broke my erg

icomefrombirmingham · Post by **icomefrombirmingham** » March 10th, 2009, 10:11 am

Last night I was erging away when a bit of my erg broke and flew off.

The piece in question is the cast (?) brass(?) ring that fits between the chain attachment and the the U-shaped bar that, in turn, attaches to the handle. The ring is flat on one side and "castellated" on the other.

Hope that is a reasonable description.

I assume the "castellations" are designed to keep the chain itself perpendicular to the U-bar.

I don't think the part is crucial so my questions are:

What is the part for?
Will I do any harm rowing with it missing?

Thanks,
Brent
p.s. (update)...It's called a bushing (duh!) and I have ordered one, but am still curious as to why it's there and what its function is.

Citroen · Post by **Citroen** » March 10th, 2009, 2:19 pm

It's there to reduce the load on the endpoint of the chain. It's an integral part of the chain so you really need to replace the chain at the same time. If you don't replace it you're more likely to snap the chain.

If your existing erg is very old and you replace the chain you may need to replace the sprocket on the flywheel as it will tend to wear at the same time that the chain wears.

(Just like on a bike, if you replace the chain it's worth replacing the front chainset and rear cassette.)

c2jonw · Post by **c2jonw** » March 10th, 2009, 2:27 pm

The bushing is part of the chain swivel connection which we designed to address problems with chain breakage resulting from people twisting the handle. The bushing provides a slippery wearing interface between the U-bolt and the swivel body, which are both made of stainless steel. The machine can be rowed without the bushing but premature wear of the hole in the swivel body could result. C2JonW

icomefrombirmingham · Post by **icomefrombirmingham** » March 10th, 2009, 3:33 pm

Thanks guys.

Dougie, the erg is only 2.5M metres and 3 years old, so I hope I don't need to change the chain yet?

Jon, I noticed that with a Core Perform seat installed I was "leaning" to the left while erging. I removed the CP seat and seem to have solved that problem. Perhaps that was also the cause of some handle twisting and put the bushing under stress? (I also noticed that during that time the chain did not seem to run vertically...the chain-end mechanism seemed to be offset by about 20 degrees).

I ordered a new bushing this morning and should have it installed by the weekend.

Thanks again guys.
Brent

Citroen · Post by **Citroen** » March 10th, 2009, 4:33 pm

icomefrombirmingham wrote:Dougie, the erg is only 2.5M metres and 3 years old, so I hope I don't need to change the chain yet?

That seems like an early failure. The machines in our gym get the chains replaced every year to eighteen months. The model D machine I had my PM4 mounted on did about 1,000,000 in three months and it's one of the less used machines (which is why I like using it).

icomefrombirmingham · Post by **icomefrombirmingham** » March 10th, 2009, 7:19 pm

Citroen wrote:
That seems like an early failure. The machines in our gym get the chains replaced every year to eighteen months. The model D machine I had my PM4 mounted on did about 1,000,000 in three months and it's one of the less used machines (which is why I like using it).

Phewf! I hadn't even considered a chain change at tthis stage. I think I was inadvertantly giving the bushing more welly than it liked.

c2jonw · Post by **c2jonw** » March 11th, 2009, 8:40 am

I'm pretty sure it's an early failure of the bushing though tough to tell without seeing the parts. Under individual use you should get many years of rowing before you need to think about chain replacement. I'd bet the new bushing is all you'll need......C2JonW

icomefrombirmingham · Post by **icomefrombirmingham** » March 11th, 2009, 10:08 am

c2jonw wrote:I'm pretty sure it's an early failure of the bushing though tough to tell without seeing the parts. Under individual use you should get many years of rowing before you need to think about chain replacement. I'd bet the new bushing is all you'll need......C2JonW

I am confident you are right re the chain itself Jon.

The bushing split almost exactly in half, clean breaks on both sides.
The breaks however, were not exactly along radiuses (radii?) from the cntre of the circle. They are both offset by 5 or 10 degrees from what would be the radius and the break lines themselves are parallel.

Is there a recommended number of metres between chain changes?

Brent

c2jonw · Post by **c2jonw** » March 11th, 2009, 2:01 pm

Chain wear depends on so many variables that it's difficult to make a recommendation other than if it starts running rough and skipping and lubrication doesn't help, then it's likely time for a new chain and sprocket. C2JonW

icomefrombirmingham · Post by **icomefrombirmingham** » March 11th, 2009, 5:07 pm

c2jonw wrote:Chain wear depends on so many variables that it's difficult to make a recommendation other than if it starts running rough and skipping and lubrication doesn't help, then it's likely time for a new chain and sprocket. C2JonW

OK. Thanks Jon.

icomefrombirmingham · Post by **icomefrombirmingham** » March 16th, 2009, 10:14 am

c2jonw wrote:The bushing is part of the chain swivel connection which we designed to address problems with chain breakage resulting from people twisting the handle. The bushing provides a slippery wearing interface between the U-bolt and the swivel body, which are both made of stainless steel. The machine can be rowed without the bushing but premature wear of the hole in the swivel body could result. C2JonW

Hi Jon,
I received the new bushing last week. However, it is totally different to the old part.

The old bushing is 25mm outside diameter, with a 13mm hole. It is 10mm high/long, but is castellated, like a castle tower, with four raised shoulders. The low points of the shoulders are 7mm. I had assumed that these shoulders fit over the U-bar and the flat end of the bushing fit against the raised collar right at the end of the chain-end assembly.

The new bushing sent to me is a simple brass tube, 25mm in length and 13mm outside diameter (it fits inside the old part), with a hole that is approximately 7mm.

The new part will not fit between the U-bar and the raised collar. Nor do I think it has sufficient inside diameter to go over the stainless chain-end (not totally sure on that as I didn't dissassemble the handle yet).
The new part is described on the invoice as "5306 Bushing Brass D Handle 6391K443".

Am I describing the part that I need adequately? If so, is there a part number I can use to describe it to the lady on the order desk?

If not, my apologies. Is there a schematic anywhere on the site that I can find the part on? The only chain-end schematics I have seen do not have a bushing. Should I forward a photo?

Thanks for your help.
Regards,
Brent

c2jonw · Post by **c2jonw** » March 16th, 2009, 2:15 pm

Looks like an error in order entry. 5306 is a part for our Dyno Strength training Machine. Call Customer service back and explain the mistake and that you need a part #1314. Sorry aboujt the mix-up.....C2JonW

icomefrombirmingham · Post by **icomefrombirmingham** » March 16th, 2009, 2:38 pm

c2jonw wrote:Looks like an error in order entry. 5306 is a part for our Dyno Strength training Machine. Call Customer service back and explain the mistake and that you need a part #1314. Sorry aboujt the mix-up.....C2JonW

Thanks Jon...but I found a picture of the part here:

http://www.concept2.com/us/support/manu ... cement.pdf

in picture #16. It's the brass bushing that is part of the chain-end assembly that the demonstrator is holding in his left hand.

Apparently, that part is not orderable separately and comes as an integral part of the chain itself.

From what they said at Customer Service that part having broken is not a major problem and I can wait until I need to replace the chain...in a few million more metres yet.

Thanks for your help.
Brent

c2jonw · Post by **c2jonw** » March 16th, 2009, 4:01 pm

Brent, Could you please email me or phone directly? It would be best to put a new bushing on. Thanks. jonw@concept2.com or 800 245 5676 ext 3020