How are BMX top tubes measured?

How are BMX top tubes measured?

Top-tube length is measured along the centre-line of the top-tube from the centre-line of the seat-tube to the centre-line of the head-tube. This is a useful dimension to know if you are building a frame, since this is the length of tube you need to cut for it. But for comparing one frame to another it is unreliable.

How is top tube length measured?

Top Tube Length

  1. Actual (Center-Center): Measured along the length of the top tube from the center of the seat tube to the center of the head tube.
  2. Effective (HT Top): The length of an “imaginary” level tube extending from the center of the seat tube axis to the top of the head tube.

How tall should you be for a 20 inch BMX bike?

What’s the right BMX bike size for me?

Rider Height Suggested BMX Size
Feet & Inches Centimetres Wheel Size
3’7″ – 4’0″ 110cm – 122cm 16″
4’0″ – 4’10” 122cm – 147cm 18″
4’10” – 6’4″ 147cm – 193cm 20″

What is the length of a BMX?

Bmx bikes come in a bunch of different sizes ranging from 12″ all the way to 26″. The most popular sizes are in the 20″ range. Including 20.25″, 20.5″, 20.75″ and 21″.

How long should my top tube be?


Frame Size 38cm 53cm
Suggested Rider Height 4’11”-5’1″ 5’5″-5’9″
Top-Tube Length, Horizontal 516mm 536mm
Seat-Tube Length, B-B Center to mid top tube 340mm 490mm

Does top tube length matter BMX?

The Top Tube (TT) measurement is the most important measurement when considering a new bike. This is more important than wheel size. Most BMX Bikes with 12” – 18” wheels, and 24” cruisers have relevant TT lengths to their size wheel.

How far should my legs extend on a bike?

Proper position: With your foot at the bottom of the pedal stroke, you should see a slight bend in the leg, reaching about 80-90 percent of full leg extension.

Does seat tube length matter?

These days, seat tube length is still important in some cases: To understand the lowest position of a saddle, especially important when sizing up to a larger frame or considering a bike with a classic, level top tube. To determine the amount a saddle may be lowered when using a dropper seatpost.

Should my feet touch ground on bike?

The height of your saddle is important for the most comfortable position and safe riding style. When you sit on the saddle, both feet should reach the floor and the balls of your feet should be touching the ground.

How important is top tube length?

For decades, top tube length served as a reasonable metric for providing bike size estimates, but it’s an arbitrary metric and always has been. The troublesome part of its continued use isn’t that it’s arbitrary, but rather that with modern bicycles it’s irrelevant and often misleading.

Why does my bum hurt after riding my bike?

A combination of pressure from your bodyweight bearing down on the saddle, friction from the constant pedalling motion, moisture from sweat, an increase in temperature and reduced blood flow can produce a perfect storm for discomfort and the formation of sores.

What size tube for a BMX?

You will start seeing double wall rims, parts based on pro models and sizes will typically run between 20.4”-20.8” top tubes. BMX Bikes $899 + Full 4130 Chromoly frame, fork and bar, some after-market parts and premium quality components. These bikes will normally size from 20.5”-21” top tubes. BMX Bikes $1500 +

What size BMX should I get?

For freestyle/street BMX bikes, you’ll generally want to choose a bike that has a wheel size one size smaller than you would for a traditional kids bike. In other words, if your child would ride a 16 inch bicycle, they’d want a 14 inch BMX bike. Learn More: For kids race BMX bikes, the wheel size is always 20 inches–even for really tiny riders.

What size is a BMX bottom bracket?

This is the most common type of bottom bracket. On a BMX bike, this measurement will typically be either 19 mm or 22 mm. This measurement will be the same on both sides; don’t bother checking the width on each side. The diameter of the bottom bracket itself is irrelevant since some bottom brackets don’t sit flush on the shell.

How big is a full size BMX?

Bmx bikes come in a bunch of different sizes ranging from 12″ all the way to 26″. The most popular sizes are in the 20″ range. Including 20.25″, 20.5″, 20.75″ and 21″. I see kids end up with the wrong size bike all too often and it makes me sad. When you ride the correct size you will be able to progress a lot faster.