Questioning Bottom Bracket installation
11-17-13 | 02:08 PM
#1
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Joined: Oct 2013
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From: Black Mountain, NC
Bikes: Jack Kane Custom
Questioning Bottom Bracket installation
Hello everyone,
I am building my first road bike and want to be sure I have the bottom bracket installed correctly... I am installing a dura-ace BB-7700 onto a older Jack Kane custom road frame I purchased. I believe I followed the instructions correctly - the crank arms move very freely and smoothly, but there is the tiniest bit of play in the bearings (guessing) - like I didn't tighten something correctly along the way.
It also seems like the crank arms, while tightened, do not push up against the seal guards, leaving them somewhat exposed??
Any help would be greatly appreciated.
Thanks,
Mike
I am building my first road bike and want to be sure I have the bottom bracket installed correctly... I am installing a dura-ace BB-7700 onto a older Jack Kane custom road frame I purchased. I believe I followed the instructions correctly - the crank arms move very freely and smoothly, but there is the tiniest bit of play in the bearings (guessing) - like I didn't tighten something correctly along the way.
It also seems like the crank arms, while tightened, do not push up against the seal guards, leaving them somewhat exposed??
Any help would be greatly appreciated.
Thanks,
Mike
11-17-13 | 02:15 PM
#2
Senior Member
Joined: Apr 2009
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
This is a cartridge bottom bracket, probably with radial bearings. There is no adjustment for bearing play or preload, so what you see is what you get, but some axial play is common and acceptable with radial bearings.
If the lockrings are properly tightened, you've installed it correctly.
If the lockrings are properly tightened, you've installed it correctly.
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FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
11-17-13 | 02:37 PM
#3
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Joined: Aug 2005
Posts: 33,657
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From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
This is a cartridge bottom bracket, probably with radial bearings. There is no adjustment for bearing play or preload, so what you see is what you get, but some axial play is common and acceptable with radial bearings.
If the lockrings are properly tightened, you've installed it correctly.
If the lockrings are properly tightened, you've installed it correctly.
https://techdocs.shimano.com/media/te...9830646804.pdf
11-17-13 | 02:46 PM
#4
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Joined: Apr 2009
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
I don't think this is accurate. The Dura Ace version of the Octalink bottom bracket is indeed adjustable and can be relubed and maintained, unlike the Ultegra (BB-6500) and 105(BB-5500) versions. A search on the Shimano Tech Document site for "BB-7700" turned up a .pdf of a Shimano tech document that describes both the installation and adjustment:
https://techdocs.shimano.com/media/te...9830646804.pdf
https://techdocs.shimano.com/media/te...9830646804.pdf
Unlike other cartridge BB, this one uses separate needle radial and ball thrust bearings. It allows adjustment for axial play by finding the bottom then backing off slightly. However, like other cartridges, there's no adjustment for radial baring wear.
The OP should follow the instructions and find the happiest medium between friction and play.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
11-18-13 | 11:56 AM
#7
Senior Member
Joined: Apr 2009
Posts: 39,897
Likes: 3,865
From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
While light preload won't hurt, it isn't necessary for this BB. The radial needle bearings are preloaded already and aren't adjustable. The ball thrust bearing will work fine without preload. The OP needs to follow Shimano's instructions and adjust for free rolling with as close to zero play as possible.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 11-18-13 at 11:59 AM.
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