Bicycle Mechanics - Chain Skips

I have an old Schwinn Paramount 10-speed with Shimano components. I'm having a problem with the chain skipping. It's happening on the back sprockets and only when I'm in either the 9 or 10th gear. It's not switching gears, but seems to miss a cog or something then resets. Does anyone have any idea what could be causing this?

By 10-speed do you mean 10 cogs in the back? If so this type of skipping often means that the shift cable tension needs adjusting. This can be done with the barrel adjuster found at the rear derailleur where the cable housing meets the derailleur.

Al

it actually has only five cogs in the rear, but I will give that a try.

Thank you!!!

Could also be chain wear.

it actually has only five cogs in the rear, but I will give that a try.

Thank you!!!

Oops! Probably a different problem if you have friction shifting (no distinct clickstops). You may need a new freewheel and/or chain. This type of slipping on a 5 cog freewheel is often due to having an old chain that was left on the bike too long replaced by a new chain. As a chain elongates, the rollers become spaced farther apart and the freewheel teeth are worn to match the worn chain. When a new chain is installed it doesn't fit the worn cog teeth and slips over the teeth. Measure your chain with a good steel ruler. A 24 pin interval should measure exactly 12 inches. When this interval becomes 12 1/16 inches the chain needs to be replaced. If your chain is in tolerance you probably need a new freewheel. If your chain is beyond the 12 1/16th limit then try a new chain. If the slipping continues you need a new freewheel.

Al

+1 to Al1943... it sounds like you will probably need to replace the FW though. I'm guessing you ride in the two smallest cogs a lot, they are probably worn out while the less used cogs (inner 3) are probably in more pristine condition. This is why you only get chain skip in the out 2.

Also check for a stiff link(s) in the chain. Rotate the crank backwards slowly. A stiff link will make the RDER "twitch" noticeably.

thanks!!

I just started riding the bike after it had sat for many years. The first couple of days I rode it, it didn't skip at all, then all of the sudden it started skipping. Still most likely FW?

also, one other thing I forgot to mention is that it seems to skip in the same place every time, about every other rotation of the cranks when I'm in top gear.

Also check for a stiff link(s) in the chain. Rotate the crank backwards slowly. A stiff link will make the RDER "twitch" noticeably.

+1
Check for a stiff chain link.

+1
Check for a stiff chain link.

It was a stiff link! I just worked some WD40 into it and it seems to work great! Thank you everyone!!