I have an old 1980's touring bicycle and was thinking of replacing the bottom bracket. I noticed on amazon that there are various types and sizes of bottom brackets. How do I know what size and type to purchase? What does 68x107 mean in reference to a bottom bracket?
why? is it doing something bad? clue: if it is old - 1980s - it will be hard to replace why not wait til it;s grinding or something? wle
You choose a bottom bracket to fit your crank. 68 x 107 means that the bottom bracket shell(the part of the frame the bottom bracket screws into) is 68 mm wide, this is standard for English threaded bottom brackets. The 107 is the length of the spindle. You have to match the length of the spindle you currently have to maintain the same chainline that you now have. You first have to remove the old bottom bracket to see what the spindle length is. When you take the crank arms off you can check to see if the spindle bearings are still smooth. If they are, there is really no need to change the bottom bracket, just re pack the bearings and put everything back together. Good bottom brackets last a long time, I have a 1973 Campagnolo bottom bracket on one bike and it still is as smooth as the day I bought the bike it came on.
