Diagnosing bicycle crank noises.?

Ok I have a 24" Diamondback Cruiser B.M.X. bike that needs some major repairs and adjustments. For the most part it has been easy, and I thought I had it completed, but then when I went for a ride around the block, the crank feels like its grinding or something. It doesn't turn very smoothly at all. I cannot figure out where I went wrong, or what needs to be re-done. I made sure I lubricated the bearings really good befre putting them back in and Im pretty sure I have every thing tightened correctly. Hopefully someone can either be a savior and explain where I might have screwed up, or they will know an awesome bicycle repair website, they can point me too. Thanks so much for any and all help.

If your crank/bottom bracket area is making noise it could be a number of things. If you have a 3 piece crank and it is a creaking type of noise this can either be a loose crank bolt or it could be a loose pedal. If it is a grinding sound then your bearings might be bad or perhaphs they were put in the wrong way (backwards).

For most low to mid quality BMX bikes with steel BB cups you would use a bearing ring. In most cases the side of the bearing ring that has the most bearing exposure is the side that should be touching the crank spindle (ie, the non-ring side of the bearing ring). Another possibility is your BB cups could be pitted as well and that might be what is causing the grinding noise.

Tightening a crank bolt is pretty straightforward. While there are special wrenches designed to tighten crank bolts you could use a socket wrench as a good alternate. The crank bolt will either be a 15mm or 14mm (more than likely 15mm). Tighten the crank bolts very firmly, but do not over do it as you might snap the head of the bolt off.

Pedals can be tightend using a thin profile wrench. If the pedals are 1/2 spindles -- which is fairly common with BMX bikes -- then you would probably use a 13mm or 14mm wrench. If the pedals are 9/16 spindles then you would use a 15mm wrench. Secure the wrench on the pedal spindles and pedal backward while holding the rear wheel, which will allow you to use it to get extra torque.

If the BB is loose then you might be able to adjust it without removing the left crank, but that will depend on the make and design of the BB. If you do have to remove the crank then you will need a crank puller. If you are not familiar with working on bicycles then I would suggest you have a local bike do that. Or you can have then overhaul the BB and replace the bearings. Your local bike shop would be able to make a recommendation either way. Hope this is enough to get you started. Good Luck!

did you try turning the spindle before you put the chain on, if that's ok , does it only creak when you have pressure on the peddle? make sure that the cotter bolts are done up tight on the peddles to the shaft, if they still have them

Usually grinding after repacking means
1. you didn't get all the dirt out before re lubricating
2. you installed the ball bearings backwards (this only applies with ball bearings in cages, loose ball and cartridge bearings can be installed in any direction.)
3. you tightened the adjusting nut too tight and it is pinching the bearings.
4. bearings or bearing races are damaged and need replacing

You can read up on bike maintenance at

either your chain is too tight or your bearing cups are too tight. chains should be tight enough so that they do not flap around, but should move up and down a little bit if u apply pressure. the bearings should not move from side to side, or rattle at all but have to spin freely. hope this helps

Well. There could be a million things.
Most likely you have tightened them up TOO much. take the chain off and spin the cranks alone. Feel them carefully. If they do not spin freely then they are too tight. Maybe too many bearings. Maybe damaged cones or cups. Maybe cups have moved.

GO TO A BIKE SHOP for help now.

good luck
OR - loosen off the outer lock nut and back out the cone a little and then lock the nut down again.