Issues with disc brake adapter upside down
#1
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Issues with disc brake adapter upside down
I recently installed post mount TRP Spyres on an IS mount using IS to PM adapter on 160mm rotors (SM-MA-R160P/S).
When the adapter was mounted with arrow up, the pads only contacted half the rotor.
When the adapter is mounted upside down, then the pads contact the full rotor, I can see the top of the rotor level with the top of the pads and the barrel adjuster is pointed up at the cable run at a good angle.
It is the same situation for front and rear.
Is this normal or expected? Have I the wrong adaptors? I can’t seem to see a safety issue with this.
Thoughts?
When the adapter was mounted with arrow up, the pads only contacted half the rotor.
When the adapter is mounted upside down, then the pads contact the full rotor, I can see the top of the rotor level with the top of the pads and the barrel adjuster is pointed up at the cable run at a good angle.
It is the same situation for front and rear.
Is this normal or expected? Have I the wrong adaptors? I can’t seem to see a safety issue with this.
Thoughts?
#2
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If you click on "Mount style" on this page, you'll see that SMMAR160P/S is a rear mount. Front mounts have F in them.
https://bike.shimano.com/en-EU/produ...MAF180PP2.html
https://bike.shimano.com/en-EU/produ...MAF180PP2.html
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Does it fit correctly now?
Yes?
Run it.
Yes?
Run it.
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#5
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If you click on "Mount style" on this page, you'll see that SMMAR160P/S is a rear mount. Front mounts have F in them.
https://bike.shimano.com/en-EU/produ...MAF180PP2.html
https://bike.shimano.com/en-EU/produ...MAF180PP2.html
It’s just that when a part has an orientation arrow and, for it to work, requires to be opposite that orientation just gives me pause.
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Both adapters are that number and both front and rear needed to be mounted upside down. The front adapter arrow points down, obviously, and the rear arrow points toward the BB.
It’s just that when a part has an orientation arrow and, for it to work, requires to be opposite that orientation just gives me pause.
It’s just that when a part has an orientation arrow and, for it to work, requires to be opposite that orientation just gives me pause.
But if it works, that's fine too.
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#11
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BUT she’s a-workin anyway.
Thank you for your help.
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...we'll always have Paris.
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I recently installed post mount TRP Spyres on an IS mount using IS to PM adapter on 160mm rotors (SM-MA-R160P/S).
When the adapter was mounted with arrow up, the pads only contacted half the rotor.
When the adapter is mounted upside down, then the pads contact the full rotor, I can see the top of the rotor level with the top of the pads and the barrel adjuster is pointed up at the cable run at a good angle.
It is the same situation for front and rear.
Is this normal or expected? Have I the wrong adaptors? I can’t seem to see a safety issue with this.
Thoughts?
When the adapter was mounted with arrow up, the pads only contacted half the rotor.
When the adapter is mounted upside down, then the pads contact the full rotor, I can see the top of the rotor level with the top of the pads and the barrel adjuster is pointed up at the cable run at a good angle.
It is the same situation for front and rear.
Is this normal or expected? Have I the wrong adaptors? I can’t seem to see a safety issue with this.
Thoughts?
Front and rear IS adapters for the same size rotors are different sizes because front IS mounts are set at 160mm and rear IS mounts are set at 140mm.
Comparing a flipped 160mm rear adapter to a 160mm front adapter, I'd be surprised if the pads were contacting the rotor properly.
#18
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How does the pad placement look on the other side of the caliper?
Front and rear IS adapters for the same size rotors are different sizes because front IS mounts are set at 160mm and rear IS mounts are set at 140mm.
Comparing a flipped 160mm rear adapter to a 160mm front adapter, I'd be surprised if the pads were contacting the rotor properly.
Front and rear IS adapters for the same size rotors are different sizes because front IS mounts are set at 160mm and rear IS mounts are set at 140mm.
Comparing a flipped 160mm rear adapter to a 160mm front adapter, I'd be surprised if the pads were contacting the rotor properly.
This (and as well as other things in my life) is why I am confused and though t to ask you fine folk for your opinion.
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Well, at the risk of sounding impertinent (that is not my intent), if the pad, as shown in the photo I provided, is contacting the rotor properly, then wouldn't the OTHER pad be the same? Yes, both pads appear to contact the rotor properly - the top of the rotor, as shown in the photo, is level with the top of the pad. If I mount the adaptor the correct way, with the arrow pointing up on both front and rear, the pads only hit about half the rotor.
One side might look fine, the other side might not.
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What's in that image mightn't look as extreme in real life it.
So when you look in where the green arrow is pointing, there's no part of the pad overhang of the rotor?
The bottom of your flipped rear adapter is similar position to a front 160mm adapter, the top of your setup is completely different, there must be some of the pads overhanging the rotor.
So when you look in where the green arrow is pointing, there's no part of the pad overhang of the rotor?
The bottom of your flipped rear adapter is similar position to a front 160mm adapter, the top of your setup is completely different, there must be some of the pads overhanging the rotor.
Last edited by cobba; 04-11-23 at 03:04 AM.
#22
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What's in that image mightn't look as extreme in real life it.
So when you look in where the green arrow is pointing, there's no part of the pad overhang of the rotor?
The bottom of your flipped rear adapter is similar position to a front 160mm adapter, the top of your setup is completely different, there must be some of the pads overhanging the rotor.
So when you look in where the green arrow is pointing, there's no part of the pad overhang of the rotor?
The bottom of your flipped rear adapter is similar position to a front 160mm adapter, the top of your setup is completely different, there must be some of the pads overhanging the rotor.
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Shimano makes two types of rotors (narrow and wide) and two types of pads (narrow and wide), they don't recommend using wide type pads on narrow 2 piece rotors, the pads used in the Spyre/Spyke brakes are exactly the same as Shimano wide type pads, the rotor you're using looks to be a Shimano narrow 2 piece like the RT76 / RT81 / RT86 / RT-EM800.
I've seen a few photos of wide pad use on narrow rotors, the pads were overhanging the inner edge of the rotor and wearing on the arms of the rotor.
What you can see from the outside looking in, mightn't show the full story, after a bit of use I'd remove the pads from the caliper to see if there's any unusual wear on them.
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