Orbea M10 - Grinding When Pedaling

[Grendel]

Took my bike to the LBS recently. They serviced pivots and replaced bearings, replaced rear cassette, new chain and did a general tune up and washed the bike (which was admittedly super dirty). Ever since, I'm having an intermittent but frequent "grinding" feel when pedaling. I can't tell where it is coming from but, to me, almost feels like the motor is grinding (maybe water got in it?). LBS says front front cassette (chainring?, I'm obviously not up on bike jargon) is worn and they will try and get one from Shimano but they are difficult to source right now. No grinding before the tune up but has been consistent since. Does this make sense? Could a new chain coupled with a year-old chainring (hope I'm using the right word here) create a regular grinding? I've only been mountain biking for about a year and don't feel I know enough to have a firm opinion but this just rings false to me. Not sure how a new chain would cause this. Any opinions from you more experienced people?

 

[Rod B.]

Took my bike to the LBS recently. They serviced pivots and replaced bearings, replaced rear cassette, new chain and did a general tune up and washed the bike (which was admittedly super dirty). Ever since, I'm having an intermittent but frequent "grinding" feel when pedaling. I can't tell where it is coming from but, to me, almost feels like the motor is grinding (maybe water got in it?). LBS says front front cassette (chainring?, I'm obviously not up on bike jargon) is worn and they will try and get one from Shimano but they are difficult to source right now. No grinding before the tune up but has been consistent since. Does this make sense? Could a new chain coupled with a year-old chainring (hope I'm using the right word here) create a regular grinding? I've only been mountain biking for about a year and don't feel I know enough to have a firm opinion but this just rings false to me. Not sure how a new chain would cause this. Any opinions from you more experienced people?

Grendel, how old is your Rise? It's really difficult to diagnose a grinding issue via the internet. You idea of a grinding noise may be different than another person's idea of a grinding noise. As an example, does the grinding noise sound like you have sand in the drivetrain, or is the grinding noise a deeper sound indicating a bearing, i.e. rear hub bearing going bad or possible a rear wheel not installed correctly and causing the brake rotor to rub? It can be a lot of things.

Unless your Rise has high mileage on the drivetrain, your bike shouldn't be making a grinding noise just because the shop replaced the chain and serviced the pivot linkage.

As cassettes or chain rings wear, the teeth will begin to hook and cup at the base of the teeth. It takes a lot of mileage to reach this point of wear. The hooked tooth catches the chain and slightly holds it as the chain rotates off of the teeth. This prevents the chain from releasing smoothly and causing noise. It's possible a one year old chain ring can cause the grinding noise. However, unless you've put a lot of miles on the chain ring in a one year period of use, I not sure the chain ring is the culprit.

The key point is that the bike was not making any noise prior to you taking it to the shop. I am curious as to why you took the bike to the shop in the first place. Was there a previous issue that made you take the bike to the shop?

Here is an example of hooked teeth. If the teeth on your chain ring or the cassette begin to look like this then they should be replaced when the budget allows.

Here are some suggestions on what to check for regarding the grinding noise:

1) Chain Guide:
a) If you have a stand, place your bike in the stand. If you don't have a stand, turn the bike upside down on the ground. Slowly turn the pedals and check the plastic chain guide to make sure it's not out of alignment or rubbing on the chain. If the bike shop replaced the chain, the shop may have removed the chain guide or possibly the whole assembly. Orbea uses two shim washers to correctly align the chain guide arm. If the guide arm was removed and the shim washers were not re-installed, this will throw the chain guard slightly out of alignment and cause a rubbing issue.

b) If just the plastic chain guide head was removed and re-installed too low onto the chain ring, this too will cause a rubbing noise. Check to make sure the shim washers are in place behind the chain guide arm where the two screws attach it to the motor. Check to make sure the chain guide head is raised slightly above the chain ring so that it is not rubbing on the chain ring.

2) Brake rotors:
Turn the pedals or spin the front wheel. Check the front and rear brake rotors. Are they rubbing and making a grinding noise? While your bike was being serviced, it's possible something make have hit one of the rotors and bent it. Sometimes it possible to install a rear wheel with it slightly out of position. When the axle s tightened, this will throw the rear brake rotor out of alignment and cause it to rub on the brake pads and or caliper.

3) New Chain & Derailleur Pulley(s)
a) Turn the pedals and watch the new chain rotate around the smallest derailleur pully. Does the chain spin smoothly around the small pulley? Do you see any chain links which appear stiff and do not rotate/bend freely around the pulley as you pedal? It's possible the bike shop may not have installed the quick link correctly or damaged the chain when removing excess links so that it will fit your bike.

b) Rotate the derailleur arm forward so that slack occurs in the chain. Lift the chain off of each pulley. Spin the pulley to see if it spins freely and smoothly. It's not likely, but it's possible a derailleur pully bearing is seizing up and causing a grinding noise.

4) Rear Cassette:
Since you are fairly new to mountain biking, it's possible you may have missed a shift or two while riding your bike. A missed shift in boost mode can easily bend or fold a cassette cog. Pedal your bike and individually watch each cassette cog rotate. Do you see any of the cogs wobble as if bent? A bent cog will cause the chain to rub and click.

