What is bottom bracket height?

Bottom Bracket Height is a measurement taken vertically from the ground up to the center of the bottom bracket. This measurement will vary depending on the tire used on the bike.

What does bottom bracket height mean?

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.

What's a good bottom bracket 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.

What is 68mm bottom bracket?

The width of a BB30 bottom bracket is 68mm or 73mm. On road bikes, it's always 68mm. With mountain bikes, 68mm is most common too, but sometimes the wider version with 73mm width can be found. The diameter of the bottom bracket is 41.96mm, and the bottom bracket bearings are always pressed into the frame separately.

Can I use a 68mm bottom bracket in a 73mm shell?

You could install it, but it will shift your chainline, shift the centerline of your feet, clearance issues might arise on the non-drive side, and you might be leaving some BB shell threads exposed on the non-drive side as well.

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.

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 stack height on a bike?

Stack is the vertical height between the bottom bracket centre and the top of the centre of the head tube. Reach is the horizontal distance between the same points.

How do you measure a bottom bracket on a bike?

To find out the size of bottom bracket needed, measure the inside of the bottom bracket shell in your frame, it will be 73mm, 70mm or 68mm. Some older frames may have Italian threaded bottom brackets, instead of the more modern English.

What does BB mean on bikes?

The bottom bracket is a bicycle component used to connect a bicycle's crankset to its frame, allowing it to rotate independently of the frame itself.

How does stack height affect bike handling?

The height of your handlebars affects the way a bike rides. If the stack is low it keeps your weight over the front, if its higher it means you sit up more and your weight shifts backwards.

Why is stack height important?

Generally speaking, lower stack heights deliver more feel for the ground and higher stack height shoes deliver more feel for the cushioning materials of the shoe.

How do I determine my stack and reach?

This is pretty easy. Just get your bike upright, on a level surface. Measure the ground to the top of the headtube, then measure the ground to BB center. Subtract the BB height from the HT height and that is your stack.

What's more important reach or stack?

reach is more important, because you will have to compromise less on stem length to dial in fit, but if your goal is less spacers for your current fit, then you'll want to maximize stack.

How do you calculate BB drop?

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.

Is a 67 degree head angle slack?

That's a slack head angle. 65-ish is for Dh race bikes. 67-ish is 'normal'. 70-ish is a road bike*.

How can I tell what size bike I have?

Look for a size label on the bottom of the seat tube first.

1. Keep in mind that the frame size may be listed in either inches or centimeters.
2. Common bike sizes range from 48 cm–62 cm. Bikes at the lower end of that size range are meant for shorter individuals, while taller people will need bikes sized 56 cm and up.

What is bottom bracket drop?

The vertical distance from an imaginary line intersecting the axles of each wheel down to the center of the bottom bracket. When comparing bikes with the same wheel diameter, a smaller bottom bracket drop will result in a higher Bottom Bracket Height (measured from the ground).

Does stem length affect bike handling?

Stem length is one of a number of factors, along with head tube angle and fork rake, that affects a bike's handling. Generally speaking, a shorter stem will result in faster handling, while a longer stem will result in slower, more predictable handling.

Are all bottom bracket shells the same diameter?

Generally, your replacement cranks may have the same or smaller spindle diameter, and the same or longer spindle length than the system your bottom bracket is designed around. For example, a BB30/PF30 bottom bracket has the narrowest shell width of any of the standards, whilst being designed for large 30mm spindles.

What does a higher stack do?

For a given reach, a greater stack puts you into a more upright riding position; your hands will be moved upwards and your body position will rise more towards the vertical.

Does lowering stack height increase reach?

If you have a 73deg HTA and a 120mm/-6deg stem, dropping 25mm in spacers would increase your reach by 8mm and decrease your stack by 24mm. Even a 110mm stem would decrease your reach when you would likely need more reach since your back angle would be lower.

What does stack height mean?

Stack height refers to the total amount of shoe material between your foot and the ground. It's typically expressed in two figures, the first referring to stack height in the heel, the second to stack height in the forefoot.

How does stem height affect handling?

A longer stem tends to slow down handling a bit, shorter stems the opposite (think about the stem as a radius going through an arc -- a longer stem swoops a larger arc for the same angle). This has a small effect for much riding, where bike lean does most of the steering.