Picture of MONSTER Chain Single Speed MTB!
This idea came to me when I broke a chain on my hard-tail GT MTB.  I have always wanted to ride a SS and now was my chance.  This Monster chain conversion (motorcycle chain) is stronger and heavier than conventional bike chain so it can put up with more abuse and last longer.
Remove these adsRemove these ads by Signing Up

Step 1: Parts & Supplies!!

Picture of Parts & Supplies!!
•40, 41, or 50  SAE chain size
• Bike (preferably with sliding dropouts)
•PBI Aluminum sprocket
•3.5" 6061 solid aluminum    or
•Hob sprocket cutter
•20 T rear steel sprocket as a pattern

•Bike tools
•Metal Lathe
•Metal files
•General shop tools and knowhow

Sprocket info

Tree Fort Bikes has a rear steel sprocket

Chain info

♦You will need a large front sprocket and a small rear sprocket for this conversion.  Ideally you want aluminum because it is stronger per weight than steel which means that is is light!!  PBI sprockets has blank aluminum motorcycle sprockets that we can use for this project.  I suggest using a 32 T front and a 20 T rear; this gives a 1:1.6 gear ratio which is perfect for mountain biking.
♦Since PBI doesn't carry 20 T sprockets and we especially need one that is internally-splined, we must machine our own.

Step 2: Machining the sprocket!

Picture of Machining the sprocket!
*For this step you must know how to run and operate a metal lathe.*

Lets get started!!
•You will need to cut a "disk" form the aluminum solid stock. (metal band saw - horizontal) This will be your aluminum blank.
1. •Next, using marking fluid or a Sharpie to color the aluminum so that you can SCRIBE the outline of the steel sprocket onto the aluminum blank.  (I use Marks a Lot)
2. •After you have your scribed aluminum disk mount it in the chuck with outside jaws.  
3.  - Drill and  Bore the inside of the sprocket to the minor diamiter of the free wheel bike wheel.

Not Pictured
***Use a Drill bit closest to the size of the roller to drill the valley of each tooth in order for the chain to move freely. ***
If anyone wonders why bother with chainstay wrap with such beefy chain, it's to prevent frame damage when changing tires, and because the chain can throw mud and objects at the frame.

benduy2 years ago
hey nice 'ible, couldnt help noticing the cable tied pipe wrap on your fork! you should try using a bicycle tire inner, as it matches the frame and doesnt get too dirty! Anyways great job