DOOM_NX

Hello,

I wasn't getting any replies in the Mechanics section so I thought I'd post it here, as well.

I just noticed this flexing brake arm. No wonder why my brake feels spongy when I brake hard.


Is this normal for dual pivot calipers? Is your 105/Ultegra caliper doing it too?

Thank you for your time.

BarracksSi

My 105 calipers flex a bit, too, now that I look at them.

They don't feel spongy while riding, however. Could be your pads, could be the amount of toe that you've set (hard to see in the vid, but it may not be much anyway).

I'll say this much -- when I had Tektro brakes on my previous bike, changing from the original pads to Kool-Stops improved the braking feel a LOT.

DOOM_NX

Yes, I've already ordered the green SwissStops. But I don't think this is pad-related... Check the rear brake video, as well:


I think the camera exaggerates the flex a bit, but should they move at all?

BarracksSi

What I mean is, even though you don't see the pads squish (I couldn't even feel mine squish when I put my thumb on top between the brake arm and the wheel rim), they'll feel "squishy" while riding and braking, especially if you brake hard. Different pads will feel different during braking even though you won't see them squish any differently while stationary.

Automotive brake compounds differ in feel while working even though they don't compress any differently. The pads used on most daily-driven cars feel more progressive, while some made for harder work (racing, etc) have measurably more "bite" with the same pressure on the brake pedal.

My opinion: the calipers are fine. The calipers don't actually touch the wheels -- it's the pads that do the real work. You'll get a more noticeable change in braking feel by using better pads, and it'll cost a lot less.

Caliper upgrades above yours would involve different bushing materials or ball bearings, completely different pivot designs, and crazy materials. Better bearings will mainly be felt when not actually braking (once the pads are touching the rim, the cable and caliper don't move a whole lot more). Different pivot layouts may increase clamping power (Campy offers a single-pivot rear specifically to specifically decrease clamping power because the rear wheel just doesn't need as much). Fancy materials decrease weight and don't have much to do with stiffness.

BarracksSi

Take it another way:

You can get the beefiest, stiffest, most powerful caliper brakes on the market and make them perform like crap by using crappy pads, fading on moderate descents and harvesting shards of aluminum from the rims like they were made of platinum.

DOOM_NX

Thank you very much BarracksSi. I'll see how the new pads compare to the current ones.

So you say Tektro R580 compares in stiffness with Shimano 105/Ultegra but the pads make the difference?

Psimet2001 

Flex in calipers determines the feel or modulation you feel in use. Yes, pads will change that feel to an extent, but different calipers will also change that feel.

Well designed and or higher end calipers typically provide a better feeling modulation. "stiffer" if you will. Where more of the for e you put into the lever is actually translating to a feel of more braking force. ....not into flexing the caliper.

Cheap brakes are cheap brakes though. If you're used to them you will notice a performance feel get better with new pads.

Use nice calipers and you'll begin to understand the difference. You really need to change it up greatly though to really see the difference. In other words the lower end shimono calipers are near identical to the Tektro offerings. 6 or 1/2 dozen the other.

DOOM_NX

So, Psimet2001, which caliper would offer obvious improvment to the Tektro R580, in your opinion?

pallen

I noticed a dramatic difference when I went from Shimano to Campagnolo.
Not sure if you can use Campy brakes with Shimano though...

lechat

I'm not sure that those brakes are flexing at all. Looks like some give in the cables/housing. To show arm flexing you need a side view taken during actual braking.
Anyway, those 580s are beefy brakes. Doubt you'd feel any improvement unless you went with Dura Ace.

BarracksSi

They're comparable enough that if you spent the money on 105/Ultegra you'll feel like you wasted the cash.

https://eecycleworks.com/VNJune%20BrakeTest.pdf

DOOM_NX

I'm not sure either...
No, I won't be spending any money for Dura-Ace brakes since there's nothing wrong with those Tektros. I'm just gonna change the pads to SwissStop Greens and that's it...

canam73

Not if you want a quick release for the cable.

BarracksSi

Right -- Campy's quick release is at the brake levers, while Shimano's is at the caliper.

Use Shimano calipers and Campy shifters, and you have two quick release options. Go the other way around, and you've got none.

lechat

Yeah, not flex, not in the brake calipers anyway. Probably cable stretch/compression. Unlike shifter cable, most brake cable housing isn't compressionless.

Psimet2001 

I would think that too if I had never run a wide array of brake calipers using the exact same cables and frame/pad combos.

If you (op) are truly having problems with all this then buy some nice calipers - don't slowly step up. If you're complaining about squishy brakes but don't want to spend to get nice calipers then save your $. Do the simple things like pad and cable swaps to improve what you have.

In all honesty the people that talk about brakes and caliper performance the most are the ones who haven't or don't ride with nice ones. Once you do....it just stops being anything you truly even think about anymore.

The newest 2012 Red clampers are the shiz. Wider stance, solid. Performance near a DA caliper but much lighter. More clearance for trend towards wider rims and tires.

Psimet2001 

Oh and cable wise - Yokozuna reaction. The brake housing is near compression less. Longitudinal wires like a shift housing with a radial outside wrap like a standard housing. Superior feel and performance, but they are so stiff that it takes some experience to run them properly. Most shops that are both clueless to their existence, and not experienced with their installation will either poopoo them or simply install them incorrectly.

DOOM_NX

No, it's OK. I'm happy with the braking performance. I was just worried I had terrible calipers that were about to fail in an emergency stop.

ThinLine

I have Dura-Ace brakes and SRAM Force .....they don't flex and are the best brakes I have ever used.

Kimmo 

Oh hey, didn't you hear about the recall? You must have the brakes Shimano accidentally made out of plasticine

Seriously man, this is no big deal at all. I bet you're hauling on the lever way harder than what it'd take to throw you over the bars or skid your back tyre anyway; you can check by sticking a bit of poster goo on your cable where it comes out of the barrel adjuster, and doing some hard stops. The goo will show you how far you pull the cable for max braking.

I'd say if you're having trouble with the capabilities of any short reach dual pivot, you've either got crappy pads or you have extremely demanding braking requirements.

lechat

The same thing happens with my TRP 920s which work great and have a great rep. you'll notice that your rear brake lever has more travel and is mushier than the front. More cable/housing = more give.
If your not concerned about weight Yokozuna is the way to go, especially with carbon wheels in the wet. Supposedly segmented housing such as i-links, Nokon etc. is compressionless but it's pricey and probably not as durable as Yokozuna. I'll find out. Putting i-links on my Caad in the quest for the low 13s.
On my daily driver the TRPs=+Koolstop+ Gore Ride On provide more than enough braking, even here on the rollercoaster terrain of the Cumberland Plateau.

DOOM_NX

Thanks for the input guys... You're amazing

BarracksSi

...and we're cheap, not being afraid to tell you to save your money.

Besides, you can buy a lot of beer n' pizza by not buying new calipers.