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Carbon Fiber Seat Post on Aluminum Frame = grease? BB Ball Bearings = grease?

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Carbon Fiber Seat Post on Aluminum Frame = grease? BB Ball Bearings = grease?

Old 07-19-13, 02:02 PM
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Distinguished
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Carbon Fiber Seat Post on Aluminum Frame = grease? BB Ball Bearings = grease?

http://www.bicyclebluebook.com/searc....aspx?id=20539

The link above lists my carbon fiber wrapped seat post, aluminum frame, and FSA BB30 bottom bracket.

As far as the seat post is concerned, I put a small amount of grease just in case you are supposed to put some on there, but not a generous amount in case you aren't supposed to put any. Should I slather more on, or wipe it down?

As far as the bottom bracket, I'd like to take it apart (out of mechanical curiosity) using this guide:

http://www.bikeradar.com/gear/articl...rackets-29544/

I'm not taking it apart completely for fun though; the spindles sometimes kind of 'jump' a little when I'm riding and I put a lot of pressure on them. I figure taking the BB apart and putting it back together might help with that. Which brings me to my next question: if the bearings in the bottom bracket are sealed, do they need grease at all, or do I just replace them every few X?

Thanks in advance, hopefully I get to do some mechanical exploration today; I'll be using the hammer and woodblock approach.

Last edited by Distinguished; 07-19-13 at 02:40 PM.
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Old 07-19-13, 03:25 PM
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coldwaves
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Originally Posted by Distinguished View Post
http://www.bicyclebluebook.com/searc....aspx?id=20539

The link above lists my carbon fiber wrapped seat post, aluminum frame, and FSA BB30 bottom bracket.

As far as the seat post is concerned, I put a small amount of grease just in case you are supposed to put some on there, but not a generous amount in case you aren't supposed to put any. Should I slather more on, or wipe it down?

As far as the bottom bracket, I'd like to take it apart (out of mechanical curiosity) using this guide:

http://www.bikeradar.com/gear/articl...rackets-29544/

I'm not taking it apart completely for fun though; the spindles sometimes kind of 'jump' a little when I'm riding and I put a lot of pressure on them. I figure taking the BB apart and putting it back together might help with that. Which brings me to my next question: if the bearings in the bottom bracket are sealed, do they need grease at all, or do I just replace them every few X?

Thanks in advance, hopefully I get to do some mechanical exploration today; I'll be using the hammer and woodblock approach.
1. I think you should not use grease in the seat post. For carbon frame and carbon seat post, people usually use the carbon assembly compound. It is essentially a grease with fine particles in it. The purpose is to increase the abrasion coefficient so you don't have to put huge amount of clamping force in the seat post clamp. For metal frame with metal seat post, people put grease on to prevent the material bonding to each other over time. In your case, I think the carbon fiber will not bond to aluminum. So if you torque the seat post clamp according to specification and the seat post does not slip, it will be fine to just put nothing there. If you torque to the spec but the seat post slip, you can try to use carbon assembly compound.

2.You don't need to (and probably cannot) grease the inside of sealed cartridge bearing. But you can put a light layer around the bearing as a water proof measure. Bearing can go bad due to normal tear and wear. You just have to replace them when they are not functioning properly. Hard to say how long a bottom bracket will last but you can just use it until it dies.
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