1FJEF

I have an E-type front derailleur mount. It's 3mm thick & uses a strange bottom bracket (Tange 68x110mm marked E-type).
Here's the E plate thingy the old BB goes through.


I'm eliminating the plate & OEM BB, getting a new front derailleur & Shimano UN-55 bottom bracket. What size do I get??
The original BB was an "E" model 68x110mm made to work with the 3mm thick funky plate. The OEM (Tange) BB looks like the drive side spindle might be recessed into the bracket flange a bit to compensate for the 3mm thick plate that went between the BB flange & the frame.
Do I get a UN-55 68x110mm, or a 68x113mm to use without the plate?

mechBgon

What crankset are you putting on it?

1FJEF

Thank you for the reply. I'm keeping the existing. I'm going to replace the BB & FD while keeping the OEM crankset.

mechBgon

I was going to look up the specific crankset's BB-length recommendations if possible, can you post the model number from the crankset? It's usually on the inboard side of the arm. If it's a Shimano, their Service Instructions sheet will specify the optimal spindle lengths for both e-type and regular setups.

1FJEF

Crank has no markings other than "FORGED 1 175 1" and a Specialized logo. It's a Specialized Expedition Elite from about 2001-2003 I think. Three chainrings retained by four fasteners on the arm. Most of the components are Shimano Acera. Thank you for trying.

LesterOfPuppets

Why ya ditching the E-type? I love those things. They're the best chain watcher available.

mechBgon

Sure thing. Well, having a look at the documentation for a typical Shimano crank that would fit on that, it looks like Shimano makes no distinction in spindle length. You use the same length of -E bottom bracket with an e-type FD that you'd use in a non-E bottom bracket with a regular FD. So the safe bet is on using the same length BB that you had before.

Alternately, smack a 2.5mm spacer into the space where the e-type bracket was, and keep using the same BB as before Your LBS will have some, they come with Shimano's external-bearing mountain BBs and there are usually some left over.

LesterOfPuppets

Yeah, a spacer or couple of big washers should work if you can find 'em. The only difference between e-type UN-XX BBs and standard UN-XX BBs is the "adjustable cup" has a thicker shoulder, so that it butts up against the rest of the BB, which is a couple millimeters off to the right due to the e-type plate.

If your BB ain't toast and you just want a plain ol' derailer for some reason you might be able to beg at the LBS for a non-E-type adjustable cup.

1FJEF

UN-55s have a shoulder on the "adjustable cup" which limits it's travel when it contacts the frames BB opening, unlike the Tange which will go all the way into the frame.

The Shimano UN-55 has a lip on the adj cup.

LBS does not have E type BB in 68x110mm. If they did I would probably just replace it & keep the E plate & FD. I couldn't find one online either. I could find the exact Tange BB except for the "E-type".
I think mechBgon is right, the E type BB is longer bodied with the spindle recessed into the drive side to compensate for the E mount plate. I guess I could go & compare it to another BB at a LBS, but they mainly just want you to shut up & buy something around here.
Thanks to all of you for trying to help. I appreciate it.