Techie Tuesday: Mavic Open Pro - How Tough Are They?

It's been a little over 2 months since I crashed in the rain, ruining my custom built Mavic Open Pro wheel, laced with 32 DT Swiss Revolution spokes 2X to a Shimano Ultegra 6700 hub.

No wheel ever built would have withstood sliding 3-4 feet sideways at a 40 degree angle, at 15mph, into a notched utility cover slot. After rebuilding my wheel with a DT Swiss RR454 rim, with Revolution spokes laced 3X, I took a closer look at the OP, and think it stood up to a tremendous amount of damage with some remarkable results.

1. None of the eyelets pulled through, despite tremendous damage to the rim
2. The tire did not go flat, nor come off the bead
3. None of the DT Swiss Revolution spokes broke
4. None of the alloy nipples were stripped, with all the threading intact

While the advertised weight of the OP is 425 grams, it's measured weight is 440 grams, but even still, the RR465 is 465 grams, so the OPs are very light. I believe the 2012 OPs have lost 5 grams, weighing in at 435 grams now.

I went with the DT Swiss rim because I've had so many problems with SUP welds on my OPs. First, my custom-built Colorado Cyclist rear wheel's braking surface started to buckle right ahead of the SUP weld, and when they rebuilt it (at no charge) they were either vindictive about selecting a new rim, or I had very bad luck.

Without ever riding the replacement wheel, I took to to MadCat here in Sacramento and had Eddy inspect it for usability. As a result of photo consultations, and caliper measurements provided to Mavic, that wheel was rebuilt a 2nd time, again at no charge to me, as Mavic paid for everything. I am extremely happy with the OP wheel Eddy built for me. Even after sticking a heel into the drive-side spokes when I crashed, the spoke did not break, and Eddy charged me $0.87 to fix and true the wheel. Excellent customer service all around!

This front wheel jammed hard into the fork and front brake calipers, leaving some deep gouges on the inside of my fork, but, as you can see, the wheel held together, although just barely at the SUP weld. I think the rim strip was actually holding the SUP joint together, or at least, the small stress of removing it so I could unscrew each and every spoke to check for stripping, broke the SUP weld.

.

Very Egg-shaped, but still a cohesive object, and it held air for 3 weeks, until I carefully disassembled it.

.



Enormous stresses borne by this wheel are evident in the tearing of the Maxal aluminum alloy. Serial number front and center for the folks at Mavic, who I hope will have a look at this

 

Note the seperation of the sidewall from the rim here. About 1" (25mm) of seperation here was the extent of this mode of failure



Mavic's SUP weld plug. It looks like concrete, but I'm sure it's aluminum alloy of some sort. Note the "T-shaped" slot

 

The other, mating side of the SUP weld, with some kind of plastic alignment plug protruding. Note the massive amount of damage here. Somehow, it did NOT break all the way. Very, very impressive!



 So this brings me to some observations, and conclusions. First, all metal rims are going to have joints, so you can chose between sleeved joints and welded joints. Carbon rims have no joints. Advantage carbon. This does bring up an interesting option though - alloy rims with carbon joints. I'm thinking of something like an inch of ExoGrid structure.

Second, anyone that says DT Revolution spokes are weak, and break easily is lying, and I would encourage you to tell them they're speaking from ignorance if you read this claim, or hear it in person. Demand they show you proof, as I have done here.

Revolution spokes are so elastic they are virtually impossible to break. I bent one around the heel of my shoe, putting a 35mm indentation in it, and it still didn't break, and neither did even one of the spokes on this wheel, in spite of totally destroying the wheel and rim. Beyond that, the 300 stainless that most spokes are made of is so elastic it can stretch to nearly doulble it's original length before failing. Titanium spokes? Yes. Aluminum spokes? Absolutely! Butted stainles steel spokes? Never!

Crashing in the Rain

Right at the end of my ride on Sunday, after riding for a full hour in the rain, my luck ran thin, and I crashed in the rain about a mile from home. I was approaching a 4-Way intersection, observing traffic for sequencing, when at the last second my Fenix helmet light picked up a color difference in the road surface 4-5 ft ahead. It was a 4x6 ft utility cover of some kind, and the steel edges formed a groove that sucked my front wheel right in as I drifted from the shoulder into the middle of the lane for better visibility.

