My favorite thing to do is troubleshooting bike repairs. One of the most rewarding parts of a repair is when someone
gives me a description of a problem, and I figure it out as quickly as possible. I will list some problems that have
popped up now and then, along with recommendations about how to deal with them. If you have a problem, feel free to
Email me at firstname.lastname@example.org with the description and let me have a go at it.
Bottom Brackets coming loose after repeated attempts to adjust them.
One possibility is that the fixed cup is loose. It can be hard to see and even harder to get to. If it has Italian or
French threads, it is very common for this to be the problem. Unfortunately, there is no really good tool for dealing
with this without pulling the cranks. Once they are removed, loosen up the adjustable cup to get to the fixed cup, or
completely remove the bottom bracket cups and spindle. Check the threads and clean them. It might be a good time to
use a mild thread-locking compound. Then, reinstall the bottom bracket and your adjustment should stay good.
Bottom Brackets with a creaking or clicking noise.
This is a very common problem, even more so now, with alloy frames being the norm. I tackle this in two parts:
I start by pulling the pedals off, removing the chainring bolts, and taking out the crank bolts. I then grease all
the threads and reinstall all the parts, making sure to get them real tight. If you are now creak-free, you are done.
If not, it's time to repack the bottom bracket.
- Everything that's connected to the bottom bracket.
- The bottom bracket itself.
Bottom Brackets with a creaking or clicking noise, part 2.
Most of the modern frames now seem to be made of aluminum. Aluminum is a soft metal. A soft metal will yield under
pressure. A tight bottom bracket cup exerts pressure on the aluminum threads in the bottom bracket. Given enough time,
the cups in the frame will loosen up, and at that point that they begin to creak. Time to pull the crank arms off, pull
out the bottom bracket cups, and clean out the frame. I sometimes install Teflon pipe tape on the threads of the cup
and grease it to help get it in tight, and fill the gaps in the threads to keep it tight. If the creak does not
completely go away, pull the pedals out, too. Grease the threads and reinstall them. Remember: the left hand side of
the bike has left hand pedal threads.
Brakes that do not move.
For this problem, I start by looking at everything 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? Is the brake lever bent? Is the rim bent? These are
all things that are hard to see until you look at it from different angles. All brakes can be broken down into three parts:
levers, cables, and calipers. The first thing I do is squeeze the brake lever while looking at the caliper. Does the
lever move? Is there room for the calipers to move, or are they right up against the rim? If the lever does not move and
the calipers are right up against the rim, follow the cable housing from the lever to the brake caliper. Does it rap
around the stem a few times? (very common on children's bikes) Has the cable housing pulled out of the stop and is sitting
on the edge of the stop? (very common problem for the rear brake) Each of these has a simple fix. On the child's bike,
just turn the bars around until the cable runs straight to the rear brake. In the case where the housing is stuck on the
stop, just pop the cable housing back into the stop. If the lever does not move but the caliper can when you squeeze it
with your hand, then the cable is probably rusted. Time to replace the cable and housing. If the caliper has room between
the pads and the rim but you can't get it to move, the caliper is at fault. Now may be the time to go pick up some new
cables and housing.
Chains are braking now more then ever before. The reason is
varied. The modern Freestyle or incorrectly called the BMX bike chains are braking at a
much greater rate. I feel it is to do with the extremely small chain ring and cogs found
on these bikes. When the chain has to make such an abrupt move I feel it just beats the
chain up. The only fix I have found for this is to make sure the wheel is in the frame
perfectly straight and the chain tension is correct too. There should be about an inch
play in the chain at its tightest point. As for the modern derailleur bike I think as
the chains are getting thinner and thinner it goes with out saying the chain will at
some point fail. The advice I will give on this is that chains are cheap if you break
one do not try and fix it just replace it. Try and look for any reason for the failure
like a bent tooth or misalign frame but do not fix the chain or ask me to fix it for
you. I will replace the chain if it comes in.
Chains coming off.
The chain falling off and sometimes jamming into the crank on the front or against the frame in the back is not all that uncommon on bikes with derailleurs. Sorry I know it is a pain and sometimes can not be avoided. But, by saying that it goes with out saying a lot of times that can be avoided. I will try and lay out the major reasons for the chain coming off and what you can do about it.
