Hi,
I have a 2006 Redline Monocog FLT Al 26" bike. The rear cog is 20. I want to try 18 or 16 to see if I like it better. Will any bmx cog work? Any recommendations. My chain is 1/8", but I still use a 3/32 cog, correct. What park tool do I need to remove the rear cog?

Thanks

Is it fixed gear or do you have a freewheel?

Not fixed, I believe it's a Shimano style cassett cog.

Edit, I found the cog I need. I am just not sure what park tool I need to remove the cog.

Does the freewheel body have 4 notches ? Most of them use Park Tool No. FR-6.

I believe those old Redline wheels have a lock ring (like on a fixed gear), then you need this:

https://www.universalcycles.com/shopp...46&category=40

Ok, thanks. I guess I'll have to take a closer look when I get home.

i recently converted a shimano freewheel to singlespeed and used the park tool FR-1 to remove the lock ring from the freewheel. you'll also need a chain whip to prevent the freewheel from freewheeling. but that was for a geared road bike.

What robb. had was a freehub. On a freehub the ratchet system is built into the hub, and the cogs just slide on. A freewheen has the ratchet system built into the gears and they thread onto the hub. The freewheel was the only system untill the mid 80s. But now any road bike worth anything(and most taht aren't worth a thing) use the free hub system. It creastes a much lighter unit, and works better for the bigger cassettes. Freewheels generally work better and are more common in single speed aplications.