I've done some searching and have come up with mixed answers. Are EAI cogs compatible with Phil Wood hubs? If not, would one be limited to Phil Wood cogs only? Re: the EAI cogs, I've read that some run them with no issues, others say that it's too thick, or that the threading is different, etc. TIA

From the Phil Wood website itself:
For optimal performance, we recommend using the Phil Wood track cog. They are offered in both 1/8″ and 3/32″. Our specification for the threading is 1.370 x 24 tpi, but Phil Wood hubs will accommodate most high quality cogs. If, during installation, the cog jams or binds, STOP. Forcing a cog onto the hub will result in irreparable damage to the threads. As with any cog installation, lubricate both the cog and lockring threads. Some cog manufacturers are making cogs that are not ideal for use with Phil Wood hubs due to their thickness (which is generally a result of plating). For this reason, we do not recommend using Surly or Euro-Asia cogs with our track hubs. The additional thickness can result in stripping of the lockring and/or hub threads because there is not enough thread engagement. Please call us if you have additional questions.

https://www.philwood.com/support/faqs.php

I've heard that even though you can GET a cog it to fit, dosen't mean the cog is right for the hub. You could be seriously stripping your $150+ phil wood hub beyond repair. IMO, just go with the phil wood cog/lockring man. They are some serious quality and will give you no headaches with your phil wood hubs.


UPDATE: I found this old link (6 years ago!) Someone apparently says Dura Ace WILL work with Phil Wood hubs...
https://www.bikeforums.net/archive/in...p/t-74592.html

i have phil wood hubs and run an eighthinch cog with no problems. the lockring threading is different though.

Hello,

I've had two sets of phil wood track hubs and have used Dura-ace track sprockets (cogs) on both.
Phil wood cogs are crazy expensive so i'll go with the cheap stuff: Dura Ace

I hope that winky face was in relation to dura-ace cogs being cheap.

IIRC, Phil hubs can use standard cogs, but their lockrings follow the Campagnolo standard rather than ISO.

This makes no sense. You bought two sets of the most expensive hubs you can buy and used cogs with the wrong thread size so you could save a few bucks? If you are going to spend the $ on Phil hubs, you should buy a cog with the proper threading.

thanks for the info...i've thought about dura-ace, but the cogs only go up to 16T, and i'm looking at 17T or 18T.

also, what type of freewheel would fit on the other side?

As long as its fixed/freewheel and not fixed/fixed any standard bmx freewheel should fit.

Actually their threading is ISO/English threaded, it's only their lockring threads that's different, so they can use a 12T cog.

yup the wink was joking about DA being cheap.

Did the DA's have "different threading" than the hub? They went on smooth.

Phil Site: "Phil Wood hubs will accommodate most high quality cogs."

A phil cog is about $66, A DA is about $20, + I'm running a DA crank set.

I guess I should clarify that i used the phil lock ring that came with the hubs.