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### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 12:25 pm
TobinHatesYou wrote:I did the math for my times up Old La Honda, a roughly 20min climb for me at a 270W. Losing 400g is like...a 7 second improvement, within the margin of error...swinging wide on a corner, slight headwind, hotter day, etc. I could just gain 5 watts instead and see better than 7 seconds.

True, you could ride a 10kg bike and lose less than a minute by that logic!

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 12:32 pm
Marin wrote:
TobinHatesYou wrote:I did the math for my times up Old La Honda, a roughly 20min climb for me at a 270W. Losing 400g is like...a 7 second improvement, within the margin of error...swinging wide on a corner, slight headwind, hotter day, etc. I could just gain 5 watts instead and see better than 7 seconds.

True, you could ride a 10kg bike and lose less than a minute by that logic!

The logic is you give up a little in extra weight for tangible braking improvements. You might even gain all of that time back on the descent because of confident braking.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 12:32 pm

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 1:52 pm
That would be true if rim brakes weren't so good already. Good descenders have no problem braking to the limit of adhesion.

And in the wet, you can't brake as hard anyway because tire grip is so much lower.

Ok, now comes the "modulation" argument:

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 2:37 pm
Marin wrote:That would be true if rim brakes weren't so good already. Good descenders have no problem braking to the limit of adhesion.

And in the wet, you can't brake as hard anyway because tire grip is so much lower.

Ok, now comes the "modulation" argument:

But you can modulate the braking much much better with disc brakes!

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 2:41 pm
calleking wrote:
Marin wrote:That would be true if rim brakes weren't so good already. Good descenders have no problem braking to the limit of adhesion.

And in the wet, you can't brake as hard anyway because tire grip is so much lower.

Ok, now comes the "modulation" argument:

But you can modulate the braking much much better with disc brakes!

Mmm ... I ride both, can't see any real difference... apart from in the rain Do you die a lot in the rain

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 3:02 pm
I've been looking at the cost for a front disc conversion using top notch stuff: campy h11, enve fork, schmolke tlo, wi hub: around 1800 euros. And then if I'd want to fix the weight penalty, another 1500 (weenie saddle, xpresso 15, super record crankset, eebrake rear). I guess for this sort of cash I'd be better buying a very nice mtb (hallo to a carbon canyon with xt di2) and expand my riding possibilities )

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 4:12 pm
TobinHatesYou wrote:I did the math for my times up Old La Honda, a roughly 20min climb for me at a 270W. Losing 400g is like...a 7 second improvement, within the margin of error...swinging wide on a corner, slight headwind, hotter day, etc. I could just gain 5 watts instead and see better than 7 seconds.

Who ever said that the ONLY reason ever to own a lighter bike was to make it up a mountain quicker?
Handling?
Acceleration?
Bunny hopping?

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 4:51 pm
Lewn777 wrote:

People rant and rave daily about how their bike handles better, accelerates better and goes up mountains a tad faster because they just switched out a boat anchor OEM set of wheels to something much nicer and saved 500 grams. Yet you show up with some kind of post-purchase rationalization disorder on a website called weight weenies of all places talking about how 900g hasn't made any difference. People spend thousands of dollars to shed that amount weight off their bikes.

Maybe you should start a website called whogivesafigabouttheweighoftheirbikeweenies.com

Enjoy riding your bike, I'm sure it's good. I'd like to own one too, just stop trying to convince everyone else, it makes you sound like you're trying to convince yourself.

A. Rotating mass in wheels will affect the feel of a bike a lot more than 400g in fixed weight. And there is nothing stopping someone from switching out their boat anchor OEM disc brake wheels for something lighter or spending thousands to shave weight off their bike.

B. Yeah, this is weight weenies, yet about 70% of the rim brake bikes I see posted weight around the same as my disc brake bike. And that is probably the same percentage for bikes out on most group rides. Unless your paycheck is coming from winning races and you need every marginal gain you can get, spending thousands of dollars to shed weight off your bike is a want, not a need.
Like I said, building light bikes is a fun hobby and that's fine, but don't push your choices as gospel.

C. Unlike the anti-disc crowd who seem to have jump into every disc brake thread and convince everyone how terrible discs are, I am not trying to convince you to buy anything and don't care what you ride. My position has always been to counter the incorrect "facts" and silly arguments like fake outrage over 400g as if that's critical to enjoying your bike or being fast.

.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 5:59 pm
This is going to sound crazy, but I'm putting it out there anyway..........I prefer rim brakes on my road bike. That said, I have disc on my cross bike which serves road duty occasionally, and I have ridden a lot of disc equipped road bikes. Does anyone feel a difference in handling when making high speed sweeping turns to the right? Like the gyroscopic effect and extra spinning mass of the rotor on the non drive side of the bike is causing a bit of understeer? Or is this in my head?

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 6:43 pm
I'd love to have a hydraulic disc bike. I'd put fat 28mm tire, full fenders and regulate it to rain/winter duties. On my posh "proper race bike" that's my pride & joy... rim brakes.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 7:01 pm
wheelbuilder wrote:This is going to sound crazy, but I'm putting it out there anyway..........I prefer rim brakes on my road bike. That said, I have disc on my cross bike which serves road duty occasionally, and I have ridden a lot of disc equipped road bikes. Does anyone feel a difference in handling when making high speed sweeping turns to the right? Like the gyroscopic effect and extra spinning mass of the rotor on the non drive side of the bike is causing a bit of understeer? Or is this in my head?

It may not be in your head, but it isn't the disks that's causing it. Most likely a difference in bike geometry. The inertial effects of a rotor are so small that they're completely negligible when considering the entire bike and rider.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 8:10 pm
wheelbuilder wrote:This is going to sound crazy, but I'm putting it out there anyway..........I prefer rim brakes on my road bike. That said, I have disc on my cross bike which serves road duty occasionally, and I have ridden a lot of disc equipped road bikes. Does anyone feel a difference in handling when making high speed sweeping turns to the right? Like the gyroscopic effect and extra spinning mass of the rotor on the non drive side of the bike is causing a bit of understeer? Or is this in my head?

More likely the geometry than anything.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 9:11 pm
CallumRD1 wrote:
wheelbuilder wrote: Does anyone feel a difference in handling when making high speed sweeping turns to the right? Like the gyroscopic effect and extra spinning mass of the rotor on the non drive side of the bike is causing a bit of understeer? Or is this in my head?

It may not be in your head, but it isn't the disks that's causing it. Most likely a difference in bike geometry. The inertial effects of a rotor are so small that they're completely negligible when considering the entire bike and rider.

CallumRD1 is exactly right; the inertial effects of disc rotors are tiny. If inertial effects were at play (and they're not, at least not at a perceptible level) then they'd be more likely due to the increase in rotating mass due to the fatter tires and wider rims people tend to run on disc-braked bikes.

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 9:22 pm
MoPho wrote:spending thousands of dollars to shed weight off your bike is a want, not a need.

So... do you need disc brakes? Or are they just as unnecessary as saving a few grams?

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 9:22 pm

### Re: Is 2018 the year proper race bikes with discs gain momentum?

Posted: Wed Nov 08, 2017 9:30 pm
themidge wrote:So... do you need disc brakes? Or are they just as unnecessary as saving a few grams?

Nope, I wanted them because they are an improvement for my riding.

.