They go through the brake better when round  :-(

As best I can figure out, I broke the wheel out of the rut, but it started skidding sideways over the slick steel. I managed to recover my balance and thought I was going to be able to ride through it for a moment, UNTIL, the wheel hit the corner turned sideways, and folded up like a cheap suit.

Rim jammed hard into front brake, and heavily gouged inside of fork

When the wheel hit the corner of the utility cover it potato-chipped, and pretty much exploded as it slammed into the fork and brake. I went down hard, but the milliseconds I was skidding sideways gave me enough time to "plan" my fall, so I stuck my fisted arm out ahead of me and landed on my right side SuperMan style. No wheel could have withstood those stresses, but I'm very grateful for those milliseconds mine hung tough. That probably saved me from a face-plant, and/or a broken collarbone.

The Garmin HR strap's plastic connector is very unkind on your ribs when you fall on it, and while I had a thigh bruise the side of a DOT-bot, and a big bruise on my left knee where it fell against the frame, it's been the ribs that have been painful enough to keep me from sleeping well. Mostly though, I am very happy I didn't break my collarbone and was able to get a ride home from a nice couple in a SUV who happened by a few minutes later.
.

Clean break at the Mavic SUP weld

The wheel is a total loss, except for the hub, so I have ordered a new DT RR465 double-eyelet rim, and DT revolution spokes for a 3X laced build - I've had enough problems with Mavic rims I'm going to try DT this time.

20-spoke semi-aero wonder. It understeers a bit in turns.

Since it will take me awhile to build the new wheel, and I have no spare front wheel currently, I also ordered a Mavic Cosmic Elite 30mm semi-aero front wheel. At 20 spokes it isn't going to make a great training wheel, but for fast club rides and TTs on the South Folsom Canal, it should be great.

I guess I could be bummed out about this, but mostly I am anxious to see if I can crank  out 200+mile weeks as a matter of course. I want to try to get toughened into the fatigue and see if I can get to a whole new level of fitness, and maybe, ditch my BP meds!

Techie Tuesday - Optimal Wheel Spoking

This is a post I have wanted to do for months and months, and never seemed to find the time. I was motivated to do the post now because disk brakes are taking off for Cyclo-Cross racing, and Johan Bruyneel has been calling for at least rear disk brakes being used in the TDF to cut down on crashes caused by carbon wheel lockups. I happen to agree there.

While a rear-only disk wheel will not impact road wheels that much, front and back disk wheels would make radial spoked wheels disappear in a heartbeat. It would also introduce all of the torque-bearing considerations to the front wheel as are present in rear wheels.






Mid-1980s 36 hole low-flange hub with very little tear-out protection. Even laced 3X, the spokes have a significant concave path across the wheel. Note that on all 3X lacing, adjacent spokes pull in the opposite direction, offsetting each other's stresses on the flange.

Mid-1980s rear low-flange hub. The larger flange, relative to the front hub, creates a flatter, more optimal spoke path across the wheel.



Ultegra 6700 32 hole low-flange front hub laced 2X. The spoke path is even more concave than the 36 hole 3X spoking above. Better than radial, and with extra material to prevent tearout, it nevertheless is NOT warranted for radial spoking.

Ultegra 6700 32 hole low-flange rear hub laced 3X. Spoke path is very close to straight across. If they're ever made available in Ultegra 6700, 28 hole hubs should produce optimal 3X spoking.

Mavic Aksium: Drive-side spokes run perfectly straight across the wheel, the optimal 90-degree pulling angle for a torque-bearing spoke, from LR corner to UL corner here. Well done.

Mavic Ksyrium: A tribute to pig-headed stupidity and marketing arrogance. The beautiful convex spoke path on the non-drive side is completely negated by the use of radial drive-side spoking. The decision to use aluminum spokes, with no fatigue limit, guarantees failure.

These two wheels, identical in all other respects, show the difference a larger diameter rim makes on spoke path. As you can see, the 29r (~700c rim) spoke path isn't quite as optimal against tear-out as the 26r's is, although both are very good.

