brilliantly simple tandem bike

Step 3: Rear bike

this doesn't necessarily need to be in any particular order, in when you do this, but on the rear bike, we're going to need to drill at least two holes through the headtube and through the steerer tube of the fork. drill holes corresponding with the size bolts you're going to use. I also wouldn't recommend smaller bolts, considering that we're going for strength here.

this drilling is going to prevent the frame of the rear bike from turning like the cargo of a semi-truck, which could be catastrophic if it happens on a left turn for the drivetrain.

MAKE SURE THAT WHEN YOU DRILL, THE FORK IS LINED UP PERFECTLY STRAIGHT WITH THE FRAME. I don't think I need to explain why. it might be easier to check this with a front wheel mounted, or if you particularly don't care about it, clamp it in a vice as I did.