Cranbrook, Chain shake/flap/slap

stilldoc · #1 10-17-2009, 04:00 PM

This is a new build and I am breaking in the engine. As you can see from the photo, I'm using the standard stock tensioner. There is little play in the chain which is a #41 that replaced the stock 415.

http://i4.photobucket.com/albums/y10...c/photo-11.jpg

Everything seems to be in line. There is very little wobble of the sprocket and it seems well centered.

Despite that, the chain shakes violently, especially at low rpm's.
I've had no problems with it coming off the sprocket.

I guess this is a newbie "Is this normal?" post.

Thanks for your help. I could post a video if needed.

bandito · #2 10-18-2009, 06:15 AM

"Everything seems to be in line. There is very little wobble of the sprocket and it seems well centered."
That sprocket needs to be centered PERFECTLY and parallel to the wheel. Its been my experience that one half inch of play up or down is all the play that is necessary on a chain. This doesnt apply to chains with spring loaded tensioners such as derailleurs. If your chain sprocket is off center by just 1/16th of an inch then the wobble will be an 1/8th when doubled by being round. The importance of having the chain parallel is to reduce wear on the sprocket and chain and to keep the chain from guiding off of the sprocket.

**Bikeguy Joe** · #3 10-18-2009, 06:22 AM

I would use the tightness of the rag jouint bolts to align the sprocket as carefully side-to-side as you can. I have had more problems with the sprocket being off-center, which causes the chain to tighten/loosen/tighten/loosen, and that causes a lot of noise and some vibration. I did run one bike like that for a loooong time with no ill effects, but it's better to get them as close to perfect as possible without tearing your hair out.

I tighten them about 3/4 of the way, then use a rubber mallet to get it close to centered, then carefully tighten the nuts, keeping the sprocket strait. You don't need to make the rag joint bolts super tight, just snug.

stilldoc · #4 10-20-2009, 12:20 AM

Thank you for your comments and recommendations.

I don't think I could get the sprocket any more centered. As you can see on the attached photo, it's installed around a ring on the hub that makes it hard to not get it centered accurately.

The lateral wobble is very small and I wouldn't think it could cause vertical shaking of the chain. How can I change it when the sprocket is pressed up against bare spokes (no other way to do it on this bike)?

The chain is quite tight. About a half inch of slack.

I think my question is, how much shaking of the chain is to be expected when everything is properly installed? I'm just lifting the wheel up off the pavement and allowing the wheel to turn at about 10 mph.

bandito · #5 10-20-2009, 01:04 AM

Ive installed alot of sprockets, pulleys and chains over the years but never a rag joint like these kits have on spokes......Bikeguyjoe could it be the chain he replaced not fitting on the sprocket correctly ie. spacing, width?

xlite · #6 10-20-2009, 10:06 AM

Quote:

Originally Posted by stilldoc

How can I change it when the sprocket is pressed up against bare spokes (no other way to do it on this bike)?

Sprocket against spokes... baaaaaaad!

Venice Motor Bikes · #7 10-20-2009, 10:35 AM

Quote:

Originally Posted by stilldoc

Thank you for your comments and recommendations.

I don't think I could get the sprocket any more centered. As you can see on the attached photo, it's installed around a ring on the hub that makes it hard to not get it centered accurately.

The lateral wobble is very small and I wouldn't think it could cause vertical shaking of the chain. How can I change it when the sprocket is pressed up against bare spokes (no other way to do it on this bike)?

The chain is quite tight. About a half inch of slack.

I think my question is, how much shaking of the chain is to be expected when everything is properly installed? I'm just lifting the wheel up off the pavement and allowing the wheel to turn at about 10 mph.

Don't use the center hole as a guide for centering the sprocket!!! Spin the wheel & use the tips of teeth for centering!!!

freewheeling frank · #8 10-20-2009, 12:01 PM

the dropouts on the cranbrook are facing forward, i dont use a tensioner on mine. but the torque pulls the axle forward lossening the chain i plan on building some adjusters like on a motor cycle when i get time till then i carry a wrench in my back pocket and tighten it up as needed.

**BarelyAWake** · #9 10-20-2009, 12:15 PM

Quote:

Originally Posted by VENICE BOY

Spin the wheel & use the tips of teeth for centering!!!

The lawyer sez to remind you, the sprocket's teeth - not yers

wow, that hurt just thinkin' about it lol

bairdco · #10 10-20-2009, 12:18 PM

Quote:

Originally Posted by freewheeling frank

the dropouts on the cranbrook are facing forward, i dont use a tensioner on mine. but the torque pulls the axle forward lossening the chain i plan on building some adjusters like on a motor cycle when i get time till then i carry a wrench in my back pocket and tighten it up as needed.

get some of these.

Wald rear hub washer. Serrated, 3/8in. | BikepartsUSA