Threading issue...

[jimbolina]

I have a situation here that's kinda bugging me...

I have a (NOS) Italian, aluminum, road frameset that I can EASILY hand-thread my old Campy Nuovo Record bottom bracket cups into, BUT when I changed course and put in a (new) Phil Wood BB using their aluminum cups, they require a wrench to install.

This is a dry-fit run, so I'm not installing the cartridge just yet...

Anyway, I can readily hand turn the first few threads of these aluminum cups and see that I'm properly engaged and not cross-threading, with no problem, but it becomes significantly harder fairly soon, to where I require said wrench.

I proceeded and fully threaded the two cups (both sides are acting this same way) into the shell and then promptly backed them out to inspect all the related threads (both cups and shell) and they appear quite normal. No cross-threading nor flattening of any threads.

I reinserted the cups and now have them awaiting in the frame for eventual disassembly and reinstallation with the cartridge, once I get some feedback here...

BTW, If I had to guess what force was needed to run these cups into the shell, I'd say about 10ft lbs. I never had to force anything, but I did use a longish wrench to aid in turning the Phil installation tool.

So, my question is, is this an unusual situation and did I potentially damage or compromise the threads on either the cups or the shell, or am I simply fretting over nothing?

Are the Phil cup threads simply 'taller' and are as a result much more snug than the Campy was in the shell? What gives?!

Thanks.

[Black Dog]

If they go in and come out looking fine then grease, or better yet, anti-sieze them and install. Manufacturing tolerances are variable and this happens from time to time. I would not loose any sleep over this. Make sure you pull them out once a year or so check for any corrosion.

[dave thompson]

I've had several occasions, on different bikes, where the same situation you describe occured. I went ahead with the normal install of the respective bottom brackets. Everything went normally and there were no subsequent issues. I have even swapped one of those bottom brackets out for a crank change and had no problems.

[Louis]

As was pointed out above, manufacturing tolerances cause running torques to vary all over the place, especially when you're talking about compatibility between different manufacturers.

[jimbolina]

The tolerance issue was my gut feel as well. Since it didn't jam or cross-thread, I assume the treads are fine and indeed it was a simply tolerance matter.

I couldn't help but worry though, as it's an old frame that I had stashed new several years ago, and when you pull out something like that and start slapping components on it you kinda worry, or at least are sensitive to figment issues and the like...!

I appreciate the feedback though.

[Ti Designs]

Italian threading is 36x24 - everybody knows that!

Is this metric or SAE or some other standard? All of the above. It's 36mm by 24 threads per inch, and it's Whitworth thread pitch (55 degrees with a flat top)

Campy uses the whole Italian standard or set of non-standards as the case may be. The frame was probably prepped with a Campy tool set. If I had to guess, I would say Phil Wood uses an SAE thread pitch (60 degree, sharp) which is where the friction comes in.

[jimbolina]

Bingo Ti-Designs!

I bet that SAE pitch is it! Thanks.