Rim brake vs Disc Brake Aero test.
12-13-14, 06:54 PM
#176
Senior Member
It's funny. At 200+ lbs. I can't ride any of these lightweight rims or wheels. But riding down a long hill last summer I did make my front rim really hot.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
12-13-14, 06:57 PM
#177
Senior Member
The funny part is these fellows keep trying to convince others of their irrationality. I wonder if Jiggles and bt actually work for a disc brake company and are doing a bit of social media engineering to get people to talk up and try a new product.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
12-13-14, 07:11 PM
#178
Mr. Dopolina
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Oh, here's one. American Classic mag clincher, 300 grams. That is claimed; but so are his weights.
MAGNESIUM|CLINCHER
MAGNESIUM|CLINCHER
Again, our weights are not CLAIMED. They are PROVEN by third parties in published articles.
And what about ENVE? Do you not believe them as well?
Utter genius, you!
12-13-14, 07:17 PM
#179
Mr. Dopolina
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Yet I post facts, while you can't remember if your own rims are 405g or 410g claimed. Probably come out 440 actual. Or as you get customers to do your beta testing for you, slowly creep up the material mass to increase durability. This happens all the time with small vendor stuff that is pushing the cutting edge.
Designed, built, tested, produced, independently verified, published, already available to consumers all at 405g.
Your hatred of me has turned your brain to mush. I pity you.
Last edited by Bob Dopolina; 12-13-14 at 08:49 PM.
12-13-14, 08:37 PM
#182
Senior Member
Cool. You got connections to a team? Or maybe lots of friends who are pro riders? That's neat.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
12-13-14, 08:54 PM
#184
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i think that if i owned a business i would hope that i had enough sense to restrain myself from attempting to shame someone on an internet forum even if i was convinced of their stupidity.
12-13-14, 09:01 PM
#185
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If you also found yourself derided, insulted, attacked, disparaged in thread after thread there may come a point where enough is enough especially when that person is doing it to you and your business with baseless bull**** and gibberish.
Last edited by cb400bill; 12-14-14 at 05:05 AM. Reason: edited censor bypass
12-13-14, 09:04 PM
#186
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I really didn't want this thread to be about me, us or any of the usual crap. I was hoping we could focus on the new data and have fun speculating how things would play out from here.
We did for several pages and it was fun. Now we are where we are.
Is it possible for the thread to get back on course and focus on the subject at hand or are we done here?
We did for several pages and it was fun. Now we are where we are.
Is it possible for the thread to get back on course and focus on the subject at hand or are we done here?
12-13-14, 10:10 PM
#187
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If I recall correctly, the Stans Alpha 340 rim is about 1.5mm thick at the brake track. They can take a little off if the brake track isn't needed, but strength will be compromised.
12-13-14, 10:21 PM
#188
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You always need enough material to hold the bead together and have enough strength to endure impacts. The AX 45mm rim is about 300 grams as well. A disc rim will not be lighter.
If I recall correctly, the Stans Alpha 340 rim is about 1.5mm thick at the brake track. They can take a little off if the brake track isn't needed, but strength will be compromised.
If I recall correctly, the Stans Alpha 340 rim is about 1.5mm thick at the brake track. They can take a little off if the brake track isn't needed, but strength will be compromised.
Mine are based on CAD modeling and then actual tooling produced to make actual products that are then tested first by machines and then in the real world by independent testers.
The weight reduction on alloy rims isn't nearly as much as with carbon as some of the carbon is there to deal with heat so more can be removed when designing a rim without a brake track.
I know you won't take my word for it but links to other brands already posted clearly show this.
Bottom line, regardless of material a disc brake rim will always be lighter than its' rim brake counterpart. How can it not be?
Even if you used the exact same alloy rim and simply anodized the brake track, that alone would shave 5g or so. Minuscule, I know (and within tolerance) but lighter nonetheless.
Last edited by Bob Dopolina; 12-13-14 at 10:27 PM.
12-13-14, 10:27 PM
#189
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Fail.
Designed, built, tested, produced, independently verified, published, already available to consumers all at 405g.
Your hatred of me has turned your brain to mush. I pity you.
Designed, built, tested, produced, independently verified, published, already available to consumers all at 405g.
Your hatred of me has turned your brain to mush. I pity you.
Add to that your continual denial of the forces involved with discs. A front disc wheel under braking undergoes FIVE TIMES the maximum radial load of a rear wheel under power. The torque acting on the left fork leg is huge, and then torque acting along the fork to the crown is about triple that of a rim brake. These larger forces require stronger material, and that increases weight.
Fact.
Physics.
In the fork, in the skewer, in the hub, in the spokes.
Great job that Specialized was able to make that already porky road frameset the same weight as the rim brake version. It doesn't matter. Physics says rim brake bikes can be made lighter. We will never see a production 1000g disc brake frameset. Ever.
We might see something close. Right now at the beginning of road discs, when producers are eager to prove the skeptics wrong. But reality and broken parts will teach them to not flaunt King Physics for long.
12-13-14, 10:28 PM
#190
Uber Goober
I don't know what goes into the decision, but my Sojourn has 140 on back, I think 160 on front, not sure if this applies to any other road bike or not.
