Shimano BB-UN300 68mm Square Taper Bottom Bracket - English - D-NL Chain Case - 122.5mm

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1 / 5| Write your review
£23.99 Please note this product has selling restrictions to your country. was
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SJS Cycles part number : 
Manufacturer part number : 
- D-NL suits a 47.5mm chain line
- To suit bicycles equipped with chain cases (right hand cup sits out a little further than regular UN300 variants)
- 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
- Better chainline stability with chain line stabilizer
Product Reviews (1)
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Product Reviews (1)
Overall Product Rating 1 / 5
Avoid this product
By Mike McFarlane
11 Jan 2023
1 / 5
ConsShort life, catastrophic fails, poor design
ProsIt fits
Avoid. I've had two of these fail now in less than 18months on a bike that has light use once a week or two. Looking around the web at other reviews I am not the only one. And unlike the old BBs which failed slowly over months these fail catastrophically on a ride leaving you with no option but to push the bike.
I took the most recent failed unit to bits and the reason was immediately clear. There are two bearing in the unit, one a poor quality sealed cartridge bearing on the none drive side, and on the drive side an open cage bearing. An open bearing in a BB! Basically this part of the bike is regularly exposed to water and salt which will quickly wash any grease out causing the bearing to fail quickly.
This is clearly planned in obsolescence meaning a regular supply of these units to landfill, or recycling if people can be bothered. Shimano should be ashamed of this sort of design practise.
Do yourself a favour, avoid this product.
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