I was wondering if I could convert this https://sphotos-a.xx.fbcdn.net/hphotos-ash4/q71/s480x480/430156_461794267240029_1042500253_n.jpg to a cycling bike like what would i have to do to that bike to convert it ? tell where and what and how much the parts are i want it so i can have better cardio and endurance i live on gravel road but i can get to pavment from my house. i dont hav any money to spend on a new one so i was just wondering if i could do tires and pedals and maybe bars if it all come less then $100 iwas hoping to sped around $70 or less*** i race motocross and saving for racing so that is why i want the cheapest way lol ih and i dont have any cycling shoes i was just going to use regular training work out shoes.. so if u guys could help me out give me websites and prices and everything that would be great
Start with your tyres. Go for slicks, the narrower the better. I used to run 1 1/4" tyres on my old mountain bike, at the time this was pretty much the lower limit on a 26" tyre. This will be by far the biggest bang for your buck.
It will probably also blow your $70 budget if you get good tyres. You may also need to invest in new tubes, depending on what you have currently. But it will make a big difference.
The other thing that springs to mind is to improve your position. Difficult to do this much given the geometry of the frame, although I have heard of people putting aero bars onto their MTBs. Should improve things but its more cost.
As for pedals - remember you'll need shoes as well - and these on their own will probably blow your budget. I'd stick with what you've got for now and think about upgrading as and when you have the cash.
For your price range and your goal, the best bang for the buck will likely be tires. You should be able to get some economy road slicks that you can mount on your current bike for $10-30/tire (check any of the "big" bike shops for economy tires).
Your bike is already rigid so no need to worry about changing the fork.
It appears that the stem and steer tube are one piece, so changing to drop bars (the "standard road bars") might not be a simple matter. Additionally, this would require changing the shifting and brakes which probably couldn't be done within the budget specified.
You mention pedals, but within your budget, the cost of pedals and shoes would be a stretch. You might consider adding a strap/basket but even this is not a huge payoff in performance.
If you have extra money in the budget, you may want to consider getting a road saddle. They are designed to support you on your sit-bones and while uncomfortable for some at first, they are essential once you build up to multi-hour rides.
Cardio and endurance are less about the equipment and more about the duration. Once you put some slicks on your current bike you should be able to ride it comfortably for long periods.
Go on Craig's list and buy an old steel road bike from the '70s. If you are patient, you will find something in the $100 range. Unless you get free parts, it will be very difficult to get a road feel for under $100 by retro-fitting your bike. Tires would help you go faster, but if you are really just looking for more cardio, use your mountain bike and push yourself harder!