Кому интересно, можно почитать статью (правда на английском;)). Источник:
http://www.avidbike.com/8_aboutavid/abo ... ation.html
Velo Vert #123
May 21 – June 22, 2001
"25 Freins au banc de torture"
By Paul Salvaire
Translation by Brett Lindstrom
"25 Brakes put to the Torture Test"
(Gold Disc 2001 Comparison)
One no longer can imagine a Mt. Bike without a suspension fork. Disc brakes are the next unavoidable change. Inasmuch, this article is about highly technical accessorizing, where it’s difficult to tell the difference between the good and the bad. Pay attention to the torture product test to dispel those preconceived ideas.
The idea is simple: to objectively execute a power test on the existing adaptable disc brakes. Everything is possible. From well-known brands to the least known, it was necessary to pull together all the influence and persuasion of Seb to test all twenty-three different models. As much energy was needed to conduct the power test. University scholars recruited from as far as Germany conducted the tests at the I.U.T. and private laboratories. When Decathlon offered the assistance of their research center, with their computerized deceleration testing equipment, and the help of their motivated and highly competent engineers, all we could do was say yes. All that was left was to start the work: one marathon week, all assembly was required, a breaking in period, and two and a half hours spent testing each brake, in the best case scenario: when a brake didn’t budge after a half hour, didn’t loosen up or didn’t stop a special wheel, or when a problematic brake didn’t cause us to start all over again. Finally to set the record strait, we added two remarkable Rim brakes, one hydraulic and the other a cable V-brake. These standards (results of the rim brakes) have brought a wealth of information; without them we couldn’t validate one disc brake from the other, well, sort of…
The Test Protocol
The measurement test is generally designed to test the whole bike for European and DIN standards. From conception and Dutch fabrication, this jewel was specifically designed for bicycle brakes. A modified version, it resembled a power test for a car or motorcycle. A rough cylinder spins the wheel to a programmable speed. A jack is pushed against the wheel to simulate the weight of a cyclist. A metal arm is attached to the handle bar with a strap attached to the brake lever simulating the action of two fingers pulling (centering 4 cm from the end of the lever). The weight is easily adjustable and calibrated. We can determine the exercised force needed to brake by the level of cylinder speed. The test includes an articulated jet, used for moistening the rim or brakes simulating wet conditions. Plus, a computer with software specifically designed for this test. The results are then transferable to a calculus-based software, for reprocessing and compilation. The protocol of this test consists of a breaking in period. We have noted that all the brakes needed this step before finding their optimal power. It’s also necessary for the rim brakes: Contrarily to an accepted idea, disc brakes do not require a longer break-in period than V-brakes, but about the same time. The break-in period is a session of thirty quick depressions of the brake (2 seconds each), strongly emphasized depressions: 120 Newton, equal to 12 kilos of pressure at the end of the brake lever, that which can cause a cable to slip when not properly anchored and require the purging of a hydraulic because of a couple of bubbles. This test is necessary because the rate of deceleration could send you over the bars the moment the calipers make contact with the disc. Moreover, in spite of the 100 kilos of pressure exercised on the wheel, and the semi slick tires, a strong depression will stop the wheel completely, rendering the deceleration immeasurable The power test properly said consists of four levels of braking effort, from the level of a light one fingered pull (50 Newton) to a strong pull (110 Newton), with two intermediate levels. Thus, we have obtained a picture, not only of the efficiency of a brake, but also of its progression. Each of these stages is measured four times, of which we take the average. One 30- second interval allows the brake to cool down between two pulls of the brake. We have determined the power level by the slowing down force exercised. Less spectacular then the notion of "braking distance"(but with which tire, and on what surface) it is worthwhile to illustrate the biomechanical results of the system: " If I apply 10 kilos, how fast will I slow down?" We can see that if some brakes experience a power loss – the leverage effect is good, hydraulic or not -, some are periodically replaced by dragging your feet on the tire or the ground.
