Cleaning BB threads Q and wrong way around???

[one-eyed_jim]

The BB def, mounts from the LHS which is indeed odd (to me)

So are you saying that it isn't the unit in the auction picture above? Because that unit (look at the threads) could only mount from the left if your three frames all slipped past Quality Control with their bottom bracket shells welded on backwards...

 

[FluffyChicken]

Just to confirm a UN-91 should not fit 'backwards' unless you frame is made backwards. Even if the cups are on back to front the 'fixed cup' will still be drive side.

I assume Italian sized would be able to go in back to front though.

Also on the left side axle MM107 will be stamped between the tapers and the seals in pretty large letters, just to double confirm the length.

Also UN-91 should not be available in 115mm*, there was no need for them to make it that long, 113 would be the longest (could be wrong and they may have made them longer later in it's production life)


* of course I just proved myself wrong, apparently they did under the Dura-Ace Brand should have D-H on the axle then ?

 

[Harryburgundy]

Yup..thats the one Jim
I'm confused
Could it be one of those italian threads ones adjusted for english shells? Different cups etc

 

[FluffyChicken]

What's written on the Fixed Cup (aka drive side or err the 'R'* side)


*also known as Right, but apparently not always

 

[one-eyed_jim]

I'm confused

You're not the only one.

The axle's clearly 107mm though, so you've got good grounds to return it based on the eBay misdescription.

Could it be one of those italian threads ones adjusted for english shells? Different cups etc

The BSC and ITA versions differ only in the cups: remove the Italian cups and replace them with BSC, and you've got a BSC bottom bracket. The mystery is how you managed to get that bottom bracket into a frame backwards, and out again, without destroying the threads on both sides, and why it wouldn't go in the right way round in the first place.

Still, I like a good mystery.

From your larger picture, it's pretty clear that the two threads are as they should be for a standard BSC bottom bracket: a left hand thread on the flanged (fixed, right hand side or drive side) cup - tightened anticlockwise, and a right hand thread on the flangeless (mobile, left hand side or non-drive side) cup - tightened clockwise.

Do you have a picture of the BB fitted to a frame? Is the flanged cup fixed to the cartridge as you'd expect it to be, or is it loose? What markings are on the face of the flanged cup?

 

[Harryburgundy]

What's written on the Fixed Cup (aka drive side or err the 'R'* side)


*also known as Right, but apparently not always

I'll check and report back

 

[Xesh]

I assume Italian sized would be able to go in back to front though.

No, it won't, as the diameter of the Italian thread is larger than a BSC thread. Also both threads are right-handed (like the non-driveside of a BSC BB).

 

[andrewl]

Off topic, I have a Pace frame which has the BB cups the wrong way round...

 

[legrandefromage]

I only know weird stuff as I had/ have somewhere an UN51/2 that is set up the same.