Singlespeed & Fixed Gear - Do I have enough space in dropout?

I have short horizontal drop outs. 42x16 fits perfectly in the middle of the dropout, but that gearing seems to low. I have an opportunity to trade my 16 for a 15 with someone but i don't know if i have enough space to do it without having to start messing with the chain length and possibly having to buy a half link. can you guys tell from your wealth of experience if i can get away with it without changing the chain length?
Thanks

I'm pretty sure you can. With the 15, the axle will move back 1/8 of an inch. You have quite bit more than that there, and some "reserve" for when the chain stretches.

Keep in mind that it's going to go 1/8" straight back on a line going through your axle and BB spindle, so it's going to move a bit more than that up the dropout, maybe like 20% more depending on the dropout angle. Trig is your friend. You clearly have the room for that, but it's something to note if you start futzing with chain links or want to regear some day.

Edit: just did the math and realized the actual move in the first place is less than 1/8" anyway. OK, enough geekyness.

Thanks, I didn't realize it was such a small shift.

Why do I have a dropout fetish? I dont know why, but to me, a nice looking forged dropout totally makes a bike look better. Do you have a full-body shot?

sure, found the frame collecting dust in a rundown bike shop, salvaged it and put it together with a mix of parts.

looks nice

Gorgeous... are those sharks on the frame? are they decals? or did you have it repainted? What brand is it? how many questions did I just ask? --- 5

Gorgeous... are those sharks on the frame? are they decals? or did you have it repainted? What brand is it? how many questions did I just ask? --- 5

Thanks, its actually the original paint. someone, i assume the previous owner, carved sharks out of the paint and used marker to fill it in!
They pretty much ruined the paint on it. I was thinking about painting it but for now i like the ruff worn look makes it less attractive to thieves.
shop owner said its a 70's Atala, don't know the model.

here's more. how do you guys post large pic files?

why are those pictures so crazy looking

I think those pictures were taken through an aquarium...

is this better? *****es!
http://img435.imageshack.us/img435/641/dscf00014tm.jpg
http://img442.imageshack.us/img442/8756/dscf00058zp.jpg
http://img442.imageshack.us/img442/6827/dscf00069ns.jpg

Nice.