The following is a summary of SRAM's proprietary XD and XDR standards, what makes them different from Shimano's, and what to look for when purchasing.
Table of contents
Definition of Wide Ratio
In sprocket gear configurations, one measure of the wide ratio is basically how large the low gear is.
However, there is no clear definition, as some people say even 28T is wide, while others say it is not wide unless it is 32T or higher.
Since cross ratio sprockets such as 11-23T are no longer often offered in the lineup these days, for the purposes of this article, a low max of 25 to 28T is considered cross ratio, and 30T or higher is considered wide ratio.
Shimano wide-ratio sprockets
Shimano’s latest road bike components have the highest number of speeds, 12. The latest DURA-ACE, ULTEGRA, and 105 have these speeds, and all are currently Di2-only, wide-ratio limited lineups.
Shimano’s 12-speed rear derailleurs for road bikes are as follows
- RD-R9250 (total: 37T, low max: 34T)
- RD-R8150 (total: 39T, low max: 34T)
- RD-R7150(Total: 41T, Low max: 36T)
Only the 105 R7150 supports a low max of 36T. This should be noted when choosing a 12-speed wide-ratio sprocket.
|model number|steps|high|low|gear configuration| |—|:—:|:—:|:—:| |CS-R9200-12|12s|11T|30T|223g|11-12-13-14-15-16-17-19-21-24-27-30| |CS-R9200-12|12s|11T|34T|253g|11-12-13-14-15-17-19-21-24-27-30-34| |CS-R8100-12|12s|11T|30T|291g|11-12-13-14-15-16-17-19-21-24-27-30| |CS-R8100-12|12s|11T|34T|345g|11-12-13-14-15-17-19-21-24-27-30-34| |CS-R7100-12|12s|11T|34T|361g|11-12-13-14-15-17-19-21-24-27-30-34| |CS-R7100-12|12s|11T|36T|-g|11-12-13-14-15-17-19-21-24-28-32-36|
Shimano’s 11-speed for road bikes is the former DURA-ACE (R9100 and 9000 series), former UTEGRA (R8000 and 6800 series), and former 105 (R7000 and 5800 series), and the medium cage rear derailleurs are as follows
- RD-R8000-GS (total: 39T, low max: 34T)
- RD-R7000-GS (total: 39T, low max: 34T)
DURA-ACE has no GS (medium cage) lineup, only RD-R9100-SS (short cage) RD-R9100-SS has 30T low max.
There are surprisingly few 11s wide ratio sprockets available for road bikes, and the two choices are 11-30T or 11-32T.
|model number|steps|high|low|gear configuration| |—|:—:|:—:|:—:| |CS-R9100|11s|11T|30T|211g|11-12-13-14-15-17-19*-21*-24*-27*-30*(*Titan)| |CS-R8000|11s|11T|30T|269g|11-12-13-14-15-17-19-21-24-27-30| |CS-R8000|11s|11T|32T|292g|11-12-13-14-16-18-20-22-25-28-32| |CS-R7000|11s|11T|30T|304g|11-12-13-14-15-17-19-21-24-27-30| |CS-R7000|11s|11T|32T|320g|11-12-13-14-16-18-20-22-25-28-32| |CS-5800|11s|11T|32T|320g|11-12-13-14-16-18-20-22-25-28-32|
Note that Shimano’s 11-speed sprockets include ultra-wide ratio sprockets such as 11-51T for MTB, but these cannot be pulled by the rear derailleur of a road bike.
Shimano’s 10-speed for road bikes is TIAGRA, and the medium cage rear derailleur is RD-4700-GS.
The RD-4700-GS has a total gear capacity of 41T and a low maximum of 34T when double-fronted, so a wide ratio sprocket with a maximum of 34T can be used.
In terms of Shimano’s sprocket lineup, the CS-HG50-10 and CS-HG81-10 for MTB have a wide-ratio model with 11-36T, which means the RD-4700-GS cannot pull it.
