- Location
- Shrewsbury, Shropshire
It's a spoke protector (also disparagingly referred to as a "pie plate" or "dork disc"). You can get replacements if you want one: LINK
Many people don't like them and take them off at the first opportunity, but they do a job of preventing the chain jamming in the spokes and damaging them if it should accidentally shift too far and jump off the largest sprocket. If your gears are well set up this shouldn't happen.
Edit: This one would save a few pennies. I didn't mention that the gear cluster would have to be removed in order to fit a replacement which means either buying a special tool or getting the local bike shop to do it for you.
Many people don't like them and take them off at the first opportunity, but they do a job of preventing the chain jamming in the spokes and damaging them if it should accidentally shift too far and jump off the largest sprocket. If your gears are well set up this shouldn't happen.
Edit: This one would save a few pennies. I didn't mention that the gear cluster would have to be removed in order to fit a replacement which means either buying a special tool or getting the local bike shop to do it for you.
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