Why is it that some bells are harder to strike well than others? It is probably because they are odd-struck. So, what is odd-struckness? It's ‘a different delay between handstroke and backstroke of the same bell’ (taken from the Ringing World 5/11/2004).
This could happen for a variety of mechanical reasons – rarely are the bells we ring all part of a perfect set! Sometimes the odd-struckness is very pronounced and ringing needs to be adjusted to compensate for this.
The effect of odd-struckness is that you need to leave either bigger or smaller visual gaps. The bell you are ringing could be odd struck at either handstroke or backstroke – or both, and the odd-struckness could mean the bell is either quick or slow at either of the strokes. The situation can be compounded if the bell that you are following is also odd-struck. If you always ring the same bell, you may get used to how you need to ring to strike in the right place. However, when asked to ring a different bell or if visiting a different tower, how can you sort out the odd-struck bells?
Here are some tips:
Janet Horton, Teacher at the Birmingham School of Bell Ringing