The goal of this article is to outline SRAM cranks’ level of compatibility with a Shimano groupset.
Definitions
Cranks – a component connected to the pedals and the chainrings that transforms the rider’s reciprocating motion into rotational motion.
Or in simpler words, the cranks (a.k.a. chainset) are the levers through which the rider transmits force to the chainring which in return pulls the bike chain which then spins the cassette and the rear wheel.
Group set – a group of bicycle components including every part involved in braking, shifting, and the drivetrain.
The group =set of a bicycle consists of the following parts:
- Front and rear shifters
- Brakes
- Derailleurs
- Cranks
- Chainring
- Bottom bracket
- Chain
- Cassette or rear cog
- Pedals
Since a group set includes a great number of parts, it’s not possible to give a yes or no answer to the question.
A SRAM crankset will be compatible with some Shimano parts and incompatible with others. Thus, it’s necessary to look into each combination separately.
Bottom Bracket
The bottom bracket is a system of cups, bearings, and a spinning axle to which the cranks connect. If the cranks and the bottom bracket are not compatible, one of the two has to be replaced.
Are SRAM Cranks Compatible With Shimano Bottom Brackets?
SRAM GPX
Modern Shimano bottom brackets operating with external bearings are designed for a thicker spindle (the axle that the cranks rotate) and aren’t compatible with SRAM’s GPX cranksets.
Shimano’s Hollowtech cranks come with a 24mm diameter spindle. However, the spindle of SRAM GXP cranks has a different diameter on both sides – 24mm on the drive side and 22mm on the non-drive side. Consequently, SRAM’s GPX cranks can’t be combined with Shimano bottom brackets by default.
Conclusion: A SRAM GPX crank requires a SRAM GPX bottom bracket and cannot be successfully coupled with a Shimano bottom bracket without tricky modifications.
SRAM DUB Cranks
SRAM DUB cranks have a 29mm axle and are therefore not compatible with Shimano bottom brackets designed for 24mm axles. Thus, SRAM DUB cranks need a SRAM DUB bottom bracket too.
SRAM Square Taper Cranks
Square taper SRAM cranks are compatible with square taper bottom bracketс made by Shimano. Of course, the bottom bracket will have to be as wide as needed by the frame.
One example of such cranks is the S-600 model.
Conclusion: SRAM cranks are compatible with a Shimano bottom bracket only in the case of the square taper mounting system.
Are SRAM Cranks Compatible With a Shimano Chainring?
For a chainring to be compatible with a crankset, both components have to be designed for the same mounting system.
Higher quality chainrings attach to the cranks via bolts.
Two parameters determine the compatibility of the parts:
1. The number of openings for mounting bolts (usually 4 or 5)
2. The distance/spacing between the openings
To make this assessment easier, chainrings and cranks have a specified Bolt Circle Diameter (BCD).
The BCD represents the distance between the centers of two opposing bolts. The BCD is labeled on the cranks and the chainrings in millimeters.
If the cranks and the chainring are designed for the same number of chainring bolts and have a matching BCD, the crankset and the chainring will be compatible regardless of brands.
If you have old components with scratched markings, you can use a caliper to measure the BCD of the units. To learn more about BCD measurement, check out this post.
Note: Cranks designed for multiple chainrings have a BCD consisting of two numbers e.g., 104/64 BCD. The first number (104) indicates the BCD of the middle/big position whereas the second (64) refers to the smallest ring.
Pedals
The pedals are another component that connects to the cranks. In this case, the threads of the pedals and those of the cranks determine the compatibility. Most pedals use a 9/16″ x 20 TPI thread.
9/16″ (14.3mm) is the diameter of the pedal’s threaded part whereas TPI is an acronym for Threads Per Inch and shows the number of threads per 1 inch/2.54cm. In this case, the threads’ density is 20 per inch or 20 per 25.4mm which amounts to 1.27mm between threads.
Consequently, SRAM cranks are compatible with the vast majority of Shimano pedals out there.
Shifters, Brakes, Chain, Pedals, Derailleurs, Cassette
The cranks of a bicycle have no direct effect on a bike’s transmission and braking system. Therefore, there is no reason to “investigate” the compatibility of SRAM cranks with Shimano shifters, brakes, chains, derailleurs, and cassettes.
That said, the cranks can indirectly create incompatibility issues between the aforementioned parts when analyzing things in isolation.
For example, a chainring may be compatible with the crankset but incompatible with the front derailleur or even the frame.
FAQ: What are the advantages of using SRAM cranks with Shimano parts?
The main benefit of combining parts from different brands is recycling and money-saving. Instead of constantly buying new components, the user relies on parts that are already available. Additionally, cross compatibility gives more freedom by allowing cyclists to choose among a greater number of products.
Summary: What You Need To Know
1. The cranks of a bicycle have no direct effect on most components that make up a groupset. Those would be brakes, shifters, derailleurs, chain, and rear cogs.
2. Bike cranks are connected to the bike via a system of bearings known as a bottom bracket. If the bottom bracket is compatible with the frame and the cranks, then those cranks can be mounted to the frame.
Higher-end SRAM cranks demand a SRAM bottom bracket for secure installation and optimal performance. Thus, they aren’t compatible with Shimano bottom brackets.
However, square taper SRAM cranks can be used with any square taper bottom bracket that would fit on the bike, including Shimano models.
3. The cranks of a bike serve as a connection point to the chainring which transmits the force generated by the rider to the chain.
SRAM cranks are compatible with Shimano chainrings when both components are designed for the same mounting system (BCD).
