What is BB drop on a bike?

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BB Drop is the vertical distance between the centre of the bottom bracket, and the axles of the front and rear wheels. This is a fixed, static measurement. Once a bike is built up and has no rider on it, this doesn’t change.

How do you calculate BB drop?

Subtract the distance from the floor of the BB center from the distance to the wheel axle center. You could so a simple measure to confirm your calculations. Subtract the distance from the floor of the BB center from the distance to the wheel axle center. You could so a simple measure to confirm your calculations.

How does BB drop affect ride?

Additional BB drop often results in a more planted and confident ride character where the rider has the sensation that they are sitting down in the frame rather than riding on top of it. A BB that’s slung low between the axles often feels better than a higher one when pushing through turns and over messy earth.

What is BB rise?

Usually the + / – refers to whether the bottom bracket is above or below axle level. This is also known as bb rise or bb drop.

How do you calculate BB drop from BB to height?

The BB drop is the distance between the center of the BB and a straight line drawn between wheel axles. To convert to BB height, subtract the BB drop from the height of your wheel axle with a tire mounted.

What is a good BB height?

With 170 mm cranks, a 10 ½ inch bottom bracket height is a good starting point. Road racing will require a slightly higher bottom bracket due to the need to pedal through some turns. 10 ¾ inch bottom bracket height is a good starting point if you are using 170 mm cranks.

How does bottom bracket height affect handling?

The higher the bottom-bracket height, the higher the centre of mass of the rider, and so the more the bike tends to pitch when faced with bumps, hard braking or steep gradients. In this sense, a lower bottom bracket improves stability in much the same way as a longer wheelbase.

Why is bottom bracket so important?

The bottom bracket is a critical component to every drive train. Connecting the left and right cranks, this is one of those important elements on the bike that directly effects power transfer between the rider’s legs and the bike’s drivetrain.

How does bottom bracket drop affect handling?

It not only establishes how stable the bike is, but it also determines how far a rider can lean into a turn while pedaling without scraping a pedal on the ground. More bottom bracket drop means a bicycle is more stable. Less BB drop means a bike is more maneuverable—but also less stable.

What is bottom bracket offset?

BB offset, could be referring to “drop” which is the distance the BB sits below the wheel centres. A larger drop means a lower BB (generally), though on trials bikes, it’s the other way round as they like to (now) sit above wheel centre.

What does a low bottom bracket do?

A low BB drops the centre of gravity of the rider a little bit and helps with cornering.

What does the 90 in BB90 refer to?

BB90 and BB95 The numbers 90 and 95 refer to nominal shell width. This unique bottom bracket shell is not a straight bore but has an internal bearing retainer built into the shell, similar to an integrated headset. Bearing outside diameters are 37mm. BB90 shell and bearing with spindle and bearing removed.

Definition BB Drop is the vertical distance between the centre of the bottom bracket, and the axles of the front and rear wheels. This is a fixed, static measurement. Once a bike is built up and has no rider on it, this doesn’t change.

What is BB drop and BB height?

BB Height is the vertical distance from the ground to the centre of the bottom bracket. This can vary on a bike for numerous reasons. Tyres and fork lengths are the biggest culprits for adjusting the BB Height of a bike. Other Factors to Consider… Typically, bigger wheels will have a bigger BB Drop.

What is BB height on a bike?

How different is bicycle geometry for each bike size?

It’s important to note that bicycle geometry is different for each bike size, given our varying heights offer different body proportions. At the bottom of each geometry feature, I have incorporated a comparison between a road, cyclocross and touring bike with 57cm top tube length.