KCvale
In memory of KCvale 1959 - 2019
I built my first MB with a Grubee kit in April 2010 and thought putting a big honking ugly tensioner pulley on the drive chain just to make the kit easier to install was a really lame solution to a mechanical problem.
So on my next one I sized the drive chain to be tight with the wheel about 1/4 to a 1/3rd of the way back in the rear mount grove, and then worried about the pedal chain.
The drive chain is in motion when the bike is, the pedal chain is hardly ever in motion so right off the bat you eliminate the need for some big industrial grade pulley.
The first thing you will find when you do it this way is your original coaster bike chain will be about 1 link too short.
No problem, I just pulled a link out the excess chain the Grubee kit came with, and used their spare master link to add it to the bike chain.
The tensioner works dandy on the pedal side, but it is still a big, ugly square plate of steel on an otherwise pretty and rounded bike, even if you paint it.
I tried one of these $20 bike chain tensioners...
But then the pedal chain was too long for the reach of the small but far better looking bike pulley!
By using the big pedal sprocket to line up the chain it turns out the chain is a 1/2 link too long with the extra link in, and 1/2 a link too short without it.
The Half Link
What a wonderfully simple $1.99 fix.
No tenioner needed at all.
The drive chain is tight with about 20 miles on it, the pedal chain has about 1/2" of play and stays on fine for the little use it gets.
Now as the drive chain stretches I can just pull the wheel back to tighten it back up ;-}
So on my next one I sized the drive chain to be tight with the wheel about 1/4 to a 1/3rd of the way back in the rear mount grove, and then worried about the pedal chain.
The drive chain is in motion when the bike is, the pedal chain is hardly ever in motion so right off the bat you eliminate the need for some big industrial grade pulley.
The first thing you will find when you do it this way is your original coaster bike chain will be about 1 link too short.
No problem, I just pulled a link out the excess chain the Grubee kit came with, and used their spare master link to add it to the bike chain.
The tensioner works dandy on the pedal side, but it is still a big, ugly square plate of steel on an otherwise pretty and rounded bike, even if you paint it.
I tried one of these $20 bike chain tensioners...
But then the pedal chain was too long for the reach of the small but far better looking bike pulley!
By using the big pedal sprocket to line up the chain it turns out the chain is a 1/2 link too long with the extra link in, and 1/2 a link too short without it.
The Half Link
What a wonderfully simple $1.99 fix.
No tenioner needed at all.
The drive chain is tight with about 20 miles on it, the pedal chain has about 1/2" of play and stays on fine for the little use it gets.
Now as the drive chain stretches I can just pull the wheel back to tighten it back up ;-}