Remember, these forks were designed in the 1980's. During that time, air assited forks, was a big deal. Supposedly you could add a couple psi of air to the forks to stiffen them and fine tune them. Obvisiouly, it was not the best idea or forks would still have them. However, yes you can add a few psi of air to stiffen up the forks untill you can buy heavier springs. I'd add like 2 psi and go up from there 1 psi at the time. I'm not sure what the max psi is.