Black oil or grease is leaking from my brand new src3 hub. Is this normal? I thought internal geared hubs like this are supposed to be sealed.

enter image description here

This the bottom of the hub with the bike upside down. I wiped away a bit of the oil because it looked like it was about to drip.

  • 1
    Provide a picture and it will help to find a better answer than without. – Christian Lindig Aug 27 '17 at 20:11
  • You might get a very small amount of leakage at the very beginning but visible oil drops or a puddle is not normal. I'd go back to where you bought the bike. – RoboKaren Aug 27 '17 at 21:04
  • Something's seriously wrong there. Your hub needs oil in it to work, and if it leaks out then the hub is empty, and quietly lunching on itself. I'd suggest you stop riding it too. – Criggie Aug 29 '17 at 8:26
  • I edited the picture to alter the contrast so it's not just shiny metal parts in a field of black. Doing so has made the leaking oil look rather grey but I think it makes the picture much clearer. Check the edit history for the original. – David Richerby Aug 29 '17 at 9:18

Definitely not normal. I'd take it back to the dealer where you bought it. If you bought it online, I'd contact the reseller and let them know you're taking it to a local bike shop to get fixed - and that you'd like to be reimbursed.


This is graphite grease, which is used in coaster brake hubs. Some hubs come packed with too much grease, which then oozes from every gap. You can wipe it, the leak will stop in some time. This happens also with non-coaster hubs and freewheels, but the grease in them doesn't have the dramatic black color.

Coaster brakes use graphite grease because of the heat from braking. Even if you manage to boil the oily part, graphite will remain at braking surfaces and bearings and provide lubrication.

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