Originally Posted by Bushman

Its very possible to make a fixed mountain bike using vertical dropouts.

First off is cog choice - you want THICK cogs, without ramps, or precut shifting cutouts. Tall teeth are your frined here.

Cog size, go a little bigger, for more tooth contact. I use a 20 - 26 range.

Chainring size: again, no ramps or shifting cutouts. I use a 30 - 36 range for my offroad setup.

Chain. use a KMC BMX or track chain., They is beefy! Or best of all is a FULL "halflink chain".Really easy to setup chain tension with a halflink chain.

now the tricky part, chain tension.......install the wheel/cog on the rear and snug up the skewer or nuts. add the chain and wrap it around the cog and chainring, until your holding one end in each hand. Figure out how much cahin you need and remove links accordingly. To join the chain, you may need to use a couple of halflinks. Tension should be "snug", just enough so that when you turn the wheel backwards you can feel a bit of tension.

Good Luck.

Fixed offroad bikes are freeaking incredibly fun, you can POWER thru mud and snow without bogging down, its like positraction.

my next project project is a Surly Pugsley with their 4" wide tires, 26 x 24 fixed gear, disc brakes. Hopefully they will have their 4" wide tires in 29" too.....