What is bottom bracket drop?

The bottom bracket drop represents the vertical distance between the centre of the bottom bracket and an imaginary horizontal line between the front and rear dropouts. The lower the bottom bracket drop, typically the better the handling, as the rider's centre of gravity is lowered.

Why is bottom bracket drop important?

The BB drop is often what riders look at to get an idea of how “in” versus “on” a bike they might feel. 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.

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.

What is bracket drop?

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).

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 fork rake?

Simply put, fork offset, or fork rake, is the distance between the front axle and the steering axis – the imaginary line running straight through the midpoint of the steerer tube. Fork offset is linked to another important measurement: trail.

Is stack or reach more important?

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.

When should I replace bottom bracket?

To check if your BB needs replacing, drop the chain off of the smallest chainring and spin the cranks. If there's a side-to-side wobble, or feeling of grittiness, it's time for a new one.

How do you measure a bottom bracket?

Calculate the length of the bracket from spindle to spindle.

Close the jaws so that they're flush with each exterior edge on your pegs. Write this measurement down after the width. This is the overall length of your bottom bracket.

What is bottom bracket rise?

BMX bikes have bottom bracket rise, that is, the bottom bracket sits higher than the axles. Between the short wheelbase and the high BB BMX bikes feature the quickest handling of any bike being raced.

Does 1 degree head angle make a difference?

TBH 1 degree dont make a difference. It feels the same, unless you change your stem and handlebar and then your bike will feel a bit more of a difference.

What is fork offset?

Fork offset is the distance between the front axle and the steering axis of the fork. The diagram above shows how the front axle is offset so it is forward of the steering axis. This offset is measured in millimeters. Its purpose is to adjust the amount of 'trail' in the steering geometry.

What is a slack bike?

Head Tube Length & Angle

A “slack” angle is anywhere from 63 to 66 degrees. This means the fork of the bike is going to stick out farther, creating a more stable ride at high speeds, but also be slower handling.

How do I calculate my bike reach?

Reach measurement. First measure distance of the head tube top middle from a wall behind (or in front) of the bicycle, then the bottom bracket distance from the same wall. Subtract larger from the smaller measurement and that gives the reach.

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.

How do I increase the reach on my mountain bike?

A bike's reach is determined by the frame and you cannot change it. However, you can artificially increase the reach by purchasing wider or longer handlebars. This will force you to sit further forward while you bike, which is effectively the same thing as buying a bike with a longer reach.

How do I know what size crankset to buy?

Crank length is measured from the centre of the bottom bracket axle to the centre of the pedal axle. If you're not sure what length the cranks on your bike are, the quickest way of finding out is typically to just look at the backside of your cranks, just below the pedal axle.

How does a bottom bracket work?

The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks.

What is a 68 73 bottom bracket?

The 68mm and 73mm dimension measure the width of the bottom bracket on the frame of the bike with no BB installed, simply the width of the shell. Most road bikes that use a threaded bottom bracket measure 68mm wide and most cross country/trail mountain bikes measure 73mm.

How much does it cost to replace bottom bracket?

A new bottom bracket can vary wildly in cost, from $15 all the way up to $250(£10-£180), so it largely depends on how much you are willing to pay.

Why does my bike creak when I pedal hard?

The most common cause of creaking is the crank being loose on the spindle. Remove the crank bolts, lubricate the threads and under the bolt head, and reinstall. Tighten the bolts to the manufacturer recommended torque. Use a torque wrench if possible.

How many miles does a bottom bracket last?

As for a bottom bracket, on the low end, maybe 5000 miles. The basic Shimano one most people use (UN51/55/similar) can reasonably expect 10k+ miles. But sometimes you get unlucky and get a bottom bracket that lasts maybe 500 miles.

What is bike frame reach?

The reach of a bike is the horizontal distance measured from a vertical line up through the centre of the bottom bracket to a vertical line through the centre of the headtube, and translates to the position of your hands on the handlebar and how 'stretched' you are on the bike.

What is aggressive stack and reach?

Your position on the bike is determined primarily by the stack and reach measurements. A higher stack and shorter reach will result in a more relaxed upright position. A shorter stack and longer reach will place you in a lower, more aggressive position.

What does bike reach mean?

Reach is the horizontal distance from the centre of the bottom bracket to the middle of the head tube.