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Disc rotor alignment

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Disc rotor alignment

Old 05-26-19, 08:00 AM
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rbrides
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Disc rotor alignment

I have a "gravel" bike with disc brakes. I bought a second wheel set/tires and brake discs to have one set up for road and another for gravel. Here is my concern. The new discs sit approximate 1/16 of an inch (maybe 1/32) more inboard than the original discs such that it slightly contacts the inboard pad, regardless of which wheel I put it on. It is as if the disc needs a washer/spacer/shim between it and the wheel To keep it off the pad. As if the housing of the new discs are that little bit more narrow than the original.




Is this a big deal? Little deal? No deal at all? How much "gap" is appropriate between discs and pads?




The Wheel spins freely enough (a subjective evaluation) so maybe the friction (if any) is not an issue. I don't know. Should I just try to adjust the pads in caliper and push the pad away from the disc? If so, how?




Both sets of discs are Shimano 160s. Wheels are thru-axles. I torque to bike's specs.




Thanks for reading.
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Old 05-26-19, 08:22 AM
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Option , ( Post mount /ISO style) reset caliper ..loosen bolts hold brake on , while you re tighten those bolts ..

only takes a moment to do..
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Old 05-26-19, 08:38 AM
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Ah, the cost of improvement.

This is some of the reality of disk brakes with their minimal pad/rotor clearances and varying tolerances of the various parts that make up the system. First- As long as there's no pad/rotor rub all is good. Second- Shims that fit between the rotor and hub are available for fine tuning where the rotor sits WRT the axle end. Third- Whatever you do do will evolve and likely need to be revisited as things wear. Andy
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Old 05-26-19, 08:51 AM
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Originally Posted by rbrides View Post
I have a "gravel" bike with disc brakes. I bought a second wheel set/tires and brake discs to have one set up for road and another for gravel. Here is my concern. The new discs sit approximate 1/16 of an inch (maybe 1/32) more inboard than the original discs such that it slightly contacts the inboard pad, regardless of which wheel I put it on. It is as if the disc needs a washer/spacer/shim between it and the wheel To keep it off the pad. As if the housing of the new discs are that little bit more narrow than the original.




Is this a big deal? Little deal? No deal at all? How much "gap" is appropriate between discs and pads?




The Wheel spins freely enough (a subjective evaluation) so maybe the friction (if any) is not an issue. I don't know. Should I just try to adjust the pads in caliper and push the pad away from the disc? If so, how?




Both sets of discs are Shimano 160s. Wheels are thru-axles. I torque to bike's specs.




Thanks for reading.
What make/model of brakes? Can you post a picture?

I have TRP Spyre mechanical disc brakes on one of my bikes. When I switch wheels all I have to do is adjust each pad in or out using a set screw - 3 mm allen. I adjust the pads inward until they rub and then back off about 1/8 turn. Simple - takes about 1 minute per wheel.

What tyoe of brake pad adjustment mechanism do your calipers have?
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Old 05-26-19, 10:16 AM
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Originally Posted by fietsbob View Post
Option , ( Post mount /ISO style) reset caliper ..loosen bolts hold brake on , while you re tighten those bolts ..

only takes a moment to do..
That's what I do, adds about 1 minute with a 5mm wrench to the wheel swap process and works every time. I also have a bigger ring on one of my wheels sets so I end up tweaking my B screw a little too. Neither a big deal.

Last edited by u235; 05-26-19 at 10:19 AM.
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Old 05-26-19, 11:43 AM
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Originally Posted by Andrew R Stewart View Post
Ah, the cost of improvement.
If OP has different rim widths, which could be the case since one set is for gravel and one for road, he also would have to adjust rim brakes between wheels. And you have to adjust rim brakes frequently even with the same wheel and rim trueness becomes more important.
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Old 05-27-19, 05:11 AM
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I'll try that. Thanks for the input.
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Old 05-27-19, 05:12 AM
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I'll look for shims that fit. I like this approach as shims will help me adjust for wear over time.
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Old 05-27-19, 05:14 AM
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Shimano BR RS505 hydraulic that came with the Specialized bike.
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