There is quite a wide variety of 10s wide-ratio sprockets available for road bikes, with a wide range of choices from popular grades to the higher-end CS-M980 model.
|model number|steps|high|low|gear configuration| |—|:—:|:—:|:—:| |CS-HG500-10|10s|11T|32T|11-12-14-16-18-20-22-25-28-32| |CS-HG500-10|10s|12T|34T|11-13-15-17-19-21-23-26-30-34| |CS-HG81-10(bL)|10s|11T|32T|11-12-14-16-18-20-22-25-28-32| |CS-HG81-10(bJ)|10s|11T|34T|11-13-15-17-19-21-23-26-30-34| |CS-M771-10(bL)|10s|11T|32T|11-12-14-16-18-20-22-25-28-32| |CS-M771-10(bJ)|10s|11T|34T|11-13-15-17-19-21-23-26-30-34| |CS-M980|10s|11T|34T|11-13-15-17-19-21-23-26-30-34（21-34がチタン）| |CS-6700|10s|12T|30T|12-13-14-15-17-19-21-24-27-30| |CS-6600|10s|12T|30T|12-13-14-15-17-19-21-24-27-30|
Shimano’s 9-speed for road bikes is SORA, and the medium cage rear derailleur is the RD-R3000-GS.
The RD-R3000-GS has a total gear capacity of 43T and a maximum low of 34T, so a wide ratio sprocket of up to 34T can be used.
Although SORA is the only road bike with 9 gears, there is actually quite a wide variety of wide ratio sprockets. However, since there are only 9 gears, the difference in the number of teeth per step is large.
|model number|steps|high|low|gear configuration| |—|:—:|:—:|:—:| |CS-HG50-9(bf)|9s|11T|30T|11-12-14-16-18-20-23-26-30| |CS-HG400-9(aR)|9s|11T|32T|11-12-14-16-18-21-24-28-32| |CS-HG400-9|11T|9s|34T|11-13-15-17-20-23-26-30-34| |CS-HG400-9|11T|9s|36T|11-13-15-17-20-23-26-30-36| |CS-HG400-9|12T|9s|36T|12-14-16-18-21-24-28-32-36| |CS-M770|9s|11T|32T|11-12-14-16-18-21-24-28-32| |CS-M770|9s|11T|34T|11-13-15-17-20-23-26-30-34| |CS-HG80-9|9s|11T|32T|11-12-14-16-18-21-24-28-32| |CS-HG80-9|9s|11T|34T|11-13-15-17-20-23-26-30-34|
Shimano’s 8-speed for road bikes is CLARIS, and the medium cage rear derailleur is RD-R2000-GS.
The RD-R2000-GS has a total gear capacity of 43T and a maximum low of 34T, so a wide ratio sprocket of up to 34T can be used.
There are quite a few options for wide-ratio sprockets, even for 8-speed road bikes, and in many cases, the initial state of a complete bike is wide-ratio to begin with. However, the difference in the number of teeth per step is basically about 4T.
|model number|steps|high|low|gear configuration| |—|:—:|:—:|:—:| |CS-HG51-8(an)|8s|11T|30T|11-13-15-17-20-23-26-30| |CS-HG51-8(aw)|8s|11T|32T|11-13-15-18-21-24-28-32| |CS-HG50-8(aw)|8s|11T|32T|11-13-15-18-21-24-28-32| |CS-HG50-8(Ca)|8s|11T|34T|11-13-15-18-21-24-28-34| |CS-HG50-8(an)|8s|11T|30T|11-13-15-17-20-23-26-30| |CS-HG41-8(an)|8s|11T|30T|11-13-15-17-20-23-26-30| |CS-HG41-8(aw)|8s|11T|32T|11-13-15-18-21-24-28-32| |CS-HG31-8(an)|8s|11T|30T|11-13-15-17-20-23-26-30| |CS-HG31-8(aw)|8s|11T|32T|11-13-15-18-21-24-28-32| |CS-HG31-8(Ca)|8s|11T|34T|11-13-15-18-21-24-28-34| |CS-HG200-8(br)|8s|12T|32T|12-14-16-18-21-24-28-32|