ClydeClydeson

Polaris OBark Generally just the left side, but if a damaged crank has been reattached and torqued down and ridden and the crank re-loosened itself more than once, then damage to the spindle can result from Al oxide or other debris embedded in the aluminium acting as an abrasive on the spindle. On a square taper spindle, you can sometimes see the previously 'sharp' corners on the edges of the flats are polished and less 'sharp', and in that case the spindle should also be changed. I haven't worked in a shop since early in the 'splined-taper era' so I don't know specific clues to indicate a modern spindle is damaged. Of course, modern cranks generally have the R side arm and spindle as one piece, so if the spindle is damaged then the whole crankset needs replacing.

icemilkcoffee 

Pic assist




I agree that the shop is at fault 100%. Now having said that, the splines don't look all that horrible. If the arm goes back on the spindle and doesn't exhibit a lot of slop, I would just put it back on and tighten it good and tight and keep on trucking. It's easy to do at home.

ClydeClydeson

I wouldn't put that back on. There is potential for damage to the spindle/DS crankarm assembly if the splines are no good and result in movement and wear. Replacement L side crank arms are not expensive.

DorkDisk

This person is either lying or is very inexperienced. NDS falling off a HTII is very common.

jccaclimber

1. This is the shop’s fault. They owe you a new crank. While I wouldn’t mention it to them now, I’m not sure if I’d let them work on my bike again, assuming that you have alternatives. While I would let them install the new crank if they want, I would also remove and reinstall it myself before actually riding it.
2. The crank arm was likely rocking back and forth ever so slightly and also making creaking noises as it worked it’s way off. The fact that you didn’t notice this does not in any way change what happened, or who’s fault it is.
3. That NDS crank arm is done for, I would not reuse it. Those splines look terrible.
4. TBD on the DS arm/spindle. You’ll need to clean it up, though I wouldn’t do anything to it until after the situation with the shop is resolved.

anotherhillyay

Thank you everyone for taking the time to reply and offer support. I apologize for not responding sooner, or individually, but I hit my post limit yesterday and was unable reply.

Update: I took my case (not the bike, the original shop still has it) to another bike shop with a Shimano service center this morning. I explained everything as best could to the service manager, adding what I learned from you all yesterday and asked some specific questions about the crank set. He said if it was a service issue, I would have most likely experienced the failure within a short amount time of the first ride after the tune up. He seemed to lean on it being a potential manufacturing issue and suggested I allow the original shop to file a warranty claim.

So that's where I am at.

My LBS has filed a claim and given me a 2 week estimate for an answer. If Shimano accepts the warranty claim I'll bring any work done on the bike to another shop for inspection. If Shimano rejects my claim I'm not sure what other options I have, other than biting the bullet so I can get back on the road ASAP. After a little research last night I learned that this shop had been bought by Specialized last fall. Maybe I'll have better luck reaching out to corporate.

Regardless of the outcome I want to thank all of you for your replies. What an awesome community. I never expected to get this level of support. So, thank you! I'll keep updating this post for the curious as I learn more.

cxwrench

2 weeks? That's complete BS. The one I did last week I received an RA to send the part back during the initial phone call. We were strongly led to believe that the warranty would be denied. They ended up covering the part and had a new one to us in 3 days from them receiving the broken one. Sounds like your shop is staffed by a bunch of monkeys.

jccaclimber

I hesitate to disagree with the second service manager, but I still firmly believe that this is the shop’s fault, not Shimano’s. If it had fallen off 6 months and 2k miles from now we could debate it, but it seems rather unlikely that a previously functional system coincidentally failed where and when it was worked on.
As to if Shimano opts to cover it, maybe they’ll do so as good will to the shop. When I worked the warranty side of a large Tier 1 auto supplier we inspected 100% of our parts that were replaced under warranty at car dealers. Somewhere around 20% of the returns were fully functional as we received them. Another 30% or so were fully functional once we undid whatever misadjustment the dealer tech had done. So, a solid half of warranty returns were in fact just fine. A few were very obviously tampered with by the customer, damaged in a collision, etc. Mind you, all of these were covered under warranty, and the incorrect ones were considered the cost of doing business.

