Trek 4100 Alpha aluminimum

[Bernie3]

Hi everyone. I picked up a Trek 4100 (2003?) from rubbish collection with the view of learning a bit more about bikes by building it up and replacing the various damaged components (pretty much all components rusted and rear derailleur bent into total annihilation). The front suspension it totally cactus so was wondering about the possibility of replacing with fixed fork? Is that possible? Thanks for taking the time to read this!