proper159 said:
Now, what is the best way to put on a new tire with the tube on the rim? I want to avoid pinch flats and make sure the tube is sitting on the rim (a lot of bike shops don't get that part right). There was a spray that they used to make sure the tire bead would sit just right, should I use soap with water? I kind of want to make sure I don't spray too much water because I have a tape job at the moment to protect the innertube from getting punctured from my cracked rim.
I've changed maybe a 100 dirt bike tires. MTBs have no rim lock so it's a lot easier. Some dirtbike tires are easy, some are mongrels.
To lube the whole tube and tire bead use talc (baby) powder. You lube the tube if your old tubes are coming out with wear marks on the sides from rubbing on the tire inner wall. Problem is that talc in inviting the bead to slip on the rim.
To temporarily lube just the bead for fitment, use Windex. Windex is great because it lubricates the rubber when wet, but dries up totally and leaves the rubber a little tacky so your bead then sticks nicely to the rim. Best if you can wait 30 mins before inflating with Windex, so it can dry up more. Don't use windex on the tube.
If you are careful you could put powder on the tube and sparingly put windex on the tire bead.
For a MTB tire you should only need the tire irons to start and end the process. Do all other tire fitting with your hands. The main trick is ensuring both beads are fully pulled up into the rim well, while trying the lift a bead over the rim edge on the opposite side. Then the tire can shift the way you need it to be. The other trick is the lube used, and the design of the tire irons.
Removal: Pull one bead off. Remove valve stem cap. Remove valve stem to deflate tube. Remove tube completely. Pull tire off.
Installing: Inflate tube so it's just holding its shape. Insert tube into tire while it is off the wheel. Match tire designed rotation direction with wheel direction. Put the disc side of the wheel into the tire, so that you can later complete fitment with the wheel flat on the ground with disc up to avoid bending the disc. Hold wheel in one hand and tire (with tube) in the other. Pull the tube out of the tire a little so you can fit the stem through the rim, and install the stem cap or nut. Now push the rim edge into the tire just beside the valve. The tube should now be back inside the tire. Starting there, pull the rest of that bead over the rim. Then do the other side. Tire irons only needed for the last bit of each bead. Air inflation should seat the bead fully. Then reduce pressure to normal ride pressure.