I did it the other way. After almost 50 years of road bikes, I now have my first mountain bike. I still ride the road bike more than the mountain bike, but I find real benefits from both. I truly feel that the mountain bike has improved my road bike fitness. My legs seem stronger and I am pushing a bigger gear more easily. Transition to the mountain bike was easy, because I already had the basic skills — I just got great new places to use them.
I spend the summer in the mountains, and I have been watching the mtn bike guys with envy for the past few years and finally saved enough money to join them. But when head west this summer, there will definitely be two bikes on the roof.
Riding a bike of any variety leads to improvement in personal well-being.
But you know that. Grab the road bike and add it to your stable, you’ll lose nothing and gain a whole bunch.