Like any job, it’s in the technique. Take your time, dont try with cold tyres, break the bead properly, use plenty of soap and make sure you push the bead well into the inside of the rim. Do yourself a favour and purchase some rim protectors, if done correctly you should whip one off in no time. Before refitting, check direction and then double check it, nothing more an than getting it back on the bike and finding it’s backwards. Then soap the new tyre and make sure you get the soap onto both sides. Clean the rim and slide the new tyre over the rim a bit at a time. Make sure that you keep pushing the new bead well into the rim well. You should then only need a rubber mallet to finish the first part off easily. Then make sure that you have any balancing spots in the correct place and use a small g clamp on the rim to stop the tyre sliding round. Start from the clamp and whilst sliding the rim protectors round a bit at a time just take small bites with a tyre lever until you get to the last tight spot, make sure again that the bead is pushed well into the rim and then you should be able to snap the last part of the tyre over the rim. Also, cheap tyre levers have sharp edges, grind the edges off and keep everything rounded and smooth. Check the tyres in the right place and blow the tyre up without the valve in to get it to seat, two loud pops will tell you that it’s seated happily, stick the valve back in and check the pressure and then balance it.
Job done
I always change the on an old blanket to stop the scratches. The spoked wheels are the harder to master as the rims are quite a bit wider but still easy enough if you’ve got the correct technique and attitude.