Author Topic: High Bottom Brackets  (Read 441 times)

Offline Rufus

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High Bottom Brackets
« on: April 08, 2020, 10:45:14 AM »
What does a high bottom bracket do?

What tricks does it help with?
It seems to be a frame feature that was never much considered in the past.
Anyone with experience on this?
 

Offline 89schwinnsting

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Re: High Bottom Brackets
« Reply #1 on: April 08, 2020, 02:57:59 PM »
Actually, during the mid school era, elevated chainstays were actually a thing. Look at the Morales flatland frame. It had a high bottom bracket, as did quite a few other frames. It would also allow you to run larger cranks or sprockets, depending on the rear end length. Nowadays, it's not an issue, as most riders run between 150 to 170mm cranks and small sprockets.

Offline Rufus

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Re: High Bottom Brackets
« Reply #2 on: April 08, 2020, 03:53:58 PM »
I was wondering if someone found it useful for their riding, as having a certain efect in handling, like head angles. The point is that it wasnt mentioned in frame specs until a few years ago. Now it seems to be something important, but I'm not sure why.
Does it have an effect on certain pedal tricks, like nose wheelies?
At the end, you can do tricks on anything if you are determined enough, but it's always good to hear opinions.

Offline mal

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Re: High Bottom Brackets
« Reply #3 on: April 08, 2020, 09:04:33 PM »
I was wondering if someone found it useful for their riding, as having a certain efect in handling, like head angles. The point is that it wasnt mentioned in frame specs until a few years ago. Now it seems to be something important, but I'm not sure why.
Does it have an effect on certain pedal tricks, like nose wheelies?
At the end, you can do tricks on anything if you are determined enough, but it's always good to hear opinions.
More clearance for upside down tricks or tricks that the bike is on a 90 degree angle.But if the bb is elevated it rises your standing height too,that may or may not feel weird.

Offline rideflat43

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Re: High Bottom Brackets
« Reply #4 on: April 09, 2020, 01:49:56 AM »

NOT only upside tricks but room overall in pivoting and not bumping into
your cranks and bottom brackets and I sorta of like that idea and Precision
Products did the same thing with one of their frames and others did too.This
was not only a practice for the bottom bracket and back end of the frames..but
also the down tube was position higher also or banked or curved to give more
clearance in the front end of the frame or both actually..what I remember in
several of the frames.


My Motel Works frame has those features and I like them...makes it easier for
scuffing and also pivoting moves!

Offline mal

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Re: High Bottom Brackets
« Reply #5 on: April 09, 2020, 10:10:35 AM »
yes,true,it elevates the downtube too

Offline DaddyCool

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Re: High Bottom Brackets
« Reply #6 on: April 09, 2020, 09:24:26 PM »
I never used a frame with a really high BB. I thought about it when I designed my custom frame. As I am not doing pedal five or nose wheelie, the issue with the higher centre of balance on those tricks was not relevant for me. But I realised that when you have a standover height of about 7" or less, the pedal gets in the way with your foot when you land a decade for example and pedal with the other foot. So you push your foot from the frame with the moving pedal. At least unless you use super short crank arms...
In the end I placed it 45 mm above the axle line which is slightly higher than on my older frames. I like it...

Offline Rufus

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Re: High Bottom Brackets
« Reply #7 on: April 11, 2020, 11:16:06 AM »
Thank you for all the replies. My main interest is how it could possibly affect front wheel pedal rolling tricks, which I have been practicing heavily, but all insights are useful.
By the way, I have been riding since 1985, with a 10-year hiatus in the 2000s. Love this forum.

Offline DaddyCool

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Re: High Bottom Brackets
« Reply #8 on: April 12, 2020, 12:01:51 AM »
Hm, as I said I cannot do these tricks, but I can imagine that the higher centre of mass will make it more difficult. Just a thought...

Offline Rufus

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Re: High Bottom Brackets
« Reply #9 on: April 12, 2020, 11:16:00 AM »
I'm not sure either. It seems to me that being higher makes it easier to lift the rear wheel, but I'm not sure it helps in keeping the balance once you reach a gliding position. Itīs all about staying there without killing yourself in the process.
« Last Edit: April 12, 2020, 11:17:52 AM by Rufus »

Offline rideflat43

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Re: High Bottom Brackets
« Reply #10 on: May 05, 2020, 08:19:48 AM »

For lifting the back wheel.it is minor and like I said scuffing and pivoting
room is the main real good reason for higher bottom bracket!