Lucky for you, Inno does actually offer a longer bolt kit for their Inno Board Locker Surfboard Carrier # INA744. You'll just need the Tall Crossbar Adapter Kit for Inno Winter and Watersport Carriers # INISF711.
These kit includes 4 80mm (3.15") and 4 100mm (3.94") bolts so you shouldn't run into any more short bolt issues, if you do then you might consider swapping the carrier with a t-slot mounted version # INXA445. view full answer...