Do I need flywheel/axle bearings?

[sota_dad]

I just got a used model D with 3.8 million meters, and the seller wasn't the first owner--he said he got it in 2022. It's a 2015, and the drag factor from damper settings 1-10 show 76 and 186 respectively. Per C2 this seems normal.

The rear top roller has the edges chipped off one side, so the seat can slide to one side if any lateral force is applied, which gouged the side of the rail. It seems the previous owner just continued to use it that way, although if you row perfectly straight nothing rubs:

https://youtube.com/shorts/V1IngJ0L4tU? ... -3gBXWltyw

Of course, I'll be ordering new top rollers. Now to my question. The flywheel vibrates, but only when in a low speed range (coasting down). I took the perforated grille off per C2's instructions and there was very little lint on the inside. Flywheel vanes were clean. With the cover off, it still vibrated when coasting down. Vacuumed the grille, reassembled, and it makes the same noise every time it coasts down:

https://youtube.com/shorts/VCMaGqdnkJY? ... q1Il0KHN93

I've never had a C2 before (or any rower), but I'm doubtful this is a normal sound.

I chatted with C2 online and they said they don't have any specifications for bearing or axle play or runout to be able to assess wear, nor any recommended maintenance schedule for part replacements, and that I should just go by noise.

Can you all confirm that isn't a normal sound?

If you've replaced flywheel or axle bearings before, how many miles were on the parts you replaced?

[Ombrax]

Welcome to the forum.

Is the issue purely a noise, or is it both noise and vibration?

As you've probably already figured out, the seat rollers are easy enough to replace, so no big deal there.

[sota_dad]

Vibration and noise. It isn’t a loose screw and isn’t related to the cover/intake, since it makes the same noise with the cover off.

[Ombrax]

You might have lost a balance weight, but I would think that would result in a 1 / rev response at all rpms. Right now it sounds like the flywheel is going through a resonance as the rpms decrease. You might not see it on the way up because you go through that speed range too quickly or because of the force the chain is exerting on the axle assembly.

Unfortunately I don't have much more to offer.

Good luck.

[Carl Watts]

The flywheel should take close to 2 minutes to stop from 2:00 pace if everything is normal.

Possible flywheel weight has come off and the imbalance is hitting the resonant frequency of the cage on the deceleration.

Pull the side cover and remove and clean the flywheel and look for the weight.

As I have said before when you get a new machine, the weight positions need to be marked on the flywheel.

[sota_dad]

The flywheel should take close to 2 minutes to stop from 2:00 pace if everything is normal.

This is on damper setting 1? I can time it later tonight.

It doesn't seem to be related to the side cover; I did take the side cover off last night and it makes the same noise consistently each time while passing through the ~30% speed mark, it just slows down faster with the cover off since it's moving more air. There weren't any loose weights inside and the vanes were clean.

[Tsnor]

There's one erg in the boathouse right now that sounds like the world is coming to an end when it spins down. Loud enough to drown out in-use ergs. So loud it's funny.

Assumption is its the bearings. Nothing loose, nothing behind, nothing hitting. Sound is with the chain motionless.

Sounds like what you are hearing. If you replace bearings or buy a new flywheel assembly and the sound goes away please post. Sorry we haven't done anything about the erg yet, so can't tell you if new bearings/flywheel is the fix. But that's our guess.

EDIT: 3.8 million meters is not a lot of km. One user for a year or two will put that on an erg. The PM may have been reset when the erg was sold the first time. I'd guess from the video of the side rail damage that the erg has more than 3.8m meter AFTER the seat gave out. Was the first owner a gym? Aside, if I do the repair for our erg it's getting a new flywheel. If someone else does it he will likely put on new bearings. Both should work. Flywheel replace repair is simple, bearing replace is much less expensive and you get to choose which bearings you use, but is not simple.

More edit, if you want to play, OILING the bearings with 20w / 3inone oil might not fixa bad bearing, but it should change the sound if the bearings are the issue. This video shows how, and you need to do this anyway to fix. https://www.youtube.com/watch?v=bxuIKL0b_uk

[nick rockliff]

I just got a used model D with 3.8 million meters, and the seller wasn't the first owner--he said he got it in 2022. It's a 2015, and the drag factor from damper settings 1-10 show 76 and 186 respectively. Per C2 this seems normal.

