Mechanics 101

I will try and add repair techniques from time to time. Come back and see if I can be of any help. If you have a repair problem please feel free to email me at The Bike Stand. and I will up load it here for anybody else that made need it too. If you need a little refreshing on the names of different bike parts open this window.


         I was asked to show how I make a conversion for older bikes to use the newer STI, ERGO or SRAM's double tap shifter systems. I figured I needed pictures so I made this page. Try it out and let me know if it worked for you. Just hit the LINK.

         Repacking the bottom bracket. There are pretty much two types of bottom brackets out there American and European. Most better bikes use the European style. The two can be distinguished by the fact that American style has the crank that is in one piece and snakes through the frame through a large bottom bracket shell. The European style is smaller and the arms are placed on to the spindle hence called a three piece crank.
         First thing to do is remove the crank arms. Either you have to remove the dust covers to get to the nuts or bolts or some of the new ones have a puller mounted in to the crank arm. If the center of the crank arm has a large hex fitting 7mm or larger you have one of the ones that have a puller built in. With the built in one you just unthread the bolt and it takes the arm off with it. If you have a 5mm hex fitting you have a dust cap. So, remove the dust cap. After the dust cover is taken off you will have either a 14/15mm nut or bolt. A nut is a type 2 and a bolt is a type 1. Remember that so you can buy the right puller for your crank.
         Take your bolt or nut off and thread the puller all the way in to the arm. Now start to tighten the outer part of the puller in to the arm and that will push the arm off the spindle. If it is too hard to get off take it to a bike shop it is very easy to damage the arm at this point. With the arms off now with either the puller or the built in one. It is time to look at the bottom bracket now. There are just two types again. Sealed bearings and cup and cone. Most modern sealed bearings take a single special tool. Take your bike in and ask if they have that tool and yes get it from them. Then if you need help they might help you pull it off too. If it is the older cup and cone there are a few tools you need. I will go over that another time. Most of the time you will remove the non-drive side first. This is always a standard right hand thread. So counter clockwise is the way to go. It may be in tight so a long handle is required here. After that is out look at the drive side and start to remove that one. Most threads are Italian or British now. If the cup has any marking look at them. British is 1.37x24tpi. and Italian is 36x24tpi. The British will have left handed thread fixed cup and the Italian will have right handed thread fix cup. When you remove it take a good look at all the parts. If you need help here it is a good time to go back to the shop that sold you the tools and ask for their help with this one. Look in the shell too. It is a great time to put some frame saver spray in to the frame to protect it down the road.
         Now it is time to reinstall it. Always grease the threads in the frame and on the cup. Start with the fixed cup on the drive side and put it in really tight. Italian threads tend to creep out easy so make it very tight. After that is in move on to the other side and tighten in the other cup. If you have a spindle do not grease the flats just the oil from your hands is fine and install the arms with the greased crank bolts. Now check your work. And recheck the derailleurs and go ride your bike.

         Derailleur adjustment. When I have got a problem with the derailleurs I always start by just looking at it, all over, from a lot of different angles. Even if you are not sure of what you are looking at just look it over. Are the cables rusted? Are the derailleur bent or broken? Is the chain or cassette bent or broken? These are all things that are hard to see until you look at it from different angles. If all that looks good lets go get a repair stand. An extra word here on Shimano STI shifting systems they are very prone to not shifting well when it gets cold. If it works when you take it in side to work on it that might be your problem and time to oil the shifting pods with a lighter oil.
         All derailleurs systems can be broken down into three parts. The shifters, the cables, and the derailleurs.
         First thing to do is separate them. So now we need the repair stand to hold the bike up to let you do some things. You can shift the rear derailleur with your thumb to see if any problem shows up. Just push it all the way in and let it go all the way back down. If you hit the spokes or do not come all the way back down it is most likely a bent rear derailleur hanger or a damage derailleur. If it is a bent hanger let the shop do it, the tool you need is more then the average homeowner needs. If it is the derailleur time to shop for a new one most are not rebuildable. On the front derailleur just pull on the cable that runs exposed down the down tube or the top tube on a mountain bike and see how the derailleur behaves. It is so nice to see it up close when you are shifting and so much easier to see problems then from the bike saddle. If the cage is not lining up with the chainring that can be a problem that is easy to fix. Just loosen the bolt the holds the derailleur on to the bike frame and move it until it lines up with the chainrings on the crankset.
    The second part is to check the cables. Undo the pinch bolt the holds the cable on the derailleur and pull the cable back and forth. It should be perfect no hang-ups at all. Remember the spring in side the derailleurs are very small and do not have a lot of pull in them so if you are at all in doubt replace the cables. The cables are the number one problem with derailleurs not working right so this is the big one.
         The third thing to look at is the shifters. With out the cables pulling on them you still can feel the pull of the cable in you hand when you shift them. So shift them up and down and count the clicks. If it is the Shimano STI shifters you may have to spray a light oil in to the shifter pod to free up the little paws and springs in side them. Use an oil not a penetrating spray. Really flood them over some paper towels and keep trying to shift them up and down. If they do not come back it is time for new ones they are not rebuildable.
         So now it is time to put it all back together. Remember to tell the store what size and type of shifters you have because the cables are not all the same. And if you are getting new cable housing take the old ones in and let the shop cut them to size the cutter for the new index cable housing is a little pricey. Also use an pick to open up the end of the cable housing to cut down on friction in the system.

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