Endurance Test
Our team wanted a power module to complete the test. The idea wasn’t in measuring the progression and the power in an urgent case, but in simulating the long and light slow-downs, often necessary in descending the mountain. This test consists of the effects of cross country riders more than a crazy down- hiller, but it does reveal many lessons: after only 30 seconds of single finger braking, many brakes, and of the more reputable, were faithful. Some discs pretending to accommodate down-hillers and free-riders had buckled or warped spectacularly, so much so that we had to separate the field, in one case a rotor broke where it connected with the caliper.
The Setbacks
…. Some brakes had not arrived before the start of our test. One of them did not survive the breaking in; the cables shattered after a few seconds. Others had arrived in indecent states and in much need of help, typically needing a preliminary purge of the hydraulic line. This is an excellent time to note the poor handling in shipment and poor packaging. Above all, had there not been a reserve hydraulic bottle equipped with an airtight membrane, somewhat flexible…More of the same, a brake group was sent with much assembly required, to one side some meters of housing, on the other side a bottle of Dot 4 liquid and a hazy bottle supposedly injecting the liquid in the housing without adding bubbles. A double flushing is necessary, and hello trouble, with all that hydraulic liquid it was inevitably spilled. The hub of an old style brake could not accommodate discs of today’s international standards of our three Rockrider bikes. The internal face of the caliper came into contact with the spokes. It was necessary to use a Grimeca wheel (a carbon composite wheel) with a Giant rotor. Leaving a lot of room to mount the hydraulic caliper of a 1400 motorcycle. But avoid this option unless you plan to customize your V-Max: at only two bars of pressure, the inner tube exploded in our faces, the slick inner profile of this rim, appeared totally incapable of holding the wire bead of the tire in place, where there is a great propensity for the tire and the rim separating. Moreover, we couldn’t figure out if it needed a tubular tire (in 26"diameter, MTB), and the glue for properly seating the tire to the rim.
The Misleading Myths
Without being extreme, our tests of torture were revealing of those brakes that only looked good but should only be used for fire road rides. Our fact-finding presentation will reveal the truths of the brakes for which you dream and can save you from some disappointments. For us as well, in spite of a good trail experience, having had some confirmations, but also some surprises, and disappointments! Here are some of the enlightenments:
1. Hydraulic is not necessarily better than cable actuated!
Indeed, the worst brakes use a cable. But contrarily, in absolute power, the urgent kind of braking, the cable actuated Avid (the Avid, Arch Rival) came in second, right behind a heavy hydraulic brake, specifically designed for descending. Moreover, the cable system had completely, and perfectly resisted the endurance test that had cause the oil of some hydraulics to boil. In contrast, only one hydraulic rim brake (the Magura HS-33) appeared notably superior in efficiency, reputing the more famous of its competitors, the Shimano V-brake.
2. A disc is not necessarily superior to a classic brake!
A good brake like the V–Brake, on a standard aluminum, grooved surface rim, proved more effective than entry-level hydraulics. Moreover, the hydraulic rim brake (HS-33) proved superior to half of the discs we tested! Additionally, the rim brakes, hydraulic or not, were put to the endurance test, and it is not strange to think that the large diameter of the rim cools faster. Modernists propose this, when wet, the lost efficiency of the pads, especially at the braking point, is more sensible with a disc. But we did not test a classic brake with ceramic rims and specific pads, a tried and true solution.
3. A double or a quadruple piston is not more efficient than a single piston!
The uncontestable winning brake, in pure power level, is the Magura Gustav. It doesn’t consist of a double piston system, but floating caliper, with a simple piston split in two. Made by the same manufacturer, with the same two rotors, the simple piston Louise largely surpasses the double piston Clara. Finally, one single caliper with four pistons was really convincing, the Hope open, named "the Enduro" by the French importer.
4. A Large disc is not necessarily more effective than a small disc!
With the same brake body, a rotor two times larger brakes two times harder. In any case, the bigger the braking surface, properly said, the better the braking. A circumference two times larger signifies four times more braking surface. It’s a big disc that won our pure power test, but the size of the rotor isn’t everything. Thus, the Hayes "Purple" and the Hope "Enduro" tested well; both have a terrifying price tag, equal to the size of their big discs. Certainly, these discs will remain close to straight if we leave them the proper cooling period, but the Formula Evoluzione perfectly resisted the heat and was equally powerful with a small disc attached by rivets to a larger one. Equally, for the Magura Louise, that raised its efficiency with the three "descenders", it doesn’t pretend to be an XC brake… Let the truth be told", each brand’s reputation is on the line...
