Brake shudder solution(s)

[TBLS]

Having severe brake shudder on my Cannondale Super-x with TRP euro x brakes. Standard set up with can't cable coming from top headset

Tried all adjustments reco but considering trying one of these before going mini v route

Worth a try?

[pinkshogun]

it works great

[darkmother]

Give the fork mounted hanger a try. I had severe brake shudder issues on my CX bike, and installing a hanger like the one you linked solved the problem.

Mini V brakes also solved the shudder issue, but I was unhappy with the tire to cable clearance (fenders in winter) and the brake pad to rim clearance (too small for my liking).

[weisan]

Originally Posted by TBLS

Having severe brake shudder on my Cannondale Super-x with TRP euro x brakes. Standard set up with can't cable coming from top headset

Tried all adjustments reco but considering trying one of these before going mini v route

Worth a try?

How does this work, I am curious?

Experienced a bit of frontal shudder with my Paul cantilever brakes yesterday during the gravel ride.

[Fatty]

Originally Posted by TBLS

Worth a try?

It is if your fork will take one.

[thwart]

Originally Posted by Fatty

It is if your fork will take one.

Yes, that's the key point. Frequently not an available feature on carbon CX forks.

Toeing in canti brakepads to avoid shudder is usually very helpful as well. Sometimes you need a significant angle, 2-3° or so may not do it.

[Hombre]

Originally Posted by weisan

How does this work, I am curious?

Experienced a bit of frontal shudder with my Paul cantilever brakes yesterday during the gravel ride.

I commonly see folks using paul cantis in the rear and mini moto in the front due to shudder.

[Cicli]

Originally Posted by weisan

How does this work, I am curious?

Experienced a bit of frontal shudder with my Paul cantilever brakes yesterday during the gravel ride.

The shutter is caused by the fork flexing backwards during braking. If you have the cable anchored above the headset you have alot more flex that can cause the brake to apply and release with the flex. Mounting the anchor point greatly reduces the amount of cable between the brake and the anchor that reduces the shutter significantly. Mini v brakes dont have the housing anchored anywhere but on the brake and that basicly eliminated the shutter.

[weisan]

Originally Posted by Cicli

The shutter is caused by the fork flexing backwards during braking. If you have the cable anchored above the headset you have alot more flex that can cause the brake to apply and release with the flex. Mounting the anchor point greatly reduces the amount of cable between the brake and the anchor that reduces the shutter significantly. Mini v brakes dont have the housing anchored anywhere but on the brake and that basicly eliminated the shutter.

Ah! That makes sense, thank you cicli pal.

Hombre pal, sorry I was mistaken. It looks like what I have is Paul Neo-retro.

[Luwabra]

I just eliminated a ton of shudder by recommendation on here to try a linear pull brake up front. That combined w koolstop dual compound pads.. viola! Zero shudder that stud mounted hanger looks legit tho

[mktng]

I bought the fork mount hanger. I run Paul touring on my CX bike. No shuddering. Dry or wet conditions. I just make sure to toe in my pads. I also road style pads. Cheaper to replace and better braking IMO.

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[cachagua]

Fabricate yourself a cable hanger like the ones that go around your head tube, only it sits on top of the headset cup. Slacken your frame angles by a fraction of a degree... which would actually improve most bikes.

There should be one you can buy. Or, Chris King should introduce a cup with one built in, now there's a thought.

[wombatspeed]

These fork mounted hangers work. Almost fool proof. No special pads or care with toe in required. My family has them on steel and carbon cx forks. NO shudder ever. Or if you need the extra power ( and are racing in dry conditions) then go miniV. Cheap Tektro work as well as fancy Paul's. They just may not looks as goods or last as long!!


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[oldpotatoe]

Originally Posted by weisan

How does this work, I am curious?

Experienced a bit of frontal shudder with my Paul cantilever brakes yesterday during the gravel ride.

What's happening is the brake application is flexing the fork, which is tightening the brake, causing shudder. With housing all the way to the stop mounted on the fork, this tightening of the cable doesn't occur, as much.

[weisan]

Originally Posted by oldpotatoe

What's happening is the brake application is flexing the fork, which is tightening the brake, causing shudder. With housing all the way to the stop mounted on the fork, this tightening of the cable doesn't occur, as much.

