TPU inner tubes are gaining attention as the third force in bicycle tires. We summarize its features, advantages and disadvantages of using it on Road bikes and MTBs, and major manufacturers.
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Shimano’s 12-speed for MTB does not have sprockets for HG spline freehubs
When Shimano released the 12-speed for MTB, they changed the sprocket compatibility from the previous HG spline to a new standard called Micro Spline.
Micro Spline is a new shape of freebody with more grooves on the freebody, so HG spline and Micro Spline are not compatible at all.
All 12-speed sprockets for MTB are manufactured to the Micro Spline standard, so as of 2023 there will be no sprockets for HG spline freehubs in Shimano’s MTB 12-speed range.
MTB 12-speed sprockets for HG spline freehubs other than Shimano
On the other hand, third-party parts manufacturers have MTB 12-speed sprockets for HG spline freehubs.
Since they are not officially compatible with Shimano, there is a possibility of malfunction, but we recommend them to those who want to try them at their own risk and with as little upgrade cost as possible.
Sunrace is a manufacturer of drivetrain-related parts such as sprockets and chains.
The lineup includes a number of 12-speed sprockets that are compatible with Shimano’s HG spline free bodies for road and MTB use.
Note that CSRZ is for road use.
In SunRace sprockets, the CSMZ90 WA5 model is also a freebody compatible sprocket for 12-speed HG spline, but note that this one is compatible with SRAM’s 12-speed.
Brand-X, a PB of Wiggle, the world’s largest bicycle shopping site, also has a line of 12-speed sprockets compatible with Shimano’s HG spline freebodies.
There are two lineups here, 11-50T and 11-52T. The 11-50T is “SRAM & Shimano compatible” and the 11-52T is “compatible with SRAM only”.
SRAM has been increasing its presence in the MTB scene since the release of the Ealge 12-speed series for MTB.
Most of SRAM’s Ealge series sprockets use freehubs with the SRAM-specific XD driver standard, but exceptionally, SRAM has a lineup of 12-speed sprockets for HG spline freehubs (Shimano free) called PG-1210 and PG-1230 PG-1210 and PG-1230 are the exceptions to the rule.
Both PG-1210 and PG-1230 sprockets are compatible with the SRAM Eagle series, so they cannot be used with Shimano 12-speed components for MTB.
However, these products have the advantage of allowing you to switch to SRAM Eagle with your existing HG spline freehub (Shimano free) wheels.
Points to consider when making your selection.
Compatibility is not guaranteed, so you are on your own.
No matter how many third-party manufacturers say “compatible with Shimano drivetrains,” Shimano itself does not check compatibility with third-party sprockets, and drivetrain manufacturers state that “combinations other than their own products are not recommended.
So, if you are going to use third-party sprockets in combination with Shimano or SRAM MTB components, please understand that there is a risk of “I bought it but it didn’t work properly,” and purchase at your own risk only.
There are no top 10T sets.
Both Shimano and SRAM are coming out with 12-speed sprockets for MTB with 10T tops, and the “500% ratio,” which is five times the difference between top and low, is popular.
However, the smallest cog (gear) in conventional freehubs is considered to be 11T, and it is said that Micro Spline and XD drivers were developed to exceed this limit.
Perhaps that is why there are no MTB 12-speed sprockets for HG spline freehubs with a top minimum of 10T.
If you want to use a 12-speed sprocket with a top 10T, you will need to purchase a wheel that is compatible with the Micro Spline or XD driver.