*The mythical Hope, pioneer of pioneers of the Mt. Bike disc, work of art of aeronautical design, decidedly so. Though, more convincing, and equally so, is its copy by Giant: when the Taiwanese industrial plants are more effective than the British craftsman, the Empire has been defeated. I’m starting to wonder why Triumph Motorcycles prefer to import their brakes from Japan or Italy. It’s all fun and games; however, you wouldn’t want to risk being thrown "over the bars" with Deore. Certainly, XT is not so bad, not anymore, with a typical disc size (little), which is not the one you see at all the downhill parks on the bikes of Factory down hillers.
*Who wouldn’t have noticed the strange relationship between the "big S" and the Grimeca four pistons? Then again, the Asian factories are becoming more efficient, with an emphasis on the counter production of the big Italian specialists. Tried and true old brakes, certainly, but we’d have to say that the memories weren’t that great. Fontana, for the drums, or Brembo, for discs, otherwise made their mark in their time.
On the subject of motorcycles, the famous maker of Harley Davidson’s that is Hayes has only been able to produce the Purple series, with a downsized rotor. The problem, are the "vapors" of Hayes when it gets hot. While you may wait for them, they ship their brakes "ready to brake"; like all the others you’d spend two hours assembling; however, you can be sure of proper assembly.
"Motorcycles are about fashion," Viva Italia! The Formula, Activa, a cable actuated that works decently, (better than most of the Hydraulics) and the Evoluzione is a hot new item for Freeriders, for those hoping for a little control on the mountain descent. We were hoping for a little control, some attention to the non- cosmetic details; that would have saved us from some Durit explosions (thankfully for the Dot 4 in the extinguisher) or the flushing of new materials. With the same Latin brilliance, but a little more continental austerity, the brand preceded itself.
Avid, was really unexpected, from V-brakes to disc, always cable actuated, the manufacturer’s brakes are proven. No it’s not Shimano for the poor. There are more prestigious brands like look; but the price is right, and the results command respect.
Of Magura, the four models tested, all did quite well. It’s not because of their appearance… with exposed seams, an unpolished finish; they’ve broken away from their competition. (Hope, Shimano, Giant, Formula) not really elegant, they’ve differentiated themselves from the competitions common practices. Like the names of their company (a Germanic name), but there is also the German efficiency: Gustav, the power champion; Louise, surprisingly effective for an ultra-light XC brake. Clara, Surprisingly, the similar price of a cable actuated brake but hydraulic; and the aging HS-33 that attests it is still needed. For the brakes in question, if we had to talk about good manufacturing, this is the one. Right now it is good to capitalize on the brand, because it won’t be long before their image is diminished by the Euro.
Demanding Test, Not Extreme!
Without talking too much about the faults, this comparative test put to light some weaknesses. See some of the failures of renowned brakes. The combined teams of Velo Vert & the research center of Decathalon were not out to slaughter them all. Our tests were not extreme, but simply demanding. The noted failure of most of the rotors we tested didn’t surprise down-hillers. Other tests are fundamentally based on European norms, the one of endurance by elimination of a product. It was not designed like a demolition derby, but with braking effort and a duration perfectly moderate. What of 30 seconds of soft slowing compared the stress of a long mountain descent or speed control? There is not a cruise control on bicycles (the Telma, is for cars and trucks), but a hydraulic brake that brutally releases, can leave painful memories – if we live to tell. That was the purpose of the test. The event that such brake had overheated until breakage not to say that the brake wouldn’t have failed under intense use. The notation that the Y disc lacks power or of improvement not misleading you nor give you a false sense of hope. But if there is a flaw, at the conception or the assembly, we had a good chance of detecting it. We noted that the most notable breakdown did not appear like complete surprises: cyclists at the parks, which would get ‘em talking about discs. When the other models-a majority-that were proven powerful and weak in the course of our tests, they weren’t doubted of their true value.
