Freewheel Chain Slipping

[Schwinn499]

Am I missing something here, or do schwinns not have adjusting screws on their derrailuers?

Most have two screws, one hi and one low, and by turning them in and out it adjust the alignment, which is the primary cause of unwanted gear changes.

Hi Low adjustment screws are just that, Hi and Low. They limit the derailleurs travel and have nothing to do with the issue at hand.

 

[bairdco]

The chain likes to slip on the freewheel when I´m ¨really getting on it¨ and it doesn´t matter the gear. I´m unsure as if it´s 1) too long of chain IE not enough tension on the derailleur, 2) a slightly bent derailleur causing the chain to try to inadvertently shift or 3) something else. The chain checks out when measured laying on a bench as being right on the money 20¨ or so down the links. The skipping/slipping on the freewheel happens every half revolution or so. I don´t see any binding of a particular link when running the chain through the paces in stand.

Ok, uhh, I didn't miss this, in the first post. which is exactly what happens when a derailluer is not adjusted properly.

Then there's 2 pages about frame straightening, buying chains, freewheels, improperly dished wheels, everything short of buying a new bike, with no mention (except by me) of turning two little screws in and out to get the derailluer aligned and shifting properly.

Adjusting the hi and low screws fine tunes the travel of the derailluer, which ensures every gear is engaged properly, stops chain jumping, and is exactly the (original) issue at hand.

 

[GTs58]

So the shift lever can be omitted then? High low screws have absolutely nothing to do with insuring every gear is engaged properly. That's what the shifter lever is for.

Adjusting the hi and low screws fine tunes the travel of the derailluer, which ensures every gear is engaged properly, stops chain jumping, and is exactly the (original) issue at hand.

 

[bairdco]

No, that's not right. If adjusted improperly, the chain can jump off the top cog and bind between the spokes and the freewheel, because the shift lever has more travel than the adjuster allows for, or not make it to the top gear because it's adjusted too low.

I'm not trying to start a fight, just trying to help the guy out, instead of having him spend a bunch of money trying to fix what sounds like a very simple problem.

 

[bairdco]

Wait. On second thought, I had the exact same problem with a 1960 ford falcon. Gears slipped under load, frame was bent, rear wheels were out of alignment...

Sold it to a junkyard. Solved all my problems.

 

[Schwinn499]

Buying a new chain and truing a wheel is just routine for refurbishing a bike. OP is the one who brought up a new freewheel and comments were made to defend its necessity. The Hi Low adjustment has zero to do with the problems of a bad chain-line and improper derailleur alignment. The only chain alignment they could effect would be the Hi and Low cogs if it was improperly adjusted, those adjustments have zero effect on the middle three cogs.

The rear wheel may have been out of true, but I still stick to my guns on it being a new chain that solves the problem.

 

[Dale Alan]

As mentioned above the high/low screws are for limiting the travel of the derailleur.A friction shifter does not care what the limits are set at .Maybe you are thinking of indexed shifting ? Indexed is set by the adjusting barrels being turned in or out to line the jockey wheels up to insure proper indexed shifting.

 

[Dale Alan]

Buying a new chain and truing a wheel is just routine for refurbishing a bike. OP is the one who brought up a new freewheel and comments were made to defend its necessity. The Hi Low adjustment has zero to do with the problems of a bad chain-line and improper derailleur alignment. The only chain alignment they could effect would be the Hi and Low cogs if it was improperly adjusted, those adjustments have zero effect on the middle three cogs.

The rear wheel may have been out of true, but I still stick to my guns on it being a new chain that solves the problem.

+1
$10 chain will likely fix the problem .If not,you have a new chain so you can start eliminating the problems from there.

 

[Dale Alan]

Have you tried shifting into the big chainring and standing on the pedals ? In the big chainring the chainline will be straighter(going by what your pic shows) and the chain tension will be greater.If you see a big difference you are narrowing down things.

 

[bairdco]

I was thinking of index shifters, but I've had friction shifters where adjusting the hi lo cured chain jumping because the adjustment was right on the edge of shifting.

But now that my first suggestion has been blown out of proportion, a dry or stretched out (or both) cable can cause jumping.

I guess my main point is to check the easy, cheap stuff first. if my car stops running, I check that there's gas before I rebuild the engine.