A messy job best done outside. This is how I do it.
Get everything ready first and to hand. This has to be slick.
Keep your wheel upright at all times but keep the weight off it.
Crack the bead off the rim at the top and carefully work your way round the tyre without moving the wheel. Get the second bead off the rim and again work round until you have a third of tyre on rim.
Now the tricky bit. Lift out the rim from the tyre, keep tyre still as you will now notice a load of sealant in the bottom sloshing around.
Put your rim to one side and find somewhere to hang your old tyre. Heavier tyres will prop up against a wall without collapsing and the sealant running out everywhere.
You are on the home straight now.
Quickly clean up your rim, get as much cheese out of the rim lip seal as possible but be quick, your sealant in the old tyre is turning to cottage cheese behind your back.
Get the new tyre onto your rim- completely fitting the bead on one side and leaving about a third on the other. Open this bit up so you can see the inside of the tyre.
Now go and get your old tyre. It helps if you have an assistant (Amy Pond from Dr Who would be great). Keeping your new tyre/ wheel upright but without any weight on it so the tyre forms it's natural shape, pour in the sealant from the old tyre.
Now the tricky bit. Carefully rotate the wheel 180deg so unfitted section of tyre is at the top. Now fit this section of bead to the rim- tricky as pushing down on the wheel will have sealant coming out everywhere.
So, now you should have the tyre on and a garden that looks like it has been attacked by giant poo-ing seagulls.
To finish, follow instructions from sealant maker on inflation. Once you have got the rim to seal it might need topping up with a little more sealant. I usually add 50-60mm to a XC wheel or 100-120ml to a AM/DH rim. If it's a car type valve this is quite easy, just unscrew and squeeze some out of the bottle.
Hope that helps. With practice is becomes second nature. First time can be messy!!!
Si
