There is an egg shaped lump on my bicycle tyre. Why does this happen? Do I need a new tyre or inner tube?
There will be an twist or fold on your inner. Or perhas the tyre isn't sitting well contained in the rim (yet i assume you would see that) I dont imagine severe stress would reason the bump.
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Two possible problems that come to mind immediately. #1) The tire (tyre) has scraped up against a curb or been run through a pot-hole breaking the cords under the outer rubber layer. The tire (tyre) may or may not show signs of a scrape. If this is the case, the tire needs to be replaced ASAP. #2) Is the tire (tyre) seated properly on the rim? This is a common problem on older bikes with steel wheels, but can also happen rarely on newer bike with alloy wheels. Flip the bike upside down spin the wheel slowly. Does it seem to be seated properly at all points? If not, deflate the tire (tyre) and put a few dabs of soapy water around the bead. This will act as a lubricant. Re-inflate the tire.
