Well, I posted a video up before Christmas showing my DIY tyre change of the front - off with a PR3 and on with a PR4. In the end, I thought it was pretty easy... and wouldn't hesitate to do it again.
http://ozstoc.com/index.php?topic=8471.0Today, I attempted the rear.... epic fail
. I'm sitting here knackered having spent vast amount of energy trying to get the sucker off: breaking the bead took about 3 times as long as the front; I managed to get the 1st side of the tyre off the rim, but just couldn't get the 2nd off - another pair of hands would have made it a lot easier, but they aren't around.
This task was just removing the PR3 - it made me think a brand new PR4 will be harder still and I'm conscious of not damaging the rims. So, next week I'm off to pay someone to do it.
Rob.
ps. I should have changed the rear a long time ago... Now at 38,500 km it's definitely not legal.