so wait, u8nles sim ******** my 42/16 simplifies to 21/8? that makes eight patches, sixteen for ambi-skidding, and basically means ima have even tire wear?

to think i was only going after a good gear-inch.

So I gots a 17t cog and I can definitely feel the difference. It is a difference that I do not like. Although the hills are no problem, it's much harder to keep the old speed going downhill. I think the next purchase is going to be a 50t or 52t chainring.

Are there any negative effects of putting a road chainring on a ss or fg?

none whatsoever

No, it is fine as long as your using the same chain size (3/32) and BCD (130).. such as the kilo uses.. it is a road chainring pretty much. You should have no problem finding many tooth sizes for the 130 BCD. I have a kilo myself.. I was using a rocket ring (dans comp), but found a nice takagi NOS bmx chainring that I like. However I was going smaller on the chainring.. I have 45x17 currently.

Did you order from this seller? The prices look good, but I don't want to wait forever for it to get from Norway.

ambi only doubles patches if the number of skid patches is odd. So ambi or not, you only get 8 patches.

good call, and since this thread started, the wear has been very even, (thanks for clarifying that)

This has been very helpful to me in determining the pros and cons of various gear ratios. Nothing new, I'm sure as Sheldon has a link to it.

You're wrong here. After you simplify the ratio of chainring teeth to cog teeth, ambidextrous skidding doubles patches only if the simplified chainring value is odd (see the skid patch theorem in the diy thread). 42/16 simplifies to 21/8, and 21 is odd, so freecycle does have double skid patches in ambidextrous skidding.

hoo-lee, thats a fair call too! i was going by denominator as well, not the chainring value.

however what all of this is really pointing towards is finding a good combination that will give you a sufficient gear-inch while still getting the longest wear from your tires.

by the way, my choice was accidental, i consulted a gear-inch chart and went for it, only after learning to skid did it occur to me to calculate such a thing. maff is gud.