Chain recoil issue/no "bite" at catch

Maintenance, accessories, operation. Anything to do with making your erg work.
gvcormac
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Re: Chain recoil issue/no "bite" at catch

Post by gvcormac » February 2nd, 2024, 9:03 am

C2 will sell you a new flywheel with clutch for about $100. Depending on your proclivities for DIY and how much you'll enjoy the hours spent doing this, you might find replacement the preferable choice. It isn't in their on-line catalog, but you can order one.

Willy.VdW
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Re: Chain recoil issue/no "bite" at catch

Post by Willy.VdW » February 2nd, 2024, 9:57 am

Carl Watts wrote:
January 31st, 2024, 6:52 pm
I replaced the standard nylon bearing with the stainless steel spring version it has faster engagement.
If possible, I would like to know the dimensions/specifications of this bearing.

gvcormac
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Re: Chain recoil issue/no "bite" at catch

Post by gvcormac » February 2nd, 2024, 12:01 pm

Willy.VdW wrote:
February 2nd, 2024, 9:57 am
Carl Watts wrote:
January 31st, 2024, 6:52 pm
I replaced the standard nylon bearing with the stainless steel spring version it has faster engagement.
If possible, I would like to know the dimensions/specifications of this bearing.
It is a standard size, and if you search this forum I think you'll find the ID number. Also a howto for how to change it with ordinary tools and a bit of brute force.

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jackarabit
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Re: Chain recoil issue/no "bite" at catch

Post by jackarabit » February 3rd, 2024, 12:43 am

gvcormac wrote:
February 2nd, 2024, 12:01 pm
Willy.VdW wrote:
February 2nd, 2024, 9:57 am
Carl Watts wrote:
January 31st, 2024, 6:52 pm
I replaced the standard nylon bearing with the stainless steel spring version it has faster engagement.
If possible, I would like to know the dimensions/specifications of this bearing.
It is a standard size, and if you search this forum I think you'll find the ID number. Also a howto for how to change it with ordinary tools and a bit of brute force.
I remember Carl’s description of replacing the free wheel bearing mentioned fabrication of a custom puller just for this job. I assume he used an arbor press to drive the new bearing into the hub bore. If the OP wants to throw money around acquiring a properly spec’d bearing and seek out a machine shop to do the job, why not? But someone posting here has turned this job around with nothing but “brute force” and what? Big ball peen and a brass drift? Please supply a link or citation.
There are two types of people in this world: Those who can extrapolate from incomplete data

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Carl Watts
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Re: Chain recoil issue/no "bite" at catch

Post by Carl Watts » February 3rd, 2024, 12:58 am

The bearing is a KOYO RC-121610-FS for the stainless version or just RC-121610 for the nylon one.

You need a press or make up a puller with some steel washers and threaded rod. You do not want to bash it with a hammer and a drift. Make sure you check its round the right way before you pull the new one back in, it is directional.

The bearing is a very tight press fit, it squeaks as you pull it out and in. Used at least a M8 bolt, maybe it was even M10 you need to be able to put a bit nut on it and crank it. I made a custom puller up on the lathe so the washers were all the right diameters and inside diameter so everything was held central as it was loaded up. It was designed so there was no need to remove the 3 screws holding the hub in the flywheel as I didn't want to remove it and possibly upset the balance, however I have known other people remove it, replace the bearing and its been okay.
Carl Watts.
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
http://log.concept2.com/profile/863525/log

jamesg
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Re: Chain recoil issue/no "bite" at catch

Post by jamesg » February 3rd, 2024, 3:42 am

When at the catch, the first 3-5 inches of the drive have no "bite"/tension.
This is normal and we see it every stroke save the first; we have to catch up with the flywheel, on low drag it might be spinning quite fast. But it won't take e second. Using the legs first and fast helps here.

The thump we may feel due to the clutch bearing not engaging is different. If constant it'll be a faulty bearing, if intermittent the grease or cold. I took off the fan cover, the nut on the shaft and the flywheel, oiled the bearings, replaced. Tested before putting on the fan cover. This a few months ago, so far so good.
08-1940, 183cm, 83kg.
Late 2024: stroke 4W-min@20-22.

Willy.VdW
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Re: Chain recoil issue/no "bite" at catch

Post by Willy.VdW » February 3rd, 2024, 3:56 am

@Carl Watts: Thanks for the part numbers and for the (dis)mounting advice!

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Re: Chain recoil issue/no "bite" at catch

Post by Basil » February 10th, 2024, 12:35 pm

@Carl Watts: I also thank you for the KOYO RC-121610-FS clutch bearing ID! I’ve ordered one from the US via eBay. I have a 10T press for automotive DIY work so should be an easy replacement.

Does anyone know the specs of the two bearings that sandwich the clutch bearing and if there are better quality alternatives?

I’m restoring an ex-surf club Model C with a failing clutch and no PM that is currently usable. Bought for AUD60 so happy to spend a bit more for quality components.

@row23: apologies for hijacking your thread - didn’t think it worth starting another.

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