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.

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.

How important is bottom bracket height?

Bikes with smaller diameter wheels require less Bottom Bracket Drop to maintain a similar rider position relative to the ground. For this reason, Bottom Bracket Height can be a more useful measure since it takes a bike's wheel size and tire width into consideration.

How do I know what length bottom bracket I need?

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 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.

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 aggressive bike geometry?

Aggressive geometry puts your upper body down lower for aerodynamics and the bikes tend to favor a more twitchy handling traits. Relaxed geometry has you sitting in a more upright position and the bike is setup to feel more stable at speed.

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 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.

What spindle length do I need?

If you have a Mid or a Spanish BB on your BMX Freestyle bike, you need the 5 5/8″ spindle. If you have an American BB on almost any style of frame, you need the 5 5/8″ spindle. If you are using the Outboard BB and the Spline Drive Sprocket, and you BB shell measures 68mm wide, you need the 5 5/8″ Spindle.

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.

What is considered a slack head angle?

The head tube angle is the angle of the head tube in relation to the ground. 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.

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.

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.

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*.

What is reach on a mountain bike?

Reach is the horizontal distance from the center of the head tube to a vertical line that runs through the center of the bottom bracket shell. This measurement represents how a mountain bike fits when you're standing up on the pedals, like when you're descending.

What is a BB30 bottom bracket?

The BB30 bottom bracket allows you to pair 30mm spindle cranks to 42mm inner diameter bottom bracket shells. Cannondale pioneered this standard along with specially-designed cranks and many have found the benefits to them. Road versions have a 68mm width, MTB has 73mm.

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.

What bottom bracket does giant use?

Giant Bicycles has a long collaboration with Shimano. It is no surprise that Giant's frames follow the BB86 and BB92 standard developed by Shimano.

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.

Does bike geometry affect speed?

The short answer is that 'it depends'. Some viewers commented that maybe it just doesn't matter. It absolutely does matter and indeed the geometry of the bike is the most powerful way that we can change the riders experience of the bike.

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.

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.

How do I increase the angle of my head tube?

Flip the bike upside down in the stand. Grease the offset lower cup and sit it on the head tube. The '-' should be at the front if you want a slacker head angle. Use the notches on either side of the cup like a gunsight to line it up centrally with the down tube.

How much does seat tube angle affect reach?

Rule of thumb: a degree change in seat tube angle changes the reach by approximately 1cm. So the difference between the frames will be about 1cm.