Brake Caliper Choice

Changing the pads is an easy upgrade if you are strapped for cash, then as you say save your pennies over the winter and buy yourself a pair of 5700 105's or 6700 Ultegra's which are now available at good discounts.

http://www.wiggle.co.uk/shimano-105-580 ... -calliper/

http://www.wiggle.co.uk/shimano-ultegra ... e-caliper/

lesfirth wrote:

If you do a bit of searching you will see that we have done this subject several times at great length.

Anyone with a technical/scientific education will agree that its all about the pads. Others will have different ideas.

I'm a science teacher and I do not agree that it's all about the pads. Shimano 5800 calipers can be bought for under £50 a pair and they would make a good upgrade, even with the stock Shimano pads. There is really no need for anything else, except for posing value.

Costley?
I use them because they are cheap and good.

6800 calipers work even better though. Of course the best brakes are Campagnolo Record but will cost you alot more.

DKay wrote:

lesfirth wrote:

If you do a bit of searching you will see that we have done this subject several times at great length.

Anyone with a technical/scientific education will agree that its all about the pads. Others will have different ideas.

I'm a science teacher and I do not agree that it's all about the pads. Shimano 5800 calipers can be bought for under £50 a pair and they would make a good upgrade, even with the stock Shimano pads. There is really no need for anything else, except for posing value.

OK lets have a science lesson. Please explain why a dura ace caliper will stop your bike better than a sora caliper.
Feel free to use any technical terminology . An expensive caliper may be lighter or it will look better, it might be made of titanium or carbon fibre but please tell me why it will do its job better.

lesfirth wrote:

OK lets have a science lesson. Please explain why a dura ace caliper will stop your bike better than a sora caliper.
Feel free to use any technical terminology . An expensive caliper may be lighter or it will look better, it might be made of titanium or carbon fibre but please tell me why it will do its job better.

Stiffer due to different materials, casting/forging techniques, different mechnical leverage/geometry, higher quality components, tighter manufacturing tolerances and better durability. The fact they're lighter is a bonus, but then that all depends if you include that factor as part of the components function.

That good enough for you? Although I'm assuming your question was rhetorical.

Also, on my own subjective experience, the new generation of Shimano rim brakes are a noticeable step up in performance from the older range. You get way more power using them from the hoods especially.

If you upgrade to 105's or better you will see a marked improvement. Check the sales for the best price, £60 seems expensive to me. The stock brakes on a lot of bikes have poor pads and cheaply made callipers.

itsnotarace wrote:

This is an old test from 2009 but Dura Ace in both 7800 and 7900 came out best in terms of power, modulation and panic stop distance, and also had the highest deceleration figures

http://www.eecycleworks.com/VNJune%20BrakeTest.pdf

Interesting article. Would be good to see how the newer Shimano calipers would fare.

DeVlaeminck wrote:

Hmmm, for me that test is something which is basically subjective trying to be scientific. Are they seriously telling us that Dura Ace stop a bike 30% faster than Record? Why didn't they just apply the brake a bit harder with the Record? All they are really saying is at either they felt more confident with one caliper over another or that they happened to execute their braking that bit better one time compared to another. I can buy that some calipers are a bit stiffer, maybe have better modulation and feel but when they start claiming relatively big differences between top end calipers it really does stretch credibility.

That also aren't using the same brake pads with each caliper either.

DeVlaeminck wrote:

Hmmm, for me that test is something which is basically subjective trying to be scientific. Are they seriously telling us that Dura Ace stop a bike 30% faster than Record? Why didn't they just apply the brake a bit harder with the Record? All they are really saying is at either they felt more confident with one caliper over another or that they happened to execute their braking that bit better one time compared to another. I can buy that some calipers are a bit stiffer, maybe have better modulation and feel but when they start claiming relatively big differences between top end calipers it really does stretch credibility.

From the test notes in the article

"For that, we used a panic stop — measuring how quickly each brake could decelerate from 40km/hr to 0km/hr. This test was preformed on a flat, windless road. For each brake, the rider accelerated to 40km/hr then grabbed the brakes — hard — on a pre-determined mark and recorded stopping distance. This test was performed 10 times for each brake, and the stopping distances were averaged."

Also from the DA7900 test:

"We had trouble harnessing the power of this brake in every situation, specifically our panic stop test. While able to produce two of the shortest stopping distances in the entire test, we also found ourselves in a few tense nose wheelies that threw its average score. Its shortest stopping distance produced an uncanny deceleration of 10.35 m/s^2, that’s over 1 G (as in g-force)."

So whilst it's not a true scientific test, it's a good enough measure for me when averaged over 10 runs. If you have any better scientific data please do share.