- The first and most common is a poorly set up and adjusted derailleurs. There is so much travel in a derailleur they have set screws to limit their travel. Even if they are mounted right they can have the limit screws set wrong and will just dump the chain off the front or rear. It is a simple fix to set the screws. But it helps a whole lot if the bike can be held up in the air to set these screws to the proper place. You should be able to shift the derailleurs as fast as you can at a very high speed and the chain will not come off. The only exception to this is the Shimano's STI front derailleur. It has a tendency to drop the chain hard and fast. I will have to say I see this a lot on the Mega Mart type bikes. With their poor quality parts and untrained people that assemble then it is no wonder this happens.
- The second one is by pedaling back wards. The derailleurs are meant to move the chain from one gear to the next. It is also a guide to the chain, to keep it on the gear that you picked. The trouble starts when you pedal backwards is the chain is not guided over the cogs and chainrings anymore. Chains are also not perfect. They all snake a bit. The cheaper the chain the more it snakes. Want to see this get behind your bike and sight down the chain and you can see it is not perfectly straight. So when you pedal backwards this snaking will let the chain just glide right off the chainrings up front or the cassette on the back.
- The third one is a bent hanger on the rear. The rear derailleur is mounted to the frame on a part that is called the "hanger". When the bike is dropped the hanger gets bent and then you can shift the chain off the rear cog set and then the wheel can lock up. If you drop the bike you can just go to the back of the bike and look at the chain. If it looks like the chain is not hanging straight down time to bring it in. If you are not sure just bring it in and we can show you what to look for. This repair is cheap but if you shift it into the wheel it can get very costly.
- The last is the least common. It is mismatched parts or bent frame. If you like to work on your own bike or you let some bad mechanic work on your bike this can happen. If you had a bad crash this can happen too. The front crank should line up with the middle of the cog set in the back. Yes they have a tool for that but a straight edge should work fine. If the crank set is too far out or to far in the bad angle that can result can pull the chain off the crank. If the donít line up because the rear of the bike is not lined up with the front of the bike this can cause this. It rarely happens to a new bike but if yours has been looked at and still does this get a shop to check and show you this alignment.
Campagnolo Ergo shifter problems.
Sometimes these shifters start doing this "vague shifting", where it just does not seem to hold on to the indent. The most common cause that I've found is that one of the springs inside the lever has broken. If they both break, you do not get anything. But, if one goes it just is not right. After you check on the cables and the like, look inside the body and pull it apart. But be careful to take notes on how you took it apart.
Derailleurs not moving
is not all that uncommon. I always start by separating out the three parts. First is the lever that your hand touches, the second is the cable and the third is the derailleur. I start by turning the crank by hand and pushing in, on a rear derailleur, or pulling, on a front derailleur to see if they are frozen. Then I disconnect the cable from the derailleur and try and pull the cable through the housing. Then last with the cable out I try and move the lever. Most of the time it is the cable becomes rusted. The fix is to replace the cable and some times replace housing too. If it is the derailleur that does not move I make sure that the limit screws are not screwed all the way in. It seems like when ever the derailleur is not working every body loves to screw these suckers all the way in and then you have set the limit to "0". If after you back them out a bit and the derailleur does not move you probably have a rust problem. You can try working a light oil into it and it may come back but here if it does not come back right away I just replace it. Last is the lever. Most older fiction levers can be re-build. Just take it apart and clean and lube the parts. Be careful to lay out the parts so you can put it back together and understand most parts for these are long gone. If it is one of the newer index style, except for Campagnolo, shifters they are not able to be re-built and you have to replace them. The key to this is to think about the shifting, as with your brakes, in three parts, and that should make it easier to figure out the problem.
Installing and/or adjusting a front derailleur,
We figured the front derailleur is the hardest thing on a bike to set up and adjust so I will try and explain what I do to install and set up a front derailleur.
Adjusting the front derailleur
- when installing a new front derailleur just pick a spot that lets the cage not hit the chainrings grease the pinch bolt and install it but not too tight.
- Sometimes new derailleurs have a little plastic thing stuck in the derailleur to push the outer part of the cage so it sits out over the largest chainring. If it does not have this just pull the cage with your hand to where the outer cage is right on top of the outer chainring and it should be 2 mm above the outer chainring at the closest point.
