I'm looking to go "Darkside" when my hack is installed. I have a few questions.
1. What is "double Darkside?
Double darkside is when you run a car tire on the rear and generally a MC rear tire on the front.
2. What is the best size for sidecarring?
That I can't tell you my friend, as I don't run a sidecar, but on the bike itself I'm going to say use the same size you normally would. Your Darkside rear should be a 195/55-16 and the front should be 130/70-18, with the Bridgestone BT-45 being one of the most popular if going double dark. If you stay with a MC tire on the front, the tire size is the same, and you have many choices. My recommendation if you stay with a MC tire on the front is the Bridgestone G709.
3. Why would I want run flat tires when they are so easily plugged.
Because if you pick up a nail, you probably won't ever know until you check your tire pressure, and you can still plug it. With a non-run flat, when it goes flat, you will know it. No different than having a flat on a MC tire.
4. What are the most popular brands in use?
For the rear, right now, the Driveguard RF, Pirelli P1 RF, and the Pirelli Snow Control RF, are the most commonly used. The Driveguard seems to be best for general riding, and with a sidecar on there, probably your best choice. Either one of the Pirelli's would be good if you're really into the twisties. For the front, as I said above, motorcycle tire I'd go with the Bridgestone G709, others may recommend the Dunlop E4. Double dark, go with the BT-45.
Thanks, Robert.
Robert, I hope this helps, ride safe and keep the shiny side up.