Singlespeed & Fixed Gear - Freewheel replacement...

I want to replace the singlespeed freewheel on a wheel I'm going to use for my conversion. I was going to order a new one and then saw that there is metric and english threaded models. How do I figure out which one I need? The freewheel currently installed says "MAIN DRIVE 1/2x1/8 (c7)". I had hoped the "c7" was a model number of some sort that would shed light on the threading, but so far google has failed me. Any ideas?

haz te du weth thrdeing uv teh wehel fere

how many teeth on the one you want to replace?.......there is only one freewheel with less than 16teeth that's not metric

there's 16 teeth on the one I have now and I wanted to bump up to 18 or 20- I had knee surgery a while ago and don't want to push any big gears yet.

They say these are the best, rebuildable, and worth every penny...
http://whiteind.com/singlespeedgearing/freewheels.html

This place has a whole range, and even some with 2 cogs in one 16/18 17/19 (if a perfect chainline is not as important and you have the room in your dropouts to use it)
http://www.bikeman.com/White_Industries_Single-Speed_Freewheels.html

For gearing and skid patch calculations
http://www.bikeforums.net/showthread.php?t=468351

This is good info, thanks, but I really was trying to find out what threading my current freewheel has before I buy another one. From some more poking around it looks as if it's 16 or more teeth then it's english threading, and less than 16 is metric. Does this sound correct?

It may be better to try and identify the hub to make sure of the threading that the freewheel is threaded onto.

Looks like the standard I see everywhere is 1.37" x 24 tpi

from:
http://sheldonbrown.com/harris/singlespeed.html#freewheels
"These have standard 1.37" x 24 tpi threads, and fit on any hub that takes a thread-on freewheel. This includes BMX hubs, track hubs, and multi-speed freewheel hubs."

yeah I think that Is probably the more common threading, but then I see freewheels like the ones in the link below listed as metric and I get confused.

http://www.jensonusa.com/store/product/CS308C00-Acs+Main+Drive+Freewheels.aspx

If you can thread a BB lock ring on the hub then it's 1.37"x24tpi.

unless its left hand drive all freewheels 16t and above are common thread I have had bad experience with Dicta freewheels and good luck with ACS, AC Racing, Shimano and even the classic Suntour unless I you really want to spend a lot of money on a White Industries buy an ACS

No tax or shipping, some larger sizes, runs about the same...
http://bikeisland.com/cgi-bin/BKTK_STOR20.cgi?Action=Details&ProdID=331

cool, thanks everybody! my knees appreciate it!

Hey guys,

the freewheel that came w/ my Madison started making odd noises so the shop gave me a new one. Long story, but he couldnt replace it so i have it with me. Its the same generica "India" freewheel, same 18tooth, but it has a different letter-number on it. The one on the bike says D5 and the new one says C7. What does this mean?

It looks like like the heavy inner part might be "dished" differently.. but i don't see any dish specs online anywhere when buying new ones...

?

I hate Dicta freewheels they just don't feel right to me, do yourself a favor and buy an ACS Claws freewheel they are worth their cost, not the slickest out there (that honor goes to White Industries) but ACS freewheels feel a lot more solid engaging than a Dicta does