FWIW - I nearly stopped lifting weights altogether for about 6yrs. to try to drop some size so I would be faster on my bikes and in the mountains. The only resistance type work I did was trail work.
All that I really accomplished was getting weak and fat. What I should say is soft and sloppy. My joints ached and my back hurt.
When I returned to weight training it only took 6 months before I was back to a solid 240lbs.
My conclusion is that the slow twitch dominant body types are always going to drop me on the climbs. If I wanted to be a faster endurance athlete I should have picked tall, skinny parents like my GF did.
As far as on bike performance I'm only limited by how much torque my rear hub can handle before I break the palls.
Good luck on your quest.