WTB Mtb 26r: Convex spoke path on 3X spoking, from LL to middle R on drive side and LL to UR on disk brake side here.

WTB Mtb 29r: Slight concave path from LL to UR on drive side, and LR to UL on brake side here.

The 24 hole drilling and 3X spoking creates straight-across path on the drive side. Uses a Hi/Lo flange strategy to make the wheel respond more symmetrically

Perfect straight-across spoking, which Mavic calls R2R (rim to rim) on their Cosmic Carbone all-carbon wheels. They must have fired some marketing people and hired some engineers.

  A few notes on ferrous (steel) and non-ferrous (aluminum) metals. The curves look like this. Note that 6061-T6 fatigues down to only 10% of original strength with symmetrical, oscillating, mean-zero stresses, and to only 4% with maximum asymmetrical stresses.

This textbook on metal fatigue spells it out much more starkly - non ferrous metals have no real fatigue limit. They fatigue to zero strength. Still think those Ksyrium spokes broke because you abused them?

As I remarked on before, drive-side spokes are tightened to about twice the tension of those on the non-drive side in an attempt to shore up the drive side's lateral strength. There are several strategies available to mitigate the resultant asymmetrical way the wheel responds to axial and lateral loads. In general, the goal is to have the spokes of the two sides yield equally with any applied stress, such that the effect on rim movement and deflection is symmetrical.

1. Radial spoking on the ND. This shortens its spokes, making them less elastic. Ironic that NDS radial lacing is used by mfgs who lace the front wheel radially to make it stiffer. The NDS is already too stiff visa-vie the drive side.  It also makes for a harsher ride, and precludes it from bearing any torque.
2. Use of a larger flange on the drive side. This moves the spoke bed outward, improving its angle, and can be helpful. It also bears torque better. It will also improve the spoke path, shorten those spokes, and thereby, stiffen them. 
3. Low (or very low) flange on the NDS. Effectively moves the spoke bed inward, and lengthens the spokes. Most helpful when combined with 3X lacing and thinner spokes to increase elasticity. 
4. Using more spokes on the drive side. This is rare, but it has the potential to soften up the NDS so the wheel responds more symmetrically to loads. One interesting option here is to use radial lacing and only populate every other hole. Fewer spokes would be more aerodynamic.
5. Heavier gauge spokes on the drive side. This was my personal choice, as I used 14/15 on the drive side, and 14/17 on the NDS. This makes for a rock solid wheel that is also supple.
6. Using a smaller freehub body, as found on Hope and Chris King single-speed hubs, and mount only 6-7 gears of a cassette. You'll have fewer gears, but a much stronger wheel. This idea is getting some traction in the mtb community. With a triple crank adequate gears are still available.
7. Off-center spoke drilling. Velocity's O/C rims can move the spoke bed over 4mm. It should help, especially if combined with other strategies. This directly attacks the problems of dishing a wheel.
8. Move the NDS flange inward. Disk brake rear wheels do this routinely. It usually results in a wheel that is laterally weak on both sides. Measure the flange to flange distance and buy accordingly.  Wider is better.
9. Use heavier spokes only where they are pulling torque. These would be trailing spokes on the drive side, and with disk brakes, leading spokes on the NDS. With caliper brakes and 28 hole drilling, only 7 spokes would have to be 14/15, all the other spokes could be 14/17. This should keep spoke weight to ~ 100 grams.

 

White Industries H3 road hub with titanium freehub body. 252 grams. Note the hi/lo flange strategy.

Tune MAG 150 weights only 150 grams. Note straight-pull zero-flange on NDS and large flange on drive side.

Techie Tuesday - The Superiority of Custom-Built Wheels

After Jobst Brandt wrote his definitive book on wheels and wheelbuilding in 1981, wheel mfgs quickly focused on the relevant factors for building light, strong, durable wheels, and soon thereafter found themselves selling commodity wheels for commodity prices.

