Speedo drive

Just changed the speedo ring drive on the S1, what a sod of a job. Had to grind it down on both sides to get it off then to get the new one on (metal) I had to heat it up and use a wooden drift to knock it on. I always wondered what held them on, now I know!
Anyway, the worm, the one I have taken out is shorter than the new one (obviously meant for S3) so will the longer one work ok or do I need to get a short one?
Cheers,
Rich'
Anyway, the worm, the one I have taken out is shorter than the new one (obviously meant for S3) so will the longer one work ok or do I need to get a short one?
Cheers,
Rich'