Bottom bracket internal sleeves

Discuss light weight issues concerning road bikes & parts.
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by Stockie

What makes some external bottom brackets run with a plastic 'spacer' between the left and right cups (FSA, GXP, Shimano, Chris King and many others), while others do it without the plastic sleeve (Campy for example). In another topic there was stated that the sleeve just is an extra protection for the bearings for water and stuff that enters in the frame via seat tube and other openings. Are the bearings without a sleeve in the bottom bracket better sealed or is the sleeve just an unnecessary part for all bottom brackets?
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by prendrefeu

Unnecessary; extra weight.

If you ride in the rain often or your frame is prone to internal leakage, they are helpful in that they will protect the inner side of the bearing seals from contamination.

Otherwise unnecessary.
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by thisisatest

if your bike takes on water, make sure you have a drain hole. with a drain hole, the center sleeve is superfluous. without a drain hole (and with a way for water to get in), the center sleeve is worthwhile. without it, bearings can be spinning while essentially submerged. in these cases, though, it's really a need for a drain hole and not for the sleeve...

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by trojancyclist

If you are running or will be running DI 2 then it will keep the wires from rubbing against the crank spindle. At least that is why I put them in.

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by bobbyOCR

It's just an extra layer of protection. Water tends to get everywhere, but pretty much all frames have drainage holes somewhere around the BB region.

I use Shimano Hollowtech II sleeves on all my external BBs since they are paper thin, very light (~10g) and I like it more than pulling cranks off to clean.

Some of them are very, very weighty.
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by BikeAnon

Old thread... I know.

Another benefit to the sleeves. When you go to remove the crank, you are sliding clean shaft through the bearings, as opposed to trying to pull a shaft covered in crap.

Even a fine layer of silt will make removing the crankset more difficult.

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by verbs4us

Like prendrefeu said, sometimes ya need the sleeve:
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by Marin

With the Masi you don't because it's got a drain M!

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by jekyll man


Internal cable routing and oversize rotating axles would suggest otherwise....


Not the first i've seen either :shock:
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by verbs4us

Marin wrote:With the Masi you don't because it's got a drain M!

Ha! Marin, up here in the Great North we got crap for roads that are filled with crap. Before I put the sleeve in, I had to clean and repack the BB 2x/year or it would start to sound like a peppershaker. Once I switched from the OEM bearings-and-cups to a sealed Chorus unit, the sleeve went away--saved 0.07 ounces! I now race like the wind.

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