Author Topic: High Bottom Brackets  (Read 915 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 mal

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Re: High Bottom Brackets
« Reply #4 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 #5 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 #6 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 #7 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 #8 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. It΄s all about staying there without killing yourself in the process.
« Last Edit: April 12, 2020, 11:17:52 AM by Rufus »

Offline sakis

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Re: High Bottom Brackets
« Reply #9 on: July 25, 2020, 08:18:18 PM »
Hello,i usually ride backwheel pedal tricks.I am 168 cm. I ride manuals and lot of pedal gerator rolling tricks-Coasting double foot caboose and coasting rolling pedal backyards and many more. Because of my height i prefer a higher bb around 12.1 for tricks like this that the bike is elevated easier. I had a heresy 19.5 with 12.5” bb height and then a fishbone 19.25 with 12.25” bb and now a heresy ascend x with 11.8” bb. The heresy was the easier for rolling gerators and all my combos when the bike is normal but it was hanging too low when i was doing caboose rolling tricks. The fishbone was ideal for both but i never liked the 74.5 ha so i gave it to a friend. I ride a longer 19.5” frame now and its more stable at rollbacks and backward manuals but more difficult to get it up from the ground. For taller riderds lower bb is better for shorter riders higher bb is better. Regards

Offline Voodoo

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Re: High Bottom Brackets
« Reply #10 on: July 25, 2020, 08:43:34 PM »





My modern flatland frames have high bottom brackets. It makes the bike waaaay more nimble / squirrely.


I have ONE flatland frame with a lower bottom bracket. A St. Martin Class X 2. Feels low when I haven't been on it for a while. Feels slammed on coilovers. Hah. Much lower center of balance. And it kinda' feels like you're crouching. It has a very stable feel to it...but I like squirrely for flat frames.
« Last Edit: July 25, 2020, 08:52:55 PM by Voodoo »
I will buy your spotless frame from you and beat it up.

Offline Mambocowboy

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Re: High Bottom Brackets
« Reply #11 on: July 25, 2020, 10:38:09 PM »
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?
Not sure about flat but with street it's for clearance on grinds...

Offline bikeh11

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Re: High Bottom Brackets
« Reply #12 on: September 15, 2020, 12:02:30 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.


Thank you so much for sharing, since Im new in this sport and I really didn't know if this was important.


 B) :D