Front-rear: a balance
When an ensemble of discs was composed of two different models between the front and the rear, we had tested only the front. * The caliper was always identical, more or less functionally; the only difference is the diameter of the disc. When the manufacturer decides to reduce the rear rotor size, it’s to balance the braking. With identical discs, it is systematically unbalanced; it is therefore desirable to reduce, a little, the power of this trajectory stabilizer, which is essentially in the front. Moreover, we gain more inertia where not suspended, the hub already cluttered with a free hub, the cassette and reinforced spokes. Evidently, if your game is Trials, or very slow speeds in general, nothing is more logical than two identical discs. In other cases, do not hesitate to mix it up: An Avid Arch (rim brake) is an excellent complement to the Avid CPS at the bottom of a fork. A Magura HS-33 harmonizes ideally with a Louise in the front. And if you prefer the Louise in the rear, it’s not ridiculous to have a Gross Gustav on the front!
All of this in waits for the foreseeable arrival, inescapably, of double disc in the front…
*Accept for the Suntour brake groupo, did we test the rear only. The front had been shipped, brand new, but unusable from the start, a leak at the point where the joint attaches the piston.
No Dot for Louise, Julie or Clara
Dot adds one I declare-aside from the color and the finish, what is the difference between a four piston Grimeca caliper and a Shimano XT? Those little letters on the fluid housing. Grimeca introduced to you DOT 3 or 4, "from Lockheed" or so it used to be called. Shimano XT requires the use of "mineral oil only". In this, it is the same as Magura. The German manufacturer is, at this time, the only proprietor of mineral oil named "Magura Blood". This little humor characterizes the company. To buy hydraulic fluid for a Citroen, or a plasma transfusion, it’s less expensive and there is more of it… What are the differences between DOT and LHM? Lockheed is an extremely synthetic fluid. In principal it is very easily compressed, it resembles the ideal liquid, presupposed by Pascal’s theory. Its principle quality is that it resists high temperatures and doesn’t boil. Boiled liquid is ruined liquid: Bubbles = sponginess. The worst, is the "fading": leading to no brakes and a white knuckled descent. Seeing the little flow of oil in bikes, fluidity is, in principle, another reason for good clean cables. On the other hand, the DOT 3 or 4 is extremely corrosive, destructive for paint jobs and clothing. You’ll end up soaking your stained clothing in Woolite for days, finding only a less obvious stain. The DOT requires special, flexible joints in order to resist corrosion. The DOT requires a complete changing every year; otherwise it will deteriorate and become polluted. That’s why a fresh bottle (of DOT) must be used, hence discarding the unused amount left in the bottle. Mineral oil (that’s to say, derived from petroleum), "Blood" or LHM, is notably more viscous, but its just oil, like that of the oil mom used for her sewing machine and dad used on the derailleur. Less corrosive, it doesn’t attack the joints. The question of its fluidity is secondary since the fluid transfer in cables caries a repercussion of pressure, not really a massif transfer of oil molecules. On the other hand, this viscosity requires a shortening of cable housing when assembling the brake: if the Durit is not secured after having cut the right length, not a drop of liquid will be lost.
Stability, mineral oil does not require periodic changing. Throughout, our tests did not reveal technical inferiority of mineral oils for bike brakes: review the comparison of the Grimeca and the Shimano XT. Be careful of the procedures, syringes and piping or Durit pay attention to mineral oil or DOT liquid because one pollutes the other. When using DOT, do not forget the precautions (latex gloves and eye protection). Cover the rolling joints (direction, hub), the rotors and calipers should be covered with a rag, then sprinkle some saw dust on the floor to soak up spilled fluids. And finally ask yourself if this poison belongs in such an environmental sport?
At first glance no! But after further inspection, yes with Post Mount!
