Two thoughts:

First, from my experience, concentrated run training will adversely affect your bike speed. I went back and forth on this for years. One year I'd be a good runner, the next a good biker, and then back to a good runner. I'd say that it takes a couple of years to put it all together (good bike/good run).

Second, I completely agree that you need to train fast in order to race fast, but the risk of injury increases. Whatever you do, listen to your body and don't rigidly stick to a daily training plan. If you feel a little tweak in your foot, or ankle, or knee during a speed session, let it go. If you feel a second little tweak, it's time to turn around and jog home. It's better to stick to a 1/2 year or full year plan.