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Old 02-19-16, 09:01 AM
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TimothyH
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Join Date: Aug 2015
Location: Northwest Georgia
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Bikes: 2018 Rodriguez Custom Fixed Gear, 2017 Niner RLT 9 RDO, 2015 Bianchi Pista, 2002 Fuji Robaix

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Shimano BB-7700 vs BB-7710

There is some misinformation out there regarding Shimano BB-7700 vs BB-7710 bottom brackets and hopefully this post will help someone avoid the confusion I went through. I believe this information is correct but am open to those who are more knowledgeable.

The BB-7700 is listed at many websites as a "sealed cartridge unit." It even says this right on the product. This is somewhat misleading as it is not a "sealed cartridge." Loose bearings are held in place by a plastic holder (cartridge?). The seals could also be called dust covers.



The loose bearing design requires preload adjustment during assembly and more frequent maintenance. Some track racers pack the bearings with light lube for less resistance and some run it without the plastic seals for the same reason. This bottom bracket is 173 grams. Light weight and low resistance but more frequent maintenance makes some feel that this bottom bracket is better suited to indoor racing and/or dry weather.


The BB-7710 uses true sealed cartridge bearings. No preload adjustment is required and there really is nothing to maintain. The 7710 is heavier than the 7700 - 230 to 240 grams - this in spite of the many websites which claim it is 173 grams. Better moisture resistance and easier maintenance make this bottom bracket more suitable for road and wet conditions. The 7710 bears the NJS stamp because Keirin racing is sometimes done in the rain.




-Tim-
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