Who is not bothered by the likes of Hayes, Manitou, Trek and Specialized who are in favor of Post Mounting their calipers? What use is it to establish an international norm if the Americans do whatever they want? In all practicality, they’re not at fault. The standard application is two screws traversing holes in the frame or fork securing the caliper; it’s not rocket science. These screws hold all the force and can result in sheer disaster. On the other hand, this system offers an appeal quasi systematic to the thin discs, so to center the caliper properly on the disc. In the case of the Post Mount in the front, the alignment is much easier: it requires securing the brake on the disc and not securing the frame bolts until after alignment: the break in period will go faster. The inconvenience is in mounting a Hayes to a standard fork. A mechanic is best suited for the precarious adjustments. That’s why Magura offers two variations of the Louise for the front: standard and Post Mount. Hayes offers a re-enforcement at the rear caliper assembly In effect; the product tests permitted us to observe the effect on the frame while braking. With a powerful disc on a rigid aluminum tube frame, we noted each braking, a torsion of the fork base, of the front triangle and the left side seat stay, all on a magnitude of many centimeters. That makes one think, should there be a standard? That’s good, if you like standards-, but don’t pay attention to all - and better, if you prefer "tinkering."
The Pascal Theory (The Law of Pascal)
The principle of a hydraulic brake is a perfect example of Pascal’s theory: an exercised force on a little piston will multiply to the energy of a large piston, in the link between the surface of it’s pistons. On the other hand, the output of the little piston is the same proportionally (a conservation of work). There in, a weak force, a long pull of the master piston (leveraged), generates a strong force on the brake piston; therefore a strong pull of the lever will result in a weaker displacement of the power. The hydraulic system is accessed by a simple mechanical lever, which utilizes a simplified flexible cable, creating the leverage between the lever and the caliper.
The exercised power of the squeezing of the lever by hand is represented from left to right (from weak to strong). The scale is in Newton (10N = 1 kgf), from low to high, the force of braking, measured by tire and ground. The gray zone represents the braking standard – here, an Avid Arch Rival -, with normal brake pads and rims. In the gray we find the brakes that superficially look good, but in actuality slow less than a properly adjusted rim brake. At the top of the scale, we find the leaders, like the Gustav, which is not new. In the middle where the lines touch, the performances are alike. They are treated cases by case in the individual reviews of each brake with an endurance curve to bout. The best possible curve for a brake is – progressive and powerful – being straight and slightly sloping. A curve straightening towards the right indicates a week action that finishes abruptly. An action that starts high then bending to the right reveals a poor brake, impressive at the start, but reaches its limit before the end.
The new 2001 disc brakes
At Hope, just in place for spring, equipped with a light caliper and a redesigned lever.
Shimano standardized the rotors to 203 mm seen as the brand of "official downhillers" with an XT caliper (four pistons). The 20 to 30% of supplemental power for the front is a welcome sight for those extreme uses. Otherwise, a new Deore cable actuated caliper in the works for 2002. Will the Big S take note of the faults of their current models?
At Magura, they will add another name to complete their family album, Marta, the youngest girl of the founder Gustav M. who died four years ago. It appears the whole line will live up to their name. The Marta will complement the entire line, high end and ultra light. The engineers paid much respect to the issue of performance and value, having finally outdone themselves. Having concocted for us a brake that is incomparable by the standards of the British and Japanese… The caliper will be a two-piston system, progressive wear system, made all in one (and not assembled, like most of the two and four piston calipers). We were also promised a futuristic lever design with an integral reserve bottle.
________________________________________________________________________
• Avid Arch Rival: the 26th brake of our test set the standard. One would have a hard time justifying the purchase of a disc brake should its performance be inferior to the Arch Rival. N.B.: the Speed Dial lever offers a rapid adjustment dial pour varying leverage ratios. It was set at the maximum leverage when we tested this brake.
Type: V-brake, Circuit: cable, Rotors (AV/AR, mm): rim, Total weight: 375 (g), Assembly: measured and tested with the Speed Dial lever (not included). Comments: quick adjustment, "on the fly," with a reduction ration adjustment on the lever.
___________________________________________________________________
• Avid CPS: The big surprise of this test! It’s the only cable-actuated brake that convinced us. Better, it seduced us: power, enduring, comfortable, it’s the economic choice but extremely efficient. Reserved for the front (cable actuated disc brakes require a short and direct cable). It offers adjustable assembly: the Avid Arch Rival is a perfect complement for the rear brake.
