Are square taper bottom brackets interchangeable?

Taper matching was important in the past but all modern day/currently manufactured Chainsets are able to cope with either the ISO or JIS standard taper if they require a square taper bottom bracket, so the products are compatible and work just as well together, just adjust your chainline.

Are all bottom brackets the same size?

There are 4 widths available with BSA bottom brackets; 68mm, 73mm, 83mm or 100mm. For road bikes, a BSA bottom bracket is always 68 mm wide. Other sizes, and particularly the 73 mm width, is commonplace with mountain bikes. The 83 mm and 100 mm dimensions have become rare these days.

Are square taper cranks interchangeable?

Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles. In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.

What is the difference between JIS and ISO square taper?

ISO and JIS are very similar – the angle of the taper is the same, but the ISO spindle ends are a little slimmer. In a pinch, you sometimes can use a JIS spindle with an ISO crank. To compensate for the wider JIS taper, select a spindle that is about 1-2 mm shorter. The taper of your cranks: JIS or ISO.

What is a square taper crank?

Traditional cotterless cranksets use a tapered square spindle (axle) end. The sides of the end taper at a 2 degree angle compared to the centerline, 4 degrees compared to each other. Square, tapered end of cotterless crank spindle with fixing bolt and washer.

Are all BMX bottom brackets the same size?

BMX frames are made in a variety of sizes and shapes and the tubing where the bottom bracket fits is no different. Bottom brackets for BMX bikes come in 19mm, 19mm mid, 22mm, 22mm mid, and 24mm. Basically, this size refers to the size of the spindle that will pass through the bearing and allows the cranks to spin.

How do I choose the right bottom bracket?

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.