Dictionary of Ebike Terms and Acronyms

[JRA]

First you have to understand that rim and tire dimensions are set to the International Organization of Standardization, or ISO. Why they call it the ISO instead of the IOS is a mystery to me however. This is so that it makes it easier for rim and manufacturers to coordinate the fitment of their respective products. Although it says International the Euro's have their own organization the European Tire and Rim Technical Organization, or E.T.R.T.O. . Throughout the years there have been numerous rim sizes and tires to match.

• 650B The ISO designation for a rim with a 584mm bead seat diameter, or BSD. The BSD represents the tires inner most edge, or bead diameter
• 24 inch ISO designation for a 547mm BSD rim However a 24" wheel doesn't measure 24"es in diameter until it has a 2" tire mounted on it
• 26 inch ISO designation for a 559mm BSD rim The wheel size that made MTB's famous. Once again needs a 2" tire to measure to 26"
• 27.5 650B rim with a 584 BSD 2.1" tire measures roughly 27.5"es.
• 27.5+ 650B rim with a 2.8 or greater tire mounted that makes it closer to 29"es in diameter Originally designed to retrofit to 29" wheel bikes
• 700c ISO designation for a rim with a 622mm BSD. Popular with track, road and mtb
• 29er 700c rim with a 2.1" tire mounted on it is 29"es in diameter, also is a sailboat racing class
• 28-36cms etc. 700c rim with a 1.75 tire mounted is roughly 28"es in diameter. The term 28"er is well known in Europe as the standard adult bicycle wheel size long before 29"ers became available.

 

[ebikemom]

(Note that the previous sentence is a gross oversimplification).

For those of us without technical backgrounds of any kind, a gross oversimplification is sometimes just the ticket!!!

 

[AHicks]

"Hi . maybe it is covered before but can anyone tell what is mosfet? I check online and most explain it in very technical terms. Can someone explain their functions in simple way"

Generally e-bikers see that term in the details regarding controllers, and more is better, as that number can help determine how much power (amperage) the controller can handle without overheating it's components.

 

[bob armani]

Thanks to JRA and David for clarifying these scientific and mathematical conversions here. With this constantly evolving, looks like one needs to take a coarse in this category alone to have a clear understanding of rim and tire measurements across the board.