Type: single piston, fixed caliper, Circuit: cable, Rotors (AV/AR, mm): 165, Total weight: 493 (g), Assembly: measured and tested with the Speed Dial lever (not included). Comments: Post Mount plus adapter. (Velo Vert Approved)
_______________________________________________________________________
• Formula Activa: This cable-actuated ensemble is a little better than a rim brake. Its competitors in this category can’t really offer much. It is a little more sensitive in braking hard. There isn’t a lot wrong with it.
Type: single piston, floating caliper, Circuit: cable, Rotors (AV/AR, mm): 160, Total weight (g): 435, Assembly: measured and tested with the Avid Speed Dial lever (not included). Remarks: adapter exists for post mounting.
________________________________________________________________________
• Formula B4: It is the pinnacle of luxury in the XC scene this year, recognizable by the gold caliper. It’s ultra-lightweight and it’s justifiably an attractive design. The weaknesses are cable seals and overheating. We noticed an over pressurization in the master cylinder when the oil spoiled during the endurance test. Does it justify the 40gm savings next to a V- brake of middle quality and equal power?
Type: 2 pistons, Circuit: open, Hydr. Fluid: DOT 3/4/5, Rotors (AV/AR, mm): 160, Total weight (g): 335, Assembly: easy.
________________________________________________________________________
• Formula Evoluzione 9.5: This brake is characterized by a proven little inner ring, soft at first then performing well under pressure. Progressive, powerful, and also exceptionally tough, it’s an excellent compromise between effectiveness and weight for the free rider or dual slalom. There is an option of 180/ and 160mm, the choice for the pros.
Type: 2 pistons, Circuit: open, Hydr. Fluid: DOT 3/4/5, Rotors (AV/AR, mm): 160/140, steel ring riveted to aluminum, Total weight (g): 460, Assembly: not purged before arrival, it was particularly difficult to adjust. (Velo Vert Approved)
________________________________________________________________________
• Giant MPH 2: It’s a fact; Giant acquired a license for cloning the closed, dual piston, Hope "Sport." It inherited an easy adjustment lever at the reach of the thumb. In efficiency, the Taiwanese engineers have largely outclassed its master in our tests, In spite of a weak rating in the endurance test for overheating. The Chinese make a superior work of art.
Not available for resale. Type: 2 pistons, Circuit: closed, Hydr. Fluid: DOT 4, Rotors (AV/AR, mm): 165, Total weight (g): 490, Assembly: Special hub for moving the spokes to the left. Remarks: Hope system: rapid adjustment with the disc-pad.
________________________________________________________________________
• 4 Piston Grimeca: The matte black finish is "industrial," in comparison to its refined Shimano clone. The efficiency over all is mediocre, not living up to its noble construction of four separate pistons. Otherwise, the endurance test revealed a tendency of overheating.
Type: four asymmetrical pistons, Circuit: open, Hydr. Fluid: DOT 3 / 4. Rotors (AV/AR, mm): 160, Total weight (g): 422, Assembly: Flexible "aviation," the longer body offers a precise command. The synthetic body is less harsh on your body than a steel one.
________________________________________________________________________
• Grimeca Mechanical: It’s on of the heavier brakes of this test by far, and is one of the least efficient. Therefore we conclude that price for performance: if it is offered to you, keep your V-brakes.
Type: single piston, floating caliper, Circuit: cable, Rotors (AV/AR, mm): 160, Total weight (g): 597, Assembly: measured and tested with the Avid Speed Dial (not included).
________________________________________________________________________
• Grimeca Semi-hydraulic: Among the pioneers of disc brakes for Mt. Bikes, this is the heaviest. Requiring urgent archival in a museum. Finally, I don’t know if I would go to Italy for vacation. If I disappeared don’t believe in the theory of suicide or accidental…
Type: single piston, floating caliper, Circuit: closed plus cable, Hydr. Fluid: DOT 3 / 4, Rotors (AV/AR, mm): 160, Total weight (g): 646, Assembly: measured and tested with the Avid Speed Dial lever (not included).
________________________________________________________________________
• Hayes HMX – 1: Honestly, for a cable actuated disc brake, this brake is not much better than a V-brake. It’s up to you to choose if you like the look of this brake (a poor choice).
