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Shimano UN55 68mm Shell English Thread Sealed Cartridge Taper Bottom Bracket

Customer Reviews (7)
4.7 / 5| Write your review
£24.99 Please note this product has selling restrictions to your country. was
Manufacturer : 
SJS Cycles part number : 
Manufacturer part number : 
- A good quality bottom bracket for traditional chainsets
- Super-accurate bearings for smooth operation and improved durability
- Durable, hard-wearing sealed cartridge bottom bracket with square tapered spindle fitting
- Lightweight hollow spindle
- Maintenance-free sealed cartridge bearing assembly keeps out dirt, mud and water for long bearing life
- Fast and easy installation without adjustment
- Narrow body allows clearance for cable routing under the bottom bracket

Requires a Shimano type splined bottom bracket removal tool. (Shimano's own is SJSC part #858)
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Product Reviews (7)
Questions & Answers (10) Q & A
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Product Reviews (7)
Overall Product Rating 4.7 / 5
Very nice, as usual!
By Nelson Silva Coelho
14 Jan 2020
5 / 5
I recommend this product
This BB is very sturdy for the old system. A most have to my old machines.
By Ian of Ldn
11 Jan 2020
4 / 5
I recommend this product
Good value, bomb proof. As far as I can see the difference between this and UN52 bb is the non-drive side fitting is alloy, not plastic. Having used the plastic type I would use this every time
usual excellent service
By Anonymous
25 Jan 2018
5 / 5
I recommend this product
Prosdoes what it says
SJS always carry a comprehensive stock of components that you actually need. other online outlets have a vast range at low prices, but are invariably out of stock ! i have dealt with SJS for years, always well served
By Chris
27 Oct 2016
5 / 5
I recommend this product
As usual, good choice and quick service!
Really Very Good
By Mal
15 Jul 2016
5 / 5
I recommend this product
ProsEasy to fit, works well
Easy to fit and works very smoothly
As Expected From Shimano
By Paul from Derbys
15 Aug 2012
5 / 5
I recommend this product
ConsNeeds special tool.
Prossimple to fit once you have Shimano tool.
Straight forward fit and forget from Shimano.Its what you come to expect really!!
Smooth And Easy
By Richard Bufton
04 Aug 2012
4 / 5
I recommend this product
ConsCheck you order the right axle length
ProsEasy to fit, smooth running, good price
Easy to fit (even for a mechanical incompetent like me).
Smooth and free running on the bike.
Questions & Answers (10)
Using a 68x107 in place of a 68x103?
01 Mar 2020
I have a Whyte Sussex that uses a 68x103 square taper BB. Finding a high quality exact replacement is proving to be problematic.

As I've always previously used UN55's, I was wondering if it would be an issue to go for this 107 in place of my 103?

The current BB is an RPM BB-7420

Many thanks
The chainline will be pushed out and shifting likely affected. Any from this page would work;

Thanks - 03/03/20
09 Dec 2019
I have a Sherpa and looking to get a shimano acera M-361 42/32/22 chainset so would I order the 68-122.5 size thanks
yes 122.5 is correct
Axle sizes
02 Aug 2019
Hi, can you let me know if the axles are the same length on both sides? If so is there a list of dimensions for all sizes available to help me choose the right one?

the axles do differ in length.
Do you have the UN55 73mm version?
01 Aug 2019
My main concern is that I don’t know what spindle length that I need. I’ve got some SuginoRD2 Cranks for a single speed, with a 52mm chain line. I’ve heard that 113mm is right, but I don’t really know. Any ideas?
Yes, it's item # 26973. Sugino say 103mm axle with a 45mm chainline, so 113mm is a pretty good guess for a 52mm chainline. HOWEVER whatever you may read, this is not an exact science, you may just have to suck it and see.
110mm Shimano BB 68mm UN51/52/53 in eccentric hub.
25 Nov 2018
2005 Raven Tour with Rohloff gears has 110mm Shimano BB 68mm UN51/52/53 in eccentric hub. if BB ever needed replacing is this part suitable and should the existing BB be inspected/cleaned or is it truly maintenance free. Thanks.
Yes this is a suitable replacement, these parts are sealed units and require no internal maintenance. It may be good practise to remove completely from the bike and clean with a rag to regrease the threads etc if going through a wet winter. Generally they are fit and forget.

Thanks - 26/11/18
What is the difference in axle length on left side
27 Aug 2018
Looking to space tandem chainset away from frame on left in order to fit extra chainwheel to link kiddy cranks, is there any difference in the left side lengths of bb’s between 123 and the 127 axle length
Hi, the 122.5 is 32mm the 127 is 35mm. Thanks
Can i use this in a brompton? i'm fed up of the plastic cups
22 Aug 2018
Hi there,

Unfortunately you cannot fit this in to a brompton im afraid.

27 Jul 2016
I wanted to swap my octalink for a square taper. Would the spindle length be the same.

As you will be changing your chainset as well there is no guarantee that the new chainset will require the same length of bottom bracket, you will need to check what is the recommended length for your new chainset.

Hi. Does It Come With The Bolts?
09 Sep 2014

Normally these bottom brackets do not come with the bolts I'm afraid.

Replacement For Ta Carmina Bottom Bracket
12 May 2014
The TA BB I have is "finished" and TA replacement BBs are hard to find (and expensive!). The axle length is 119, shell width 68. Reviews say the TA is "JIS taper". Will the 118mm version here be a good replacement? Many thanks.

As long as you don't mind the axle being 1mm shorter (it will probably not even make a noticeable difference) then yes, this is a good reliable replacement.