Concept2 Forum

Hi
I changed the chain & sprocket according to the model D kit instructions. (Old one ~7m m)
It feels significantly harder to row now =DF/SR/pace?
It seems to be working fine.
Is there something I might have done wrong?
Is there a “bedding in@ time?
Df120/18spm/2:05 feels pretty hard now…
Thanks for any advice!

Mark wrote: ↑

November 22nd, 2022, 2:59 am

Hi
I changed the chain & sprocket according to the model D kit instructions. (Old one ~7m m)
It feels significantly harder to row now =DF/SR/pace?
It seems to be working fine.
Is there something I might have done wrong?
Is there a “bedding in@ time?
Df120/18spm/2:05 feels pretty hard now…
Thanks for any advice!

At equal drag factor it should feel the same, not harder to row.

Drag factor measures the spin down of the flywheel so we know at equal drag factor your flywheel is behaving the way it used to. If you are getting extra load not captured in the drag factor it will be from the chain running over the sprockets or the shock cord off it's pulleys.

Maybe verify chain/ shock cord routing from this video https://youtu.be/kA-rW268Ils, and verify that the sprocket you replaced is not binding. Binding would not be captured in the flywheel (clutch disconnects) but maybe would show up in slow/poor chain retraction.

(glad you did not change the shock cord, heavier load with a new shock cord could have set off an internet implosion)

The new chain and sprocket take a bit of time to bed in but the only difference you should notice is the feel of it, it becomes smoother over time if kept lubricated.

Is misalignment of a sprocket (leading to friction) even a likely issue?

Thank you!
I can’t see anything wrong…
The chain seems to be routed correctly.

Sorry I don’t know what binding means above?

Could the sprocket be axially misaligned?
Is there a correct way around for the sprocket?

Any other ideas would be gratefully received!

Thanks again!

Tsnor wrote: ↑

November 22nd, 2022, 6:33 pm

(glad you did not change the shock cord, heavier load with a new shock cord could have set off an internet implosion)

Good point Tsnor. Hey Mark, did you change the shock cord too?

Mark wrote: ↑

November 23rd, 2022, 7:08 am

Sorry I don’t know what binding means above?

Maybe I used the term binding wrong.

Imagine a freely spinning bicycle wheel bolted on a bicycle.

Now tighten the bolt holding the wheel hard. No change. Wheel spins.

Now what if instead of spinning freely when you tighten the bolt the wheel starts dragging. This shouldn't happen, but it can if at some point the pressure pulling the nut onto the bolt squeezes the wheel and the wheel no longer spins freely. The wheel is now binding. Here is a thread that talks about bike wheels and how to fix binding. First thing though would be to see if the erg sprocket is actually binding. Best way to do that is to see if the chain pulls and retract easily. Here's the example bike thread. https://www.mtbr.com/threads/rear-wheel ... se.712751/

Tsnor wrote: ↑

November 23rd, 2022, 12:37 pm

Mark wrote: ↑

November 23rd, 2022, 7:08 am

Sorry I don’t know what binding means above?

Maybe I used the term binding wrong.

Imagine a freely spinning bicycle wheel bolted on a bicycle.

Now tighten the bolt holding the wheel hard. No change. Wheel spins.

Now what if instead of spinning freely when you tighten the bolt the wheel starts dragging. This shouldn't happen, but it can if at some point the pressure pulling the nut onto the bolt squeezes the wheel and the wheel no longer spins freely. The wheel is now binding. Here is a thread that talks about bike wheels and how to fix binding. First thing though would be to see if the erg sprocket is actually binding. Best way to do that is to see if the chain pulls and retract easily. Here's the example bike thread. https://www.mtbr.com/threads/rear-wheel ... se.712751/

But the sprocket is fixed to the shaft so nothing to bind. The shaft has a bearing at each end which can't really be wrong. The only other moving part on that assembly is the flywheel. You can't really go wrong with the chain guides either unless you have missed one.

nick rockliff wrote: ↑

November 23rd, 2022, 4:13 pm

But the sprocket is fixed to the shaft so nothing to bind. The shaft has a bearing at each end which can't really be wrong. The only other moving part on that assembly is the flywheel. You can't really go wrong with the chain guides either unless you have missed one.

Yes should have said axle, not sprocket.

What happens if you overtighten the bolt being tightened here in this video at 3:06 https://youtu.be/IjbnINLJvgM?t=186
and here at 8:57 https://youtu.be/IjbnINLJvgM?t=537 ? Can you compress things enough the axle binds like in the bike video ?

Tsnor wrote: ↑

November 23rd, 2022, 4:30 pm

nick rockliff wrote: ↑

November 23rd, 2022, 4:13 pm

But the sprocket is fixed to the shaft so nothing to bind. The shaft has a bearing at each end which can't really be wrong. The only other moving part on that assembly is the flywheel. You can't really go wrong with the chain guides either unless you have missed one.

Yes should have said axle, not sprocket.

What happens if you overtighten the bolt being tightened here in this video at 3:06 https://youtu.be/IjbnINLJvgM?t=186
and here at 8:57 https://youtu.be/IjbnINLJvgM?t=537 ? Can you compress things enough the axle binds like in the bike video ?

Tsnor wrote: ↑

November 23rd, 2022, 4:30 pm

nick rockliff wrote: ↑

November 23rd, 2022, 4:13 pm

But the sprocket is fixed to the shaft so nothing to bind. The shaft has a bearing at each end which can't really be wrong. The only other moving part on that assembly is the flywheel. You can't really go wrong with the chain guides either unless you have missed one.

Yes should have said axle, not sprocket.

What happens if you overtighten the bolt being tightened here in this video at 3:06 https://youtu.be/IjbnINLJvgM?t=186
and here at 8:57 https://youtu.be/IjbnINLJvgM?t=537 ? Can you compress things enough the axle binds like in the bike video ?

No, the shaft bearing on the flywheel side is floating and mounted in a rubber cup. The other end is tightened against inner bearing race. This is also mounted in a rubber cup. The shaft bearings don't do a great amount of work per stroke.

Tsor, the “bolt being tightened” isn’t [being tightened]. It is the threaded end of the axle shaft and the jam hexnut is being snugged up to a position or limit determined by a shoulder of greater diameter than the threading. The nut does control end play of the axle by very lightly contacting the inner race of the outboard axle bearing. You can see the nut turn with the axle during the time the one way clutch bearing in the flywheel is engaged [the drive portion of stroke]. There is no “binding” condition created which would produce frictional contact acting as a brake on the free rotation of the axle shaft and it’s fixed cog [sprocket]. Nick R is pretty much spot on regarding the physical arrangement and operation of the shaft and sprocket. The multiple attempts at embedded quotation gave me a headache! Please cease digging this hole deeper. Or throw Edmundson in and backfill it would also work!!

jackarabit wrote: ↑

November 23rd, 2022, 6:48 pm

... Please cease digging this hole deeper...

So you say to the topic poster that it cannot be true that he has to work harder for the same pace after renewing chain and sprocket (because he equalized the drag factor).

jackarabit wrote: ↑

November 23rd, 2022, 6:48 pm

Please cease digging this hole deeper. Or throw Edmundson in and backfill it would also work!!

BEST ADVICE EVER

While you had the machine apart did you happen to clean 7 million meters worth of lint/dust/crud from the flywheel and airscreen? Are you going by actual drag factor or by the old damper setting?