Sram eTap rear derailleur sporadically stops shifting - then performs all queued shifts at once?

Discuss light weight issues concerning road bikes & parts.
jbattermann
Posts: 14
Joined: Mon Feb 20, 2017 10:47 pm

by jbattermann

I've a ~9 months old Sram eTap groupset on my road bike and recently it started to act quite strangely, in two occasions outright dangerously by stopping to perform any rear up or down shifts.. for about half a minute. Then it performs/performed all 'queued' up shifts at once.. meaning when going uphill it is only super annoying or hard to keep pedaling, however on a busy / open road with lots of passing traffic this has caused me some.. worries, to say the least.

This behaviour only happens every few rides and then only one or two times.. so at first you often don't notice it after the first shift it didn't perform.. but when you keep shifting and nothing happens, you intuitively hit the shift button again and again to get it to work etc.. and once you realize it is happening again, you have an unknown / 'uncounted' amount of shifts queued up which all get executed after (what I assume) is some sort of timeout period.. at once. Meaning you may end up dropping a sh*tlaod of gears / going up and down etc.. and when this happens (as I don't know the exact time it always is a 'surprise' when it starts shifting again) you might end up slightly surprised... tumbling.. which is never ideal. Front derailleur shifting works during that rear derailleur "blackout" regularly.. so I can shift from large to small chainring and back.. only the rear derailleur is not reacting for a period of time.


I've contacted Sram but haven't heard back yet and I was wondering if anyone else has noticed / had this problem before?

I've obviously recharged and even replaced the two derailleur battery packs, replaced the shifters' batteries (and all 4 indicator leds are green), I've repaired the entire groupset - both didn't help.

This bike and groupset has never seen rain, the problem occurs 'all over'.. so not in one particular location where I might ride by and have some sort of radio interference.. so.. yeah. I am somewhat clueless what's going on and it's a bit more than just annoying by now.


The only thing that might be related.. or well.. correlated time-wise is that I think it started when I paired the groupset with my Wahoo Elemnt Bolt. That's roughly when I noticed it first.. but I've removed it from the Bolt gain and also repaired the groupset (not with the Bolt but by itself the 4 components).. so it might just be a mere coincidence.

Does anyone know if there's a way to reset the groupset to bare factory settings or anything else I could try?

Thanks,
-J
Last edited by jbattermann on Fri Aug 17, 2018 1:06 pm, edited 2 times in total.

by Weenie


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VTR1000SP2
Posts: 320
Joined: Tue Nov 05, 2013 8:21 pm

by VTR1000SP2

I have the exact same issue and am unable to resolve it. As I bought my groupset 2nd hand, I have not contacted SRAM for any warranty.
42.

Jugi
Posts: 109
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

There is one mechanical reason I can think of. The rear derailleur has a safety circuit built in, which is trying to prevent the servo to run the cage against an obstacle. This can be demonstrated by removing the chain and adjusting the RD so far inboards, that it ends up resting against a spoke. The RD stops when it confronts that obstacle. If the rear wheel is then spun enough for the spoke to move out of the way, the RD will continue to the next indexed position.

So I'm speculating whether the RD's joints are moving freely. If not, that might engage the safety circuit. I'm not at all certain whether the safety circuit would "remember" all shifts done after stopping.

sungod
Posts: 1644
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

if an electronic system starts behaving erratically and there's no likely external factor, it's generally a sign that it's on the way out

the effect you report matches a few other posts about rd failure, in those cases i think the problems were resolved by replacement

i'd just warranty it before it fails completely

Jugi
Posts: 109
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

Although it would require some time to troubleshoot, I would definetly try to make it pause when the bike is standing still with the chain removed. If that would be repeatable, it is most likely and electric issue.

Noctiluxx
Posts: 388
Joined: Tue Feb 07, 2017 7:17 pm
Location: Southern California

by Noctiluxx

Two of the guys I ride with have eTap on their bikes. Both have had multiple issues with derailleurs not shifting and battery issues.
2018 Bianchi Oltre XR4, (Celeste Matt)
2018 De Rosa SK Pininfarina (Blu)
2017 Giant TCR Advanced SL (Red)
2016 Specialized Allez DSW Sprint (Gold)
2016 Giant Anthem Advanced SX (FS)
2018 Trek Farley EX 9.8 Fatty (FS)

jbattermann
Posts: 14
Joined: Mon Feb 20, 2017 10:47 pm

by jbattermann

So Sram's service wrote back yesterday with the exact same reply others have gotten - to bring it back to my bike shop / dealer and have them contact the affiliate service center.

