On 2/3/2020 1:26 PM, jbeattie wrote:
On Monday, February 3, 2020 at 9:11:47 AM UTC-8, Frank Krygowski wrote:
On 2/2/2020 11:13 PM, jbeattie wrote:
On Sunday, February 2, 2020 at 5:15:10 PM UTC-8, Frank Krygowski wrote:
On 2/2/2020 7:11 PM, jbeattie wrote:

The OE direct mount brakes on my Trek stop well enough but have a slightly different feel than Ultegra dual pivot. Their reason for being is aerodynamics and light weight.

And everyone knows how critical aerodynamics are. Why, just look at how
Shimano AX absolutely transformed everyone's riding experience!

And light weight? Yep, pedaling your 180 pound bike+rider weight up a
hill is a completely different experience than pedaling your 179.9 pound
total bike+rider weight. That extra tenth of a pound absolutely sucks!
Thank God for 0.06% improvements!


Pfff. My Trek is a 15-16lb bike. It's like riding an eBike compared to my commuter-pig. Can't you tell the difference between light and heavy bikes? Riding blindfolded, I can tell the difference between all my bikes within one or two pedal strokes -- just before crashing. I love my super-light, modern racing bike for fast road riding, hanging in with the other, sputtering old former racers.

Focus, Jay! What are we going to talk about - the effect of a change in
weight, or you distinguishing the "feel" of your bikes?

I don't doubt you can detect the different "feel" of each bike you own.
I can do that with mine. But it has far more to do with frame geometry,
tire characteristics, center of gravity location, handlebar variations
etc. than it has to do with any weight difference.

A smart high school junior should be capable of understanding the
physical effect of a change of weight. The effects - speed vs power on
uphills, acceleration vs. force on the flat - depend on the percent
change in _total_ bike+rider weight or mass. And since you brought up
the weight savings of direct mount brakes vs. ordinary calipers, that
percent change is microscopic.

Want proof? The weight difference between a Shimano direct mount and a
comparable Shimano single bolt mount is about 56 grams per set. That's
two ounces. So do some blind tests. Have your son duct tape two ounces
of lead out of your sight at the fork crown of your favorite bike. Do
multiple test rides with and without that horrendous extra weight, at
random. I'm betting you couldn't tell when it's present or absent, just
like you can't feel the difference in weight of direct mount brakes.

0.06% is 0.06%, no matter how you advertise it.

Focus Frank! I was talking about the effect of riding a bike that is five pounds lighter than my commuter. And yes, there are a multitude of other differences, but weight is a big one.

We weren't talking about any five pound difference. We were talking
about "Better braking" (see it there in the subject line?). And at the
moment, I was responding to your sentence:

"The OE direct mount brakes on my Trek stop well enough but have a
slightly different feel than Ultegra dual pivot. Their reason for being
is aerodynamics and light weight."

Again: "Their reason for being is aerodynamics and light weight." Their
weight difference is about two ounces, or roughly 0.06% of the moving
weight. Their aerodynamic difference is even more negligible.

And what is the problem with a lighter more aero brake?

No problem, provided there are no detriments that negate those benefits.
But many people seem to hold a mindset in which any benefit is all that
matters, despite how small it may be; and any mention of detriment is
heresy. And the phrase "good enough"? HERESY!

I guarantee you that the direct mount brakes on my Trek kick the living sh** out of any cantilevers I've owned, and that's Shimano, Mafac, Paul, Scott, DiaCompe (and maybe others, I don't recall).

In what way are they that much better? Lighter lever force? Fine, but
generally irrelevant, unless you have some problem with grip strength.
And with cantilevers, I have adjustable lever force.

We're having a rare sunny, mild day and my wife and I just got back from
a little ride on the tandem. Nothing impressive, max speed only 30 mph
on a couple downhills. But the cantilevers stop well enough I never even
thought about the brakes, despite this discussion. What more do I need?

The OE dual pivots are good brakes, and they provide more tire clearance than ordinary dual pivots. Where's the crime? Seems like a win-win to me.

But they have less tire clearance than what I'm using, so if you're
going to count that as an advantage, you're losing.

I'm not trying to say anyone should not use those if they choose. But
let's look at both sides of the balance sheet. To go with that
better-than-the-worst tire clearance (whoopee!) and the 0.06% reduction
in weight, you've committed to a bike frame that can't use any other
type of brake - unless, I suppose, someone makes some sort of adapter.
If that brake goes the way of bottom bracket U-brakes or roller cam
brakes, you'll be scrounging 2025 Ebay for parts.

To me, that incompatibility is a disadvantage. But I guess to someone
who is already three product cycles deeper into "No, THIS is the new
incompatible standard, because it's BETTER!!" incompatibility wouldn't
matter. Because "Why wouldn't you want what's BETTER?"

That .06% added up with all the other .06%s has produce a really light, fun bike.

I took a guess at typical bike+rider weight to compute that 0.06% from
the two ounce (56 gram) differenc. Let's just work with the "five
pounds lighter than your commuter" bike.

You'd need 40 of those tiny weight reductions to drop five pounds; and
that still wouldn't turn your commuter pig into a lithe, snappy sport
bike. Or to turn things around, if you added two ounces to your light,
fun bike you'd never notice the difference. Really, it's just the same
as adding one more rear cog but changing nothing else; it makes
negligible difference.

If you could drop the two ounces or add the cog with no detriments,
sure, why not? But in real life, that's not how it works. So it's more
logical to look at both sides of the balance sheet. How is this not obvious?

--
- Frank Krygowski