Measure your old cylinder. We’ll show the size that fits.
Tell us the size of your old cylinder and how far it sticks out past the handle. The guide shows the size that will sit right, and every cylinder we sell in that size: key both sides, thumbturn or half cylinder.
How to measure
Before you remove it: note how far each end of the old cylinder sticks out past the handle, in mm. Flush counts as 0.
Then take the old cylinder out. Undo the long fixing screw on the edge of the door, turn the key slightly and slide the cylinder out.
A (inside): measure from the middle of the fixing screw hole to the inside end.
B (outside): measure from the middle of the fixing screw hole to the outside end.
C (overall): measure the whole cylinder end to end. It should equal A + B. If it doesn’t, measure again.
Between two sizes?
A cylinder should sit flush with the handle or stick out by no more than 3mm. That’s why the guide asks how far your old one sticks out: a new cylinder 2mm shorter is right if the old one stuck out 2mm, but wrong if it sat flush, because it would end up below the handle. With that measurement the guide works out exactly how each size will sit.
Key both sides cylinders fit either way round, so a 35/45 also fits a door that needs 45/35. For thumbturns, A is always the thumbturn side.
Not sure? Send us a photo or call 01209 200564.