At the end of the day, there are a lot of variables involved and there is a trade off between the options. Pad compound being one variable - soft compound will stop you faster but produce more brake dust and wear faster. Harder compound will produce less dust and have a longer life but not stop you as quick. Rim material being another variable. Tyre compound being another variable. Road surface and also temperature also play a part. Rider experience too - it takes a lot of confidence to really slam on the brakes and have no fear of the back wheel coming up off the ground and being able to control it without going over the bars

What I can say for sure having tried a bunch of lightweight calipers myself is that Ultegra and DA calipers, and the top end TRP calipers give excellent results both from the hoods and the drops, and leave you with less fatigue at the end of a long ride due to less force being required through the levers to fully stop or check speed.

It's also worth noting that the higher end Shimano calipers & levers have a 1:4 cable pull ratio compared to 1:3 for most other levers/calipers. This reduces the amount of lever pull required to get the same amount of braking

DKay wrote:

Of course flexing of the caliper will make a difference the amount of force applied to the rim. For a given amount of force at the lever, a stiffer caliper will transfer more of that force to the rim instead of flexing the actual caliper.

Think about this carefully. Lesfirth is partially correct - if you pull on a spring, stiffness only affects how far you have to pull for a given force, not the reaction force at the other end.

Where lesfirth is wrong is that a brake caliper is a 3D device, and you only "don't care" about stiffness in one plane of operation. If you pull hard on the brakes with the bike stationary, watch how much the arms move and in which directions. Not all the force applied to bending the caliper gets transmitted to the pads.

Anyway, this is all about modulation/control anyway - the person who can brake fastest is the person best able to keep the bike on the point of doing a stoppie for the longest period of time.

itsnotarace wrote:

DeVlaeminck wrote:

Hmmm, for me that test is something which is basically subjective trying to be scientific. Are they seriously telling us that Dura Ace stop a bike 30% faster than Record? Why didn't they just apply the brake a bit harder with the Record? All they are really saying is at either they felt more confident with one caliper over another or that they happened to execute their braking that bit better one time compared to another. I can buy that some calipers are a bit stiffer, maybe have better modulation and feel but when they start claiming relatively big differences between top end calipers it really does stretch credibility.

From the test notes in the article

"For that, we used a panic stop — measuring how quickly each brake could decelerate from 40km/hr to 0km/hr. This test was preformed on a flat, windless road. For each brake, the rider accelerated to 40km/hr then grabbed the brakes — hard — on a pre-determined mark and recorded stopping distance. This test was performed 10 times for each brake, and the stopping distances were averaged."

Also from the DA7900 test:

"We had trouble harnessing the power of this brake in every situation, specifically our panic stop test. While able to produce two of the shortest stopping distances in the entire test, we also found ourselves in a few tense nose wheelies that threw its average score. Its shortest stopping distance produced an uncanny deceleration of 10.35 m/s^2, that’s over 1 G (as in g-force)."

So whilst it's not a true scientific test, it's a good enough measure for me when averaged over 10 runs. If you have any better scientific data please do share.

At the end of the day, there are a lot of variables involved and there is a trade off between the options. Pad compound being one variable - soft compound will stop you faster but produce more brake dust and wear faster. Harder compound will produce less dust and have a longer life but not stop you as quick. Rim material being another variable. Tyre compound being another variable. Road surface and also temperature also play a part. Rider experience too - it takes a lot of confidence to really slam on the brakes and have no fear of the back wheel coming up off the ground and being able to control it without going over the bars

What I can say for sure having tried a bunch of lightweight calipers myself is that Ultegra and DA calipers, and the top end TRP calipers give excellent results both from the hoods and the drops, and leave you with less fatigue at the end of a long ride due to less force being required through the levers to fully stop or check speed.

It's also worth noting that the higher end Shimano calipers & levers have a 1:4 cable pull ratio compared to 1:3 for most other levers/calipers. This reduces the amount of lever pull required to get the same amount of braking

Maybe the testers just set the Dura Ace calipers up in a way that suited them - they do say the Record pads sit quite far from the rim - maybe they should have had them closer. Maybe they are just used to the Dura Ace brakes and don't often use Record. Did they use the same bike with the same levers - if so maybe some levers suit some calipers in terms of cable pull?

Bottom line is in what way could a Dura Ace caliper make that much difference compared to Record or any other high end caliper? If they can't explain why then the whole thing is meaningless.

Yeah that's right, you've got me, that's why I have Ultegra on my race bike, because I hate Shimano.

You are right, no point thinking for yourself in the face of such "science"', case closed.