Fixed wheel newbie question

3b4bikes

Just got my first track/fixed wheel bike and fitted a new sprocket. The inner normally threaded part of the hub is wider than the sprocket which means when it is fully tightened there is a gap between the sprocket and the lockring on the outer, reverse threaded section.

Just wondering if this is normal or whether I should fit some kind of spacer on the hub first so there is no gap between sprocket and lockring?

marcusjb

As long as your chainline is straight, it shouldn't cause a big issue. Depends on how big a gap between sprocket and lockring though I suppose!

If it's small and you do end up in a situation where the sprocket is unscrewing, then it will hit the lockring pretty quickly and that will do it's thing.

But, yes, I'd say straight chainline is more important than any gap between sprocket and lockring.

3b4bikes

Thanks Marcus. The gap is about 4 or 5 mm, I just wondered whether the lockring should be tight up against the sprocket.

Monty Dog

Phto?
If the lockring isn't tight against the sprocket, then it won't work properly - if it's not tight enough or you have a predeliction for skidding, then there's a risk the sprocket will unscrew slightly - then you'll either strip the hub threads or possibly launch yourself over the bars...you chose.
You need to fit some sort of spacer there so the lockring is tightening against the spacer - your LBS should have something suitable for little money.

marcusjb

3b4bikes wrote:

Thanks Marcus. The gap is about 4 or 5 mm, I just wondered whether the lockring should be tight up against the sprocket.

I'd call that a big gap! Too big for sure. As Monty dog said, get a spacer in there.