Most square taper bottom brackets come in cartridge form. Here are the key points setting the scene for our look into square taper cranksets.
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The post gives you all you need to know about square taper bottom brackets including how to remove and install them in great detail. The Ultimate Guide to Square Taper Bottom Brackets The crankset gets the square taper name from the type of bottom bracket to which the crank is mounted.Ĭheck out our Ultimate Guide to Square Taper Bottom Brackets for more information on these. You should read it and evaluate the argument for yourself. Or rather, you need to select the appropriate crank, which includes the appropriate crank length, for the specific riding context. The general rule has always been that the taller the rider-and the longer the leg-so too the crank should be longer.īut here’s a scientific study that says crank length doesn’t matter. Although depending on who you talk to, 170mm may be “standard”. This one measures 170mm, center-to-center. The second point is the center of the pedal spindle. So the first “center” is the center of the bottom bracket spindle-which is the imaginary point right in the center of the aperture. Yeah, but the expression is so common that I’ll mention “crank arm” here and there. Now, you should be about to protest loudly right now.ĭidn’t I mention above that there is no need to mention “arm” when talking about cranks since a “crank” is a crank-arm by definition? And the arm length is measured from “center” to “center”. The “arm” is what we are talking about here specifically. You can achieve a corresponding increasingly wide variety of gear ratios.
You’ll also need to take the BCD ( Bolt Circle Diameter) into consideration. You’ll also need to take into consideration the rear derailleur cage size-you may need to change the derailleur as well. You’ll need a front derailleur just for that.
Let’s say you are running standard 53/39T chainrings on the front and swap them out for a compact, say 36/30T. The Spider allows you to swap your chainrings to achieve different gear ratios, within reason of course. You’ll usually find the spec printed somewhere on the crank, often on the inside face opposite to this one. 170mm, 172.5mm, and 175mm are the most common. Spiders are limited cranks come in more variations most variety is with chainrings.Ĭrank arms come in specific lengths. the arm, the spider on the drive side, and the chainrings which bolt onto the spider.Ĭrankset is a way to indicate the whole assembly comprised by these components. The same can be said about crankset: the crankset is the crank, ie. That means you don’t need to talk about crank “arm”. It forms an angle with the rest of the shaft which for bikes is the bottom bracket spindle. To be fussy about definitions, the crank is actually the bent part of the shaft. Let’s first of all deal with the issue of crank vs crankset.Ī “crank” is part of a shaft that translates energy directly from the source into the movement of components in a mechanical system. This guide provides everything you need to know about a square taper crankset includingīut, first of all, what is a crank? And why can’t we say “crank arm“? Crank vs Crankset