rickyhmltn

I have a friend who has been trying to bike with me. He's very casual and has a Schwinn Avenue. He's thinking about picking up a Trek 7100. That's neither here or there for now.

On the Schwinn when he pedals it makes a slip like sound crunky sound and causes him get half pedals in. It's like he pedals and it half slips (and crunks) and he can half pedal it, eventually it'll catch or something and ride good for awhile.

Any ideas?

10 Wheels

Take it to a bike shop.

rickyhmltn

Any other ideas? My LBS is about 40 miles away and I don't have a truck to take the bike in.

Kimmo

Dude, what?

From the top.

Are you trying to describe a slipping freewheel? If so, try a bit of WD40 in it.

cny-bikeman

Wait for the posts telling you what it might be, then the ones telling you how to find out what it might be, then try out all the suggestions, then find out you need tools to fix the problem.

OR...

Check the sheldonbrown.com link post at the top of this forum under chains, freewheels and derailleurs and learn what it might be and how to check for each problem.

OR...

Give us more info and fewer made-up terms.
What gears does it happen in?
Only under high pedal pressure or at other times?
What is the frequency of occurence - random, every pedal revolution, every 2-3, etc?
Did it just start recently, did the bike just come out of storage, recent accident or equipment change, etc?
What if anything have you tried so far?

AND... Know that you may still have to take it in to a shop.

p.s. The 2nd and 3rd options are recommended if you want qualified, accurate information. The first option will require much more of your time but will help you more longer term (Teach a man to fish...) and the 3rd option will involve less time and frustration for both you and the persons on this forum who offer their assistance.

Homebrew01

WD-40 is not good for much on a bicycle.

Assuming the bike has indexed shifting (1 click of the shifter per gear), then it's likely a bit out of adjustment .... the chain is not centered over the cog when in gear, but is off a bit, and trying to shift to the next gear (up or down).

If you want to tackle it yourself, you can try the Parktool.com website, and go to their "repair" section, then to the gear adjustment part.

FBinNY 

There are too many possibilities for a comprehensive answer, but here's one thing to look at (the easiest to analyze).

A stiff link in the chain can cause problems similar to your description (skips roughly every 3 pedal revolutions). They're easy to check for. Shift to high, and back pedal while pushing the lower pulley forward slightly to slacken the lower loop so it sags a few inches. Watch for any links that don't immediately straighten into the line of the chain. If you find any stiff links, oil them (better yet, the whole chain) and flex the link sideways so the bending inner link presses the outer links apart very slightly. This should free the link.

Also, often if you simply lube a chain and ride it a while, the flexing works stiff links out within a few hundred yards, but only if they're only slightly stiff.

If you don't see a stiff link, and/or chain lube doesn't help, then go to the troubleshooting sites others mentioned, and check and eliminate each possibility starting with the simplest and working to the more complex.