Bottom bracket removal (Result!)

[peetee]

I wouldn’t leave that cup in place. I believe the sleeved section inside the loose cup has varied from bracket to bracket over the years .....

How do you come to that conclusion.

Because I had a large tub of spares and there were differing LH sleeves in there.

[slowster]

the price on Amazon has shot up to £19.

No need to pay that much, unless you have an excessive fondness for Amazon

I was not sufficiently clear. I paid £5.48 for mine incl. postage from an Amazon seller last year, hence my surprise at the price increase to £19.

[slowster]

I wouldn’t leave that cup in place. I believe the sleeved section inside the loose cup has varied from bracket to bracket over the years .....

How do you come to that conclusion.

Because I had a large tub of spares and there were differing LH sleeves in there.

Brucey reported the same in a past thread (as well as noting more recently that Shimano appeared to have fixed the inconsistent fit). Simlarly from the 2015 page of the blog on the Dutch language version of m-gineering's website (courtesy of Google translate):

I had been amazed before about bikes with a rattling left cup and how that is possible, but after measuring a whole stock of bottom brackets I believe it is Shimano's fault. Shimano has several factories, and the UN55 bottom brackets come either from Indonesia or Singapore. In Indonesia they make the left bottom fit of the bottom bracket 31mm in diameter, in Singapore they finish the cartridge at 30.50mm. However, the enclosed left cup has an inner diameter of 31mm in both cases!

[Brucey]

….The TL-UN54 goes into a UN55 cup....

shouldn't that be TL-UN74?



Not sure what the 'S' suffix means....? Yet another variant?

cheers

[slowster]

shouldn't that be TL-UN74?

I wondered why "Shimano TL-UN54" was not throwing up many results when I tried googling today to check the price.

[rogerzilla]

I have an unused UN55 where the LH cup is a surprisingly slack fit.

[fastpedaller]

No need to remove the RH side fully - just undo it a turn or 2 to relieve any possibility of pressure, which will also enable the use of pedro or similar to help remove the left cup.

[De Sisti]

Remarkedly, the Pedros tool that I ordered yesterday arrived this afternoon (I didn't pay for next day service).
I managed to remove the bottom bracket. However, I had to do it from the drive-side, as the Park tool kept
on slipping and rounding off the grooves. Will have a think about how to remove the non-drive side cup.
Bottom bracket felt very notchy, so will be replaced in due course.

[531colin]

Flat piece of steel just too wide to fit inside the cup.
File or hacksaw 2 notches opposite each other on the inside of the cup.
Use flat bit of metal like a screwdriver.

[531colin]

Alternative....2 really big washers, one each side of the cup, bolt/nut through the middle and screw it out with the bolt/nut

EDIT picture of fixed cup removed like this....https://www.genkin.name/wordpress/wp-content/uploads/2016/03/IMG_20160317_232735-825x510.jpg

[Brucey]

aluminium cup? Possibly it is corroded in place (Ti frame...?).

Two near-radial saw cuts in the cup about 1/2" apart, then chisel out the section between. If the cuts are made carefully you can avoid scarring the inside of the BB shell, leaving a just a sliver of aluminium cup for the chiselling to overcome.

cheers

[531colin]

Or do you know anybody old enough to own one of these..https://www.bing.com/images/search?view=detailV2&ccid=K3c3XhZX&id=069AE8BF4906005B9ABD16BD51499831BEDAA362&thid=OIP.K3c3XhZXUk5Nf63hUxekZQHaE7&mediaurl=https%3a%2f%2fcdn10.bigcommerce.com%2fs-1rmgckn%2fproducts%2f5741%2fimages%2f65893%2fvintage_bicycle_frame_building_tools_campagnolo_var_park_13696__75360.1499299344.1280.1280.JPG%3fc%3d2&exph=853&expw=1280&q=var+fixed+cup+removal+tool&simid=608005964430117060&ck=452345ED1424F7FD0A994FABEF56D31E&selectedIndex=0&FORM=IRPRST&ajaxhist=0
Fixed cup remover for loose ball BBs....even then, might require some bodging to get a pair of fittings to clamp up one each side of the cup.

[531colin]

aluminium cup? Possibly it is corroded in place (Ti frame...?).

Two near-radial saw cuts in the cup about 1/2" apart, then chisel out the section between. If the cuts are made carefully you can avoid scarring the inside of the BB shell, leaving a just a sliver of aluminium cup for the chiselling to overcome.

cheers

Just for information, not disagreeing....do ali cups corrode in often in Ti ? Is it worth warming it up to dry out oxide(?) and run in penetrant?

[Brucey]

I think that when Al and TI are in contact, and there is some suitable electrolyte present, corrosion can attack the aluminium part.

It is certainly worth trying all kinds of things to shift the cup, but in this case the cup seems to have lost its splines completely, so some form of destructive removal seems appropriate.

Alternate hot-cold cycles will often work on parts like this; the differential CTE (CTE of Ti is about half that of Al) ensures that the Aluminium 'heaves' against the TI when hot, and may yield in compression. If so this (plus any beneficial drying out of oxide) will help the parts to be less well bonded when they are cool again.

If you can get an aluminium BB cup to ~200C (eg using a hot air gun) it will try and heave by almost 0.1mm. If you can get the aluminium to ~250C it will be much softer than at room temperature and will almost certainly yield.

cheers

[slowster]

Flat piece of steel just too wide to fit inside the cup.
File or hacksaw 2 notches opposite each other on the inside of the cup.
Use flat bit of metal like a screwdriver.

An alternative to the flat bit of metal might be to use two long handle flat blade screwdrivers. Inserted into the notches at 180 degrees, such that the shafts are crossed and braced against each other. They would effectively provide two handles similar to the Cyclus tool handles.

Bottom bracket felt very notchy, so will be replaced in due course.

I take it you are aware that Shimano has discontinued the UN55 and UN26 bottom brackets? If not and you intend to replace it with another UN55, note that only a few retailers still have stock, and not of all sizes.

Incidentally, I note you refer to a Park Tool extractor, which I presume you have also just purchased. It would be interesting to hear later your assessment of how the the two tools compare, e.g. when inserted into an undamaged LH UN55 cup is the engagement and fit of the FWE tool noticeably worse than the Park Tool one?