Thursday, March 19, 2009

Quick Release and hub info

A young lady sent me an email on using a quick release on a fixed. I wrote her back and thought maybe some other people could use the info so I copied it. Below:

The flip flop hub is a hub that has threading on both sides. Meaning you can have a different gear on either side of the wheel. To change your gear you just need to take your wheel off and flip sides. Now you can get a hub that is fixed/ fixed which means you would have to use a track cog on both sides or you can get a hub that is fixed/free, which is threaded on one side for a cog and the other side for a freewheel.
The cog and freewheel threads are not the same. The cog side will have two rings of threads the first which is closest to the spokes is where the track cog spins on. The second threads are smaller and tighten in reverse so you go left to tighten. This is for your lock ring which locks down the track cog.
Your freewheel side will only have one set of threads. So you want a fixed/ free hub. You put a freewheel on one side and a track cog on the other. You can switch back and forth as you like.
Now reference the quick release hub as far as I know nobody makes this type of hub with a quick release. They will either use a standard bolt or an allen bolt.
On a derailleur bike you don't put that much torque on the rear wheel because the derailleur keeps the chain tight. On a fixed gear the chain is direct drive so it has to be locked down super tight. A quick release was not designed for this type of application.
Let me know if this helps. If your buying a commercial/new fixed gear bike it will be set up this way. If your buying something used or converted then there's no telling.

1 comment:

Richard said...

I'm not sure I buy you argument as to why a QR hub is impractical for single speed. Firstly, Sheldon Brown states that QR hubs are OK, so long as the skewers are good quality and tight.

Secondly, the point about chain tensioning normally being done by the derailleur doesn't seem to be valid - the force from the crank is transmitted to the rear wheel along the top of the chain, which is no different on a single-speed than on any other bike. Admittedly, if the wheel should move, it is more noticable on a single-speed, but the fact is that the wheel doesn't (often?) move on any other bike.

But there does seem to be a paucity of single-speed hubs that will take a QR skewer.