Thank you old pal.

>>Lennard Zinn

Why does shudder occur?

Brake shudder is widespread because it’s built into the design of almost all ’cross bikes; it’s inherent to the design of a center-pull cantilever brake. To understand the reason why it happens and why reduced pad size, lots of toe-in, and a tight headset help take a look at the chart titled “Brake Shudder in cantilever brakes.”

As the brake is applied, the ground applies a force directed backward on the tire as shown, causing the fork to flex backward. Problem is, the brake cable is fixed at one end at the brake caliper and at the other end at the cable stop above the headset (as you can see in my case, at a cable hanger attached to a bolt on the stem face plate).

Think “bow and arrow” and imagine the fork between the cantilever bosses and the top of the headset is like the bow, and the cable is like the string. As the fork flexes back due to braking, the cable tightens like the string in the bow, because its two ends – the cable hanger and the brake calipers, have moved further apart. So even though you may have pulled the brake lever carefully enough to modulate it properly, as soon as the pad slows the wheel down, the fork flexes back and tightens the cable, which in turn pulls the pads harder against the rim. This in turn flexes the fork back further, which tightens the cable more, which pulls the pads harder against the rim, and so on.

Eventually, something has to give: Either the tire must slip on the ground, the rider must go over the handlebars, or the pads must break free from the rim. It is the latter that creates the shudder, the pads bind and release, bind and release, each time allowing the fork to flex back and forth and the tire to roll and stop, roll and stop. This is why the problem goes away in mud and wet sand, because the pad can break free smoothly. It is also why smaller pads with more toe-in help.

If the headset is loose, the problem is greater, because the length change between the brake posts and the cable stop atop the headset is greater as the fork moves back when the brake is applied.

image: http://cdn.velonews.com/wp-content/b...s_pb130006.jpg

Specialized fork-crown-mounted cable hanger.Now you can understand why the advent of suspension forks with the cable stop attached to the brake arch bridging between the fork legs improved braking performance on mountain bikes with center-pull cantilever brakes – the arch with the cable stop took the steering tube’s flex out of the equation. And you can see why my answer from five years ago of a brake booster would not have worked unless the booster had a cable stop on it.

Almost certain to eliminate shudder is to affix the cable stop at the fork crown. The fork could still change length a bit between the crown and the brake bosses, but the length is very short, and there are two fork legs, both generally wider in a fore/aft dimension than the steering tube, so the fork flex would probably not ever be an issue. You can see three versions of a fork-crown-mounted cable hanger in the photo gallery.

Using one of these hangers will solve many riders’ shudder issues, but it won’t help those with full carbon forks. The problem with all of these hangers is that they require a hole drilled through the fork crown. This is not a problem with a steel fork or a carbon fork with an aluminum crown like the WoundUp, but I imagine your warranty would be void if you were to drill a hole through your crown on a full carbon fork.

You can see from the photos taken in the snow that I solved the problem on my red bike by using a front V-brake (a.k.a. “linear-pull cantilever brake”). The V-brake completely takes fork flex out of the equation, but you probably know that you can’t just run a standard V-brake with a road brake lever because it won’t pull enough cable and it will have too much leverage. I replaced my front brake lever (I run a single chainring with double chain guards, so I don’t have a dual-control lever on the left) with a Cane Creek Drop V lever, which pulls more cable and has less leverage than most road levers. Another option is to use short V-brakes designed for use with road levers.

image: http://cdn.velonews.com/wp-content/b...s_pc070041.jpg

Shimano XT parallel-push V-brake and SRAM road pad holders.Close inspection of the picture will reveal that I have installed SRAM road pad holders with yellow Swisstop road pads to reduce the area of pad contact to improve brake modulation. It still stops very fast and squeals on carbon rims, but there is no shudder, and brake performance is perfect (and silent) on aluminum rims.

The other way to eliminate the problem and still use the traditional ’cross center-pull cantilever setup is to get a fork that is very stiff fore-aft. As you can see below in the letters from Jochim Aerts, owner and founder of Ridley, perhaps the most sought-after ’cross bike today, and Edwin Bull of Van Dessel, this is the method that they have employed.
Lennard


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