Motolite pad squeal - HELP!

[Brian Turner]

Everyone, I am at my wit's end this morning trying to eliminate the squeal on my front Motolite that is on my new Sam. I'm usually pretty good at this, but for some reason nothing I am doing seems to work. For starters, this is a newly built Sam, with less than 30 miles on it. Pads are brand new Kool Stop thinline salmons.

I've set the toe-in like I normally do, using a dime or a penny on the back end of the pad when tightening them in order to get the front of the pads to touch just slightly before the back of the pad. Squeals like crazy.

I've tried adjusting the pad holders just slightly inward (same as toeing). Squeals just as bad.

I've adjusted everything parallel to the rim (no toe-in). Squeals like crazy.

I've cleaned the rims with alcohol. I've sanded the KoolStop pads. Nothing is working.

This isn't my first bike with Motolites. I've always been able to get rid of it, but for some reason nothing I'm trying is working today. Any advice? I'm truly feeling like an idiot.

Brian

Lexington KY

[Brian Turner]

A friend here reached out to say that the rims may be non-machined, which could be causing the squeal coupled with the fact that everything is still relatively brand new. I'm pretty sure all my other bikes running Paul brakes have all had machined sidewalls, so maybe that explains why I've never experienced squeal like this before.

Brian

Lexington KY

[Isaak Oliansky]

I had terrible squeal on non-msw rims with motolites as well, fwiw. 

[Brian Turner]

Thanks, Isaak! I'm going to assume for now that's what's going on here. I'm going to leave it alone, crack open a beer, and maybe try to take it on a long, dusty ride later today and see if it gets less the more I ride it.

Because I've done everything I can think of up to this point!

Brian

Lexington KY

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[Josiah Anderson]

My "dirty" trick for otherwise incurable brake squeal, after trying all the things you listed, is dirt. Throw a handful at the pads, making sure some gets between the pads and the rim, and take it down a hill. Mud puddles also work well. That'll "machine" the sidewalls pretty quickly.

Josiah Anderson 

Tacoma WA 

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[Ginz]

You can also try spraying the pads with your water bottle and see if that quiets it for the right. Otherwise, I'd drive a different brand of pads, then give up on those brakes.

I'm just guessing that we are talking about front brake.  I have also found that headset can play a role, specifically a Tange-style loose ball headset. 

[Joe Bernard]

Motolites with salmon pads are notorious for this. I replaced mine with the "ebike pads" Riv sells, they're awesome. 

[Ron Mc]

Toe-in is the problem.  

I first set up my Racers with toe-in, and front didn't squeal on test ride, it squaled.  

I searched this forum, and someone where found no toe-in with Paul brakes.  

As soon as I removed the toe-in and set them flat, problem solved.  

[Bill Lindsay]

In my experience, Kool Stop Salmon compound is a very good compound for many set ups, but not for all set ups.  Try the things that are "free" to try first, but I'd recommend putting on your list to try Kool Stop black, and/or Kool Stop E-bike compounds when you run out of the free things to try.  I think it's a perfectly good practice to try salmon first, because it's usually good.  

Bill Lindsay

El Cerrito, CA

[Brian Turner]

Thanks for all the helpful advice, everyone. I was starting to lose my mind!

I especially like the “dirt” trick. Makes total sense to me. I’ve just never used Paul brakes (and salmon KoolStops) on non-machined rims before. I bought these rims new and unbuilt from a friend for this project. In the past, I’ve always ordered machined because the option was there, and honestly I never thought it would make much of a difference in brake squeal.

Brian
Lexington KY

[Drew Fitchette]

Hey Brian! 

I just remedied this problem yesterday with the exact same set up by using this on the rim sidewalls: https://www.mavic.com/en-us/p/abrasive-rubber-oc0831

Although it says it "cleans" the side walls, the abrasive rubber actually helps give the surface more texture to grab onto. 

All credit to my friend who's an ace mechanic for having this thing handy. Instantly made the howling go away!

- Drew

[esoterica etc]

And if you can pronounce the German word for that Mavic tool (Felgenreinigungsgummi), they give you a free Kreuzschlitzschraubenzieher (Philips screwdriver)!

~Mark

On May 20, 2026, at 12:34 PM, Drew Fitchette <drewfi...@gmail.com> wrote:

Hey Brian! 

[Mathias Steiner]

I'm going to disagree with everyone else.

My Cannondale T400 front brake squeals.

It has always squealed. 

I've changed:
- toe in
- brake pads, more than once
- cantilever brake model

- headset

It still squeals.

In the end, I got so I liked it. Indispensable on campus when the freshmen come in and walk hither and yon without looking. Pull the front brake, and it gets their attention. 

...but I had a new fork made for that bicycle, and wouldn't you know it.... kept the brakes exactly as they were, but no more brake squeal.
It's an expensive fix, and the squealing wasn't the reason for the new fork, but I thought I'd add my observations.

cheers -m

[Kim H.]

@Brian

I had a similar experience with my Dia-Compe 980 cantilever front brake with the KOOL-STOP E-BIKE brake pads. I cleaned the sidewall of my Alex DM 18? rim with lacquer thinner and sanded my brake pads. I even readjusted my brake pads. All this to no avail in solving my squealing pads.

I remember from a long time ago when I had Tektro cantilever brakes on my 2008 Surly Long Haul Trucker with the same issue. I took my Dremel tool with a narrow rounded sanding bit and went in and ground down the upper stirrups of the cantilever brakes with the brake pads removed at different angles. Reinstalling the pads, I discovered that this solved the problem after riding the bike again. 

Taking that resolution, I applied it again to the front wheel brake of my Clem with great success. The squealing sound has not returned whatsoever. 

Kim Hetzel. 

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[Ron Mc]

Different animal.  

DiaCompe just need Yokozuna spherical washer and proper toe-in set.  

[ascpgh]

When I started riding my bike with the polished silver Pacenti Brevet rims, the RH front canti definitely squealed. 

The smoothness of the polished brake web was definitely the major contributor, which I addressed by using some contact cement to attach pad-shaped emory paper to the brake pads' contact faces, and did some light braking on the downslope in front of the house until I got what looked like a nice wear-in of the polished finish. I did the back too for aesthetic symmetry. 

Cantilever squeal/squawk does have many causes, as others have pointed out. It helps to imagine that, until the wheel is locked,  friction by a brake can be a state of oscillation, like a violin string being played by the horsehair of a bow. A Google AI response to that as a question says: 

Sliding friction (or kinetic friction) is not an oscillation in itself. Rather, it is a constant or resistive force that opposes motion. However, when sliding 

friction interacts with elasticity, it often leads to physical systems entering a state of oscillation. 

This has helped me wrap my head around how pads (in density or coefficient of friction), brake arms, rims, headsets, and forks themselves can contribute to a result of noise as the rim rotates against the contacting brake pads. Mathias' experience mirrored mine when my shop sold that Cannondale model. Its fork was made for serious touring loads, on those large-diameter aluminum frames, seriously reducing both the frame and fork from bearing any of the oscillation the front braking produced and without the weight of a load to damp things, the squawk was nearly constant

The slight difference in the lower race bearing surface of a headset could sometimes be enough to quiet those bikes when nothing else worked, but it was very rider and bike-size-specific. I would have one (small for me) finally braking quietly, then the customer would come to retrieve, and it would sqawk on the way to their car with them riding it. 

Andy Cheatham

Pittsburgh