Hi folks,

I don't have a tape measure or ruler handy so I can't tell for certain if my chain is too loose, but I think it might be.  The chain is rubbing on the chain guide and is starting to tear it up.  I greased the hell out of it for the time being.  How loose is too loose to ride safely?

Also, my rear sprocket is really nasty (grease + dirt + twigs + what seems to be little bits of squirrel), can I clean it off without causing problems?  Should I grease it back up afterwards, or is chain oil enough to keep things lubed?

Finally, I noticed that when I have my bike up on its centre stand and I shift into 1st (keeping my hands far away from moving parts) I noticed that the chain seems to stick, causing the wheel to jerk a little and the chain to bounce up and down.  Is this because the chain is loose?  Is it being up on the centre stand making the problem seem worse than it is?

Quote from: cayI don't have a tape measure or ruler handy so I can't tell for certain if my chain is too loose

You're looking for 20-30mm of slack.  One inch is 25.4 mm.  And guess which handy (pun intended) part of yourself is perfect for just such a "close enough" measurement?

Quote from: cayThe chain is rubbing on the chain guide and is starting to tear it up.

Yep, it sounds a little loose.

Quote from: cayAlso, my rear sprocket is really nasty (grease + dirt + twigs + what seems to be little bits of squirrel), can I clean it off without causing problems?

You're talking about the sprocket itself, right?  While you have the bike up on the centerstand, take a paper towel and some grease-cutting stuff (Simple Green, dishwashing soap, etc.) wipe off the exposed section, and rotate the rear wheel to expose some more.

Quote from: cayShould I grease it back up afterwards, or is chain oil enough to keep things lubed?

Nope, no need to lube the sprocket itself.

Quote from: cayFinally, I noticed that when I have my bike up on its centre stand and I shift into 1st (keeping my hands far away from moving parts) I noticed that the chain seems to stick, causing the wheel to jerk a little and the chain to bounce up and down.  Is this because the chain is loose?

The chain will usually bounce a little, but if the wheel is jerking and the chain is bouncing quite a bit then the chain is DEFINITELY loose.

Quote from: cayIs it being up on the centre stand making the problem seem worse than it is?

Being up on the centerstand means that the rear wheel can be turned with very little effort.  The wheel "jerks" because of the slack in the chain; it's able to move past where it would normally go with a tight chain.  Then when the chain catches up it happens all over again.

Thanks Kerry, I appreciate the help.  My chain has around 32mm of play when I apply force, putting me within the prescribed 20-30mm range when I'm more gentle.  I got the same measurements with the bike on its side stand and upright with my girlfriend on it.  I think I would like to tighten it a bit regardless.  I really don't like how the chain rubs away at the chain guide.

Actually, can anyone describe for me correct chain guide / chain action? Maybe I'm making too big a deal out of this.

Otherwise, does anyone know what size cotter pin I need?

Quote from: cayMy chain has around 32mm of play when I apply force, putting me within the prescribed 20-30mm range when I'm more gentle.

Just to make sure, was the 32mm range read using the same spot on the chain both times?  (If you measure from the TOP of the chain when it's hanging loose, and then from the BOTTOM of the chain when you push it up, you won't account for the width of the side plates.)  You're probably doing it right - I'm just being a stickler....

QuoteDoes anyone know what size cotter pin I need?

After work I could post a pic / description of the pins I've been using.  They aren't quite as beefy as the stock cotter pin, but at least they'll give you an idea.

Yup, I measured from the bottom of the pin at both extremes.  It was most convenient to do it that way, with the edge of a small ruler resting on the centrestand foot.

Here are the cotter pins I bought at a home center a while ago:



The larger ones on the right work for my rear axle.  I can't remember whether the smaller ones are OK for the front axle (2 are missing) or if I used them for something else....  :dunno: