Hi I currently ride my youngster in a full cheek french link but have noticed it has started to rub on one side slightly - I want to change to a happy mouth but which is kinder on a horses mouth straight bar, jointed or with a link ?
regards
If its rubbing on one side only, check the fit of your bridle and bit first and then look at your rein contact.
Is the bride correctly fitted? Are both cheek pieces the same length and is the headpiece central on the poll?
Is the bit damaged at all, especially on the full cheeks? Even a tiny nick in the steel can rub the horse.
If the bit and bridle are in good order and correctly fitted, your horse is almost certainly leaning on one hand, which itself is almost always down to the rider riding with a stronger contact on one rein, usually subconsciously.
Are you right or left handed? And which side has rubbed?