My cx bike curretly has a 36/46 chaingring set up with 11/28 outback. I use the bike for mix of on road and off road forest road / bridleway / sustrans type stuff. I was think of putting a 34t inner chainring on to help out with some of the long grinding forest road climbs around here (s/mid wales). Will this muck up the chain length?? Will the chiain be too slack when I am in the higher end of the casette i.e. 28 etc and would I need something like a corresponding 44 outer chainring. Ta.

Dropping a couple of teeth should be fine and will only have an affect on chain tension when in the smallest sprocket or two at the back.

Hmm, it’s this slackness that would be a worry – might look for a 44t outer ring.

If you start going much smaller in gearing, it’s quicker to shoulder it and run.