Frustrating Caliper Alignment Issue

[Epicus07]

I cant seem to get my rear caliper (Force D2) to align with a new centerline XR rotor without the outer pad touching the rotor. No matter how much I brace it and slowly tighten the bolts, when they snug up it shifts so that the rotor is fulling touching the outer pad.

This is on my Moots Routt RSL which had a 3d printed drop out so I would imagine a high level of accuracy here. I was running GRX previously without issue. Wheels are HED emporia PRO. I have confirmed that the rotor is torqued to spec.

Anyone have any creative thoughts?

[in_version]

have you tried completing the tightening while holding the brake lever?

[prototoast]

Did you try resetting the pistons (remove the brake pads and press the pistons all the way in)?

When you tighten the caliper, is it hitting the pad because it's at an angle, or hitting the pad because it's straight but too far inboard?

If you loosen the bolts just enough that you can wiggle the caliper, can you manually place it into a position where it doesn't rub?

[Epicus07]

Originally Posted by in_version

have you tried completing the tightening while holding the brake lever?

Yes, i have tried both lever and visual alignment many times. I'm used to fighting with finicky calipers but this feels like something else.

Originally Posted by prototoast

Did you try resetting the pistons (remove the brake pads and press the pistons all the way in)?

When you tighten the caliper, is it hitting the pad because it's at an angle, or hitting the pad because it's straight but too far inboard?

If you loosen the bolts just enough that you can wiggle the caliper, can you manually place it into a position where it doesn't rub?

Yes, ive tried the reset a few times. Caliper is too far outboard, not angled. Yes, i can loosen the bolts enough to position it so that it doesnt rub but once i start to tighten them (no matter how much counter pressure or bracing) it forces the caliper back into the outboard position.

[Old School]

When all else fails, these things work perfectly for me.

https://www.youtube.com/watch?v=MVn5kL55FzA

[Epicus07]

Yeah I have one of those too.

At this point I’m confident it’s not an adjustment issue. Just not sure where to go next. Caliper mount facing? Seems unlikely on a 3D printed top tier moots

[many_styles]

I know this might seem absurd, but could your brand new rotors be actually bent or warped?

I had a brand new bike with brake issues for months, turns out the brand new rotors were bent.


Sent from my iPhone using Tapatalk

[m_sasso]

Sounds like you are having a problem with movement of the calliper while securing it tight to the drop out mount surface? Even if the two mounting surfaces are not square to each other this should not create movement of the calliper while securing it, the process should only result in final secured misalignment.

Are your mounting bolts correctly threaded into the calliper and not cross threaded into the calliper? Are the mounting bolts too long and bottoming out into the calliper, are the bolt mounting surfaces square with the calliper mount surface?

If you are getting movement while tightening the calliper mounting bolts, have you tried to progressively tightening each mounting bolt in smaller increments, switching from one to the other, until fully torqued.

Are the bolt washers distorted and not flat? Possible irregular or compromised calliper mounting face or a problem with 3d printed drop out mount surface?


Long shots, not if you are creating calliper movement while securing the calliper. If the rotor needs to be moved inboard, do you have an axel spacing issue, are your end caps fully seated correctly and on the correct sides of the hub, have you tried a different rotor?

[Jdm]

I’ve had not fully tightened center lock rings and thru axles throw off my rotor spacing

[JMT3]

When I have the same issue I slip a folded in half business card on the offending side before torquing the caliper down. Works every time! For me.

[.RJ]

Originally Posted by Epicus07

This is on my Moots Routt RSL which had a 3d printed drop out so I would imagine a high level of accuracy here.

That is really frustrating.

[unterhausen]

Even though it's Moots, everybody makes a mistake from time to time. I would take it to the lbs that I trust.

[Epicus07]

Originally Posted by m_sasso

Sounds like you are having a problem with movement of the calliper while securing it tight to the drop out mount surface? Even if the two mounting surfaces are not square to each other this should not create movement of the calliper while securing it, the process should only result in final secured misalignment.

Are your mounting bolts correctly threaded into the calliper and not cross threaded into the calliper? Are the mounting bolts too long and bottoming out into the calliper, are the bolt mounting surfaces square with the calliper mount surface?

If you are getting movement while tightening the calliper mounting bolts, have you tried to progressively tightening each mounting bolt in smaller increments, switching from one to the other, until fully torqued.

Are the bolt washers distorted and not flat? Possible irregular or compromised calliper mounting face or a problem with 3d printed drop out mount surface?


Long shots, not if you are creating calliper movement while securing the calliper. If the rotor needs to be moved inboard, do you have an axel spacing issue, are your end caps fully seated correctly and on the correct sides of the hub, have you tried a different rotor?

1. I think the movement of the caliper when I’m securing it is that when I’m holding it off of the rotor it must be angling out and then when it’s tightened down against the face it levels out to 90 degrees, the top swings in and pushes against the rotor again.

2. Bolts are correct.

3. Yes, I have had this issue with fussy calipers in the past and alternate turning the least detectable mount of movement until snug.

4. I ran these wheels for a few months with Shimano and had none of these issues so it shouldn’t be a wheel issue. But I did swap the freehub driver which required me to pull the axle. I’ve checked my work a second time and measured the distance between end caps at 142.1mm so I don’t think that’s it. I did reach out to HED to confirm my process and troubleshoot. To me this seems like the most likely issue since the flatmount holes have a decent amount of lateral adjustability and the bolts are slammed outboard and still can’t go far enough. I have to think there’s an axle spacing issue but I can’t figure out what or how. I have tried two different rotors which are both true.

I guess it’s about time to quit and I should take it to LBS.

[NHAero]

Are the top surfaces of the caliper flat and in plane to the mounts? If they were on a slant that might move the caliper when snugged up.

I understand the frustration! I had similar on a frame and ultimately it was the mounts, getting them re-faced solved the issue.

[windsurfer]

If the caliper is shifting when you tighten it, the mounts need to be faced. Could be the caliper, the frame, or both that are not flat or at the right angle. Once you get this right adjustment will be easy. Dykem will help.