I started doing deadlifts with the following modifications a few weeks ago, 1) Try to stay as stiff legged as possible and 2) only use 25 lb plates instead of 45 lb plates, which increases my range of motion by about 6".
I notice that most people at my gym stay away from both of these modifications. The only indication I have of their effectiveness is that I was sore as shit the next day in my hamstrings and other target muscles.
I am confused. Those modifications no longer make this a true deadlift. So if your trying to train the hamstrings then your golden, but why not just do romanian deadlifts.
If your trying to get more range in your deadlift then do it from a deficit and don’t muck with the form.
I believe you are now doing a stiff-legged deadlift. But, I still would switch it out with deadlift every once in a while so that your can keep training your deadlift.
An increase in 6" ROM seems a lot, that would imply that the 45lb plates have a diameter of 12" more than the 25lb plates.
Perhaps you meant an increase of 3" ROM?
BTW make sure stiff legs doesn’t become straight legs.