anotherhillyay

Perhaps it is a regional issue? The other bike shop mentioned it was unlikely to take that long but he had experienced delays in some cases. I'm hoping it is a matter of under-promise, over-deliver in this instance.

anotherhillyay

Encouraging to read, thanks for sharing this. After looking up the exploded view of the crank arm I'm feeling 50/50 about it. The left hand adapter on the NDS crank arm would be an easy fix. I'm assuming it machined pressed so just pop out the bad one and replace it with a new one. But the DS crank arm, from what I can tell, is unibody construction so that might be the cost hang up. I'm placing a call with corporate today just to cover all my bases. Thanks again for replying.

himespau 

If all the rides were roughly the same length, we're talking at most 100 miles. I'd put that within the time frame to be a poorly tightened crankset by the shop, but, if you can get Shimano to warranty it, it'll let the shop save some face and get you the new crankset without having to fight them (but, yeah, it's most likely their mistake).

cxwrench

No, it's not regional. The shop calls Shimano. They speak to a rep that uses his experience and Shimano's guidelines to determine if a warranty is in order. If it is a warranty situation he processes the order and has a replacement part sent out if they have it in stock. They generally will provide an RA# for return of the damaged part. If they need to inspect the part before approving a warranty they provide the RA# at that time and you send the part in asap. Generally the ONLY waiting is for shipping time.

anotherhillyay

Suppose Shimano looks at the crank and determines it was a service issue. Would they have any means to enforce the LBS to replace the part? My only contact with them is through the LBS so I have to trust whatever they tell me is sound, which I can't do at this point. As a customer, would I ever be involved in the RA process? Could I follow up with a Shimano rep personally?

smd4

Could this be the reason for a long delay?

anotherhillyay

UPDATE: Warranty claim was accepted.

I received a call from a store manager informing me Shimano was warranting my claim. They are giving me two options: 1. Replace just the NDS crank arm and call it a day. 2. Replace the entire crankset. Option 2 however has a couple of caveats. In order to get my issue resolved ASAP the crankset ordered will come with a chainring of 52-36 vs. the stock 50-34. Also, they informed me there's a possibility that it wont work with my current derailleur given the increased size of the chainrings. They will swap the chainrings if I would prefer to keep it stock, and of course if it isn't compatible with the derailleur.

I'm going with option 2 as I feel more comfortable with a complete swap, especially after the feedback I received about the spline damage on the axle. I'm going to do a little homework on what the difference in chainsets will mean to my riding. It may not matter at all if the chainset isn't compatible, but if it is, it may even end up being an improvement. I have until early next week when the part is scheduled to arrive to figure it out.

Once I have the bike in my possession it'll bring to a different LBS for inspection. If all goes well I hope to be back on the road by the weekend after next, which just so happens to be the weekend following my 40th, so HBD to me I guess.

All in all I am satisfied with the outcome, assuming nothing changes and they deliver on their word. I'll probably never know what happened exactly, but I'm choosing to focus on the positives; no one was hurt, I learned a ton, and discovered a great community of fellow enthusiasts.

Huge shout out to all of you that took the time to reply and offer insight. I could not have done this without you. I'll be sure to update with pics as soon as I can.


-anotherhillyay

bboy314

Sounds like a good resolution. Is there a reason you can’t have the new crankset installed but swap the chainrings with your old ones to keep your gearing the same?

jccaclimber

I think this is what the OP meant by “swap the chainset.”, though it wasn’t clear.
The chain might need to be a link longer with the larger front ring. I’d assume the front derailer could be shifted up. Tooth delta hasn’t changed so the rear derailer shouldn’t care assuming the chain length is acceptable.

To the OP, option 2 was the right choice. If you don’t routinely run out of low gearing then the difference in ring size likely won’t impact your riding.

