PS: Extra points if you can get away with calling them “L’oreiiles de porc St. Menehould”

Bratwurst; the Germans wish they would have made.

Doree. . .

A Best friend for over 25 years
Playmate
Soul sister
Damn! I didn’t get to say good-bye. I love you!

There is no simple answer to “which bb do I need,” because no one uses the same parts. For one Twenty, I used a 68mm shelled, 107mm spindle (the narrowest) UN72 with a mid 1990’s Shimano Ultegra 600 double crank (with inner chainring removed) I got from one of the deep discount shops. I used a Shimano Nexus 7 on the rear (and later a Sturmey 7, and am now back to the Nexus). Remember, you are taking off the lips of the bb via grinding, so you can adjust the chainline as far as the parts will let you–which is to say, the point at which the left crank arm touches the bb shell, or the right spider or chainring (or chainring bolts) does the same at the shell, or on the chainstay. That said, you will also want to look at overall symmetry (measure the distance between each of the crankarms and the chainstays and try to keep them somewhat equal). If you are heavily skewed to the right, you will need a longer bb just to compensate. No big deal. In fact, most cranks are not fully symmetrical from the factory, and no one seems to notice. There is also this thing called Q-factor (overall distance between the crank arms), which is another story I will refrain from talking about.

I’d say if you are looking for a single ring setup and some sort of internal hub in the rear, get a 107 or 110 bb and go from there. As long as the lips you will be grinding down are metal, you are fine. You are not limited to Shimano. I was able to use my stock chain guard with my 107 spindle and Ultegra 600 cranks. Unless you want to grind the chain guard down to fit a 42mm chainring, find a 36mm chainring (I’d suggest the Sugino XD-600 with 26-36-46 rings). I will also say that this same 107mm bb was able to hold a quadruple chainring I set up with Sugino XD cranks (20-30-42-54)–I used the now-unavailable Avid “Microdapter” to add the fourth chainring. That mod was another story, and I did not keep it. It was more of an experimental thing.

Know that some setups (like my Nexus) will require you to spread the rear triangle. There are pages on the web telling you how to do this, should you decide to go that route. If I were to reveal my specific method of how I have spread several of my old Raleigh frames, someone would call me a ham-fist. To my credit, they all have come out aligned and fine.

And one of these days, I’ll have to get a video up.

A Best friend for over 25 years
Playmate
Soul sister
Damn! I didn’t get to say good-bye I love you!

Glad you like the page.
With careful use of a punch, you can remove the right side “fixed” cup on a UN-72; or you can suspend it loosely between the jaws of a bench vice and punch the b.b. body away from the fixed cup side with a soft head, dead blow hammer (using wood to protect the spindle and a towel to catch the bb unit!!). No need to use the torch, really, but you can if you want. I’ve never damaged the housing of a UN72, or the threads.

The shoulder needs to be ground down on the Shimano unit because the Shimano units have a shoulder built in on the right side–either on the right ring, or, if the right side is integral to the bb, which is the case on modern units, machined into the shell itself. To make a Shimano unit serve in lieu of a Phil unit and/or parts, this lip needs to go bye-bye. Moreover, Shimano units are made for a 68mm (or 72mm) shell The Twenty has a shell that is 78mm wide. Now, if you are using Phil rings in tandem with a Shimano unit that has two metal “lockrings” that have been removed, you do not need to do any grinding, as Phil rings have no lips. If, on the other hand, you grind your Shimano unit’s right side lip down to nil, you will not need to buy Phil rings. I’d suggest saving yourself some money and buying a cheap grinder instead of a pair of Phil rings. But that’s just me.

Hope that helps.

I assume that by “Twenty” bottom bracket, you mean “UN72,” or some sort of Shimano unit.

Great stuff! Thanks.