Bottom brackets with long tapers

For discussions about bikes and equipment.
Post Reply
NickJP
Posts: 797
Joined: 24 Sep 2018, 7:11pm
Location: Canberra, OZ

Bottom brackets with long tapers

Post by NickJP »

I have a pair of Middleburn RS7 cranks - square taper, never fitted - and several Shimano UN5x/UN7x bottom brackets of (I think) the correct length for the chainline I want. However, all the bottom brackets have a collar at the bottom of the drive side taper - see attached image - and when I fit the cranks on the tapers by hand, without any tightening down of the bolt, there is only about 1mm between the crank and this collar. The crank is going to bottom out on this collar before it is secure on the taper.

So a) can this collar be removed - will it just prise off?, or b) what brand of square taper BB is suitable for use with these Middleburn cranks?
PXL_20210918_055139378.jpg
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Bottom brackets with long tapers

Post by mattsccm »

I had one of those. Mine was plastic and I chucked it away. Can't see any problem with mine.
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Bottom brackets with long tapers

Post by 531colin »

NickJP wrote: 18 Sep 2021, 7:17am ........So a) can this collar be removed - will it just prise off?, ..........
Yes
rjb
Posts: 7200
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Bottom brackets with long tapers

Post by rjb »

As Colin says. I prised mine off a shimano un26 using a pair of large screwdrivers. I was a bit concerned at the force i had to use which loads up the bearings whilst i did it. Bearings still felt smooth afterwards so i hope ive not indented them. The collar stopped me using my original shimano splined bottom bracket installation tool. :(
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
Post Reply