Cog slipping?

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Cog slipping?

Postby scrubnbash » Wed May 18, 2011 9:32 am

Hello, I've just started riding fixed and today something unpleasant happened. Turning right I stepped on the gas and something slipped rapidly forward, I thought it might have been a loss of traction but I didn't hear anything. It made me take a tumble so pulled the wheel off to have a look. The lock ring on the hub is now loose, finger tight. My question is: do cogs take a while too really tighten up or am I stripping my hub? PS I've flipped the wheel and am riding SS today, no more excitement until I've got this sorted.
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by BNA » Wed May 18, 2011 10:06 am

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Re: Cog slipping?

Postby skull » Wed May 18, 2011 10:06 am

convenient post, I just stripped my hub today.

I like to think it was because I am too powerful, lucky I had made it into town and only had to walk a couple hundred metres.
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Re: Cog slipping?

Postby beachbum » Wed May 18, 2011 10:09 am

ok first things first... what hubs are you using? something like Quandos or those Star Rimmed wheels? and secondly who tightened your lock ring. I assume you have a lock ring? The main reason for your cog slipping is A) Stripping the hubs because the cheap hubs and here threads, cant handle the stress placed on theme and they strip. or B)the lockring and cog where night tightened enough.
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Re: Cog slipping?

Postby familyguy » Wed May 18, 2011 10:20 am

My money is on the factory and store not check the lockring was tight and sitting hard up against the cog. Fixed cogs tighten as you pedal, with the lockring being an opposite-handed thread to counter any unwinding. They've got to be tight againts each other, to stop the fixed spinning back and forth (even a tiny bit). If it wasnt tight, its been spinning a little bit each time, and might have stripped the threads, and your hub will only be good for freewheel.

Does the fixed cog still spin if you twist it with your fingers??

Jim
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Re: Cog slipping?

Postby scrubnbash » Wed May 18, 2011 10:25 am

Formula hubs (cheap yes, but I read as many reviews as I could and they seemed a safe bet). Yes there's a lockring that is now loose, I didn't put it on to be clear, it came already screwed on. I have been using lots of back pressure for slowing the bike but haven't been skidding down no hills or anything. I was giving it a bit more hell than usual in a forward direction.

Fixed cog isn't going anywhere with my fingers, it's real tight. The lockring on the other hand...

Hope I haven't stripped it, just got a new 15t cog I was planning on putting on there. That and the control of speed is pretty addictive.
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Re: Cog slipping?

Postby familyguy » Wed May 18, 2011 10:39 am

If the fixed cog isnt turning freely, then there's hope.

What might have happened:
Lockring became loose somehow
As you slowed, fixed cog unwound to meet lockring, and you might not have noticed
As you pedalled, fixed cog tightened, sending you off
Fixed cog is now tight, but lockring remains loose

Check the threads, if they're ok, tighten the lockring properly, go riding.

Jim
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Re: Cog slipping?

Postby rustychisel » Wed May 18, 2011 11:03 am

what family guy said, in all cases.

It's worth whipping the wheel and cog off and taking a good look at it, checking threads etc for obvious damage. Cheap cogs are cheap cogs, unfortunately, and they will rip the threads when given a chance. Grease yer threads. Tighen up, tighten lockring, ride a bit then re-tighten.
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Re: Cog slipping?

Postby scrubnbash » Wed May 18, 2011 2:31 pm

Thanks a bunch guys! Can I tighten the lockring up sufficiently with a C spanner or am I looking for a different tool?
This could end up being fortuitous, seeing as I have a new, I assume better quality (roselli?), cog to put on there.
...Just hope the threads aren't damaged :( .
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Re: Cog slipping?

Postby familyguy » Wed May 18, 2011 3:44 pm

scrubnbash wrote:Thanks a bunch guys! Can I tighten the lockring up sufficiently with a C spanner or am I looking for a different tool?
This could end up being fortuitous, seeing as I have a new, I assume better quality (roselli?), cog to put on there.
...Just hope the threads aren't damaged :( .


Should work, thats what I use.

Jim
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Re: Cog slipping?

Postby Moe » Wed May 18, 2011 4:34 pm

I've bought two sets of wheelsets with Quando hubs, and had this problem both times. Luckily they weren't stripped, the cog and lock ring just weren't tight enough. My advice would be to check for any rethreading, if it's all clear, tighten them up using the appropriate tools, and you should be good to go.
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Re: Cog slipping?

Postby slidetaker » Fri May 20, 2011 2:06 pm

I just want to share 4 things that I think is important for installing cog and lockring. I run formula hub, Surly cog and lockring. Holding strong.

1. Ensure the cog is absolutely tighened before installing the lockring. This can be done by riding some steep hill. At this time, no reverse peddle. Don't care how you get back downhill, use brake or walking.....

2. Grease the threads

3. Get good quality lockring with generous amount of width. The Surly lockring is 5.5mm wide, which I think is adequate. More threads engagement, less force per length of threads and less likeihood of slipping/stripping.

4. Do some short rides and retighten lockrings at least 2 times before any abuse..
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Re: Cog slipping?

Postby scrubnbash » Sat Jun 04, 2011 4:29 pm

Happy ending.
Got the cog off with some gumption and that rota fixed method. It wasn't obvious that any grease had been used in putting it on. Threads were fine and dandy. Tossed the 16t and put on a better 15t, used the rota fixed thingo again going in the opposite direction, tightened the lockring RIGHT up (all with a healthy dose of grease). Took it for a forward-pressure-only ride just then, going up some steepish hills near me and nothing has moved yet (I'm running a higher gear now and up out of the saddle everything felt solid). Tentative success! I'll ride it around for a couple of weeks being careful not to use any back pressure, re-check everything and then I reckon I'll feel confident with it again.
Thanks for your help everyone.
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Re: Cog slipping?

Postby Green » Thu Jul 14, 2011 11:25 pm

I was directed to this thread after also having a problem with slippage

I just picked up a new masi fixed, the shop converted it from SS to FG for me but on the ride home I had some slipping, I just had a look at the lock ring and it was only finger tight. The fixed cog is still spinning okay so I imagine the lock ring just needs to be tightened up and then it will be all good?

There was also some creaking under load, would this have been caused by the loose lockring?
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Re: Cog slipping?

Postby slidetaker » Mon Jul 18, 2011 1:37 pm

Took off your finger-tight lock ring and do a proper installation again...[read the above]

Regardless of the creaking, you need to make sure the cog and lock ring is secure first...
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Re: Cog slipping?

Postby Green » Sat Aug 20, 2011 12:30 am

Hey guys I find that after doing a lot of skids, bunnyhops and whatnot that my lockring becomes completely loose. Is this normal as in you just need to make sure you re-tighten it often or is there something wrong?

do i perhaps need a better/different ring?

cheers
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Re: Cog slipping?

Postby slidetaker » Wed Aug 24, 2011 4:47 pm

What's the material and the brand of your ring?
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