so i finally got my 09 rush hour. it comes with a 46x16 combo and i wanted to swap out the 16 for a 18 freewheel. Without knowing the current chainring/cog setup is a 1/8", i went ahead and bought a 18t 3/32" freewheel cog to replace. Can i still use it?

https://farm4.static.flickr.com/3219/...0a2ea728_b.jpg

yes

Likes that 09 RH.
Yu Running a Singlespeed with one brake!?

Yes as long as you run a 1/8 chain.

i doubt his bike came with a chain/chainring combo that isn't compatible with itself. It's either all 3/32 (in which case this setup will work fine) or it's all 1/8 stock in which case putting a 3/32 cog on will also work. Assuming a bike is currently rideable (ie you don't have a 3/32 chain on a 1/8 chainring before you even thouch it) you can replace either chainring or cog with 3/32 and it will work 100% of the time

In general this is what I was saying.
I think.

Probably. My explanation went all over on account of my doctor prescribing me hycodan as a cough suppressant. I'm a bit scattered presently...

But yeah, I guess if you're ever in a situation where you don't know what's on your bike, 3/32 cogs and rings will always work, and 1/8 chains will always work.

i was going to freewheel, but i think i am going to try out the fixed thing once i swapped out the 16t to a 18t fixed. the area i live and ride in is somewhat hilly, hopefully a 18t is enough. i've been riding 50x17 or 19 on my geared bike so i can somewhat get use to the fixed gearing.

just to shave some weight, i took off the rear brake, reflectors, stock pedals. i am swapping out the saddle, seat post, fork, stem, track bar for a longer deda stem, a normal road bar, carbon seat post, fork and selle slr xp saddle.

this thing is a 50cm, stock weight is a little over 21lbs. i am hoping to take it down to around 18-19.

This should be stickied or maybe added to the Gearing Primer sticky.

yes.