I bought an old road bike, and after fixing it a little went on my first ride and ended up with two flat tyres. Replacing the front tyre was fine, added new rim tape repaired the tube and was good to go. The rear tyre however, has 3 spokes which are poking through the rim and I have no idea how to fix them. Is there anyway I can repair it at home or will I need to visit a shop?
Well, the easiest would be to trim off the excess of the spoke, preferably with the spoke not in the rim during this process. Or, more preferably, replace the spoke with the one of correct length.
However if you tend to keep the current spoke it may occur that due to incorrect length it does not have enough thread for the nipple to provide proper tension adjustment.
What is more important here is why is this spoke protruding the nipple? Is it of incorrect length? Is the rim not true? Is the lacing wrong?
Could you, perhaps, post a picture showing how this wheel is laced?