Thanks, Kenny... Here's my top working set this morning, 285 lb x 5. Probably normal speed for this weight. Still slow off the floor... that's always the hardest part for me. Lockout is always easy.
Better Speed But Still Slow
Yea, your Speed is better but still slow.
Your Conventional Deadlift is an anomaly; weaker and slower off the floor and stronger and fast at the top.
As you know, the reverse is true with the majority of Conventional Deadlifters; strong and faster off the floor and slower and weaker in the knee area.
Strong Pull Off The Floor
As McLaughlin's research indicated, the majority of Conventional Dealifter initiate the drive off the floor with the back with the legs assisting.
Based on your technique and how slow your pull is off the floor, it appears that you are utilizing more Leg Drive than Back. Based on that here's some basically common sense suggestion. Since I am not familiar with your Training Program, you may already be performing some of them.
Working The Weak Point
To increase your Limit Strength off the floor, I'd suggest employ and rotating these exercise in and out of your Training Program.
1) Deficit Conventional Deadlifts
2) Stiff Leg Deadlifts (with a slight break in the knees). These can also be performed as "Stiff Leg Deficit Deadlifts"
3) Good Morning; This is essentially a "Standing Deadlift"; the bar is on your back. The overloading is in the lower part of the movement, as with Deadlifts.
Yea, my buddy Mark demonstrates this.
The Haulting Deadlift movement is a partial range movement that focuses on your weak point to make it stronger. The Haulting Deadlift can be performed for Deficit Deadlifts, Stiff Leg Deadlifts, Good Mornings, etc.
5) Trap Bar Stiff Leg Deadlifts; This work the back from a somewhat different angle; as noted in some of my previous post, Varying Exercise has been shown to increase Limit Strength in a movement.
Avoiding The Weak Point
Another alternative is to avoid you weak point and play to your strength.
In other words, if you can pull more with a Sumo than Conventional, go Sumo.
If you can pull more with a Conventional than Sumo, go Conventional.
Since you appear to have a great deal of "Leg Drive Strength" in your Deadlift, you might experiment with the Sumo Deadlift; it play to the Limit Strength of individual whose "Leg Drive Strength" is greater than their "Back Drive Strength" in the Deadlift.
With that said, a Conventional Deadlifter can increase their Limit Strength by using Sumo Deadlift as an Auxiliary Exercise.
A Sumo Deadlift can increase their Limit Strength by using Conventional Deadlifts as an Auxiliary Exercise.
My Personal Conventional Deadlift Weak Point Training
I have a strong pull off the floor. So, years ago, I stopped training my Deadlift off the floor.
Instead I worked on Partial Heavy Rack Pull Deadlifts and Partial Heavy Good Mornings from my knee area sticking point to increase my Limit Strength.
To increase my Power in the knee area, I preformed Olympic Hang Power Cleans and Hang High Pulls.
That method dramatically increased my Deadlift.
A third alternative to consider is...
Tip: Do the Squat-Stance Deadlift | T Nation
This is a hybrid between the Conventional and Sumo. A friend of mine wasn't doing well with Conventional or Sumo. He found the "Squat Stance Deadlift" work and felt better to him.
Ed Coan is the "Poster Child" for the "Squat-Stance Deadlift.