5) Rear Hub Bearings:
Place your finger on a rear chainstay. Spin the rear wheel. As the rear wheel spins, do you feel any roughness transmit through the chainstay? There should be no roughness transmitting through the chain stay, only a smooth sensation. If you feel a grinding or rough bumpiness sensation, you have either a rear hub bearing or freehub bearing going bad which will cause a grinding noise.

I hope this helps get you started in the right direction.

Be safe,
Rod

 

[BobR]

Also some chains are directional and if you put them on backwards they can grind…

 

[Rod B.]

Also some chains are directional and if you put them on backwards they can grind…

BobR,
That's a very good point. Shimano 12 speed chain is directional and should be installed with the logo stampings facing outwards away from the frame. The Shimano quick link is also directional and should be installed with the arrow on the link plate pointing in the direction of travel. If Shimano chain is installed backwards it will cause noise in the drivetrain and degrade shifting.

I wonder if the bike shop screwed the pooch with the chain?

I have a SRAM AXS drive train on my Rise. SRAM chain is not directional but SRAM's quick link is.

 

[Grendel]

This is all brilliant information and I cannot thank all of you enough for providing such a thorough explanation. I'm away on business but will take a look at the bike as soon as I'm back in my home town. They were genuinely rushing the job (had the bike for a week but didn't really start fixing it until they called me to pick it up and I had to watch them work on it for 2 hours) and I wouldn't be surprised if they goofed it up by hurrying. Will check all these things when I get back.

 

[steve_sordy]

@Rod B. I recognise that photo in post #2 (of the two gears, one worn, one new). I took it on 5th Jan'14. Maybe I should have copyrighted it! Who knows I could have been a millionaire by now!
Feel free to use it as many times as you like.
Do you have this one? It was taken later but published at the same time as the one before. Shows a worn ring

 

[Grendel]

Hey All,

Here's a brief update:

• Front Chain Ring - I've looked at these pictures and compared it to mine and I don't see any obvious wear to this degree. I really don't think this is the issue and the bike shop just doesn't have any other ideas or is trying to have me spend more money. TBD. I don't have enough experience to be entirely sure of anything.
• Chain Guide - The shop actually lost the nut that holds this in place. Generically mentioned they could order a new one but I doubt they do and it is not on the bike at this time. How important is this? They seemed unconcerned about it but it seems like if bikes come with them, they are there for a reason.
• Brake Rotors - Seem to be fine. A couple of months ago, one was rubbing but (based upon info I saw on this forum) I was able to loosen the screws that hold it in place, squeeze the brake and retighten when it was centered. All good here.
• Chain & Derailleur Pulley - Great idea. I checked as indicated above and can't see any stiffness/dysfunction as it goes through the derailleur. Derailleur also seems to be turning smoothly. However, it does look like the quick link may have been installed going in the wrong direction. Can't swear to this because the writing is small and my eyesight isn't perfect but it looks like the writing on one of the links is upside down compared to the others. This may be the culprit.
• Rear Cassette - I can't see anything bent out of shape and I noticed the noise immediately upon picking up the bike before I even got to my car so it would have had to come out of the box bent since I hadn't ridden it yet to bend it.
• Rear Tire - I am noticing something rattling around in the rear tire when I spin it. Sounds like they dropped some small metal piece in there and it is spinning around with the tire. I'll remove the tire to see if I can fish it out although I would think it would be stuck in the tubeless gunk. I'm sure this is unrelated gargling marbles/grinding feel.

Everyone's input has been super helpful. I'll try to flip the quick link first which I've never done but looks pretty easy and get some recommendations to another mechanic for a second opinion if that doesn't do it. Many thanks!

 

[Grendel]

@Rod B. I recognise that photo in post #2 (of the two gears, one worn, one new). I took it on 5th Jan'14. Maybe I should have copyrighted it! Who knows I could have been a millionaire by now!
Feel free to use it as many times as you like.
Do you have this one? It was taken later but published at the same time as the one before. Shows a worn ring
View attachment 101554

This is helpful! Mine is showing a little wear and tear from use but is nothing like the worn ring shown int his picture.

 

[Rod B.]

@Rod B. I recognise that photo in post #2 (of the two gears, one worn, one new). I took it on 5th Jan'14. Maybe I should have copyrighted it! Who knows I could have been a millionaire by now!
Feel free to use it as many times as you like.
Do you have this one? It was taken later but published at the same time as the one before. Shows a worn ring
View attachment 101554

Steve, here’s what I’m going to do. Someday in the near future, I plan on visiting England and doing some riding there. My family (Barton) immigrated from Lancashire County, I believe the town of Preston, in the 1500’s. I‘d like to visit the area and see where it all started. I’ll make a side trip to Lincolnshire. In exchange for your excellent photography, let’s do a ride and I‘ll buy you a pint post ride and let’s talk bikes.

As a side note, you got you money’s worth out of that chainring….

 

[p3eps]

BobR,
That's a very good point. Shimano 12 speed chain is directional and should be installed with the logo stampings facing outwards away from the frame. The Shimano quick link is also directional and should be installed with the arrow on the link plate pointing in the direction of travel. If Shimano chain is installed backwards it will cause noise in the drivetrain and degrade shifting.

