Shimano Dura-Ace Track Cog Lockring – 1.29 X 24 Tpi, Left-Hand Thread, Y27819000

Building up a fixie or track bike?

This is the lockring you need to keep that cog tight.

It's a genuine Shimano Dura-Ace unit, part number Y27819000.

It's got the standard track thread: 1.29 x 24 tpi with a left-hand thread so it doesn't spin off when you backpedal.

It's brand new, small and light, but it's a critical part.

Don't trust your knees to a cheap ring—go with Shimano.

Locks your cog on and keeps you safe on the track or the street.