I wanted a cheap commuter bike, and just received this bike from Amazon. I have little knowledge about bikes, but looks like the middle chain-ring is broken to me.

  1. Is this indeed broken, or is it something that is not too big and can be safely ignored? (I am still to get my tools so haven't yet assembled the bike, so can't say if it shifts/rides alright in that ring.)

  2. If it is not something to worry about for now, how long do will it last till major problems start showing?

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(Larger version of the picture here.)

  • 1
    Yep, the bike is OK -- nothing broken -- the funny-looking spots are "ramps" to help the chain shift. Inexpensive bikes like that look a little rough/crude, but they still work pretty well. Commented Nov 7, 2012 at 22:34
  • Thanks Neil. I should have done that, I mean the circling. I couldn't post pics then, since I was new and didn't have enough credits :).
    – Sumod
    Commented Nov 8, 2012 at 17:06

2 Answers 2


Those notches are used when shifting gears, as you move the derailleur, the chain moves and catches on a notch and switches from one chainring to another adjusting the gearing.

You do not need a replacement bicycle, this is a nice bike and with proper maintenance (keeping the drive train clean and lubed) should last a long time.

  • I like the comment about lube - it does not look like that chainring has ever had any on it.
    – mattnz
    Commented Nov 7, 2012 at 20:43
  • 1
    The chainring doesn't need lube. Nor does the chain, if it still has it's factory lube. Wipe the chain clean with a rag after riding it in "sloppy" conditions, and get a bottle of chain oil to put on it after maybe 200 miles or 3 months (and then a bit more often). (Apply oil while back-pedaling chain, then work in a couple of minutes and wipe off the excess.) In 400-500 miles you should clean the chain with a chain washer or some such. Commented Nov 7, 2012 at 22:32
  • I assembled it and it shifts alright. Thanks all.
    – Sumod
    Commented Nov 8, 2012 at 17:09

There's more going on with the tooth on the right than shifting ramps. There's a manufacturing defect as well, but it's likely not something that will lead to premature wear, skipping, or failure, given that it appears to be a steel chainring. If you had bought the bike from a good shop, they would likely recommend that you ride it as is, with the assurance that they would replace the crank if troubles came up later; then they'd offer you a $10 discount on accessories. Since it was a mail order bike, and Amazon support doesn't know what a crankset is, let alone have one to send you, your only recource would be to ship the entire bike back and hope the next one didn't have any defects. I would definitely advise trying it first and, if it works, don't fix it.

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