How to centralise bmx chainring

[lewis1641]

I've got some 3 piece bmx cranks in my cruiser. Can't for the life of me make the chainring sit centrally. It is locating on the pin on the crank alright but the centre hole on the ring doesn't locate on anything. Is this normal?

How do i make sure the ring is central? Its doing my head in. Tried to do it for about half an hour but i still haven't got it. Am i missing something?

 

[8690q]

Sounds like you're missing the tabbed washer that goes on the b\b axle.

It fills the gap in the chainring.

 

[FMJ]

is it a sloppy fit on the axle? There should be a shouldered sleeve that fits on the axle that the chainring (or spider) rides on.

 

[lewis1641]

Yep missing a part. What's it called? Are they pretty much universal?

 

[FMJ]

They're universal. I don't know what it's called. I just call it the chainring/axle spacer. Anyone worth their salt at a BMX friendly shop should know what that is and be able to dig one out of the spares for you.

 

[lewis1641]

Thankyou

 

[stevet1]

its called a top-hat washer.
You will need to know you're axle size (probably 19mm but check) and the chainring hole size (probably 23.8 but check).
CRC stock them
http://www.chainreactioncycles.com/Models.aspx?ModelID=47632
, but you can get a better fit if you go into a bike shop with the chainring and try and find the one that fits snuggest in the hole. Oh and sometimes the width/depth varies - make sure it doesn't extend past the outer face of the chainring when pressed in place or you will not be able to tighten it all up properly.

 

[lewis1641]

wicked. i'll get the verniers out