Say a 50x18 instead of a 44x16 even though they are pretty similar gear inches?

its actuallly better to use the smaller as far as effort goes.

From the chain's point of view, its better to be layed out over more teeth.

I wouldn't exactly call 73 vs. 68 GI "pretty similar".

badassness?

Depending on your frame bigger rings may not clear the chainstay. Other than that, and other things being equal, i think bigger is better for the reason given by lyledriver. I think as jacobpriest says there is a belief among track racers that smaller rings and cogs are quicker or easier or something than bigger pairings with equivalent mechanical advantage. However, I suspect this is one of the many old wives tales of cycling, ie something that everyone repeats but that probably wouldnt stand up to serious testing.

Gear inches are gear inches are gear inches. Can you feel a difference between 72" with a 52T chainring over a 42T? I doubt it. There might be a bit longer chainlife with a bigger setup because the chain doesn't bend as much wrapping around the cog, but I highly doubt it extends the life that much.

Let the armchair physics begin.

it's easier to find 14, 15 or 16 tooth cogs, than it is to find 18 or 19 tooth. if you use a smaller front ring, and blow out your rear cog, you'll have an easier time finding a replacement at your lbs. at least, this is my experience.

wrong actually. the reason 10 pitch was never NJS certified is because when using smaller circles it makes the effort easier. so since we are talking about the smal pitch and same gear inches, it is easier to use the one with the smaler front.

Actually, it seems that, with the bigger sprockets ("cogs"), as the links rotate less around the rivet's axis, there is less stress on the bushings/inner plates and rivets. Some american scientists have determined that efficiency is slightly increased, with larger sprockets.

It is better for the cog and chainring to have more teeth "in" the chain. As far as the physics is c6ncerned, I'll leave that to the brainiacs out there.

Bike mechanic gave this reason to me exactly as the reason that rear freewheel (sorry I have no idea why I'm posting here, I don't have a FG yet... =) needs to be replaced as opposed to the front chainring. He said that your rings will last a lot longer because the force of pedaling is spread out over more teeth, whereas your freewheel (or in the case of FG/SS, cog) has fewer teeth engaging so more wear on the individual teeth.

So maybe that doesn't answer to the chain wear issue, but cog wear?

Since when has "Singlespeed & Fixed Gear" become "Fixed Gear Only" ? I missed that transformatory moment. Oh, wait, no, we're still in "Singlespeed & Fixed Gear"! So, it's your lucky day PsySal, you are still allowed to post here, without going to jail. Rejoyce!

Less chain wear, less stress per tooth, looks nicer.

So it's a little heavier. You can make up that weight by taking a big dump in the morning.

If I do that, I compensate for about 1 Kg-worth of bike hardware.

I think the smaller the rear cog is the nicer it looks.

And those gear inches seem pretty far apart, but it looks like most people understand what your talking about. I might add, that the bigger-bigger combo might be able to handle more power with less strain.

I build gear combos around two things desired gear size and skid patches thats all

I think a track bike looks cool with a big ring/small cog in back, like the 1 hour record holders use.

Wish I had the thighs to power a 52x14!