I recently purchased an 03 XR100 to turn in to a mini moto bike for kart tracks and possibly some flat track. I found an XR80 front wheel so I can run 16s on the front and rear. I bought a pair of BT45s in 100/90/16. When I mount the rear tire, which direction should I mount it in? Should the arrow be pointing towards the front or should I flip it around on the rear? I read that I can use 3.25/3.50-16 tubes. Does this sound right for both wheels? It looks like the rear wheel is slightly wider. What is a good starting tire pressure for these tires? Any tips for mounting the tires and tubes? I have a NoMar but have never mounted a tubed tire. Thanks!