Formula hub lockring

i just got a rear wheel with a formula flip-flop hub, do I require a particular type of lock ring and if so which one?

standard iso

cheers

anyone know how to get a replacement freewheel for a formula singlespeed hub or should I just try and take it apart?

anyone know how to get a replacement freewheel for a formula singlespeed hub or should I just try and take it apart?

http://www.chainreactioncycles.com/Models.aspx?ModelID=7805

The freehub is narrower than the usual 7/8/9 speed freehub and not a screw on one like you linked to on CRC

Hi, I've been utfs but nothing seems to answer my question...
My girlfriend's bike is a Fuji frame with wheels from a Charge....as far as I know, they are the standard white deepish rimmed ones with formula fixed/free rear hub.

Currently, she rides the freewheel side with a (46/18), but she wants to move to fixed (yay!), which has no sprocket on. I want to put a sprocket on the fixed side of the hub for her so she can ride it fixed, but I'm unsure if I'd be doing it right. (She lives in Nottingham, so LBS won't necessarily know shit)

I was thinking of a 17 or 18T sprocket, which should be OK I think as the axel isn't very far back.
But will it need a lockring? I don't understand how to check which side is 'threaded' (?) to put a lockring on.
The way it seems from reading around, is that if the freewheel side has a lockring already on it, I can simply screw a sprocket onto the fixed side and then it'll be ready to go?? Am I totally wrong?!

Any help appreciated...sorry I have no photos :)

there will be definate step down on the threading of the hub if it is threaded for a fixed sproket.

despite what some numpties might say, only used a hub that has this threading for riding fixed and you definately need to fit a lockring. if you dont she will loose her teeth, simple as.

i would recomend fitting either the same gearing or going to 19 sprocket as the effort of leg breaking and pedalling the whole time will initially but quite tough on someone used to freewheeling and brakes.

as far as positioning in the dropouts, this can be sorted out by adding or subtracting chain links as appropriate.

Tash, you're totally wrong, sorry.

Fixed side of the hub is double threaded... one clockwise thread next to the hub for the sprocket and one anti-clockwise thread (that's slightly smaller in diameter) next to it to thread the lockring onto once the sprocket's in place.

Freewheels don't need lockrings as they only ever have clockwise forces put upon them, so the freewheel side of a hub just has one clockwise thread.

There are loads of threads/images on this forum about it, UTFS a bit more.

Cheers peeps, that is really helpful, especially the bit about the clockwise-ness. Now makes sense. I will get a 19T then and step it down for her, and obv get a lockring too. I've tightened the lockring on my own fixed hib before, so should be fine.

Yeah, I'd rather she wasn't less some teeth :)

so does the formula hub have 1.370 hub thread?

The freehub is narrower than the usual 7/8/9 speed freehub and not a screw on one like you linked to on CRC

no idea what you're talking about mate. a freehub takes a cassette or cog and spacers. a singlespeed hub takes a freewheel.

the thread on a formula hub, what size is it? is it 1.375" or 1.370", or are they both the same size?
because i want to buy this: http://cgi.ebay.co.uk/Fixed-sprocket-1-8-nickel-high-spec-15T_W0QQitemZ350260857460QQcmdZViewItemQQptZUK_sportsleisure_cycling_bikeparts_SR?hash=item518d2c8a74
but i dont know if it will fit.

it will be ISO - which is 1.375" x 24 tpi

1.370" x 24 tpi is British standard, but i think they are interchangeable.

sheldon thinks it makes no difference

There is theoretically a 5/1,000" difference in diameter, too small to matter in practice

but why get this when you can get much better for x2 price?

thanks