BB Stiffness?
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bluebirdbiker posted 2 years ago.
Is it an open bearing set or closed. If open then chances are that the seal on the crew of the BB is/has tightened and compressed it. If sealed, it could be the BB itself. Do you know which BB style it is? Post a pic if you can/want, let's have a look.
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Triguy98 posted 2 years ago.
If the crank is tight, most of the time any flex you perceive will be the frame. The crank/BB interface shouldnt flex enough to be noticable.
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rma posted 2 years ago.
I'll see if I can get a pic of it tonight and post it.
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rma posted 2 years ago.
just got back a little bit ago. Here is a pic of the BB.
http://tinypic.com/view/?pic=nmm5g5
Does that help any?
.jpg "rjkowski's picture")
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1315 days
rjkowski posted 2 years ago.
From the picture it looks like you've got Shimano's Octalink bottom bracket. The newest Shimano design uses outboard bearings which allows for a larger diameter tube to connect the two crank arms. How much stiffer it actually is has been debated. If you go to FSA's website they've actually got an article comparing their ISIS (stands for "International Spline Interface Standard", which is the industries answer to Shimano's proprietary Octalink design) bottom bracket to their MegaEXO (outboard bearing design).
If you do make the switch to an outboard bearing bottom bracket, you'll have to buy new cranks too. I don't know if you would be able to tell the difference between the Octalink and outboard bearing design. I doubt that I would personnaly be able to tell the difference, but I bet a pro rider would.
I guess it comes down to how much you are willing to spend to possibly gain some stiffness. If your bottom bracket is 4 or 5 years old and has a lot of miles on it, it might be time to replace it anyway.
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Triguy98 posted 2 years ago.
But replacing a BB doesnt mean its gonna be any more stiff. I'd take the frame to hop and have em look at it. Make sure there's no hairline cracks in your frame or anything.
The"upgrade" to the external bearing BBs isnt necessary, and you can save a bunch of $$ by just replacing the BB. For reference, I have an Octalink XT BB on my MTB and feel NO flex whatsoever, and my BB is 2 years old.
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rma posted 2 years ago.
yeah the flex isn't that bad (enought to get new BB AND cranks), but I guess i feel it more in my head compared to my old bike. I'm riding a couple mph faster than on my old bike, i think based on weight savings alone,so I think the trade off is worth it, if the frame is a little more giving.
On my "new" bike (2002 Ciocc, got it on Craigslist and love it so far) I am noticing a little bit of flex if I am really hammering. Nothing too bad, but more than my old bike. I did shave off about 4-5 lbs, so I'm not too upset. My question is, would a new bottom bracket stiffen up the bike any? Or is it just a frame thing? I'm not sure what type of BB is currently installed, but the other components are Ultegra, so I am assuming it is along those lines. Any suggestions?