The DSF

I just bought a Langster with flip/flop rear hub. (don't start on the paint or the top tube or the geo please ... I'm happy with it) However I have a question regarding the replacement of the fixed cog. Currently both freewheel and fix ar 16T and I'm wanting to changes the fg to 14 (42 Front end). I've noticed that track hubs come in differing threads. How do I know what I want??

cheers
DSF

bigvegan

Most track cogs use the same thread. Some are spaced slightly differently, but they're pretty similar.

Buy what you can afford, or what seems best for you. Some people think the forged cogs have better threading that's less likely to strip your hub than the stamped cogs. The Shimano Dura Ace are pretty well thought of.

Raiden

I'm pretty sure that all modern track cog threading is universal (though anyone is welcome to correct me on that). You might be referring to chain/cog width; you want a cog for 1/8" chain (as opposed to 3/32"- a narrower cog that you CAN use, but I wouldn't suggest it).

Next-I would suggest AGAINST using a 14t cog with a 42t chainring, due to the fact that it creates only one 'skid patch'. Google the term, or check at sheldonbrown.com; in short, that specific crank-to-cog ratio (among others) creates a circumstance that puts the wheel and crank in the same place over and over, creating premature wear, especially if you plan on skidding. Use a 15 or 13-toothed cog. Obviously, you have to weigh your options- 42:15 isnt that much different than what you're using, and 42:13 is a little tall. I went with 42:13 and have, over the last year or two, allowed myself to get used to it.

The DSF

Thanks. I didn't really understand "skid patch" or bother looking at till your reply. Makes sense even though I don't intend to "skid". I may look at a 13 and 15 perhaps (13 may defeat the idea of improving my spin!). Thought it would be a cheaper option than getting a new front chainring.

Geordi Laforge

I thought miche hubs have a weird threading...

Cyclist0383

Campy, Phil Wood, and Miche use a slightly different threading than most of the others (Formula, Shimano, Surly, etc). In reality they are interchangeable. For example, I've used Campy cogs on Formula hubs with no problems. The only possible problem you might have is if you regularly change from one style of cog to the other, but I highly doubt you'll do this.

JohnDThompson 

Campagnolo lockrings are threaded differently than most others (1.32" x 24tpi left vs ISO 1.29" x 24tpi left) . Miche and Phil use Campagnolo's threading for their lockrings.

The cogs themselves are ISO 1.375" x 24tpi

Cyclist0383

Actually they are 35mm x 24 TPI, which is close enough to be compatible with ISO.

Eggywootah

A guy once told me that Surly cogs were thicker than other cogs, not in the teeth, but the whole thing. Is this the case? Can you adjust chainline with thicker or thinner cogs?

clink83

Yea, because all those cheap, high quality road chains you can use are really bad

beer slayer

The Surly cog is pretty thick at the threaded section so is the EAI cogs. I made up a batch of my own cogs to sell to shops. I looked at all the cogs on the market and took the best that I could from the best cogs out there. My cogs aren't cheap, but they'll last a long time. I made them as thick as I could at the threaded section with still having plenty engagement room for the lock ring. The tooth profile is rounded up on top to run as smooth as I could make it. What I'm really proud of is the width of thetooth. If you place one of my cogs in a tight chauin and twist it side to side it rotates less than all the cogs that I've checked. They're also made in USA from American made Cromoly. The Finish is a clear zinc wash, it's a tuff and durable finish that resist rust and wear. The brand is Brewtal Componenents. I'll try to figure out how to post a photo...I'm a fricken ludite when it comes to copmuters.

jhaber

Here you go

beer slayer

Thanks!

Soil_Sampler

to get technical, it is 1.370"=34.8mm

"Phil Wood track cogs are hardened stainless steel (thread of 1.370" X 24 tpi)
designed to be as durable as any cog available".

https://www.philwood.com/Track%20Cogs.htm

mander

I think a 15 will be fine for you. Even a single tooth change is pretty significant on a fixed gear---you will notice a big difference. 42-14 is going to start to be a pretty big grind going up hills, and I think that on average you'll tend to spin such a big gear at lower than optimal rpms.

dectangle

If you want to improve your spin you should get a higher tooth count cog. That way you will be pushing a lower gear at a higher cadence. If you get a smaller cog then you will just be pedaling a higher gear at a lower cadence, which won't help you improve your spin.

idiq

Just to finish this off, there is an article on Sheldon's website which lists the width of track cogs in 3/32 and 1/8, as with lockrings (mavic, campy, d/a) NO not all cogs are the same width. Typically you should stick with branding to get an exact chainline... for instance, I ran a HF D/A hub with Miche Cog/Carrier to Omnium cranks... chainline was off by about 1-2mm, nit picky yes, but noticeable looking down at it (there's a thread with pictures somewhere archived). Moving to a D/A cog fixed this.

Renny

Sheldon also advocates an even-numbered drivetrain to reduce chain wear. IMO, the article doesn't make any sense. He actually suggests making sure you align your inner/outer link orientation to the same teeth any time you remove the chain. Nevermind the fact that it contradicts his suggestion to use odd-numbered gearing to increase skid-patches.

If you aren't skidding, I don't see how skid patches affect anything. Just because my chainring is at a consistent position relative to my rear wheel doesn't imply any kind of accelerated wear, as far as I can tell. Just use whatever gearing works best for you, regardless of whether it's even or odd, or how the gearing simplifies. But I'll start a thread if the 42x14 gearing causes my bike to spontaneously explode.

operator

And then the phil wood cogs will last longer because they're stainless...? The finish on those cogs look like cheap zinc plating. Which doesn't last. Please educate us how exactly your cogs are superior to everything on the market again.. and the MSRP.

operator

It means you're putting power down at the exact same spot(s) all the time.

Renny

[pro]I apply even power all the way through the pedal stroke.[/pro]

beer slayer

Yes, they're clear zinc. We tossed chrome plated cogs as well as zinc plated ones in a LARGE rock tumbler. Asian chrome plated cogs lasted 3-4 hours the zinc ones lasted 3 days. in two months time we've had zero complaints of the finish failing. One rider is a 6'5" guy that rides the track (he has a few medals) plus he rides 50 miles of road a day. I'll hit him up with regards to the finish.

Yes Phil Woods rock I have much repect for him. I was first going to have Stainless ones made put my machinist recomended Chromoly, he said that it would last longer. Price is $50 usd

Raiden

I just felt it only fair to mention the idea of skid patches, since his first inclination was to set up 42x14. I do feel that the theory applies to me, as I've been running the same pair of Armadillos that I bought and equipped a week after I bought my first fixed-gear, and that was a couple thousand miles ago. I do practice pushing an even circular stroke, and I don't skid much, but I do find myself pedalling with a non-circular stroke when I'm out of the saddle, and I tend to slow/stop in a pattern. Over countless rotations, I would tend to believe in the theory.

Even if I do happen to be right, though, and it wears tires out a little more quickly, if it creates just the right cadence for you/him, then a tire is a small price to pay.

The DSF

Thanks for all the advice. Been great. Today I bought a Roselli 15T for the FG and I'll probably end up changing the 16T freewheel to a 17T version. Shimano, I like the white ind ones better but they are too rich for me at the moment.

cheers
all for the info

idiq

I applaud your efforts. People just don't seem to get it.