235 is the width
35 is the profile/thickness which would affect the circumference
but you are right about the grip in a way but it would not make much difference really
Sorry I didn't explain fully. :embarassed:
If you move from 235mm width to 225mm width you will alter the rolling circumference as the profile is a ratio of the width.
235 x 35 means the wall is 35% of the width
If you moved to 225 the wall would change as a ratio and that is what would affect the rolling circumference. It isn't a vast amount, but is something to consider when trying to fill the arches
