Help! I need parts, I just don't know which ones...

[StarSprinkled]

Hello everyone!
My friend gave me an old bike with missing parts and a bent up back tire. I am in need of the seat post, a derailer (I think.), and the back tire. I wanted to see if I could replace these items for cheaper than I could buy a new bike. I have gone to mongoose.com with no success to finding these parts or even the size/type/kind that I need to buy. Can I purchase any derailer and install it or does it need to be the same brand? Are there many different KINDS? And the seat post comes in so many different sizes (so I've been told) that I need to know how to measure this.
I know I probably seem ridiculously ignorant in this, but when I try looking anything up online there are so so so many different specs and names and components that I get overwhelmed and confused. I can't seem to weed out any helpful information. Any suggestions, advice, websites, info would be exceedingly helpful. Thanks!

[cny-man]

Bikes are not like other items where a model number can tell you a lot. On the other hand many parts are standardized. For the seatpost measure with calipers or take the bike to a shop or co-op. Tires don't get bent but wheels do. The tire will tell you what wheel size you need, but sometimes they can be straightened (trued).

Best sites to learn are sheldonbrown.com and parktool.com/blog

[cny-man]

p.s. Derailleur does not have to be the same brand, but there are some other considerations. Check the resources I gave above.

[nfmisso]

If you provide close up photos of the current parts that you think need to be replaced, we can probably help you more.

If you still have the seat post, it is probably marked with the diameter. It will be a number like 25.4

[StarSprinkled]

Thanks guys! I guess I thought the parts would coincide more T
With the model and brand of the bike. Here is a picture of the derailleur. The bike post I will measure out the diameter. and the wheel I can probably find online. Thank you both so much for the help!

[StarSprinkled]

Here's the deralieur.

[nfmisso]

This RD will work fine for you:
http://www.amazon.com/Shimano-RD-TX35-Tourney-Derailleur-Regular/dp/B003ZM9RLI/

The hanger is probably bent; which means replacement - hopefully the frame is not bent, as an aluminum frame will not tolerate being bent back. This requires a special tool to check ($65 on Amazon for the Park Tool version). You can make one, if you have the equipment, but it is generally cheaper to purchase the tool.

Remove the wheels, fork, and trash the chain. Then get the frame checked out. It may be scrap....

[cny-man]

Do you have any local resources to help you, such as a bike co-op, a store that offers repair classes, or a knowledgable friend? There are several things to consider when replacing parts, and it's easier to check/explain in person. Also, don't assume the hanger is bent. Even if it is buying an alignment tool is a very poor investment. As a mechanic I used them no more than once or twice a month, and since leaving the profession I have needed to align a derailleur perhaps a half dozen times - in 15 years. Have a shop check it. Checking and alignment should not cost very much.

[StarSprinkled]

There is a bike shop a few cities away from me. I was hoping to be able to just buy the parts and stick them on myself, but it seems like there is a lot more to it than I first assumed. I will try to get a friend with a truck to help me drag it out to have it looked at, since that seems to be the most logical and suggested solution. Thank you all so much for the help. Once again, I appreciate it so much!

[GeorgeET]

(03-05-2014, 06:59 PM)StarSprinkled Wrote:  There is a bike shop a few cities away from me. I was hoping to be able to just buy the parts and stick them on myself, but it seems like there is a lot more to it than I first assumed. I will try to get a friend with a truck to help me drag it out to have it looked at, since that seems to be the most logical and suggested solution. Thank you all so much for the help. Once again, I appreciate it so much!

^^^^^^^^^^

Its a good idea to add location to your bio. Here in LA CA we have bikerowave which is a rented by the hour shop with tools along with parts and advice. You can browse and probably find donated parts there for a few bucks and get help installing them, Perhaps there is something like that in your area.

Have you checked what a bike like that would cost new? Sometimes fixing a gift bike costs more than a new bike, but you learn a lot.
Yes have a shop look at it. Do not need a truck you can take both wheels off turn handle bar sideways and may fit in a car. Truck is nice.