You can also pick up a set of crank shorteners that would give you the extra inch and more. I had a similar problem with my 6 year old and solved it with crank shorteners and a special seat I made by epoxying a seat post so the underside bottom of the seat so it would sit just on top of the sear tube. Together that gave me an inch and a half so I could stick in a gel seat pad. The gel pad made it a lot more comfy for the stoker because they never know when bumbs are going to hit.