Bicycle Mechanics - Pardon my newbie ignorance - changing cranks

So I have a couple of department store mtb's; neither of which is currently useable. These were purchased before I was enlightened. I want to change a couple of things over from one MTB to the other to at least make one bike useable for visitors etc. to ride. The cranks on one seems to bent from a crash I had years ago. Is it relatively easy to do? do I need special tools? What should I look out for? How will I know if they are interchangeable. I am also going to swap out the wheels from one to the other. The bike I want to make useable seems to have painted black rims and never braked well. Should I swap the cog set to keep it with the bike. Is this easy to do or do I need special tools? Are the big box bike cog sets removeable from the wheels and interchangeable usually? Or can I just swap the complete wheel and cogset. The shifter on the bike I am putting the good parts on appears to have a basic index shifter system.

Thanks in advance for your help.

So I have a couple of department store mtb's; neither of which is currently useable. These were purchased before I was enlightened. I want to change a couple of things over from one MTB to the other to at least make one bike useable for visitors etc. to ride. The cranks on one seems to bent from a crash I had years ago. Is it relatively easy to do? do I need special tools? What should I look out for? How will I know if they are interchangeable. I am also going to swap out the wheels from one to the other. The bike I want to make useable seems to have painted black rims and never braked well. Should I swap the cog set to keep it with the bike. Is this easy to do or do I need special tools? Are the big box bike cog sets removeable from the wheels and interchangeable usually? Or can I just swap the complete wheel and cogset. The shifter on the bike I am putting the good parts on appears to have a basic index shifter system.

Thanks in advance for your help.You'd likely be ahead to dumpster them both and buy a new one for $59 at wallymart,Target or Kmart.

You'd likely be ahead to dumpster them both and buy a new one for $59 at wallymart,Target or Kmart.


Even at a big box store we would have to spend $150 as I am in Canada. I was kind of hoping to piece something together so I don't see another bike go to the landfill or police compound as is the case in Regina.

Thanks for the suggestion though.

We need pictures. Without providing a more detailed description of the stuff you want to do, impossible to say.

We need pictures. Without providing a more detailed description of the stuff you want to do, impossible to say.

Will do.

Thanks.

You'd likely be ahead to dumpster them both and buy a new one for $59 at Wally,Target or Kmart.

Statements like that are kind of indicative of the current mind set. "Throw it away and get a new one."

Will you be a head if you do that? Well, maybe, but, ... you won't learn anything, it has to cost you money, you'll end up with no sense of achievement and less money in your pocket.

If you can piece the two bikes together, you're bound to learn something (even if, it's only "don't ever do that again!"), feel a little better about yourself (if it goes well) or know your limitations. If you can salvage enough interchangeable good parts to do it, you've got a bike for nothing.

I could go buy a new bent or whatever, but I chose to build one. Will it be better than one I could buy? ??? Probably not. Will I have less in it than a new one? Probably not ..., if time is worth anything. Will I learn anything? Definitely! Will I enjoy it? Definitely!

Sorry Sydney, you are no doubt, much younger than I.

If you aren't mechanicaly minded and don't like playing with things, then it might not be worth the work. But if you enjoy a challenge and have the time to waste then I say go for it.

The bikes probaly use a freewheell. you would need a chaind whip $15+ and the correctly splined remvover socket $6+ to get it of. Or your local LBS should be able to change it over in like 5 mintues for $5.

It should be fairly easy to tell if the cranks are compatble. Does the point where the arms connect to the bottom back look the same? you might have to lift up a little plastic wring to see a nut or allen bolt. There's a fairly good chance that they don't use a normal square BB but instead use a cheapo one peice crank, in whioch case it becomes more work. Could you jsut bend he cranks back?

You are never gonna make a depertment sote bike shifter or brake well, but if you are lucky than you can get something the will at least roll and wont kill you.

Statements like that are kind of indicative of the current mind set. "Throw it away and get a new one."

Will you be a head if you do that? Well, maybe, but, ... you won't learn anything, it has to cost you money, you'll end up with no sense of achievement and less money in your pocket.

If you can piece the two bikes together, you're bound to learn something (even if, it's only "don't ever do that again!"), feel a little better about yourself (if it goes well) or know your limitations. If you can salvage enough interchangeable good parts to do it, you've got a bike for nothing.

I could go buy a new bent or whatever, but I chose to build one. Will it be better than one I could buy? ??? Probably not. Will I have less in it than a new one? Probably not ..., if time is worth anything. Will I learn anything? Definitely! Will I enjoy it? Definitely!

Sorry Sydney, you are no doubt, much younger than I. Well actually,sydney is older than dirt. Given the questions asked and the lack of knowledge and tools, the proposed swap out won't be a free ride either.

Well actually,sydney is older than dirt. Given the questions asked and the lack of knowledge and tools, the proposed swap out won't be a free ride either.

If you are that old, then you know, "nothing in life is a free ride". Sometimes, the only thing to be gained is an education.

There was a time when none of us had knowledge or tools. ... but, we didn't have deraileurs, multiple cogs and chainrings, etc. to drive us nuts and require special tools. .. I still lean toward a big hammer.

With the cheap 1pc cranks, if the arm is simply bent, they are easy to bend back. As one mechanic I worked with always used to say "if it can be bent--it can be bent back". This is especially true on cheap bikes. Heck, after I got rear ended with my bike on the back, the shop had no problem bending back an old Sugino crank I had on my singlespeed.

If you can piece the two bikes together, you're bound to learn something (even if, it's only "don't ever do that again!")

That's exactly what I learned when I tried the very same thing with two "free" Magna's. :D Cost me half of a Saturday.

If the bikes are similar and have the same amount of gears, the wheels should swap with maybe some brake/derailluer adjustments. The Magna's I played with actually had tapered crank spindles and pressed steel chain rings. They came off and were interchangeable. You'll need a crank puller for that, although I did manage to pound mine off with a long heavy screwdriver and a big hammer (left some scars, though!!)

John D.

If you are that old, then you know, "nothing in life is a free ride". Sometimes, the only thing to be gained is an education.

There was a time when none of us had knowledge or tools. ... but, we didn't have deraileurs, multiple cogs and chainrings, etc. to drive us nuts and require special tools. .. I still lean toward a big hammer.

I'm with ya CATZ. Sometimes I just want to see if I can do it. Besides, I can ALWAYS use an excuse to buy new tools... :D I have LOTS of big hammers. I call them BFH's... I'll leave it to you to figure out what the "F" stands for...

Thanks. I wasn't looking for the easy way out. I have many years of mechanical experience; just not with bikes. So basically I will give it a go and see what I can do. I am going to try to bend the cranks back into shape (if I have a big enough hammer!) I am sure I can rig up something to straighten it.

Thanks for your help (you too Sidney).