Lockring keeps on coming off

Hi guys,
Just joined this website at it looks like a lot of you participate on this.
introduction: i'm a new fixie rider in London - just got my bike 2 months ago 2nd hand and i've only been into cycling for the last 9 months - meaning im not all that good with the mechanics!
the bike: Fuji Track 06 (http://www.fujibikes.com/2006/bikes.asp?id=139)
this is the second time this happens now: chain comes because the lock ring and sprocket get loose, the chain locks in between the sprocket and the spokes - so the wheel gets locked and i see myself skidding over 20 meters (aquaplanning last night after the hailstorm!!). this probably happens becomes im a fan of skid stopping but there must be a way to secure that lockring so it doesnt come out...

I was wondering what i could do to get it sorted! The lockring has got 6 'teeths' and i just cant find the right tool for it... would this work (http://www.hubjub.co.uk/etc/duratoolzm.htm)? also what are the chain attached to the tool for? Could it be because the back wheel is not fixed at the right distance (chain is a bit loose)? How tight should the chain be?

Sorry for so many questions, but i'm sorta new to this!! I hope i can find some answers here :) I dont fancy sending the bike to a store so they 'fix' it and i get to learn nothing new :(

Thanks a mil again!

¬FixAxioN

i used a big flathead screwdriver and a mallet to smash my lock ring on
nice and tightley. havnt had any problems. also when i tightened my sprocket
i broke my chain whip i did it so hard. just be brutal.

The lockring may keep coming loose cause you've buggered the threads. Take it off and visually inspect both the threads on the lockring and the lockingring threads on the hubs.

As for ensuring the lockring stays put you need something like the DA tool you linked too or a Hozan lockring wrench or even an screwdriver and hammer to punch it on. You need to get it nice and snug against the cog.

Now check that theres no gap between the lockring and cog, this can be another reason for the lockring popping off. Some cheapo cogs have narrow shoulders and regardless of how tight the lockring is, the lockring won't touch them to hold them in place.

BTW: the chain bit on the DA tool is for removing the cogs.

heard a few people had problems woth fuji rear hub.
have you tried tightening the lockring with a special spanner?
if this doesn't work the your thread might be gone which unfortunately for you means that you gotta get a new hub.

Could you please rewrite this bit again please

"this is the second time this happens now: chain comes because the lock ring and sprocket get loose,"

It does not make any sense to me.

The hubjub link is a correct tool to do up the lock ring, although if it has come undone several times I would not be suprised if you had striped some threads by now.

Your chainline may be off but it should not be with a newish bike like yours so it prob is your chain tension it too slack, you don't want it too tight either. This is prob what is causeing your chain to come off. Google sheldon and chain tension.

that would suck

if the thread had gone do you
think you could weld it on?

use rotafix to tighten the cog down (http://204.73.203.34/fisso/eng/schpignone.htm). You can put a rag around you BB if you're worried about scratching the paint

If your get a aluminum cog you could but most cogs are steel and most hubs are alu, so in genral no.

ha dt i was about to post that link

arrghh! thanks for your comments.
the bike is about 1 year old (bought it 2nd hand).
i'll try to check if the threads are ok on the hub... i just hope i dont need to buy a new one, but last time i fixed this problem was to put the chain back on the sprocket, and 'pedal forward' so that the sprocket is nicely tight as close as possible to the center of the hub, then use my bare hands to get the lockring (rotating the other way) as tight as i could (obviously i dont have super human strength!). it has been fine for the last 2 weeks...

rewrite, missed out a few words, opps: "this is the second time this happens now: chain comes "off the sprocket"because the lock ring and sprocket get loose"

I will try to check tonight when i get home and maybe also push the backwheel back some more so that there is a bit more tension in the chain.. let's hope the hammer technique works!

you will definitely need to tighten the lockring using more than just your bare hands. the flat-head screwdriver and hammer technique has always worked for me. good luck.

Yep and def use the rotafix method to secure the cog on nice and tight first.

my chain is too short to do the rotafix method.
low gear grrrrrr

You must be doing it wrong un less you chain ring is very very small.

its 38T

38? what are you running at the back? you must be spinning like mad...

i think 15, cant really remember.
i live in wiltshire its quite hilly so i would struggle with anything much higher.

hey guys! thanks for your tips yesterday. I managed to get the lock ring back on after checking if the threads were worn out! I used the technique with the flat driver + hammer :)

The ride into work this morning was great :)

hammer does work but really aint the best method, use a proper chainwhip and lock ring tool, like the dura ace one you linked to. really mate dont just use your hands, that willl never really work. if you are not putting the lock ring on tight this can thread the hub, then you is buggered. maybe try putting a decent lock ring on...dura ace campag (this depends on the thread). but remember no more fingers.

i don't think a lockring is very important, unless you do a lot of skidding - anyone else ride without one?

A lockring is pretty much required if you apply any back pressure to the pedals. Its there solely for safety and in the case FixAxion he obviously needs one if he keeps spinning his cog off.

You may ride without one if you've rota-fixed the bejesus out of your cog, jb-welded it on, used massive amounts of loctite, ride only the track, used vodoo magic [...insert favourite technique for lockring less riding here], but really its a small tiny piece of metal that does a good thing.

the idea of my sprocket being able to spin off when i really need it dont really appeal to me, if you ride on the track you dont need a lock ring, but on the road, better to be safe than sorry. Although i do know of people that have ridden without, though they were quite litttle.

yeah i suppose

The rotafix method is the best bet (if you can work it out). I use it to fit my sprockets without a lock ring on a brakeless bike. After experimenting with tightness it has never come off.