so, I got my hands on a nice Cr-mo KHS frame. Rode lot of fixed gear bikes, but also like some SS, wich I would build now (I used to ride my FG as road training, and some of that long descents at 160+ rpm with a 18 wheeler going 100km/h at you side got scary real fast ) So with a SS i still got that nice feeling of conquering the hills but can actually rest on the descents.

but I got some questions I hope some experts here would answer:

1 - the frame got semi vertical dropouts. I got what looks like a fair amount of adjustment. Since in SS the tension can be a little slackier, should I get away without any kind of tensioner? (I believe I can, but doesn't hurt to ask). If my measures were right, i could use a 46X17 in magic gear, wich is a nice ratio for me.

2 - the frame got 130 rear spacing. So what would be better/easier to mantain? A road wheel with some of that single speed kits, or a SS wheel with a nice freewheel and some spacers ( don't want to cold set the frame - will keep it original) ? The road wheel seens like a obvious solution, so unless someone got some really bad experience with those kits, maybe it should be the way to go. Even if it's a bit of a pain to find single cogs with cassete drilling.

I've never heard of semi-vertical dropouts. Perhaps they are semi-horizontal ? As long as the chain slack isn't excessive, you don't need a tensioner. As to wheels, a spaced track hub with a single freewheel is the simplest solution, and bolted or nutted axle is more secure.

With 130 spacing I'd go w/ a single speed freehub conversion kit on a wheel already owned w/ the 17T cog from a cassette set-up for the proper chain line on a 1/2 X 3/32 road chain. If you have enough adjustment in the dropout: Good to go. Otherwise use an old rear derail as a chain tensioner. Easy/inexpensive, functional and the QR still works.

-Bandera

I prefer using a wheel with a freehub but if you already have a flip-flop wheel then just use that with some spacers. If you choose the cassette wheel you can look up Surly for some good SS cassette cogs.

hmm, would a single cog from a cassette and a normal road chainring work properly if I got a nice tension on the chain? Later on I can always buy optimal parts (like a narrow wide chainring and a single speed cog), but just to get it running, the former option is cheap and fast

Yes, this works. One sees people riding around on single speed conversions of this nature. It's one way of dealing with a bike that is functional except for a trashed drivetrain. Someone sells a kit of spacers that lets you remove all but one of the cogs on a cassette, otherwise you can just leave them there.

Don't waste the extra money for a narrow wide chainring, just get a good road ring.

Dropouts like the Shimano UF and Gipiemme 1800AX were often described as "semi-vertical:"

Or perhaps they should be called semi-vertical-horizontal ?

really? I use a narrow wide on a hybrid with rear derailleur and it works nice. But I built a bike for the wife with a single road chainring and it also works nice. Maybe i was fooled, and for road usage a narrow wide is not required?

TejanoTrackie: change the Y to X and everything is fixed. Semi vertical becomes semi horizontal and everyones happy

Since they have not been required for the last century or so of use on any flavor of road drive-train thus far : No.

-Bandera

Go on eBay, get an old Sugino ring for like 10 bucks, case closed.