Help... Scared for my safety!!!
 

So i was riding my recent fixie conversion (fixed hub not bumbike) home today in the rain and was trying to do a little skip to check my speed coming up to a light and when i resisted the pedals there was suddenly no resistance. It was like the hub suddenly became a freewheel... i don't know what could've caused this and tried another skid once i'd turned onto a side street and the same thing happened. I tried another skid when i was just outside my house and it worked... i'm very confused.

This reminded me that in the first few days of riding my fixed a couple of time i would stand up to pedal from a stop and the pedals would slip in the same manner (which i chalked up to wheel slip and so didn't worry about). All of these were silent however so i think that rules out the wheel slipping, and it has happened when both pedaling forward and resisting the pedals.

WHAT COULD THIS BE... HUB... BB? I'm not sure where to start. I was considering going brakeless but this has me rethinking this!!! Any suggestions would help and be GREATLY appreciated!!!! Let me know if there's important information i might have left out as well cause i'm somewhat ignorant of the functioning of hubs and bbs.

lockring threaded?

my guess: the cog wasn't threaded all the way on, and riding tightened it down, when yout tied to skip it unthreaded again, until it hit the lockring.

tighten it down all the way, then tighten the lockring again. if you don't you'll strip your hub.

1. Your cog/lockring are not tight enough. Tighten them.

If that does not work then:

2. Your cog's threaded area is not wide enough (older Surly cogs had that issue). Get a cog with a wider threaded area (DA, Phil, EAI).

how would i check that?

you have a fixed gear bike, no give at all in the drivetrain. backspin the wheel against pedal resistance, wheel in the air (on a stand if you have one, broom handle between two chairs if not. if you feel slippage you know there's a problem, can start to look for the causes


cog too narrow
you can visually check the cog width looking straight down from above

the hub has two threaded sections, one for the cog, which threads one way and is wider in diameter (from the axle). the lockring threads are smaller in diameter. if you've tightened the lockring all the way and there's still a gap between it and the cog then the cog is too narrow, which would allow it to loosen with backpressure. that's a visual check you can do.

lockring incorrectly tightened
to check the other option you have to take the wheel out and use a chainwhip, or rotafix it in situ, to make sure the cog's threaded all the ay on, then tighten the lockring to it.

does that make sense?

The same exact thing happened to me. It's your lockring. After riding my bike for a week or so, the lockring came loose and scared the **** out of me. Buy a tool to fix it, or just take it to a shop. I doubt it's your hub.

The lockring must have come slightly loose, which is why you felt the wheel 'slip'. The slip is actually the cog unscrewing (when skidding, or slowing down) and rescrewing itself when you accelerate.

What hub-cog-lockring are you using?

-Chris

yeah... I'll give that a try once i'm done eating... I was just wondering if there's any possibility that it might be the BB. It doesn't happen everytime I skid/skip and there seems to be no connection between it slipping when pedaling and back pedaling. The two incidents with it slipping when starting to pedal was when i first got the bike and hasn't happened in a while and then this skidding issue wasn't followed by the pedals slipping when pedaling forward and i was going up the biggest hill on my ride right afterwards.

Also the hub, cog, and chainring were professionally installed and brand new... the bb came with the bike which was a garbage find.

"jedi_steve420"... either use your jedi skills to fix the problem or smoke some dope (420, woo!) and forget about it.

don't worry shants... that was my first reaction!!! turns out the force doesn't work on fixies... perhaps explaining why they are the bike choice of ninjas and pirates?

Get a chainwip and tighten that cog like a mickyficky. Then tighten the lockring with slighly less english. If it stops slipping good if not get a cog with a wider thread area and repeat.

just to be vaguely constructive.. you can always use really thin bottom bracket spacers to bump the cog out a bit instead of buying a new one.. that is, if the problem is that your cog is too narrow.

Yeah some professionals make mistakes too.

The reason it is not slipping all the time is because the initial slip usually tightens or losens the heck out of your cog so it remains stuck for while. Until it slips again.

pirates = the suck
ninjas = the suck

your bike knowledge = pirates and ninjas

your gonna strip that hub!

alrighty then wrench... I guess i'll just try sucking for not knowing everything about bikes and see if that helps... wait... oh... wait..... nope. Damn... i guess it's down to checking the cog and lockring. Damn i'm just so much better and making jokes about pirates and ninjas; sorry jokes about the suck and the suck.

Thank you all for the help! saved me lots of time and guessing. I'm gonna go check the locking and cog right now and will post results. Wait with bated breath for update.

helpful.

special guest apperance by The Wrench! jedi_steve should be honored!

hugs for the wrench.

he's so h8 edge.

Aaron, too funny
I like the fact that, although this question seems to come up often, the threads they spawn are still usually fairly long. At least the answers seem to stay consistent.
Why is is so hard for people to believe that their lockring may actually be a loose-ring? Denial this powerful should be reserved for more important things......like cancer and alcoholism.Or, for that matter, a poorly planned and illegal invasion of Iraq. :)

I work in a shop full of professional mechanics, none of whom ride fixed gear bikes besides me. I took out a cannondale track that had been on the floor about a year (built by someone else in the shop) for a spin around the block, and exactly the same thing happened: a moment of distressing "coasting," followed by the cog spinning forward again when I stood and cranked hard on the pedals.
There is a degree of tightness that takes quite a bit of force to achieve, one which your mechanic might not have known was possible or necessary. One method I'm fond of is zip tying the chainwhip around the cog (to keep it from popping off) and using a deadblow mallet to tap the cog just a hair tighter than I could easily get it with my hand. This is not a pounding procedure, but the mallet lets me get it nice and tight without putting all my weight on it and busting my knuckles on the spokes. I do the same thing with the lockring, and it seems to be sufficiently tight to prevent what you're describing here.

ok i read through some of the posts. He said he has a fixed wheel ... see if the wheel moved.

Since it is direct drive the wheel moves forward that is why our dropouts/ends look the way they do.

Double check the drive train(wheels,cog, chain).

S/F<
CEYA!
Gotta go Prospect Park series last race in 1 hr! it is 39 F with wind..so it feels like 32F

I'm late on this, but most fixie riders I've seen had to have the jedi skills, esp the brakeless ones....

And agreed with everyone else on the cog/lockring. I recommend the rotafix method to make sure the cog is tight, then hit the lockring. If you have a brake, go out and pedal really hard without backpedaling, then take your feet off and stop with the brake. Hit the lockring after that.

Would some JB weld help?