Another boring newbie question sorry
...
Front tyre inflates easily to 110 but the back tyre will only inflate to 50, before i inflated it i pressed the valve in for a second ..but no matter how many times i try it will not go past 50...any ideas or is it a new tube...

Front tyre inflates easily to 110 but the back tyre will only inflate to 50, before i inflated it i pressed the valve in for a second ..but no matter how many times i try it will not go past 50...any ideas or is it a new tube...