In particular, Mavic and DT Swiss both developed the ultimate box-section rims in what have become the OpenPro and 415/465. With 3-cross lacing and quality Campy or Shimano low-flange hubs, standard 32 or 36 spoke wheels in the 1500-1600 gram range soon became ubiquitous, and lasted 10-25,000 miles. These wheels made the wheel mfgs NO money. With everyone selling the same wheel, it was a race to the bottom on price.

Wheel mfgs responded by making wheels with all kinds of goofy designs, and promoted them with huge marketing budgets, and flashy decals. In most cases, the result is a wheel designed to fail in 3-5 years, impossible to service, and that falls out of 'fashion' after the mfg's marketing campaign moves on to promote some new tinsel wonder.

Some fads, promoted as having some rider benefit, are really cost-cutting measures. The most prevalent of these is radial spoking, and cartridge bearings. Anybody can build a radially-spoked wheel. Even factory workers in Cambodia, paid 22 cents an hour, can build a radial wheel using cartridge bearings. They don't even need to know how to count - bearing balls, holes, or spokes!

A radially-spoked wheel, as Brandt goes to great lengths to show, is inferior in every dimension to 3-crossed lacing, but the myth of radial wheels persists, reinforced by intense marketing campaigns, in an industry addicted to unskilled labor. In particular, radial spoking creates so much force pulling away from the flange that most mfgs specifically exclude them from their hub warranty.

It is not radial spoking that creates stiff wheels, it is larger flanges, and more spokes - overwhelmingly. First by allowing for shorter spokes, 2nd because the flange flexes very little with lateral loads, and 3rd, because the spoke angles are necessarily steeper/stronger. Fewer spokes can be used with deep section rims as they are much more resistant to bending, but this does nothing to prevent low-spoke count wheels breaking spokes, hubs, and pulling through rims. For mtb front wheels with disk brakes, all the caveats of rear road wheels apply.

Being 5-10% shorter for current flange sizes, and therefore less elastic, radial spokes are more likely to break, rip through the rim, and have a harsher ride. The larger the flange, the greater the difference in spoke length. A typical medium-flange hub with 32 spokes is in the 6% range. My best guess for the increased elasticity of DT's 14/17ga Revolution spokes over straight 14ga is 30%, based on values reported for 16ga spokes. Taken together, this makes my new 32 spoke 2-cross front wheel with Revolution spokes about 35% 'softer' than the original 20-spoke wheel made with straight 14ga spokes.

Other myths surround rotational weight, the inferiority of J-hook spokes, the supposed superiority of straight-pull spokes, and hub-side spoke adjustments. It seems lost on people that the real reason mfgs like these technologies is because it's easier to make a machine to tighten a few spokes at a central location, than many spread out along the rim. It should also be noted that the cost of building a wheel is roughly proportional to the number of spokes, as that's where the labor cost of wheel building is.

As for the classic J-hook spokes, especially with double-butted spokes having heavy 14 gauge ends, the alleged excessive stretching at the bend is infinitesimal, and far less than the change in length due to temperature changes. In fact, the difference caused by heating of black, vs sliver spokes on a hot summer day is probably greater than J-hook spoke stretch. The weight of those 'evil' spoke nipples? 8 grams for 32 spokes! That's less than 3 tenths of an ounce! The dirt on a road bike tire weighs more than than.

IsoPulse: Engineering idiocy trumped by marketing hubris

The Mavic Ksyrium SL has been the standard-bearer for non-aero, factory-built wheels for almost 10 years now, and it suffers from almost all of the above nonsense. First, those goofy hub attachment points for the lauded straight-pull spokes take up so much space side-to-side, that they can only be used on the non-drive side on the rear wheel. This means that to get the drive-side spokes all in the same plane, they must be radially spoked. On the drive side! IsoPulse lacing is such rubbish I know of no other wheel in the world that uses it.

Physics 101 says the drive-side spokes (also true of the rotor-side spokes on a disk brake wheel) should never, ever be radially spoked, because they'll have no ability to resist the wind-up attendant with the application of torque to the hub, positive, or negative. The other reason is radial spoking weaker for any given spoke tension, and since the drive side is deeply dished, it's already at it's max tension on a properly designed wheel - typically at 175% of the non-drive side.

