Remember that when you adjust the eccentric position with the spanner wrench, you are as you know adjusting chain tension, but you are also now changing ride height and the length of the bike. Both bike geometry changes that should be accounted for. The ride height can be counter-adjusted by adjusting the ride height rod. The new position of the axle in the eccentric as it influences the length of the bike is what it is. No way to change that, but you can account for it.Hi all, looking for the size of the c-spanner used to adjust the chain tension on the 1198.