it, probably original chain too at about 50% worn).
I do have a spare cassette but am not sure I can be arsed with the faff of swapping it all over; I guess it could rule out another component however.
When I changed the RD I also swapped back to the original inner cable (since the run is shorter and I didn't want to crimp the replacement I had been using inboard of its previous clamp-point in case I wanted to refit the original RD). I'd waxed this, which retrospectively might not be the best lube against the outer's synthetic liner...
Since a number of things have changed I've again been trying to note the circumstances under which the problems occur.
One definite example was a surprise shift up (to a smaller sprocket) just after down-shifting to hit a small hill; so I guess this could have been due to slop / creep in the shifter (being pulled to the necessary point to shift to the gear it was initially in, then "relaxing" / creeping back to allow the gear to shift to the next smallest) however IME it takes quite a lot of lever displacement to actually shift, and I've not noticed this much (or indeed any) movement of it's own volition.
I don't think cable drag could be responsible for this one since it had already been pulled enough to select the larger sproket, if this makes sense.. while I could understand this argument had it happened after an upshift.
I also had another couple of nasty ones under high load (although thankfully at low speed) - cadence and speed were that low that I'm not sure whether the two near-consecutive jolts could be attributed to a shift between sprockets or the chain skipping on the cassette.
Tbh this is really starting to piss me off now - it was much less of an issue when I was covering all of about 10 sedate miles a week on the bike; now I'm doing double that in a day it's breeding a lot of mistrust in the bike and making it feel really unrefined; which is a shame as it's a real pleasure to ride otherwise.
Maybe I'll pile all the necessary bits into the car and swap the cassette at the weekend; just in case.
Another tedious update..
I've not (yet?) replaced the cassette as it's a pain in the arse and I'm not convinced it's the problem. It's seemingly not covered that much distance, the problem has remained largely constant despite the addition of many more miles since purchase, the problem persists throughout the whole cassette rather than just on the most-likely-worn sprockets and @Gunk's suggestion of checking teeth for lips / burrs revealed no such issues.
I've still been attempting to consciously log the circumstances under which the shifting issues occur, and since replacing the RD it appears that all those I've been able to remember have been surprise shifts up (to a smaller sprocket) after an intentional shift down (to a larger sprocket).
This suggests to me a lever issue - with tension being applied to the cable via the lever, which then falls slightly when the lever is released allowing the RD spring to pull it towards the outside of the cassette slightly. Since this could be caused by a lack of lever tightness I've wound it up a little and fingers' crossed it's been fine for about 15 miles, with the exception of one little indiscretion which felt a bit different and could possibly have been the result of poor shifting on my part.
For the 72nd time, time will tell I suppose.
EDIT: Still behaving much the same as it was (i.e. ghost-shifting in both directions) on the way into work today... closest it's ever come to going in the river tbh
I've not (yet?) replaced the cassette as it's a pain in the arse and I'm not convinced it's the problem. It's seemingly not covered that much distance, the problem has remained largely constant despite the addition of many more miles since purchase, the problem persists throughout the whole cassette rather than just on the most-likely-worn sprockets and @Gunk's suggestion of checking teeth for lips / burrs revealed no such issues.
I've still been attempting to consciously log the circumstances under which the shifting issues occur, and since replacing the RD it appears that all those I've been able to remember have been surprise shifts up (to a smaller sprocket) after an intentional shift down (to a larger sprocket).
This suggests to me a lever issue - with tension being applied to the cable via the lever, which then falls slightly when the lever is released allowing the RD spring to pull it towards the outside of the cassette slightly. Since this could be caused by a lack of lever tightness I've wound it up a little and fingers' crossed it's been fine for about 15 miles, with the exception of one little indiscretion which felt a bit different and could possibly have been the result of poor shifting on my part.
For the 72nd time, time will tell I suppose.
EDIT: Still behaving much the same as it was (i.e. ghost-shifting in both directions) on the way into work today... closest it's ever come to going in the river tbh
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More idle and inconsequential thoughts while I wait for water to stop falling from the sky outside..
I've investigated the float in the top RD jockey wheel and found that it's apparently a Shimano thing that's intended to improve shifting, presumably because it reduces the precision required on the derailleur position to give correct alignment between chain and cassette.
