I'm one of the confirmed UL gram weenies, so I won't bore you with details. My first bike tours were 100+ pounds with bike. The camping was fun, but the cycling was not. Eventually I decided I wanted to enjoy the cycling more so I started learning how. UL hiker forums and gear makers can help.
As mentioned already, spare clothing is a big one. A tip--you should be able to wear all the clothing you pack at once, as part of a coordinated layering system.
Another tip--managing consumables. Don't carry an extra day's worth of food "just in case." You won't die if you miss a meal. Just carry the water you need plus a reasonable cushion depending on weather. A liter water bottle is heavier than any other single item in my load, so I consider carefully whether I need it, and will sometimes dump it early if guaranteed water is just over the next climb.
So decide if you want to go on a cycling trip or a camping trip, and pack accordingly.