The dimensions of the lockers are as follows.
Small locker: 420 x 800 x 273 mm (~ 90L)
Large locker: 615 x 930 x 472 mm (~ 270L)
(https://community.bahn.de/questions/1582543-schliessfacher-frankfurt-hauptbahnhof-aktuelle-preise - please note that this information is from 2018)
If your bags can be arranged into that volume, then you should be fine.
If you are on a bicycle tour, consider using Warmshowers (also on Android and iOS). This app/web site connects cycle tourists to people who are willing to host them, usually overnight, but you may also be able to find someone who can store your bike while you go home.
Near the Centraal station, I used a service called Eelway (https://www.eelway.com/en/luggage-storage/brussels). I left my luggage there for 3 days while I was in Ghent. I think they have other locations in Brussels as they work with local shops where you can store your bags