- Now put your head up against the seat tube and look down. The outer part of the cage should be parallel with the chainrings.
- Now tighten the pinch bolt again.
- If you did that right the body of the front derailleur is set correctly now so it is now installed.
- Shift the rear derailleur into the lowest or largest cog in the back
- If it has the plastic thing in the front derailleur remove it. The cage should go to the lowest point and should stop when it hits the limit screw. They are mostly on the top and should have a very small marks of L and H to indicate High and Low
- If the cable is tight loosen the cable pinch bolt, grease it now, and turn the limit screw in or out until the chain is 1 mm away from the inside of the inner cage.
- As you turn the screw you should see the cage move in or out as you turn the screw.
- When the chain is 1 mm from the cage reinstall the cable pinch bolt and tighten it down.
- Now shifter the rear derailleur to the highest or smallest gear in the back
- Then shift the front derailleur to the outer most chainring.
- If it does not go all the way out try backing out the outer limit screw until it does.
- When done the outer part of the chain should be 1 mm away from the inside of the outer part of the cage.
- Now try and hit all three gears in all the different cogs in the back.
- Because of the way it works you may have noise in the extremes. The smallest front chainring should only be used with the inner largest 4 gears in the back, and the largest front chainring should be used with the outer 4 smallest gears in the back and the middle front chainring should be used with the middle set of cogs in the back.
- They should reach them all but the extremes can make noise.
Shifting issues with modern index systems has started to show up more and more
lately. Most of the systems out there have been doing this so long now the bugs are all
worked out. So it is not the shifters problem it is something else now. With these index
systems one click and boom right into another gear. The problem stems from the fact that
the index is in the shifter or brifter not in the derailleur. So if anything is not
perfect between the shifter and the derailleur it just does not line up right. So the
latest problem is with internal cables the angle of the cable as it enters the bike
frame prevents it from being perfect. The last one I had what I did was pull every
thing apart replace the cables and ran the right shifter to the left side of the
bike and had the left shifter to the right side of the frame. Then played around
with the length of the housing to try and make it the smoothest angle as I could
and yes it worked. So if you are having problems with these newer systems donít
automatically blame the shifter it may be the frame.
These don't just happen on their own, they need help to happen. I know it is nice to try to say that the tube is "defective" but it just does not happen that way. I have had maybe two tubes that I think were bad and I might have been wrong on that too. Tubes are just balloons. They hold air from seeping out the tire. If anything nicks it or if any opening occurs in the tire, you will have a flat. Sorry but that is it. So instead of getting ready for a battle with your bike shop dealer, just go back and ask for help. Maybe they will even show you some steps that you can take to stop giving yourself so many flats.
Shimano Rapid Fire not reaching all the gears or not coming back down.
Like the other Shimano problems, you need to have a little understanding of the inside of those levers. There are a few spring loaded paws inside that push and release a gear that holds the cable end. These paws rotate on a steel pin, and when they dry out they stop working. This also holds for the road STI shifters. You need to get inside the pod and lube the pins. I pull the outer cover off the shifter and DO NOT LOSE THE SCREWS! Then I spray Tri-Flow into the pivots while I move the paw with a pin or small nail. After a short time, it moves faster. It is back to working. Make sure to do all the paws. Most have three in them. One thing to note: on some shifters, you will need to remove the cable and adjuster before you take the cover off. The cables are very hard to reuse, so have extra before you start.
Shimano STI shifting systems.
Dumping the chain from the front derailleur when you down shift is a very common problem with the STI shifting systems. The Shimano STI front shifter dumps the chain down so fast that it will shoot right over the smaller chain ring onto the bottom bracket. This is not a fun thing to have happen. The first thing to do is go over the bike and make sure that the chain line is good and the adjustment is correct. If that is all good then my fix is one of these two things:
- Add a chain watcher onto your seat tube. It is a little plastic part that will keep the chain from coming off the smaller chain ring. It's very easy to put on, and it is very light, but it does not fit every bike.
- Set the front derailleur to just rub the chain in the lowest gear. It is not a great fix, but it does work. After you do this, try changing how you pedal and you can get to the point where the chain stops coming off, but not until you have trashed the paint down on the bb shell.
Shimano STI, part 2.
