While Shimano's fairly recent, first gen flat-mount road and gravel disc brakes (105 BR-7070, Ultegra BR-8070, GRX BR-RX810) are generally well regarded, they evidently get a lot of (deserved) flak for their use of a soft, cheese-head screw / "pad axle" to retain the pads. It seems these corrode, sieze in place then become damaged when removal is attempted.
While there are aftermarket (usually Titanium) alternatives it seems that Shimano have addressed this issue on their later / current calipers - fitting a (hopefully tougher) hex-head bolt instead of a cheese head.
I've been trying to track down the correct replacement item to retro-fit to my 105 R7070 calipers as a preventative measure. This has proven less-than-straightforward but I think I've found the right one. Train of thought below; heed at your own risk!
According to the SJS site, this is listed as correct fitment / "A" match for:
- Shimano Ultegra BR-R8170 (2nd gen. flat mount)
- Shimano 105 BR-R7170 (2nd gen. flat mount)
- Shimano SLX BR-M7100
It's also listed as a "B" match for:
- Shimano Ultegra BR-R8070 (1st gen. flat mount)
- Shimano Deore XT BR-M8100
- Shimano SLX BR-M7000
Looking at the exploded diagrams for the BR-R8070 and BR-7070 we can see that both use the same cheese-head "pad axle" (part no. Y8J798060 including the "snap retainer"); which suggests that the Y2M98020 above from SJS should also be a "B" match for the 1st gen 105 BR-7070 calipers. This also holds true for the earlier post-mount RS-505 non-series / pseudo-105 road calipers that marked Shimano's first foray into discs for road groupsets.
I hope / suspect that these are a "B" match because the head profile and finish are different; while being otherwise geometrically identical.
The pad axle for the GRX BR-RX810 (as well as GRX BR-RX400 and Tiagra BR-4770) has a different part number to the two road groupsets from the same era (part no. Y2EN98010 including the "snap retainer"); I think because it has a different finish (black as opposed to the silver BZP finish on 105 and Ultegra); however I can't find any official sources that confirm this supposition. Equally I'm not sure what the crack is with Dura-Ace parts.
I'm interested to hear any thoughts on this and might take the plunge and buy a couple of these hex-head replacements if I can be reasonably sure they'll fit..
While there are aftermarket (usually Titanium) alternatives it seems that Shimano have addressed this issue on their later / current calipers - fitting a (hopefully tougher) hex-head bolt instead of a cheese head.
I've been trying to track down the correct replacement item to retro-fit to my 105 R7070 calipers as a preventative measure. This has proven less-than-straightforward but I think I've found the right one. Train of thought below; heed at your own risk!
Shimano SLX BR-M7110 Pad Axle & Snap Retainer - Y2GM98020 - SJS Cycles, £1.99
According to the SJS site, this is listed as correct fitment / "A" match for:
- Shimano Ultegra BR-R8170 (2nd gen. flat mount)
- Shimano 105 BR-R7170 (2nd gen. flat mount)
- Shimano SLX BR-M7100
It's also listed as a "B" match for:
- Shimano Ultegra BR-R8070 (1st gen. flat mount)
- Shimano Deore XT BR-M8100
- Shimano SLX BR-M7000
Looking at the exploded diagrams for the BR-R8070 and BR-7070 we can see that both use the same cheese-head "pad axle" (part no. Y8J798060 including the "snap retainer"); which suggests that the Y2M98020 above from SJS should also be a "B" match for the 1st gen 105 BR-7070 calipers. This also holds true for the earlier post-mount RS-505 non-series / pseudo-105 road calipers that marked Shimano's first foray into discs for road groupsets.
I hope / suspect that these are a "B" match because the head profile and finish are different; while being otherwise geometrically identical.
The pad axle for the GRX BR-RX810 (as well as GRX BR-RX400 and Tiagra BR-4770) has a different part number to the two road groupsets from the same era (part no. Y2EN98010 including the "snap retainer"); I think because it has a different finish (black as opposed to the silver BZP finish on 105 and Ultegra); however I can't find any official sources that confirm this supposition. Equally I'm not sure what the crack is with Dura-Ace parts.
I'm interested to hear any thoughts on this and might take the plunge and buy a couple of these hex-head replacements if I can be reasonably sure they'll fit..
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