Fibber

I'm working on my '81 Fuji S12-S and had a question about the correct placement of the rear axle in the basically horizontal dropouts. There is better than an inch of slot available, but it is currently limited by a little screw-in stop (two little plates and a screw). With this in place, the axle resides in the forward half inch or so.

I was recently down in Fredericksburg, VA visiting family, and I asked the question to an older shop owner that seemed to be CV friendly. He has a beautiful Schwinn Paramount (his toy) hanging from the ceiling, and it has an elaborate dropout stop with a fine thread adjustment screw.

He told me that he usually aligns the axle with the intersection of the seat stays, but that you need to have (and I didn't quite understand this...) three chain links from the smallest(?) cog to the first jockey wheel of the derailleur??

Could someone please elaborate/clarify this? With the stop in place I cannot get the axle back far enough to align with the seat stay (within a quarter inch or so forward of it now). Should I remove the stop and slide the axle back? Am I overthinking this?

Old Fat Guy

Are you having problems shifting? I think you are over thinking the situation. The derailleur pulleys should be nearly vertical when in the top gear (little rear-big front), that is more a function of chain length than axle placement.

miamijim

In theory aligning the axle directly under the stay joint will direclt transfer road shock/vibrations the stays and allow them to do the job they were designed for.

I regards to the chain. He's talking about chain 'wrap' and I dont neccesarily agree with is '3-link' old wives tale way of adjusting the chain. Visualize the upper jockey being directly under the axle centerline. Move the wheel foward and the jockey will sit to the bacl of centerline an have less 'chain wrap' on the small cog. Move the wheel back and the jockey wheel will be more forward and have more 'wrap'. In theory re wrap is better and will shift better.

I would:

1. Set the wheel directly under the seat stay joint.
2. Run your chain as long as possible as that will increase 'chain wrap' maximize cog life.
3. If your derailleur has 'D' screw (manual angle adjustment srew) adjust so the derailleur body is parrallel with the chain stay then turn it in touch to open the angle.

onetwentyeight 

i tend to use those little drop out screws in lew of a b screw like found on modern derailleurs.