Shimano BB-UN300 68mm Shell Square Taper Bottom Bracket - English Thread

Customer Reviews (4)
5 / 5| Write your review
£23.99
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£23.99 Please note this product has selling restrictions to your country. was
Manufacturer : 
SJS Cycles part number : 
Manufacturer part number : 
Details
- 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
- 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
Product Reviews (4)
Questions & Answers (9) Q & A
Specification
Downloads
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Product Reviews (4)
Overall Product Rating 5 / 5
Excellent service and product
By Martyn Wilson
05 Oct 2021
5 / 5
I recommend this product
ConsNone
ProsQuality
SJS went the extra mile in their advice. The bottom bracket is high quality and good value at the price. Recommended
Top quality
By Martin chant
25 Sep 2021
5 / 5
I recommend this product
ConsNon yet
ProsQuality and price
Recommend as an alternative for a Gates belt drive, time will tell but quality is super and price is good.
Biggest problem for BB on belt drive is the belt tension.
There is an app to get tension correct
A good replacement
By Giles Phillips
16 Jun 2021
5 / 5
I recommend this product
Consnone yet!
Proswell made and finished
Fitted this bearing set as a replacement for a BB-UN71 which had started clunking. Very nicely made and finished, and fitted in the hole with no issues. Only covered 20 odd miles so far but the clunk has stopped, so winning so far.
A good replacement
By Giles Phillips
16 Jun 2021
5 / 5
I recommend this product
Consnone yet!
Proswell made and finished
Fitted this bearing set as a replacement for a BB-UN71 which had started clunking. Very nicely made and finished, and fitted in the hole with no issues. Only covered 20 odd miles so far but the clunk has stopped, so winning so far.
Questions & Answers (9)
I have a thorn sherpa 5 years old, will the 68mm shell fit?
By
07 Dec 2021
Thank you for your enquiry, yes 68mm will be fine

WD 07/12/21
Bolts required for vintage chainset
By
28 May 2021
I am looking to replace the traditional cup and cone bottom bracket with a sealed unit to cut down on maintenance. the Chainset is a 1984 shimano golden arrow. Can you confirm if this BB would be a suitable replacement and recommend some options for compatible crank bolts?

Thanks,
Rob.
BB is very likely to suit if the cranks are JIS taper- being Shimano this will certainly be the case! Crank bolts wise- SJS part 37320 is the best bet.

JK 28.05.21
Could this replace a BB-UN71?
By
10 May 2021
I'm rebuilding a '92/3 Marin and have extracted a BB-UN71 bottom bracket with 122.5mm spindle. Would this be a suitable replacement regarding fit and durability?
Thanks
Giles
Thank you for your enquiry, yes will be fine

WD 11/05/21
Can you tell me what's the difference?
By
04 Apr 2021
between this and the the Shimano UN55 68mm?
Thanks, Greg
Thank you for your enquiry, Shimano have discontinued the UN26 and UN55 and they have been superseded by this part

WD 06/04/21
Is this ISO or JIS?
By
17 Mar 2021
Thank you for your enquiry, it is JIS

WD 17/03/21
Thread length on this BB in reality
By
03 Feb 2021
Hello, are there really 13 threads on the RHS cup as per your picture please? What is the depth in mm from underside of the lip?
I have a UN300 in front of me with 9 threads/ 12mm max of threads from the lip underside.
I need just that few more threads due to a partially semi-stripped BB for peace of mind.
Thanks
Thank you for your enquiry, from base of lip to bottom of thread is 12mm.

WD 03/02/2021
Will this fit with FSA triple chainset.
By
25 Oct 2020
Hello, can you please tell me if this is the right length to mount a FSA triple chainset to an old (1980s) raleigh bike that I am rebuilding. The width is 68 mm but I'm not sure of the length.
Thank you.
Hello, I'm afraid without knowing the existing length we cannot assist. The BB to crank arm fitting is correct but you need to ensure the BB shell threading, width and length are known in order to purchase a 1:1 replacement unit.

Thanks,

JK 26.10.20
Plastic / Metal Ring On Axle
By
24 Sep 2020
Hi guys, just wondering if you knew what the ring on the axle is for?

And if so is it removable?
The ring is a limiter, it is no removable.

Thanks
Bracket bolts
By
30 Jul 2020
I was wanting to purchase the Shimano BB UN55 68 - 122.5 to replace my old bottom bracket but it is not in stock so I was advised that this bottom bracket is an alternative. Do I also need now to purchase different bracket bolts to fit this different model bottom bracket when purchasing it?
You can reuse the original bolts.

Thanks - 04/08/20