Some Retrobikes passing through Bikeworkshop in Bristol

If the bb is an inch higher, the centre of mass is (almost) too as the average rider weighs almost 10x the bike.
My most comfortable bikes i ride all the time have low bb, including the TiBride

I know that is how it works but i personally do not believe 1 inch makes any real difference that can be felt. What can be felt is more in the mind like the magical differences some people feel between the same spec tubing from different manufacturers. Comfort can be felt and maybe this is what is being experienced and not a balance thing to do with CofG. That is just my opinion and how it feels to me though.
 
To my thinking, the number that defines frame handling more than bb height, is bb drop.
p50-51~2.webp
BB height can be changed with tire height, as you did by switching to 700, but the distance from axle level to bottom bracket will remain constant.
 
I know that is how it works but i personally do not believe 1 inch makes any real difference that can be felt. What can be felt is more in the mind like the magical differences some people feel between the same spec tubing from different manufacturers. Comfort can be felt and maybe this is what is being experienced and not a balance thing to do with CofG. That is just my opinion and how it feels to me though.
One inch may not immediately be obviously felt, but how about four? Where is the line? I certainly notice the difference in clearance, given similar drivetrains.
 
To my thinking, the number that defines frame handling more than bb height, is bb drop.
View attachment 989281
BB height can be changed with tire height, as you did by switching to 700, but the distance from axle level to bottom bracket will remain constant.
The bb drop has also been reduced by around 10mm as the fork is 20mm longer than the original p2

It's one (or 2) of those things that definitely has a part to play in how much an owner loves his bike
- but the best bike ever is the one you're actually riding😎
 
One inch may not immediately be obviously felt, but how about four? Where is the line? I certainly notice the difference in clearance, given similar drivetrains.

If you could get the BB and the rider down four inches then that would definitely be noticed. Pedal strike might be an issue though!! 😆 . This is where dropper posts have been used effectively, on Occassion, in the pro peloton for crazy downhill madness.

What makes me think the relatively small differences of BB heights between cruterium/road/CX/TT/touring/MTB/gravel bikes is not making any real difference is when you see CX riders stand on the pedals , when the cranks are horizontal, and lift themselves out of the saddle to negotiate some sketchy terraiin. The kind of rutted, lumpy, bumpy downhill that would make me wish i was sitting in the triangle and not above it! .
You see the same thing with pro road riders who when descending will lift there weight off the saddle, when braking, but not just when they are braking in an straight line for a hairpin, for example. Ben Healey is a really good descender and he does it a lot and i noticd some of the women doing it, too, during the womens Tour. It was either that young frenchie who won a couple of stages, or Prevot herself.

It has got me thinking that there might be some kind of sweet spot that makes it all feel amazing and that it might be dictated by body weight ,and where that weight is spread around the body affecting the CofG, the riders height effect on frame size and CofG and also where the rider sits between the wheels which also affects CofG. This fore and aft thing is very important in the world of aeroplanes, for example . It could be that riders and bikes with particular proportions notice small differences in BB height/drop, and riders with different proportions are less affected. I think i am saying that it is a fluid thing and not set in stone that a particular BB height is going to be better than another as there are so many other parameters that can be adjusted, on the fly.
 

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