Shimano
Shimano Disc Brake Mount Adapter SM-MA
For postmount caliper
| PERFORMANCE INDICATOR  | 
FORK AND FRAME MOUNT STYLE | DISC BRAKE ROTOR SIZE | ||||||
|---|---|---|---|---|---|---|---|---|
| 140 MM (SS) | 160 MM (S) | 180 MM (M) | 203 MM (L) | |||||
 ISMMA90F180PPC  ISMMA90F203PPM  ISMMA90F160PS  ISMMA90R140PS  ISMMA90R160PS  ISMMA90R180PS
 | 
![]()  | 
Front | Post mount | 140 mm direct | Direct mount | ISMMA90F180PPC | - | - | 
| 160 mm direct | - | Direct mount | ISMMA90F180PPC | - | ||||
| 180 mm direct | - | - | Direct mount | ISMMA90F203PPM | ||||
| 203 mm direct | - | - | - | Direct mount | ||||
| International A-standard | - | ISMMA90F160PS | - | - | ||||
| Rear | Post mount | 140 mm direct | Direct mount | ISMMA90F180PPC | - | - | ||
| 160 mm direct | - | Direct mount | ISMMA90F180PPC | - | ||||
| 180 mm direct | - | - | Direct mount | ISMMA90F203PPM | ||||
| 203 mm direct | - | - | - | Direct mount | ||||
| International A-standard | ISMMA90R140PS | ISMMA90R160PS | ISMMA90R180PS | - | ||||
Mounting post mount type brake caliper with flat mount converter on the bicycle frame
- Converter fixing bolt
 - 
Converter fixing bolt length (mm)
bolt length
 
| CONVERTER FIXING BOLT LENGTH | ||
|---|---|---|
| FRAME THICKNESS | BOLT LENGTH | CODE NO. | 
| 10 mm | 16.8 mm | Y81743100*2 | 
| 15 mm | 21.8 mm | Y81743150*2 | 
| 20 mm | 26.8 mm | Y81743200*2 | 
| 25 mm | 31.8 mm | Y81743250*1 | 
| 30 mm | 36.8 mm | Y81743300*2 | 
| 35 mm | 41.8 mm | Y81743350*2 | 
Bolts for 25 mm thick frames are included with converters. Other bolts lengths are sold separately.
- *1 Included in mount converter SM-MA-R140P/D (ISMMAR140PDH), SM-MA-R160P/D (ISMMAR160PDH)
 - *2 Not included in mount converter
 
How to identify the optimal bolt length using the bolt length selector.

- 
6.8 mm
 - ABolt length selector
 - Including post mount adapter
 
Insert the adapter fixing bolt into the frame mount area, and make sure that the length of the protruding part is 6.8 mm.
Note:
- When using a bolt length selector, make sure that the tip of the bolt fits within range A.
 - When checking the length of the bolt, do not use a washer.
 
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