If you run into the problem of not shifting at all or down shifting long after you tried, you need to understand how the Shimano STI's work. The downshift on the STI shifters is done by the spring in the derailleur pulling the cable all the way from the derailleur to the lever. When you release the paw by pushing the smaller blade on the shifter, this releases a paw that lets a gear ring inside the lever pod rotate. There is a lot of chance for the pod or the cables to dry up and not come back down. Sometimes it will drop down more than one gear, and then the paw does not reengage the gear ring. This happens a lot when it gets colder outside. I have had a lot of repairs come in, and by the time the shifters reach room temperature, they shift great. Most problems can be fixed by changing the cable and housing. But sometimes you need to flood the shifter pod with a light oil to bring it back to life. I have had great luck with a lube called WD-40.
Threads that do not seem to fit
I got an email from someone that was having problems with trying to install a Italian threaded Dura-Ace octalink BB7700 bottom bracket into am Italian made steel frame but, it just did not want to go in and it seemed to get way too tight. Okay a few different things are going on here and they need to be look at separately. The first is the Shimano Dura-Ace octalink bb is the only Shimano octalink bb that can be adjusted. It is a very hard to adjust bb because there are four sets of bearings and to find that sweet spot can be very hard to do. My answer would be go for the cheaper Ultagra bb instead. Now the second part is even more important and is a problem on other so called same threads. The problem is not all countries use the same angle of thread. So even if the threads are the same 36 mmx24 tpi bottom bracket they may not be the same angle so the bb made in Japan will have a different angle then the frame that was made in Italy. This same thing happens with pedals and cranks. The easy fix is to tap out the frame, crank or what ever if it is not going in well and that should clear up the fit problem. As for adjusting that Dura-Ace bb just take your time.
Tubular Chromo 3pc cranks
are falling off. I think the modern Freestyle or wrongly called BMX cranks are falling off the splines of the bottom bracket spindle. The older four sided tapered cranks when put on correctly never fell off. But, these seem to fall off after a short time. At first the manufacture would send me new bolts for free but even they stopped that. What they told me is to tighten them up on a regular bases. So what I would do is buy the correct size Allen key and when ever you air up your tires to also tighten up the crank bolts.
Twist grip shifting
that does not move the chain all the way up on a new bike that was bought at a bike shop. Seems to be more from the smallest chainring in the front to the middle one. Most front twist shifters are set for you the rider to slightly over shift it. It is not meant for you to click it over then pedal. So before you try and change all the adjustments just move the twister slightly past the click point and see if it pops over. I describe it as coming from a bike shop because of two things. One most bike shop bikes have front derailleurs that are well made and just work and second even if most bike shops do poor assemblies they seem to get the adjustment on the derailleurs correct.
I got a letter asking about a problem with a wheel someone built where every set of two spokes were tight, and then the next two were loose. First of all, we need to use the correct terminology to deal with this. There are four spokes in a wheel. There are heads inside the hub flange and heads outside of the flange, which are called heads in and heads out. Then you have pulling spokes and static spokes. Pulling spokes are really used for the rear wheel, but in description terms they help for the front. Pulling spokes, as the name implies, are spokes that go from the hub flange back toward the rear of the bike and pull the rim. Remember, spokes are only pulling, never pushing. Now, last you have sister spokes. If you look through the wheel in line with the hub axle from flange to flange, you'll see two spokes that rotate off the flange in the same direction as the rim. If one side is laced wrong, that's the problem. Hold the wheel up in front of you. If you look through the wheel,
the spoke that is just to the right of its sister spoke should also be to the right at the rim. Sometimes when trying to build a wheel, it will go to the wrong side at the rim, which leaves you with two spokes that are long and two that are short.
If a frame is out of alignment, the problem is more than just a bent chain stay. You will most often just feel a problem. For instance, maybe the bike pulls to the left. Maybe the chain keeps coming off and you have been over the derailleur again and again. Another possible cause for a bent or out of align frame and fork is that the wheels are sitting to one side more than the other. If you want to save yourself a few dollars, pull off as many of the parts as you can, especially the bottom bracket, so the shop can put it up on an alignment table. You may have to get on the phone and find a shop with the table, but I know I am not the only one that has one. Then, give it up and hand over your baby to the shop, and please do not ask to watch. It is not a pretty sight.
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