Using radial spoking on the drive side means all of the torque must be transferred across the hub body to the non-drive side spokes. On a conventional 3-X spoking, only 12% of the torque is transferred through the hub body, as it's elasticity is much greater than the flange and steel spokes on the drive side. Hub bodies are VERY bad at transferring torque, as their torsional rigidity is surprisingly poor.

Larger flanges resist wind-up better, keeping torque on the drive side, while larger diameter hub bodies transfer torque to the non-drive side better. For low spoke count rear wheels with small diameter hub bodies, hub fatigue may become a durability issue. For mtb rear wheels with disk brakes, both flanges should be large and use 3-X spoking.

A serious implementation flaw with Ksyrium wheels is the use of aluminum spokes. Unlike steel, aluminum has NO fatigue limit, so it will eventually fatigue to zero strength. Two of our club members had their Ksyrium wheels fail within a few weeks - one one the Death Ride, with its high speed descents.

Finally, Ksyrium wheels are said to be extra strong because they start with a very thick rim body and machine away the aluminum between the spoke beds. Yes, but that leaves a surface that acts like a pump, and creates a lot of aerodynamic drag. The bladed spokes used to compensate make for wheels that are very hard to control in heavy cross-winds - especially on high-speed descents - and bladed spokes cannot pass through conventional round flange holes, so a lot of tricks must be used to bed spokes on the hub side.

You always know you have a good engineering solution when one change makes everything else easier, better, lighter, etc. In short, with good engineering solutions, everything gets better. Instead of trade-offs, you get virtuous cycles of synergy. It should be clear by now that the Ksyrium fails this fundamental test of engineering, as many trade-offs had to be made, all of them with side-effects that are only partially mitigated by other induced engineering requirements.

Still not convinced? You're thinking that factory-built wheels are lighter, and more aerodynamic? Ksyrium wheels weigh 1485 grams, and are one of the lightest non-carbon wheels on the market. Keep this in mind as you view the weights of custom-built wheels below. Also note, many factory built wheels are only sold in pairs, so expect to end up knee deep in extra front wheels you'll never wear out - chronically buying pairs when you only need a new rear wheel.

Custom built wheels can be rebuilt many times, as usually the braking surface on the rim is the limiting factor on their life. They also typically have loose ball bearings, which are superior at any price point to cartridge bearings. If you do buy hubs with cartridge bearings, make sure you can still get those bearings 20 or 30 years from now. If not, the hubs will be worthless. On the other hand, if loose ball hub cups get pitted, the hub is worthless, whereas a cartridge bearing comprises both cup and cone, so replacing the cartridge replaces all bearing components.

Chris King, and DT Swiss use cartridge bearings. Shimano and Campy use loose balls, which can be easily purchased, and upgraded to ceramic balls if desired. If you like a hub with cartridge bearings, and they aren't a common industrial bearing, buy a half-dozen extra, and store them in Moble 1 Oil (with seal conditioner). By the time you use the last one you'll appreciate having paid 20% of its 2025 price.

If you break a Ksyrium spoke on an event ride, good luck finding anyone who can help you replace it. You're done for the day. Custom built wheels using standard J-hook spokes are usually on hand at event rides. No problem finishing the ride.

There are some other interesting options available on most custom builds. One I am interested in is radially spoking the non-drive side spokes. These spokes have very low tensions, as normal tensions would pull a dished wheel out of dish. Radial spokes are shorter, so less elastic, which may create a wheel that responds more uniformly under load when used on the non-drive side.

Another approach is to use 14/15 double-butted spokes on the drive side, and DT Revolution 14/17 spokes on the non-drive side. In both cases you're trying to get the spokes, at dramatically different tensions, to respond as equally as possible to side loads. For me, at 190 lbs, and capable of torquing out 1,000+ watts, this seems like the better option. Also, the less elastic drive-side spokes minimize wind-up, so less torque will be transferred through the aluminum hub body, reducing fatiguing stresses. The two strategies can be combined for maximum effect.

