Rear wheel catching after changing tube

[Ajax Bay]

tyres are 700 x 23c , i'm approx 80 kgs

If your tyres are 622-23 (see their side) and you are 80kg and the bike is 12kg, the attached article which is recognised as decent practice, suggests 82psi on the front and 117psi on the rear (or whatever the tyre says is max).
If you ride the rear with only 80psi in, carry several tubes and expect to improve your puncture repair skills. Also expect 2 little holes next (ie 1cm apart) to each other. Or get a pump that'll do the business - for 110+psi, probably a 'track pump' eg https://www.evanscycles.com/tools-maintenance/pumps_c/track_pump-pump_type

 

[Rowano]

Agree with everyone else - your tyre pressure will depend on the size of your tyre. If you have narrow tyres (say 23 mm width) then you will need more pressure than if you have fat tyres (say 32mm). It will say on the side of the tyre - something like this https://guides.wiggle.com.au/inner-tube-buying-guide

Around the same area will also have a max pressure.

Now the pump - of you've got a track pump which stands up and allows you to pick down on it to pump up the tyre you should easily be able to get more than 80psi in it. However if it's a small hand held pump then it can be hard work to get more pressure in and you might want to think about getting a track pump.

Hope this helps you?