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Discussion Starter · #1 ·
I am using my first outboard-bearing crankset: a DA 7800 model. Before it was always a Campy BB and crank. I have about 1000 miles on the cranks so far, and last night I took them apart. I noticed that with the chain dis-engaged, there was much more drag on the bearings than on my Campy crank. For example, if I spin the Campy crank, it will probably go around 3-4 times before stopping. The DA crank was about 3/4 of a revolution with a similar push (of course, this is not a scientific method of testing).

When setting preload on the Dura Ace crank, am I doing something wrong? I put the non drive-side arm on, and used the big torx-like preload screw to tighten it up snugly hand-tight, then tighten the 2 retainer 5mm hex bolts to 10N-m.

Is there something wrong with my cranks, or is there just more drag on this system than, say a Chorus BB/crank?
 

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dawgcatching said:
I am using my first outboard-bearing crankset: a DA 7800 model. Before it was always a Campy BB and crank. I have about 1000 miles on the cranks so far, and last night I took them apart. I noticed that with the chain dis-engaged, there was much more drag on the bearings than on my Campy crank. For example, if I spin the Campy crank, it will probably go around 3-4 times before stopping. The DA crank was about 3/4 of a revolution with a similar push (of course, this is not a scientific method of testing).

When setting preload on the Dura Ace crank, am I doing something wrong? I put the non drive-side arm on, and used the big torx-like preload screw to tighten it up snugly hand-tight, then tighten the 2 retainer 5mm hex bolts to 10N-m.

Is there something wrong with my cranks, or is there just more drag on this system than, say a Chorus BB/crank?
Hmm... Interesting. They usually break in.

The performance differences are pretty negligible. Supposedly packing your hubs with sand instead of grease only yeild like a %3 decrease in performance with your bodyweight on the bike. 1 revolution vs 3 revolutions freely spinning in relation to the force your body makes is pretty... negligible.

But still... top dollar for DA crankset- I would expect them to be perfect.
 

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Discussion Starter · #3 ·
Cruzer2424 said:
Hmm... Interesting. They usually break in.

The performance differences are pretty negligible. Supposedly packing your hubs with sand instead of grease only yeild like a %3 decrease in performance with your bodyweight on the bike. 1 revolution vs 3 revolutions freely spinning in relation to the force your body makes is pretty... negligible.

But still... top dollar for DA crankset- I would expect them to be perfect.
I have at least 1500 miles on this set of bearings (a new bike that I built up last fall) and a couple of races, both in wet weather. I wonder what the life expectancy of the DA bearings are? If I have trouble, I could always go the Phil Wood/Campy route.
 

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dawgcatching said:
I have at least 1500 miles on this set of bearings (a new bike that I built up last fall) and a couple of races, both in wet weather. I wonder what the life expectancy of the DA bearings are? If I have trouble, I could always go the Phil Wood/Campy route.
Check your bearings, some grease might have flushed out or become contaminated.



When there's discoloration of the grease just flush it out blow it dry with compressed air and repack the bearings with a good grease. Be careful not to damage the inner lip when removing and replacing the seal. Put some bearing grease on the outside of the seal as well.
 
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