A single unbutted 14ga spoke will not fail under 700+ lbs of load, is generally about 10% stronger than a 14/15 butted spoke, will fail at the J-hook bend, and has at least 20% less elasticity than 14/15 butted spokes. By contrast, DT's 14/15 butted spokes will stretch over 6mm without breaking (testing was stopped at 6mm of strain), mostly in the thin, center section. I don't have data for DT's Revolution spokes, but expect this general trend would continue. There is much anecdotal evidence that this elasticity makes for very tough, resilient wheels. It also makes for a more supple ride.

These builds were done at Excel Sports, and WheelBuilder.  I encourage you to play, dream, and then take the plunge. In the case of Excel, you can send the hub back and have another wheel built on it as many times as you like. Bike shops will typically NOT reuse old spokes, but provided you keep the spokes in the same hub holes - so you don't bend them in new ways - reusing spokes is completely safe within reason. Rear, drive-side spokes will fatigue first, so worth checking the nipples to see if any have been taken up excessively.

As most of you know by now, I bought my wheels from Colorado Cyclist. They are an excellent shop, but don't have item-specific weights on their web site. I had my wheels built with DT Revolution spokes, and except for some rear wheel flex in left-hand turns under power, swear by them. They weigh about half as much as straight 14ga spokes. Chose silver nipples, as the colors all fade to silver in 2-3 years and look crappy in the meantime.

 

 

Build #1: Classic Campy Record hubs with OpenPro wheel weighing 1,500 grams for less than $550. This will support Campy's 9,10 and 11-speed gearing and for any rider under 200 lbs, should last 25,000 miles. Since the life of a wheel is limited by braking surface wear, go with the OpenPro Ceramic rims for ~ 100,000 mile life. 12 yrs at 8K/yr, or 20 yrs at 5k/yr. Repack and replace the bearing balls every fall, and repack each spring.

Build #2: Chris King R45 hub and OpenPro rim with radially spoked non-drive side rear wheel. Weighs 45 grams less than the Ksyrium SL and is $690. Buy extra bearings when you buy the wheels. Go with Open Pro Ceramic for longer life. 1440 grams

Build #3: Ultra-light 65mm aero wheel build. 1450 grams. Blows away SRAM's S60 60mm aero wheel at 1850 grams.

Build #4:  Lightweight metal climber's wheel using DT Swiss's RR415 single-eyelet rims for riders under 165 lbs. For riders under 135 lbs, save 25 grams by using 24 spokes front and back. 1390 grams

Build #5:  Semi-aero metal wheel for riders under 175 lbs featuring Mavic's CXP-33 double-eyelet rim. With 32 spokes, a real Clydesdale special, up to 225 lbs, and with Shimano DuraAce with 36 spokes in back to 250+ pounds. 1504 grams

Build #6: Iowa Hill Special. Ultra-light climber's sew-up wheel featuring Enve Composites 1.25 tubular rims. Using Zipp hubs will shave 41 grams and get you under 1 kg. 1020 grams

Build #7: Metal aero wheel featuring DT Swiss RR 585 rim in front and CXP-33 in back. 1650 grams

Techie Tuesday - Wheels & Wheels of Details

My spare rear wheel arrived at the local Performance Bike Shop - shipped free of charge from the online store - in good shape, but with a 100mm front skewer instead of a 130mm skewer. I walked around the store and picked up a few items, especially, a new pair of gloves, squeezing the spokes to relieve them, and then handed the wheel back to the mechanic to have it trued.

It was in pretty good shape, so I am very happy with the purchase, as the cost was a screaming deal at $118 - about half of $205, plus shipping, from Colorado Cyclist. In their defense, my CC wheels were custom built by hand with DT Swiss's Revolution, 14/17 super-butted spokes, so I expected to pay more for them. The PBS wheels use double butted 14/15 Wheelsmith spokes, which as you will see in the photos, have much more abrupt butts. Spokes with abrupt butts usually fail at the butt, if and when they fail.

As indicated a few posts back, the CC wheel has developed a serious flaw at the SUP weld, so the catalyst for buying the PBS wheel was as a spare I can use to keep riding while my CC wheel gets shipped back for a warranty inspection.

I took a lot of pics to get these, which I think are quite good, and highlight contrasts between these two wheel builds. I went through a lot of trouble to get some good shots of the manufacturer's trade-mark stamp on the spoke heads. Once you know what to look for, this makes identifying the spoke mfg quick and easy.