I've also read suggested that the float is also of benefit to friction shifting; however I can see how it could potentially be a hinderence. On an indexed system (as everything was by the time the 9sp on the bike was established) a floating guide wheel might be handy for accounting for small discrepencies in alignment; where each click might consistently get the wheel within say half a mm of where it needs to be.
Conversely on a non-indexed setup it seems a given that RD / chain / cassette alignment will be far less consistant and precise. I can see a situation where the lever is operated just enough to cause a shift from one sprocket to the next, which could then potentially be "undone" by the c.1mm lateral float in the jockey wheel. This would be consistant with some of the "indecision" I sometimes experience after a shift, as well as the fact that the problem occurs when shifting in either direction.
To counter that idea it would seem reasonable to assume that during a shift the jockey wheel is pushed to one extreme of its lateral float within the cage (presumably resisting / lagging the direction of cage travel) so if anything float should push it further into engagement rather than out when floating.
Anyway I've had the pulleys out of the old RD (which I believe to be the same as those in the new one) and found that it should potentially be straightforward to shim the setup to effectively remove the float; I just need to get my hands on some appropriate shims.. worst-case it might at least rule out the float as the problem (although after this I'm out of ideas).
It was quite interesting to look at the different formats of the jockey wheels - the upper / guide one having a pretty neat four-segment plain bush pressed into the plastic wheel to run on the boss that's clamped between the sides of the cage, while the lower tension pulley just makes do with the plain placcy wheel running on the bush.
In other news I've made an effort to tidy up the cable ends on the bike. For reasons many will never understand I don't like crimped-on ends, so this time the cables have been cut to a nice clean square end with the cutting disc on the rotary tool and sealed with a blob of superglue applied to the end, which capilliaried in fairly nicely.
I'm hoping this will be enough to prevent them fraying; time will tell. Ideally I'd have preferred solder (which won't bond to stainless) or the neat fused finish you get on new cables although obviously I lack the kit to do this... I did wonder if a battery spot welder could be repurposed as it shouldn't take a lot of power.
Finally I missed the Fuji's "birthday" last month; it now having been with me for a bit over three years and covered around 4300 miles in this time; with about 2k miles having been since I moved in April. Persistant ghost shifting notwithstanding it's served me really well in this time even if the bar end shifters and arguably drops aren't ideal for city riding
I've investigated the float in the top RD jockey wheel and found that it's apparently a Shimano thing that's intended to improve shifting, presumably because it reduces the precision required on the derailleur position to give correct alignment between chain and cassette.
I've also read suggested that the float is also of benefit to friction shifting; however I can see how it could potentially be a hinderence. On an indexed system (as everything was by the time the 9sp on the bike was established) a floating guide wheel might be handy for accounting for small discrepencies in alignment; where each click might consistently get the wheel within say half a mm of where it needs to be.
Conversely on a non-indexed setup it seems a given that RD / chain / cassette alignment will be far less consistant and precise. I can see a situation where the lever is operated just enough to cause a shift from one sprocket to the next, which could then potentially be "undone" by the c.1mm lateral float in the jockey wheel. This would be consistant with some of the "indecision" I sometimes experience after a shift, as well as the fact that the problem occurs when shifting in either direction.
To counter that idea it would seem reasonable to assume that during a shift the jockey wheel is pushed to one extreme of its lateral float within the cage (presumably resisting / lagging the direction of cage travel) so if anything float should push it further into engagement rather than out when floating.
Anyway I've had the pulleys out of the old RD (which I believe to be the same as those in the new one) and found that it should potentially be straightforward to shim the setup to effectively remove the float; I just need to get my hands on some appropriate shims.. worst-case it might at least rule out the float as the problem (although after this I'm out of ideas).
It was quite interesting to look at the different formats of the jockey wheels - the upper / guide one having a pretty neat four-segment plain bush pressed into the plastic wheel to run on the boss that's clamped between the sides of the cage, while the lower tension pulley just makes do with the plain placcy wheel running on the bush.
In other news I've made an effort to tidy up the cable ends on the bike. For reasons many will never understand I don't like crimped-on ends, so this time the cables have been cut to a nice clean square end with the cutting disc on the rotary tool and sealed with a blob of superglue applied to the end, which capilliaried in fairly nicely.
