phil wood hubs cog compatibility

excerpt from article published on hubjub.co.uk today -

Being premier suppliers of both Euro Asia and Phil Wood to the UK, we are often asked about the compatibility of Euro-Asia cogs on the various Phil track hubs. The official advice remains not to do it.

It is interesting that when you fit the official Phil cog and lockring, the lockring has exposed threads too! Our measurements show that with the Phil cog the overhand is 3.23 mm and with the EAI cog it is 3.05 mm, so the amount of lock ring thread engaged is 4 mm or 3.3 mm respectively.

Yup, there is less than one thread in it. In practice this means a degree more precision is required when using the Euro-Asia cog. The margin for error is less - to little torque and the cog might be able to move (eventually damaging the hub), too much and you might strip the locking thread on installation.

We respect the advice from Phil and Co and would not hold it against users who wish to avoid the combination of EAI superstar on Phil hub, although those with high degree of mechanical sympathy are unlikely to encounter problems. But in light of the advise given by Phil Wood on their own website we must also advise customers it will probably be difficult to claim under warranty if you were to damage your Phil hub doing so.

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. - Phil Wood Webstore
Phil cog/Lockring on a Phil Hub