I wonder if the bike shop screwed the pooch with the chain?
View attachment 101522

I have a SRAM AXS drive train on my Rise. SRAM chain is not directional but SRAM's quick link is.

View attachment 101523

Both sides of that SRAM quick link have the same arrow - which then point in different directions when assembled. The arrow must be symbolising which way to lock it, rather than which way the chain goes?

 

[Grendel]

Both sides of that SRAM quick link have the same arrow - which then point in different directions when assembled. The arrow must be symbolising which way to lock it, rather than which way the chain goes?

On mine (which I'm not sure is a SRAM), I noticed that all the links have the writing facing the same way except for one link which I'm thinking is the quick link but am not sure. I've spoken with a different bike shop and am taking it to their mechanic next Monday to review all the issues. I hate being incompetent but just don't know enough about this stuff yet. Again, I really appreciate everyone's help. I'm amazed how much I've learned on these forums over the last year. It's a really helpful community of people.

 

[p3eps]

Here’s the old one off my bike that I keep as a spare. Both sides have the same direction on the arrow.

 

[Rod B.]

Both sides of that SRAM quick link have the same arrow - which then point in different directions when assembled. The arrow must be symbolising which way to lock it, rather than which way the chain goes?

Yes on the arrows. The SRAM quick link is shaped like a banana and goes on one way only with the link curved to match the profile of the cassette and chainring. It can be installed upside down and work. I did it once when I was not paying attention on a trailside repair. The shifting suffered a bit as a result.

 

[Rod B.]

On mine (which I'm not sure is a SRAM), I noticed that all the links have the writing facing the same way except for one link which I'm thinking is the quick link but am not sure. I've spoken with a different bike shop and am taking it to their mechanic next Monday to review all the issues. I hate being incompetent but just don't know enough about this stuff yet. Again, I really appreciate everyone's help. I'm amazed how much I've learned on these forums over the last year. It's a really helpful community of people.

Grendel,

We all had to start somewhere. Do not be ashamed of not knowing. The fact you want to know is a good thing. Start small and do minor maintenance things on your bike, i.e. like cleaning and lubing the chain, check and add tire sealant, adjust/fiddle with the suspension to understand how it works. As you become more familiar with the bike, step up your game and experiment with tires and change a tire, replace worn grips, replace a derailleur cable, adjust the rear derailleur, replace/clean the brake pads, lube the rear freehub, etc. Become familiar with your bike.

When you really know your bike, you'll know immediately when something isn't quite right with it. This will save you a long walk in the park. There is absolutely nothing wrong with taking your bike to the shop. However, try not to immediately do so. If you have a problem, reference the bike problem online, via this forum, YouTube, etc. If the repair appears to be within your tool/skill range, then give it a shot. If you screw it up, no biggie, take it too the shop and let them sort out the mess. Lastly, you don't need high dollar tools to make a repair. Amazon sells cheap tools that will work. As you become more skilled, replace the cheap tools with quality tools.

Know that each time you work on your bike you become better, it's a cumulative event, worthy of a cold beer, and it all takes time. You'll get there.

Be safe,
Rod

 

[YokoOno]

Could a new chain coupled with a year-old chainring (hope I'm using the right word here) create a regular grinding?

Unfortunately, yes. If the chain stretched enough, it may have damaged other drivetrain components.

 

[Lee Dove]

Also some chains are directional and if you put them on backwards they can grind…

No they are not.

 

[Lee Dove]

A new chain on an old chain ring can make a grinding noise. The worn chainring does not match the chain.

 

[Rod B.]

No they are not.

Lee, I apologize if I'm getting your "No" reference wrong. However, if it does refer to chain direction, then it's slightly incorrect.

Some Shimano chains are directional, while several older model Shimano chains i.e. 9 speed chains are not directional. There are other brands of chain, i.e. SRAM which are not directional. However, modern Shimano 10, 11 and 12 speed chains are directional. I don't know if this also applies to road bike chains.

Shimano applies a special machined chamfering to the chain link plates. According to Shimano, the chamfering promotes quicker and more accurate shifting. For reasons unknown to me, Shimano only chamfers one side, i.e. the bottom inside edge of the chain and not both the top and bottom inside edges of the link plates. Because of the one sided chamfering, the chain has to be installed directionally correct (With logo's facing outwards).

If the chain is not installed directionally correct, i.e. upside down, the bike will suffer noisy and poor lagging shifts. This is because the chamfered link plates are not engaging the cassette shift ramps correctly. If a Linkglide chain is installed upside down, the bike will still shift however, the chain's engagement on the cassette shift ramps will be poor and noisy.

Here's a good general article on chains:

Bicycle chains explained: everything you need to know

Chain structure, speeds, compatibility and more explained

www.bikeradar.com

Here's a YouTube video on Shimano chain direction.

 

[Grendel]

Unfortunately, yes. If the chain stretched enough, it may have damaged other drivetrain components.

The chain was definitely stretched out when they replaced it. We measured it together when I was dropping it off to get serviced.