The rear top roller has the edges chipped off one side, so the seat can slide to one side if any lateral force is applied, which gouged the side of the rail. It seems the previous owner just continued to use it that way, although if you row perfectly straight nothing rubs:

https://youtube.com/shorts/V1IngJ0L4tU? ... -3gBXWltyw

Of course, I'll be ordering new top rollers. Now to my question. The flywheel vibrates, but only when in a low speed range (coasting down). I took the perforated grille off per C2's instructions and there was very little lint on the inside. Flywheel vanes were clean. With the cover off, it still vibrated when coasting down. Vacuumed the grille, reassembled, and it makes the same noise every time it coasts down:

https://youtube.com/shorts/VCMaGqdnkJY? ... q1Il0KHN93

I've never had a C2 before (or any rower), but I'm doubtful this is a normal sound.

I chatted with C2 online and they said they don't have any specifications for bearing or axle play or runout to be able to assess wear, nor any recommended maintenance schedule for part replacements, and that I should just go by noise.

Can you all confirm that isn't a normal sound?

If you've replaced flywheel or axle bearings before, how many miles were on the parts you replaced?

If it's noisy only when spinning down it's nothing to do with the axle bearings. The only bearing moving at that part of the stroke is the flywheel bearing.

In general use the axle bearings don't do much work at all.

[Ombrax]

The only bearing moving at that part of the stroke is the flywheel bearing.

Which might explain why it doesn't do it on the drive - the flywheel bearing is locked up at the clutch and not moving relative to the axle.

Bottom line - I'm putting my money on the flywheel bearing as the guilty party.

[Tsnor]

If it's noisy only when spinning down it's nothing to do with the axle bearings. The only bearing moving at that part of the stroke is the flywheel bearing.

In general use the axle bearings don't do much work at all.

Nice. Makes sense.

[c2jonw]

Funny thing- Mine has had that noise for a few years now and your post inspired me to look into it. It's never been a concern for me because I'd heard it before and it's most often got to do with the generator unit vibrating inside the generator housing. So first thing to try is tightening the two Philips screws on the top of the generator housing. If that doesn't do it, undo both screws, remove the cover and take the generator unit out of the Housing Base. If the noise goes away, you've pretty much confirmed the culprit and you may be able to fix it by placing a bit of tape on one of the features that is clamping the Generator Unit inside the Housing. Reassemble and try again. If you still get the noise then it may be the generator Cover or Base vibrating against the Flywheel Cover and a small wedge or tape might fix it. Good luck!

[Carl Watts]

Funny thing- Mine has had that noise for a few years now and your post inspired me to look into it. It's never been a concern for me because I'd heard it before and it's most often got to do with the generator unit vibrating inside the generator housing. So first thing to try is tightening the two Philips screws on the top of the generator housing. If that doesn't do it, undo both screws, remove the cover and take the generator unit out of the Housing Base. If the noise goes away, you've pretty much confirmed the culprit and you may be able to fix it by placing a bit of tape on one of the features that is clamping the Generator Unit inside the Housing. Reassemble and try again. If you still get the noise then it may be the generator Cover or Base vibrating against the Flywheel Cover and a small wedge or tape might fix it. Good luck!

Might be better with a small dab of silicone under the tach pickup. Its not going to stick to the plastic that well if you ever need to pull it out but it will definitely take out the movement and the resonance.

[c2jonw]

Might be better with a small dab of silicone under the tach pickup. Its not going to stick to the plastic that well if you ever need to pull it out but it will definitely take out the movement and the resonance.

The tape is just to act as a shim, not an adhesive. The generator needs to be held tight inside the housing.

[Tsnor]

.. because I'd heard it before and it's most often got to do with the generator unit vibrating inside the generator housing.

Will this be true for both "jet engine spooling down" sound on spindown AND for rattle sound during the drive ? We have one erg doing the first, and one doing the second.

Will definitely try this. TY.

[c2jonw]

Will this be true for both "jet engine spooling down" sound on spindown AND for rattle sound during the drive ? We have one erg doing the first, and one doing the second.

Will definitely try this. TY.

It's worth a try. Sometimes the Generator Cover screws get stripped, resulting in the generator rattling inside the housing.