I first saw this in September but never heard back from the owner when I tried to see it. Then yesterday it popped up in the local ads again. Went down this morning and brought it home. It was just too nice of a condition and too nice of a price to pass up. If my other one is a 22" this is a 21" going by the top tube measurements. Rear wheel was totally taco'd in a drop and is toast. But that's the only issue at all that I spotted today as I peeled off layers and layers of grime. Underneath I found a paint job with hardly any marks on it. So much better than my other Circuit. The chrome is the only let down. Lots of really small spots of rust that will probably polish right out. Other that than a few small marks on the fork and on the top tube. The rest is pretty much pristine. Not much wear on the parts either. Surprisingly it didn't have the original Suntour Sprint setup.

Instead it is rocking a full Shimano 600 groupset. There's a 52/42 Biopace (don't groan) crank on it with a 13-32 Shimano 6 speed freewheel on the back. 600 headset and brakes round it out. The bars are happily my favorites, cinelli giro d'italia 64, size 42. My favorite! A Cinelli stem adorns it too with San Marco Concors saddle mounted on a Strong 27.0 seatpost. The 600 brake levers and hoods are in really good shape too. The 600 hubs are laced to Rigida SX 100 rims, 32h with some nice looking Continental Ultra 3000 tires. Size 700 x 23. All and all this is a really nice old bike. Since I already have one I have to figure out if I'm keeping this or moving it on. I just wish my other frame was as clean as this one. Oh, one odd thing. No date code on the head badge.

And now the pics I took today after doing nothing more than wiping off the grime.

And a few more:

These flat black Schwinns are so nice. Long cage 600 RD too, which is really cool.

That looks sweet! Nice score!

Very cool.

That's a clean Circuit. Did the seller know why the Sprint was replaced with the 600 gruppo? I wonder if the Schwinn dealership swapped the components per the original purchaser's request.

Wouldn't surprise me. If you look at the 87 catalog the components and even the wheels are matching up pretty much to a 1987 Super Sport. It had the 600 series 6 speed stuff, just a stock different freewheel. It originally belonged to the father in law of the guy I picked it up from.

It seems fairly small, maybe a 20 vs a 21?

Gonna see if my son fits on it or it may wind up a trade fodder.

I was going to ask about that- if the perspective was messing with me.

The later 600EX stuff is really cool.

I think the cage has been replaced. It's a RD-6208 body but everything I found online says that's a short cage RD. The RD-6207 was the long cage one.

Good news is the RD will cover the 8 speed range. So until I find a proper replacement wheel I should be able tor friction shift it through an 8 speed setup. I have several "extra" 8 speed wheels around the house.

Well, had a new (used) rim laced to the rear hub for now. And then a bittersweet moment as I turned this over to my son and he took it home. Such a beautiful find, I hope he really appreciates it and rides it a lot like it should be. He was excited about it so we'll see. Hopefully this spring will be riding our Circuits out on the road together.

Well...... My son has decided he doesn't like to road bike and is going to stick to mountain biking. So he brought the Circuit back to me. Way too small for me to use so I took a bunch of pics to day preparing to list it locally. Seeing how really nice the Shimano 600 components are and how it has a sweet Cinelli stem and handlebars made me decide to possibly break down a bike. So if this one doesn't go locally I'm going to do a first for me and pull the components to keep for a future build. I wish my son had fallen in love with this bike, it's such a sweet machine.

I wish the one I have in my size was this nice.

Stem is 22.2mm, and note that the headset is JIS 27.0mm.

Some of the early SS bikes had 21.1mm stems, my '71 models both do.

Can I be the only one here that thinks this bike left the factory with this 600 gruppo?

It's the Giro D'Italia 64 in size 42 cm. So probably an upgrade.

Yep, that was discussed earlier or in another thread. It has the build group from a 87 Super Sport so seems likely done at the factory or original shop build. Even the rims match the S.S. I just had to replace the trashed rear.