Notes for a Saturday morning.
On a street bike rim locks are not to keep the tire from moving on the rim. They were used before rims were designed to hold the tire in place when the tire rapidly deflates. I can speak from experience. You want the tire on the rim when you have such an experience! Of course you pay your nickel and take your chances!
If you need tire irons to mount a vintage tire longer than 6-7" you are doing something wrong. In fact the guys doing the Six Day Trials learn to change tubes without tire irons. That is WITH rim locks and stiff dirt tires.
When offering the bead from the first side to be mounted you locate the part of the rim between the tire stem and one of the rim locks. With the bead lubricated with your committees favorite tire lubricant push the edge of the bead over the edge of the rim and as up close to the rim strap as you can get it. Your problem is the inner diameter of the tire bead is going to be inches smaller than the diameter of the rim. The only way you can get the tire bead over the rim is by moving the far edge of the bead away from the rim. You did this when you first offered the bead and pushed in up against the center of the rim strap. Then you should be able to put all but 6" of the bead over the the rim by hand. Take up the last 6", or so, with a small tire iron (our your hand).
Wet the iron with rubber lube. Slide the tire iron between the last 6" of the bead and the rim. Then slide the tire iron sideways as far to one side of the unmounted bead as you can. Then lever a little bit of unmounted bead at a time. If you lube the bead well you should be able to push the last 4" or so over the edge of the rim with the base of the palm of your hand. Do the same to the second bead starting at the same point between the valve stem and one of the rim locks.
I prefer to put one side of the tire on the rim before offering the rim locks. Then offer the locks, then the tube and when all of this is in place mount the second side.
While in my younger days I did all this on the floor (or the turf when woods riding), today I prefer using a round steel trash can (don't know what you call them in the UK. This raises the tire and is a bit easier on the back. The one i use has a rubber tube around the top edge to protect the spokes.
The tire should be inflated to seat the bead, but never to more than the maximum figure printed on the side of the tire. Then the tire should be deflated by removing the valve in the tube stem. Then inflate to the pressure recommended by your committee, board of directors, or manual if you think it is correct. NEVER fail to use a valve stem cap especially if it is one of the dice varities
Good points already mentioned:
Points already made:
The tube should be partially inflated. Just enough so that it will bend over and form a "V" when supported at diametrically opposites points.
The tube should be coated with any form of talc... smelly or not.
When offered, the rim lock and tube stem should have the nuts threaded on a couple of threads until the tire beads are seated and tube is ready to be inflated for the last time.
Although there is a lot of people who like putting the rim strap over the rim locks, I am a bit old school about this and like the option of moving them out of the way easily. I use the ball end of a ball peen hammer, and another hammer to strike the blow, to cut the holes in the strap for the rim locks. Place the strap on the rim. Locate the rim lock hole in the rim. Place the ball portion of the hammer head over the rim lock hole with the rim strap in between. Strike the small hammer which will cut a nice round hole.
The guys on my tire lube committee prefer using P-80, but its what ever you have available.
If you are struggling with a vintage type Dunlop, Avon, Michelin, etc. tire stop, take a break and go over in the head what needs to be done. You are trying to move one edge of a smaller circle over a larger circle. It just happens the larger circle has a drop center which will allow you to move one edge of the smaller circle away from the opposite edge of the larger circle. When you get all things in line, just like those Six Day riders you will be mounting tires with your hands, or using a couple turns with a very short tire iron.