Use the money you would have spent on a new crank and get a torque wrench so you can do this yourself next time. It’s not a ton more difficult than changing the attachment on a Kitchenaid mixer, but as you’ve learned, the correct torque value and process is important.

cxwrench

The first bolded part is complete BS. There is no way you won't be able to use any chainrings that will fit that crank. Anything that will fit on that crank will work w/ your derailleur. The second bolded part I don't really understand, I think you mean chainrings not chain set. If I were you I'd pick up the bike w/ the new crank, say thanks, and walk away. I'd ask them to remove the chainrings from the previous crank and have those installed and the derailleur adjusted by a shop that doesn't have their head up their ass like your current one does.

cyclezen

Totally agree !
The new 52/36 will work fine with whatever RD you have on now.
If you stay with the New 52/36, there is the possibility that the current chain may be a link or 2 short - depends on how the bike was originally set up...
I would definitely not trust that shop to do a good job in adding links - can be done, but does require a 'good' mechanic.
Like Cxwrench says, the 50/34 chainrings on your damaged cranks can easily be swapped onto the new crank arms (and the 52/36 can be given back with the damaged crank arms...)
this is dependent on both cranksets being from the same model /year.
That crank in pic seems to be an RS510 (105) which is different from the more current 7000 105 model. If the 'replacement' proves to be 7000 series, I wouldn't know if the chainrings are interchangeable between the 2 diff. models - maybe ... but there could be cosmetic differences also. Maybe Cxwrench might have more solid info...
In terms of 'riding', the 52/36 will give you different gearing than the 50/34, using the same cassette... that's a consideration if you're quite happy with the 50/34...
I have both on a few bikes, and 'age' is pushing me more and more to the 50/34... sad... but expected.
But if the replacement is an RS510 crankset, just have the rings swapped !
Ride On
Yuri

anotherhillyay

My mistake, I meant chainrings, not chainset. I edited my previous post. I took your advice and ordered a torque wrench and watched a maintenance video on Part Tool's YouTube channel. And you're right, it's not nearly as complicated as I originally thought. TBH I feel a little embarrassed now that I've watched it. The only other tool I need is the one that removes the pre-loader bolt, after that I should be good, for the crank at least.

Thanks for the suggestions.

anotherhillyay

My mistake, I meant chainrings, not chainset. Do warranty claims initiated by the LBS need to be completed by the same LBS to guarantee the work? Either way I am planning to bring her to the shop I got a second opinion from yesterday. Is there an better way I'm not seeing?

anotherhillyay

You're spot on, it's an RS510 crankset. I found this compatibility chart on Shimano's website, but I'm too tired to make sense of it. I'll take a look in the morning.

jccaclimber

There was a nice long rant about that silly tool on here recently. In short, it’s $6 on Amazon for the official Shimano version.
Just don’t forget about the little plate that goes in the gap when you remove and reinstall the NDS arm.
The good news for you now is that almost all maintenance items on a bike are about as simple as the video you just watched. Sure, some things require a special tool, and a few like bearing replacement and wheel truing require a little art if done in a garage, but they’re generally straightforward. When they aren’t, just ask here.

cyclezen

well, there ya go! that's pretty clear.
Chart is easy to read - the 'Crankset' box for 11 spd contains both the RS510 & R7000 (plus the other compatible sets), the connecting lines for boxes shows what works from the other component groups. Like going right to BBs, it shows which BBs will work with the RS510/R7000 group.
Crankset group compatibility - means the rings will wor and the bolt holes line up. That doesn't mean the cosmetic is the same, nor does it assure that the 'interface' where the ring meets the arm is as seamlesss as 'correct' version might be. I know the RS510 is a glossy Black finish, the R7000 is matte black, how different or 'funky' that might look, dependz... same for any variations where the rings meet the arms - would be your decision on how that appears...
But my guess would be that Shimano will send a replacement RS510 replacement crankset. Given the popularity now of 'compact' 50/34, them being sold out on the older version (often used for OEM bikes) and still having the Mid-COmpact 52/36 in some stock, seems very plausible... so an easy-peasy direct swap of rings...
the hassle would be minimum, and you'd end up Whole, with only the memories of the event hassle... nice...
Ride On
Yuri
I gotta download that chart... LOL!

anotherhillyay

Looking at it now, it makes sense. Good to see I won't have a fit issue.

Here is the link to the compatibility chart. It's a doozy. As far as I can tell, it covers every component dating back to 2004, MTB, road, etc. In the upper right hand side, just under the header and next to the dates (2004-2022) there's an option to download it as a PDF as well.

https://productinfo.shimano.com/#/co...-432&cid=C-432