Got a new cog - Hub help!
 

Bike is an 04 Bianchi Pista. Got a new, sweet 18T cog.

But, it seems on my hub only one side is threaded for the lockring. Why? Do Pista's have a fixed/free flip flop hub?

I wanted to leave my stock 16T cog on there so I could flip it back whenever I wanted...

yes.



you cannot run 18t fixed/16t fixed on that hub... you could run an 18t freewheel (doesn't require a lock ring, or lock ring threading). a new rear wheel is not a bad upgrade for a pista, then you could get fixed/fixed.

Confused...
 

I just got into fixed/single speed, and bought a '06 Pista. I wanted to put a freewheel on the other side of the hub, so I got 15T x 3/32"C BMX freewheel that a guy at my LBS recommended for my set up. So I get home, take off the wheel and it wont fit, am I missing something completely obvious?

*********** isn't the 06 pista fixed/fixed? why don't you trade w the above poster?

Unless it's an AC racing freewheel (highly unlikely), it won't fit standard freewheel threading. 16t (other than the aforementioned AC racing model) is as small as you can go and still fit on a standard freewheel hub. The smaller sizes are for BMX hubs, which have a smaller-diameter threading on the flop side of the flip-flop.

It won't thread on at all?

From what DMC wrote the Pista has a fixed/free, which is what I thought aswell, but I'm new to all this so I don't really know.

I couldn't get it to, the hub seemed to large for the cog threading, but I may be missing something super obvious as this is the part I was told would work by someone familiar with track bikes...any suggestions?

Its possible he sold you a metric freewheel instead of an ISO, which is what i believe the pista would use.

Eureka! That looks like it could be the answer. Can anyone else confirm that the Pista hub requires an ISO freewheel?

the 06 pista comes with a fixed/free...not sure about the ISO...

I say...get a new hub( I got the Iro fixed/fixed) have 16t and 18t

I just reused th eold rim and my LBS laced the new hub for $30...didnt charge me for sspokes(what nice guys)

The 05 was fixed/fixed. Why did they change that? It seems much more versatile than a fixed/free hub.

Well if I'm trying to run fixed/free then I'd want a fixed/free hub, so I don't think I'd want to change it. But I guess that puts the problem with the cog being metric.

ugh! no, that's not the answer

Aeroplane got it right
the smallest standard freewheel you can get is a 16T (with the exception of the AC Racing one)

15T and lower require the flop-side of a BMX flip/flop hub. They have a smaller diameter.

Ok, I am really new to all of this and am just trying to learn, and get what I want. So for my '06 Pista w/ the stock hub, to put a freewheel on the other side of the the fixed cog, I need at least a 16T? Does it need to be metric or ISO?

Forgive me for my ignorance.

Just about any BMX freewheel that is 16t or larger will fit. The smaller ones have a metric threading, which is what your 15t freewheel had.

The BMX kids really have things figured out, stuff either fits or it doesn't. There is no small differences that cause you to screw up your BB or hub threadings.

What is the difference between a fixed and a freewheel hub?

Ok so I went back to my LBS and they exchanged the 15T for a 16T, no sweat. Get home, cog threads right on; moment of rejoicing. Moment of glory quickly fades as I try to put the chain on. Chain doesn't fit. The teeth, upon closer inspection, are much wider than the fixed cog. :( Well at least I'll have something to do tomorrow.

Thanks to everyone who helped, failure is really only prolonged success.:)

http://www.sheldonbrown.com/fixed.html

http://www.sheldonbrown.com/singlespeed.html

A fixed hub threading has one diameter of threading in one direction, for the freewheel to go on. A fixed hub has two different threadings with different diameters: The larger one for the cog, and the smaller one for the lockring. Read EVERYTHING on sheldon brown's websites above, and then ask more questions.

What kind of chain do you have? You may need 1/8" chain, it will work on just about any SS/fixed drivetrain.

use an 1/8" chain

So would it be better in general to run a 1/8" chain or to just get the freewheel cog with thinner teeth? The wider chain won't affect the performance of the stock fixed cog right? Just curious.

I did go sheldon brown's website by the way thanks for the link!

Thanks guys!

The fixed/free hub on the Pista will take standard fixed sprockets or standard freewheels on either side.

It is a Bad Idea however to use a freewheel on a Pista because there's no provision for a rear brake. Running a single hand brake on a coasty bike is not safe, there's no backup system in the event the brake fails.

You can put a fixed sprocket on the freewheel side, but there's no provision for a lockring. Loctite works pretty well for this, though it's dicey to rely it as a "brake." I officially advise against this, though I'm not always smart enough to take my own good advice.

If you do this, put the larger sprocket on the lockring side, and the smaller one on the "freewheel" side. Smaller sprockets generate less torque than larger ones.

Sheldon "Coasting Wastes Momentum" Brown

Fixed/Free hubs make no sense since you can safely use freewheels on the fixed side.
And then in the event that the fixed side gets stripped somehow, you have the other side as a backup.

Point well taken, I borrowed my friends bike one night somehow not realizing it was a SS COMPLETELY BRAKELESS, needless to say I picked up the ol' jam foot in back wheel trick, which is reasonably effective.

Thanks for the reply, I enjoyed your website very much, keep it up!!!