Type: single piston, fixed caliper, Circuit: cable, Rotors (AV/AR, mm): 160, Total weight (g): 521 Assembly: measured and tested with the Avid Speed Dial lever (not included). Remarks: Post Mount or standard adapter.
------------________________________________________________________________________
• Hayes Purple: With its huge disc in the front, the Hayes Purple will throw you! This reinforced (heavyweight) closed system by Hayes presented a straight line of power, showing off its progressiveness, and pure power. Each time, we had to abort the endurance test: not because of the Hydraulics for fear of the rotor rupturing the brake.
Type: 2 pistons, Circuit: closed, with expandable ball, Hydr. Fluid: DOT 3 / 4, Rotors: (AV/AR, mm): 205/ 160, Total weight (g): 640, Assembly: very difficult, shipped in a kit, purging and replenishing left to the customer, Remarks: Post Mount, tested and weighed with adapter.
________________________________________________________________________
• Hayes Standard: Right at the start of the power testing, the Durit broke off. After repairing, we had noted honest power, with a good linear response. The endurance test was a good testimony of the efficiency of the Hayes closed system, with its absorption of pressure.
Type: 2 pistons, Circuit: closed, expandable ball, Hydr. Fluid: DOT 3 / 4, Rotors (AV/AR, mm): 160, Total weight (g): 425, Assembly: post mount, tested and weighed with an adapter, The Durit was broken off during testing.
________________________________________________________________________
• Hope Enduro 4: The appearance is exceptional, that’s if you like the "crude Aeronautic factory" look." Power and progressiveness are there, moreover if we await the "cherry" a 185mm size… the over pressurization and the strong distortion of the rotor at the end of the endurance test should make Hope rethink the conception of large diameter discs.
Type: four pistons, four pads, Circuit: open, Hydr. Fluid: DOT 5.1, Rotors (AV/AR, mm): 185 / 165, Total weight: 510, Assembly: Easy, Remarks: distortion of the disk was an issue of the endurance test. o Hope Sport: This entry level model should soon be replaced by a model named Mini, taking the idea of the "Pro," with its assured adjustment dial for the closed system. Appropriately so, Hope, is phasing out this product: it brakes rougher than powerfully and it overheats terribly.
Type: 2 pistons, Circuit: closed, Hydr. Fluid: DOT 5.1, Rotors: (AV/AR, mm): 165, Total weight (g): 530, Assembly: special hub for moving the spokes to the left. Remarks, spoiled fluid during the middle of the test.
________________________________________________________________________
• Hope XC 4: The concept is noble, the realization of all the beauty and thumb adjustment, "a delight!" Finally, the tiny rotors, different, attributing to an elegant XC brake. The results were, progressive and linear, good endurance for a closed system. But at this price it should have more power.
Type: 4 pistons, Circuit: closed, Hydr. Fluid: DOT 5.1, Rotors: (AV/AR, mm): 150 / 130, Total weight (g): 450, Assembly: easy, Remarks, quick adjustment of the pads.
________________________________________________________________________
• Magura Clara (2001 model): A "popular" Magura, two pistons with auto-wearing pads. The power is up there with the giants, a little weakness when the brakes were pulled hard. In its defense, it revealed a perfect endurance, an excellent choice.
Type: 2 pistons, Circuit: open, Hydr. Fluid: mineral, Rotors: (AV/AR, mm): 160, total weight (g): 421, Assembly: easy.
________________________________________________________________________
• Magura Gustav (2001 model): OK, the good ole Gustav redesigned levers for 2001 aren’t always the lightest choice. OK, so its free-floating caliper rattles while descending. But what a dream…more progressive, more powerful and more tough. A must for tandems, and a smart choice for DH bikes if practicality is what you want.
Type: 2 x 1 piston, free-floating caliper, Circuit: open, Hydr. Fluid: mineral, Rotors: (AV/AR, mm): 190 / 160, Total weight (g): 523, Assembly: easy. (Velo Vert Approved)
________________________________________________________________________
• Magura HS 33: Hydraulic control clearly, is never spongy, a linear power response, and less of a chance of overheating than discs. For increasing the power a ceramic rim combo can be added. Except for its weight, this brake remains an excellent choice, more so than a closed circuit XC disc brake. Moreover it is the perfect compliment for a disc brake in the front.
