Bicycle Mechanics - pedal and crankset.

Some of you guys know I bought a bike recently. This is the problem, the crankset thread for the pedals is somewhat shredded (can't spell), so I have problem putting the pedals on. It goes half way in, then it suddenly locks up, and wishes to go no further unless I use a wrench and force it in. The other problem is when I tighten the pedals in the beginning they are impossible, they don't line up straight therefore not tighting correctly. I mean should I rethread the crankset, or buy a new one, maybe just jam it in there for now. OR is this just the predal that is causing the problem. Some suggestion most wanted.

Do you have the same problem using another set of pedals? If so, your crank threads are shot. Or do you have another bike where you can test your pedals?

the left side pedals are reverse threaded. you probably stripped the threads. your crank is ****ed.

Well you think I should rethreaded the pedals cause I can bring it into my auto shop class to do that. If not I will have to buy another crank, so any more suggestion.

If you rethread them, do it from the backsidfe of the crankarms. Those threads should allow you to start the tap straight. You will need the 9/16 pedal tap set.

If your LBS doesn't have them you can probably order them from Harris on line.

If the threads won't clean up, you can also use Helicoils made for crank arms. They come regular and reverse thread. This is a very common fix for stripped threads.

How much would you think this would cost at a LBS, and this is a shimano 105 crank arm (little more reference)so i'm still guessing it's a 9/16 tap. Would you think my any rethreader could do it (saying from my autoshop class) using the right measurement of course.

Your cranks are definitely threaded for 9/16" x 20TPI, rather than 14mm x 1.25mm (obsolete French) pedals. Assuming you have a left-threaded tap for the left crank, you may be able to repair the damage; you have nothing to lose. It sounds as though someone cross-threaded the pedals when attempting to install them.

The thing is the right side is as bad as the left side, however the left side is by far a lot worse. So I think i got the bike like that, anyhow if i can rethread it with a 9/16 tap then i'm not really afraid, but anyone know how much this would cost for the LBS to do this, since they are professional, so i trust them more.

You do understand what Phatman and John E said?: The R pedal is right hand or standard threading but the L pedal is a Left hand thread? These threadings have almost no use except for bike pedals. Automobiles have not used English threads in more than 10yrs. If your threads are as damaged as you indicate, rethreading will only delay the inevitable failure of the threads. The cranks are aluminum alloy, the pedals are steel and bicycling stresses will trash what is left of the threads. Helicoil inserts are available for repair. Cost will depend on whether the LBS have the tools and equipment and expertise.
New cranks will run $50-80 (without chainwheels) and the shops may have a takeoff set they can sell for less. Steve

I totally understand what they are talking about, but I am just planning to get the bike moving. As for long term, if they last then great, but I am planning to upgrade the bike later on, so I really don't care how long it last, just looking for good deals on parts for replacement.

You can go to the extreme of drilling and helicoiling the hole, but just buying new bits is quicker.