i've got this pink bike that nobody uses but i like the gears. on the left (or by the petals of bike) it's got 3 gears and on the right (by the back wheel) it's got 7. on MY bike it only has 5 gears on the right and i want to swap them out. is there a way that i can take off the sprockets so i can swap them? if not please answer my question so i know.

CaptainRich

You should refer to them as "front sprocket and back sprocket"

And, if once the items are removed from the original chassis, they fit your, well, then they fit!

There are too many manufacturers to say without you holding them both up to the monitor for us to measure. lol

koopakid

do you know how to take them off? and i'm pretty sure they are are the right size. i just need to know HOW to get them off.

CaptainRich

At the front sprocket, first take off the chain and the pedals and set both aside. Then, on one side of that center crank, there's a large nut that retains the center bearing. Remove that (this is where it gets messy) nut and the whole "crank" will feed out the side.

At the rear sprocket, things work similarly, but instead of pedals you've got a tire and the derailer. Usually the tire comes off and the axle with it (maiking it easier to sork on it, too). On some the derailer is part of the axle, others it will seperate.
Keep plenty of rags handy and watch out for pinching your fingers.

Once you're done, you still gotta run the shift cable and their controls. This is pretty big project.

Good luck!

ScottGem

Unless you know someone who is a bike mechanic, I say forget it. You will need specialized tools to remove the cranks (a crank puller) and another tool to remove the rear freewheel/cluster. These are 2 different things so you need to know which is its. Then you need to know whether the 7 speed freewheel/cluster will fit on the rear hub of the other bike. It might not. There is also the issue about the front, the bottom bracket spindle needs to be longer to accomodate a triple chainwheel instead of a double.

CaptainRich

That's true, what Scott said. I've warned about this becoming a big project. I'm an auto tech so tools slips my thinking sometimes.

This could be a great learning experience but you could end up without two bikes.

ScottGem

I actually converted and old 3 speed english racer to a 5 speed, derailleur equipped bike, and that was a project. But that was also many years ago.

I just recently bought a new wheel for my road bike and moved the rear cluster from the old wheel. And that was a job. I did have the lock ring tool, but I didn't have a chain whip and had to jury rig something.

CaptainRich

I'm currently bringing an old mountain bike back to health. New shift cable and tubes. I like something I can beat on.
What do you think of the auto-bikes out now? I've never actually seen one but the concept seems worthy...

ScottGem

Define auto-bike? I tried converting an old Mt bike to linear brakes and I couldn't get them to fit in the rear, so I bought a new bike. the new bike has a suspension front fork.

CaptainRich

I haven't seen ads for awhile but the company was called CSA Autobike.
It was equipped with front and rear suspension but the really cool part was centifically(sp) controlled shifting based upon road speed. The rider never has to shift - going uphill or down, it's always in the correct gear. When you come to a stop, it shifts into the lowest gear.

I had a brochure but my wife made me throw it away (too much clutter) but the price was about the same as most others, around $250 or so. I'm going to Google it.