Stripped hub

[αdαmsκι]

I've got a flip flop hub (ie it is threaded for a fixed sprocket and lockring on one side and t'other side it is threaded for a freewheel to be fitted).  After being told to put the fixed sprocket and lockring on as tight as you can, I've stripped the thread    Yip, I don't know my own strength.....  So, a two part question:

Q1a)  Would it be possible to get the hub re-threaded?
Q1b)  Assuming the answer to 1a is "No", what Loctite should I use to glue the fixed sproket to the hub (Fixie FAQs suggest the blue stuff, but somewhere else was suggesting the red stuff   )

[border-rider]

1a

No, doubt it, unless the damage is minor.  It'd likely just strip again.  I'm not sure that just doing it up tight should have stripped it though.  That's what happens when you climb a hill

1b

Don't bother

You don't need a lockring, and loctite alone won't make much difference anyway. 

What some people do use loctite for is when they put an old BB lockring onto a freewheel hub to hold the sprocket in place - they're RH threaded, like the sprocket, and the loctite is meant to help stop them undoing.

As I say, I wouldn't bother unless you are skid-stopping a lot.  Once the sprocket is torqued down it won't go anywhere

[αdαmsκι]

Yeah, I was a bit confused how I managed to strip the thread.  I was using a using one of the Shimano Dura Ace chain whips, which doesn't give stupid amounts of leverage.  I am pretty strong and it was a second hand wheel, so maybe it was already damaged.

Once I've got the bike working (I'm currently trying to find for bits & pieces for it), I'll try just screwing the fixed sprocket to the freewheel thread and seeing if it stays put once it's torqued down.  I certainly do a lot of leg braking riding around London, but I don't skid stop all that much (I cannot be affording new tyres every few months!), so hopefully it'll be OK.

[Che]

Quick mental calculation. Assume 70-inch gear. That's a ratio. of 70/26.22 = 2.7ish. Torque provided at front when climbing if not pulling up is 170mm * Adam = 500 Nm ish. So tightening torque when riding is 2.7*500 = 1300Nm ish.

Whereas with a 35 cm (about right?) chain whip, you'd need to provide 3.7 kN of force to the end to achieve the same torque, which is about 370 kgf, or a third of a ton. I am not inclined to suppose that Adam, strong as he may be, was producing such forces, so the threads ought really not to have stripped. Something dodgy at work there.

[Che]

N.B. Since the designers of such things will want to ensure that even Chris Hoy pulling up on his pedals can't strip a hub, and will build threads that can withstand the torques he generates by a factor of two, I reckon you'd need to apply about a ton-force to the lever to actually strip the threads on a non-faulty hub.

[iakobski]

Did the sprocket spin all the way on ok, before you started using the chainwhip?

I've never bothered tightening a sprocket on more than finger-tight, riding does that for you.

[Che]

Did the sprocket spin all the way on ok, before you started using the chainwhip?

You thinking cross-threading? More likely that Adam having 1-ton arms, I think.

I've never bothered tightening a sprocket on more than finger-tight, riding does that for you.

Yeah, but then the lock-ring comes loose as the sprocket tightens. I had one fall off once. Fortunately, I was right by Two Wheels Good, and scrounged a c-spanner.

[αdαmsκι]

Did the sprocket spin all the way on ok, before you started using the chainwhip?

You thinking cross-threading? More likely that Adam having 1-ton arms, I think.

This was a while ago and since then the wheel hasn't been used, so it's difficult to remember exactly what happened.  However, I'm happy to say it wasn't cross threaded because I'd have noticed that while trying to get it started. 

I've never bothered tightening a sprocket on more than finger-tight, riding does that for you.

I'll remember that for next time!

[iakobski]

Did the sprocket spin all the way on ok, before you started using the chainwhip?

You thinking cross-threading? More likely that Adam having 1-ton arms, I think.

No, that would imply adamski was cack-handed  I was thinking more of a Miche sprocket on Shimano thread hub or vice versa

I've never bothered tightening a sprocket on more than finger-tight, riding does that for you.

Yeah, but then the lock-ring comes loose as the sprocket tightens. I had one fall off once. Fortunately, I was right by Two Wheels Good, and scrounged a c-spanner.
[/quote]

Never had one fall off, but must admit I've never had to use a c-spanner to remove! Not sure why I bother putting it back on, to be frank.

[αdαmsκι]

I was thinking more of a Miche sprocket on Shimano thread hub or vice versa

Hmm, I honestly cannot remember what sprocket I was trying to put onto the hub.  I'll try to check that out when I get home.

No, that would imply adamski was cack-handed

Watch me do some work on a bike and you will then be happy to consider me cack-handed.....

[Che]

That would explain why you've never developed a true love of fettling::
Fettling: your views

[Ian H]

To fit a fixed cog and lock ring: screw on the cog to moderate tightness, follow with the lockring, similarly. Fit the wheel, ride once, re-tighten lockring in situ. job done.

Edit: if it's an old hub, the damage was more likely to be done removing the old cog.

[αdαmsκι]

I don't know the history of the hub as the bike was second hand.  However, there was sprocket on the hub, which I removed in order to replace it with a larger 1/8'' sprocket.

[teethgrinder]

To fit a fixed cog and lock ring: screw on the cog to moderate tightness, follow with the lockring, similarly. Fit the wheel, ride once, re-tighten lockring in situ. job done.

Edit: if it's an old hub, the damage was more likely to be done removing the old cog.

When I used to use a lockring, I did that, but never bothered retightening the lockring. It tightened itself up after a while.

Chris Hoy might have been using splined sprockets, so may not have had to worry about stripping threads. I think they are made by Miche. But you slide the sprocket onto the spline (same sort of thing as on a cassette), then tighten up the lockring to hold it in place and hey presto. A sprocket held as firm for forward pedalling as it is for backpedaling. Not sure if that system is still going around though.

[border-rider]

still around

The sprocket carrier screws onto the hub the usual way, but yes once it is one you can leave it an d just change the sprocket with a lockring spanner

I use one on PBP

They're good, but after a while there's a bit of play

[αdαmsκι]

The hub says "sonos" but I cannot find anything about sonos hubs.  I assume the name is something similar to sonos and i have copied down the name incorrectly from the fancy font that is displayed on the hub.  Any hints?

[border-rider]

Sovos ?

more here

Going Fixed - The Art of Cycling without Gears

[αdαmsκι]

Aye, that makes sense.  Ta.  There's a picture of one on Sheldon Brown's site that matches the text on my hub.  I still claim the "v" is actually a "n"!