@Jugi - that makes sense and I was "hoping" that maybe the derailleur was dirty, dry as bones or had maybe caught some small piece/obstacle that might interfere with the shifting but the derailleur is (as far as I can tell as) clean as new, the moving joints are lubricated and nothing appears to be causing any problem here :-/

So yeah - I am not particularly happy that this appears to be more common than "just me" oh well - I hope the replacement doesn't take all too long..

sungod
Posts: 1644
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

unless you know what % of devices develop a fault there's no basis for thinking it's a "common" issue

it's simply an issue that there's been a few posts about, there're more posts about other issues with other electronic groupsets, without knowing the population and operating hours there's no way to determine actual failure rate, and that's still excluding whatever effects environment/installation/operation may have

imho as most cyclists will have been used to mechanical components for years/decades, there's an unconscious expectation that electronic components will behave in similar ways

i.e. with mechanical...
- degraded performance will often be due to it needing a clean/lube/tweak
- some failures will have a workaround to keep going with some functionality
- it'll pretty much go on forever until it wears out, which could be decades

electronic groupsets are different...
- broadly speaking, digital electronic systems either operate perfectly or they are dead, sometimes there's a period of intermittent problems between the two
- batteries will need replacing every few years
- components do degrade, sometimes unexpectedly fast if there's a problem in manufacturing/assembly/application/usage, you can't get at them to replace
- the internal mechanical elements will be subject to wear, they're not accessible to repair/replace
- it's probably not going to last decades (but then how often do you replace your tv/phone/computer/etc. ?)

these are generalisations, electronic systems can deliver remarkable reliability and survivability if designed/built for it, but in the consumer world there's a need to also be commercially viable, and for bikes we want lightweight/sleek stuff, there's a compromise to achieve this

if etap, or di2, or eps start doing odd things or die, then unless it's plausibly related to a software update i'd say it's a fair bet that there's a fault and that it is not going to get any better, cleaning/lubing/tweaking probably isn't going to help, just accept the inevitable and either invoke warranty or replace

if you can't afford failure, get a complete set of spares, and test it regularly, because it will also fail one day

Global
Posts: 28
Joined: Fri Nov 24, 2017 4:50 am
Location: Temecula California

by Global

Have had three wifli rear derailers fail since March on my tarmac. Fourth quit today will be changing shifters and derailer this time. My wife has had no problems with hers.
Global :)

sungod
Posts: 1644
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

makes one wonder if there's a batch problem, it does seem like most of the reports of this have been over the last few months, but without population data available only sram will know

SLCBrandon
Posts: 733
Joined: Fri Oct 05, 2012 3:52 am

by SLCBrandon

Knock on wood but I’ve had 4 etap groups and all have been flawless, for what it’s worth.

ArtV
Posts: 13
Joined: Tue Mar 01, 2016 3:23 am

by ArtV

I returned one for warranty work due to the same issue.

Fisherfreerider
Posts: 164
Joined: Thu Sep 29, 2011 1:19 am

by Fisherfreerider

I have been having this same issue recently as well. I plan to reach out to SRAM this week.

Frankie13
Posts: 431
Joined: Thu Jan 27, 2011 9:52 pm
Location: USA

by Frankie13

I had same problem and contacted competitive cyclist and only 3 days Sram shipped a new one to CC and they overnighted the new one. You have go through the place you bought it from for warranty. New one works trouble free so far.

pulmark
Posts: 1
Joined: Tue Sep 13, 2011 9:54 am
Location: Finland

by pulmark

I have the same problem. I bought the eTap road upgrade kit (short RD cage) early May this year from Germany. The RD worked without problems for 2 months and then started to jam and miss the shifts. Really annoying and even dangerous that RD seems to queue missed shifts and then executes them later at random time. Especially during sprints RD suddenly making multiple shifts randomly poses a serious fall hazard.

My opinion is that it is a serious software design flaw if RD does spontaneous, random shifts without any warning or any user input. The user input (in/out shifts) buffers should be cleared and user input disabled immediately when RD freeze happens and cage should not move afterwards but it should stay on the same cog until failed state is over and then user input allowed again. Just wondering why SRAM doesn't do a recall or at least provide software update to fix the random shifting after RD freeze problem.

The consistency that I have noticed is that freeze always happens 1st when shifting inboard. I contacted SRAM support and they adviced to sent RD to shop where I bought it for warranty evaluation. I asked about lubrication of the pivot joints and they don't recommend it at "sale level" so I haven't done it to avoid voiding the warranty.

Usually a bunny hop with the bike releases the RD jam when riding. When bike is on service stand, gently pushing pivot joint often completes the shift. The freezing doesn't depend on setup (chain length, limit screws, B-screw) because it happens also when wheel and chain is removed.

The package box for RD has part number (00.7518.085.000) and time stamp, mine stamp is 2017, week 07. It would be nice to know what your time stamp is... I suspect that there might be some sort of batch problem in manufacturing.

by Weenie


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