I'm hoping this will be enough to prevent them fraying; time will tell. Ideally I'd have preferred solder (which won't bond to stainless) or the neat fused finish you get on new cables although obviously I lack the kit to do this... I did wonder if a battery spot welder could be repurposed as it shouldn't take a lot of power.
Finally I missed the Fuji's "birthday" last month; it now having been with me for a bit over three years and covered around 4300 miles in this time; with about 2k miles having been since I moved in April. Persistant ghost shifting notwithstanding it's served me really well in this time even if the bar end shifters and arguably drops aren't ideal for city riding
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I had the pleasure of experiencing some sprocket indecision earlier - characterised by the bike randomly shifting from one sprocket to the next and back again perhaps every 10-20 seconds.
Fortuitously this happened on a really quiet back road, allowing me to eyeball what was going on at the guide pulley. Sure enough (unsuprisingly) each unwelcome shift was accompanied by the guide jockey wheel moving from one extreme of its float to the other across the cage.
To put some numbers on this, IIRC the sprocket pitch on the 9sp cassette is around 4.3mm while as previously mentioned the lateral float in the guide wheel is around 1.0mm; about 20-25% of the pitch between the sprockets. Presumably it takes a fair bit less movement in the derailleur than the entire sprocket pitch to actually cause the chain to shift, however I can't off the top of my head think of a way this could be measured accurately / repeatably so it's probably easier just to remove the float and see if anything changes.
Finally I'm half tempted to pull to bits the GRX RD810 on the CdF to take a look at / measure the jockey wheels as these feel really tight laterally-speaking; suggesting that they're probably running on ball races which would probably be a better idea all around and probably quite a nice upgrade if they're a straight swap.
Fortuitously this happened on a really quiet back road, allowing me to eyeball what was going on at the guide pulley. Sure enough (unsuprisingly) each unwelcome shift was accompanied by the guide jockey wheel moving from one extreme of its float to the other across the cage.
To put some numbers on this, IIRC the sprocket pitch on the 9sp cassette is around 4.3mm while as previously mentioned the lateral float in the guide wheel is around 1.0mm; about 20-25% of the pitch between the sprockets. Presumably it takes a fair bit less movement in the derailleur than the entire sprocket pitch to actually cause the chain to shift, however I can't off the top of my head think of a way this could be measured accurately / repeatably so it's probably easier just to remove the float and see if anything changes.
Finally I'm half tempted to pull to bits the GRX RD810 on the CdF to take a look at / measure the jockey wheels as these feel really tight laterally-speaking; suggesting that they're probably running on ball races which would probably be a better idea all around and probably quite a nice upgrade if they're a straight swap.
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DCBassman
Guru
- Location
- The lumpy far South West
I'm beginning to think, having read these two posts, that you may have answered your iwn questions. As you effectively have a new setup with tjis replacement RD, go for a from-scratch setup as an indexed system. If it plays nicely, then non-indexed is perhaps not the way to go with those components. Otherwise, I'm still thinking misalignment somewhere. The float is definitely supposed to be there, but I can see why it might screw it up in non-indexed mode.
My memories of early indexed stuff, which nearly always had a non-indexed setting, was that they were less generally accurate, so needed the alternative.
My memories of early indexed stuff, which nearly always had a non-indexed setting, was that they were less generally accurate, so needed the alternative.
All uphill
Still rolling along
- Location
- Somerset
Have you tried the bike with an unwaxed chain?
Well, to an extent as I've not replaced everything. In principle I agree with your suggestion although in practice indexed options are very limited and I'm not prepared to expend the time and money in exploring this route.
The current shifter will do indexed, but as previously mentioned in this thread I can't set this up properly as the indexed increments on the shifter appear to be mis-matched with those at the RD.. although I wonder if the effect of this is being exacerbated by the floating setup too - i.e. as the position of the RD becomes progressively more out of phase with the sprockets, the float is allowing the chain to skip to the adjacent sprocket earlier than it otherwise would had it been fixed.
Ultimately it seems that the far easier and cheaper route currently is to investigate the role of the jockey wheel float by removing, or at least minimising it.
Not consciously / intentionally since it was all cleaned up post-purchase; and given the mess involved I'm reluctant to do so now.
