I have notice a few people mention that these can be expand at a later date if need , but the Sportsblock 2.4 be probably the only powerblock set that can not be upgrade with extra weight . if you be like I and be use this for a training program like p90x , go with a bigger set that go up to 50lb instead of try to save yourself some cash upfront . re-sell these and buy a heavier set be not cheaper in the long run . I have also have the same problem with the pin slip out during use , particularly with the lighter weight . it be a little concern and I tend to find myself worry about whether the pin be go to slip out rather than concentrate on the exercise . my suggestion would be to go with a heavier set -lrb- or double check with the manufacturer that whatever you get can be expand -rrb- and to make sure it have a secure fastening system . it might take you a little longer to change the weight , but you 'll be thankful in the long run .