It will take time.
Most people know I put on a great deal of weight over a year, and now I'm struggling to get it off. I do know one thing- after dropping about 13 pounds so far, I have a particular route I chose to take and clock myself on. At first, I was only able to do the route in like 3 and a half hours. Now, at 13 pounds lighter, I'm able to do the same route in 2 hours and 25 minutes. I'm now working to get the next 10 pounds off and see if I can get down to 2 hours. And this is on my hybrid bike, with my day pack and my heavy kryptonite locks bungee corded to the rear rack.
I know when I get back to my idea weight, I'll be zipping along, and when I get that road bike I'm working towards after the weight comes off, I'll be as fast as anyone else out there. I continue to work on cadence and keeping my speed up- 80- 90 rpms is my average cadence right now, and after the next 10 pounds come off, I'll be working on building up my cadence to 90- 100 rpms.
Keep the faith and keep up the weight loss. It'll take some time, but if you stick with it, the rewards will be well worth the weight.
Good luck!
Koffee