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12-13-14, 10:34 PM
#192
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I don't hate you in the least. You're just not going to convince a rational observer that disc rims are lighter when 1. it's currently physically impossible to find a disc rim lighter than the light normal rims and 2. the weight that you and enve claim to have shaved is within manufacturing tolerances.
Add to that your continual denial of the forces involved with discs. A front disc wheel under braking undergoes FIVE TIMES the maximum radial load of a rear wheel under power. The torque acting on the left fork leg is huge, and then torque acting along the fork to the crown is about triple that of a rim brake. These larger forces require stronger material, and that increases weight.
Fact.
Physics.
Add to that your continual denial of the forces involved with discs. A front disc wheel under braking undergoes FIVE TIMES the maximum radial load of a rear wheel under power. The torque acting on the left fork leg is huge, and then torque acting along the fork to the crown is about triple that of a rim brake. These larger forces require stronger material, and that increases weight.
Fact.
Physics.
Fact.
2. Tolerance on carbon prepreg is closer to 3%, which is not the 10% difference already shown by ENVE and others (which would still have the same tolerances involves) So, no.
Fact.
12-13-14, 10:36 PM
#194
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The 41, elevating stupid since - wait, what were we talking about, again?
12-13-14, 10:37 PM
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And you base these assumptions on what exactly?
Mine are based on CAD modeling and then actual tooling produced to make actual products that are then tested first by machines and then in the real world by independent testers.
The weight reduction on alloy rims isn't nearly as much as with carbon as some of the carbon is there to deal with heat so more can be removed when designing a rim without a brake track.
I know you won't take my word for it but links to other brands already posted clearly show this.
Bottom line, regardless of material a disc brake rim will always be lighter than its' rim brake counterpart. How can it not be?
Even if you used the exact same alloy rim and simply anodized the brake track, that alone would shave 5g or so. Minuscule, I know (and within tolerance) but lighter nonetheless.
Mine are based on CAD modeling and then actual tooling produced to make actual products that are then tested first by machines and then in the real world by independent testers.
The weight reduction on alloy rims isn't nearly as much as with carbon as some of the carbon is there to deal with heat so more can be removed when designing a rim without a brake track.
I know you won't take my word for it but links to other brands already posted clearly show this.
Bottom line, regardless of material a disc brake rim will always be lighter than its' rim brake counterpart. How can it not be?
Even if you used the exact same alloy rim and simply anodized the brake track, that alone would shave 5g or so. Minuscule, I know (and within tolerance) but lighter nonetheless.
Yes, you take off a few grams by reducing the amount of carbon otherwise used for heat absorption. But over 400g for a rim is by no means light. If a weight weenie was building a disc wheelset, he would choose a lighter rim brake rim. AX claims that their fiber layup allows better heat dissipation so they do not need as much mass. I speculate that Zipp is concerned with braking, as well as impact resistance, since their wheels are used by so many pro teams in cx and on cobblestones.
12-13-14, 10:41 PM
#196
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1. Cherry picking an alloy rim and comparing it to a 24-25mm wide 40-45mm deep carbon rim is silly. Several links have been provided proving that a disc specific rim is, in fact, lighter than the compatible rim brake version.
Fact.
2. Tolerance on carbon prepreg is closer to 3%, which is not the 10% difference already shown by ENVE and others (which would still have the same tolerances involves) So, no.
Fact.
Fact.
2. Tolerance on carbon prepreg is closer to 3%, which is not the 10% difference already shown by ENVE and others (which would still have the same tolerances involves) So, no.
Fact.
Classic, Bob.
A smarter approach would be to say that 500g only matters to weight weenies, but you choose another hill to die on.
12-13-14, 10:59 PM
#197
Mr. Dopolina
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Ok. Tell us why a disc specific version of a rim brake rim, of any dimensions, will not be lighter and just as strong.
Show your work.
Show your work.
12-13-14, 11:37 PM
#198
Senior Member
All this thrashing around..
I am riding 300 gram alloy rims -tubulars obviously. Using rim brakes I have no problems with rim strength, braking, heat dissipation, whatever. Even in the rain.
Despite regular monster descents, I have no need for disc brakes on my road bikes. They are expensive, heavy, fussy, and are a pain on wheel changes. I have several sets of wheels I swap between several bikes, and I don't want the hassle of trying to dial out caliper rub with each wheel change.
Pros will never use discs unless they are all forced to - everyone, to level the performance handicap.
The only reason why this is even an issue is that the bike industry needs something new to sell.
Lots of new road bikers are transplants from mountain biking. These newbs inappropriately think that all MTB technology is useful on the road. Like sloping top tubes and discs. Not the case.
I am riding 300 gram alloy rims -tubulars obviously. Using rim brakes I have no problems with rim strength, braking, heat dissipation, whatever. Even in the rain.
Despite regular monster descents, I have no need for disc brakes on my road bikes. They are expensive, heavy, fussy, and are a pain on wheel changes. I have several sets of wheels I swap between several bikes, and I don't want the hassle of trying to dial out caliper rub with each wheel change.
Pros will never use discs unless they are all forced to - everyone, to level the performance handicap.
The only reason why this is even an issue is that the bike industry needs something new to sell.
Lots of new road bikers are transplants from mountain biking. These newbs inappropriately think that all MTB technology is useful on the road. Like sloping top tubes and discs. Not the case.