Type: rim brakes, Circuit: closed, Hydr. Fluid: mineral, Total weight (g): 405, Assembly, delicate initial adjustment, Remarks: rapid adjustment with the lever and brake pads.
________________________________________________________________________
• Magura Louise 2 (2001 model): We didn’t expect the capabilities of the Louise: its power puts it at the same level of DH discs in endurance. Who could ask for more, an aggressive disc smaller and lighter for the rear? It is as much of a convincing XC as it is a Trials, DH and Dual brake, always for the rear. It wins the award for versatility!
Type: single piston, fixed caliper, Circuit: open, Hydr. Fluid: mineral, Rotors (AV/AR, mm): 160. Total weight (g): 370, Assembly: delicate centering; Post Mounting exits for the front. Remarks: power adjustment of the levers, the space between the pads can be manually adjusted. (Velo Vert Approved)
________________________________________________________________________
• Promax DC 800: The mixed concept of cable + oil is technically justified by the dual piston concept. Now, after seeing the weight and mediocre performance, does it have a chance against the other entry-level hydraulic brakes?
Type: 2 pistons, Circuit: closed + cable, Hydr. Fluid, DOT 3 / 4, Rotors (AV/AR, mm): 160/ 140, Total weight (g): 503, Assembly: tested and weight with the Avid Speed Dial lever (not included).
________________________________________________________________________
• Promax DSK 900: A decent attempt for the Taiwanese. The relative base power when braking and sloping endurance revealed with a propensity for over heating. There’s no reason to reject this brake if you are putting together an "Enduro" bike (for the price).
Type: 2 pistons, Circuit: open, Hydr. Fluid: DOT 3 / 4, Rotors (AV/AR, mm): 160, Total weight (g): 511, Assembly: Post Mount, with a standard adapter included.
________________________________________________________________________
• Shimano Deore (hydraulic): It appears that Shimano has made this product for the beginners, so they do not fear braking. In this spirit, the initial force is too rough (to be serious?), but it’s for sure that one would not be thrown over the bars by an urgent braking. It wouldn’t have been worth it to invent the V- brake had it not been for brakes like this. If someone were to give you this brake, don’t try using the other adaptable pads.
Type: 2 pistons, Circuit: closed, Hydr. Fluid: mineral, Rotors (AV/AR, mm) 160, Total weight (g): 478, Assembly: easy.
________________________________________________________________________
• Shimano Deore (cable actuated): This is the brother of the Deore hydraulic, but worse, closest to last place. At the start it responded ok but as soon as we applied effort, there was nothing left. There is a reason for the positioning of this brake in the series…
Type: single piston, fixed caliper, Circuit: cable, Rotors (AV/AR, mm): 160, Total weight (g): 512, Assembly: tested and weighed with a Deore lever (not included). Remarks: Post Mounted plus adapter included.
________________________________________________________________________
• Shimano XT: A deception, we were expecting a little more refined performance judging by its appearance. In actuality, we found it rough, powerful and yet mediocre. It embodied the right amount of endurance (not more), Shimano could make this better with 180 mm disc for the front, maybe a better combination of rotor and pads.
Type: 4 asymmetrical pistons, Circuit: open, Hydr. Fluid: Dot 3 / 4, Rotors (AV/AR, mm): 160, Total weight (g): 422, flexible "aviation (flight control)," the length determines the control. Remarks: It appeared less flexible than it was.
________________________________________________________________________
• Suntour 700 HD: Very heavy, this brake appeared properly constructed; accept for its Stalinist look and its choppy feel. We had hoped for a better quality of control. Good endurance, adequate power for the rear. You can count on a 20% increase of power with the front disc.
Type: 2 pistons, Circuit, open, Hydr. Fluid: Dot 3 / 4, Rotors (AV/AR, mm): 180 / 160, Total weight (g): 578, Assembly: by adapter to small rods, Remarks: broken front piston: tested with the rear.
День хороший всегда!!! 
uppydogeyes: . Но впечатления остались не самые приятные: по сравнению с гидравликой - это мощные "выключатели", по моему скромному мнению.
