Schwinn tandem

[SchwinnNut]

:) Hello there - -i am so pleased to have discovered a tandem forum on the net. My wife and I bought a Schwinn Tango cruiser tandem last summer and have really enjoyed riding it. Towards the end of the summer though the front chain kept coming off under load - -going up a hill etc. We are not technically savvy and i wonder if anyone could advise us how to adjust the chain? Would we need special tools etc?

[TandemGeek]

Lets assume that the chain has been lubed and wiped clean on a regular basis and that the cranks and everything else associated with the drive train is properly adjusted....

The first thing to check is the tension on the sync chain that runs between the front & rear cranks on the right side of the bike. If there is a lot of slack in the chain you'll need to adjust the idler wheel that's mounted a few inches behind the front cranks. I'm not sure what size bolt is used, but it should be somethat you can adjust with an adjustable spanner. You would want to raise the idler wheel just enough to take out the excess slack in the sync chain so that it doesn't bind and as a little play.

If you find that the chain is not all that loose I'd start to suspect that the cranks aren't properly aligned or that there may be some other maintenance issues which could warrant a check by a bike mechanic, e.g., excessive chain wear (not likely), frame alignment, bent timing rings, etc... only because it's sometimes very hard to trouble shoot problems on certain types of bikes, and your Schwinn Tango would be one of those types of bikes.

[SchwinnNut]

Thank you so much for your reply TandemGeek --that's the sort of basic info that I need. I will check out the sync chain slack as you suggest but i have noticed that the chain comes off the front crank at an angle before it passes over the idler wheel. Is it supposed to do that or should it come off perfectly straight? May I email you some pictures so you can advise me?

[TandemGeek]

If by angle, you mean "up" and over the idler wheel then yes, it's normal.

If by angle you to the left or right of a centerline drawn between the front & rear timing chains, then it sounds like something (probably the very vulnerable idler wheel) is out of alignment.

Feel free to post up photos.

[SchwinnNut]

:) Hi again - -thank you for your continued help. The chain leaves the crank at an angle going to the left: towards the viewer in the pic I have uploaded.
Might that mean that the metal bracket that the idler wheel is attached to may have been bent out?
http://i125.photobucket.com/albums/p48/mjyuk/P3280054.jpg

[TandemGeek]

The chain leaves the crank at an angle going to the left: towards the viewer in the pic I have uploaded.Might that mean that the metal bracket that the idler wheel is attached to may have been bent out?

A photo taken looking from front-to-back so that the relationship between the front & rear timing ring, the sync chain, and the idler pulley was presented would provide more concrete evidence. However, what you are describing suggests the idler pulley is indeed bent but I would have guessed it was bent "away" from the camera (and toward the boom tube) based on how things appear in the photo.

Regardless, the idler pulley should be sitting directly in-line between the front & rear timing rings such that there is no sync chain deflection left or right of dead center (period).

If it's not, and if you're comfortable doing so, the idler bracket simply needs to be bent back so that the pulley is once again in line with the timing rings. If not, a competent bike shop mechanic (ideally, a competent recumbent bicycle mechanic as they're usually quite familiar with idler pulleys) should be able to correct it in about 30 seconds.