Without further adieu then...

 

Sorry there are no captions, but BlogSpot's captions currently screw up the HTML so badly that you lose the ability to click on the pics and get full-resolution click-throughs..

Pic #1: Note the prominent "W" stamped on the spoke head for Wheelsmith, the manufacturer. Also, if you look closely you will see the butt area quite distinctly about 30mm out from the spoke head. The transition is done in about 4-5mm.

You might also notice a characteristic of 3-cross spoking - that adjacent spokes are pulling in opposite directions and form an almost unbroken and unbent line from one side of the rim to the other. This arrangement limits stresses on the flange to those pulling along the curve of the flange, nearly eliminating forces pulling away from the flange directly towards the rim. (which is characteristic of radially spoked wheels)

Pic #2: Shows a close-up of the flange and spoke head.

Pic #3: Shows a shot along the drive-side of the wheel, with the halographic Mavic OpenPro decal in focus.

Pic #4: Shows the same shot, but with the Shimano Ultegra 6700 steel freehub body in focus. You can see the butting quite clearly on several of the spokes in this shot.

Pic #5: Shows the DT Swiss head stamp and the very tapered butting. It is very hard to see the butting, it is so gradual. It is easier to feel it, but you can see it somewhat here, and the butting is all over by about 20-25 mm from the head. The same is true on the nipple side, leaving almost the entire length of the Revolution spoke at a very thin 17 gauge.

Pic #6: Shows a close-up of the head stamp and flange.

Pretty New Wheel

Mavic Open Pro black rims with double eyelets for maximum strength
DT Swiss Revolution 14/17 super-butted stainless spokes
Lightweight silver alloy nipples
Ultegra 6700 rear hub with annular contact bearings, labyrinth seals, and steel freehub body
Handmade in Colorado by Santa's mountain-top elves

The final effect. A very handsome wheel that is ~ 5 times as durable. The hub is a bit under-par relative to the rest of the wheel, but the steel freewheel hub is bomb-proof and the new seals and bearings are excellent. The freehub ratchet is nearly silent, and extremely smooth. The color is gunmetal grey - a kind of pale bluish tint grey. Very nice on a blue bike!

Invisible butting on the DT Swiss Revolution, as compared with the abrupt butting on my mtn bike wheels. Note too the ratty and ripped rim joint on my mtn bike wheel. None of that on the Mavic Open Pros.

Note how the 3-cross pattern has the spokes bending across each other for mutual lateral support. The super-butted 14/17 spokes are 17 gauge everywhere but the first 10mm at the hub, and the last 10mm at the threads. They are about half the weight of a straight 14 gauge spoke, and support high spoke tensions without breaking for a super-responsive, resilient wheel, with a buttery ride. They cheat the wind like a bladed spoke, but without the cross-wind problems.

Gunmetal grey hub with steel freehub body. Mavic Open Pros come with a halographic decal indicating very clearly the spoke count, so you don't have to count. In adidtion, Colorado Cyclist puts a special decal on their hand-built wheels. These are nice touches you expect when paying for custom wheels. Oddly, the total price was only ~ $200. Very reasonable for what you get.

Notice how the eyelets support the pull of the spokes on both the surfaces of the rim? These are called double eyelets, and the Open Pro is one of very few rims to offer this. It makes the spokes almost impossible to pull out. With the high-elasticity of 14/17 butted spokes, and 32 of them, I'm assured these never will. The rim is super-light too. Only 425 grams. Riders over 200 lbs should opt for 36 spokes, while riders under 150 lbs should use 28.

 A final glamor shot

 Update 1/10/2010

It appears that the Mavic website is very misleading about the color of the CD and Ceramic rims. The Open Pro CD is a bit heavier, but the trade-off is the braking surface is thicker and anodized to make it harder, and therefore, longer lasting. While this is not a big deal, given the small amount of wear the rear braking surface gets relative to the front wheel's, I'm now faced with an awkward choice between getting a more durable braking surface for the front wheel, or having the two wheels match. I would recommend getting Open Pro CD rims front and back for maximum durability.