76SLT 

I just rebuilt the wheels on my 78 Schwinn Superior using the original Weinmann 27" rims and Schwinn Approved Deluxe / Normandy Luxe 36 hole hubs. The old spokes were corroded, and I wanted to bring back the shine like when it was new in 79 when I bought it. I measured the old spokes and found that the ds and nds were both 306mm so that's what I used to rebuild them. They are 4 cross btw. This was just my fourth set of wheels that I've built, and the first that used the same length for both sides. When I was done with the back wheel, it was off centered with the frame by quite a bit so I took it to the lbs for their advice. They said you need to tighten the ds more to pull it over which made sense, so I just had them do it for me. It's better but still not centered. Should I re-lace the ds with shorter spokes, and how much shorter?
The wheel was properly centered before I rebuilt it so I know the frame is good. Here's a pic of it. It's not bad and it rides ok but it's not centered like it was.

Bill Kapaun

Loosen the NDS spokes some.
On a multi cog rear wheel, the NDS spokes have a greater effect due to the bracing angle being different than the DS.

bitpuddle

Drive and non-drive side spokes should be a couple of mm different, but those old hubs might have required so much less dish that the factory used the same length spokes to save money. Any reasonable mechanic should be able to re-dish that wheel; a proper dishing tool makes it straightforward.

ThermionicScott 

You sure? Could be that the frame is tweaked a little and the wheel was trued off-center to work with it.

Try flipping the wheel in the dropouts to see if the rim is still too far to the left, or if it is now too far to the right.

76SLT 

I think I'm going to replace the ds spokes with some 304mm spokes and see how it comes out.

Russ Roth

This, or run a string from one dropout to the headtube, and down to the other dropout. If the distance between the string and the seat tube is different on both sides the rear isn't straight.

76SLT 

I haven't checked the frame for straightness but I've had it since new and it's never been crashed. If it has 200 miles on it I'd be surprised. I didn't ride it much and only got it out of storage a few years ago.

HerrKaLeun

Use truing stand and dishing tool.

Spoke lengths should be calculated based on hub and rim measurement.

Bill Kapaun

WHY?
It's the difference in spoke tension that causes the dish.
Back off the NDS spokes a bit. You probably don't need more than 1/4-1/2 turn.
It's either tighten DS or loosen NDS spokes.
Once your DS spokes get too tight, you only have one other alternative.

76SLT 

I'll give it a try, thanks.

Mad Honk 

76SLT,
If memory serves me right all of those old five speed Schwinns were built with the same size spokes. Back then they were using 12-1/8" spokes made by Union and all of the wheels were four cross patterns. The difference was that the wheel build required a difference of about two turns of each spoke less on the non drive side than the drive side. As BK points out it is fairly easy from an engineering mindset, But to put it lay terms: one side is not tightened as much as the other, and in this case it is about two turns of the spokes on the NDS. HTH, MH

Prowler 

When I build a wheel (or retension one during a rehab) I start with checking the dish, spokes barely tensioned, then recheck dish often as it's brought up. Same with hop and runout. Much easier than correcting after the fact. As I built my own truing stand, with the means to easily flip the wheel to check centering, this is just part of the process. I suppose manufactured stands have the means to do it too. Caution: the two Park truing stands at work are not aligned to check for dish and no one seems inclined to correct them. Fine with me, but do not assume that any professional or credible stand is properly aligned. Maybe that's why dishing tools sell well.

I prefer ensuring, first, that the rim is centered over the lock nuts. Then, knowing that is fine, see how it does in the frame, is the frame or fork ok?

76SLT 

You all had great advice, and with that advice I was able to make adjustments that resulted in a perfectly centered wheel. Thank you all.
Bernie