Ultegra 6700 Hub: Near Death Experience

Last fall my back wheel, the expensive, custom built one, developed an annoying creak. It's an Open Pro Mavic Rim attached to an Ultegra 6700 rear hub via 14/15 butted DT spokes on the drive side, and 14/17 super-butted spokes on the NDS.

After spending hours trying to relieve the spokes, and generally driving myself nuts trying to remedy the creak, I gave up and put my nearly identical spare on, and have ridden that the last 8 months. A couple of months ago though, I realized it was time to get ready to replace my "winter" wheel with my summer wheel, and decided to repack the bearings on both in the process of swapping them out.

Parts replaced were 5,6,8,9, and 10,11,12,13. Photos are of #10's cup surface. BTW, part #11 has an allen wrench internal engagement area for removal.

I was shocked to find both cups and cones on the drive side pitted and spalled on my spare wheel, (purchased from PBS at a huge discount). I realized that since it was my spare, and having few miles on it, I had NOT repacked it in 2 years, as it still had factory grease in it. This was either an appalling factory lubrication failure, and/or, a serious QA problem for Shimano. I really have no idea where the blame lies, but you will note there is micro-pitting and a bit of rust all over the cups.

Pitting and spalling of an Ultegra 6700 rear hub

It's important to understand that normally for loose ball bearings, a pitted cup has no remedy,and the hub is ruined - garbage to be hurled into the trash can in disgust. For Shimano hubs (and many others), there is one exception though, and that's the drive-side cup in back, as the cup is actually part of the free-hub body, and is NOT pressed into the hub as all the other cups are, both with front and rear hubs. (the other side of the cup is a cone for the internal free-hub bearing - pretty clever)

 I took the good free-hub body of my creaky, custom wheel, the axle with 2 good cones, and was able to put together one good wheel by cannibalizing two bad ones. There's definite advantages in having two identical, or in my case, nearly identical wheels (the PBS wheel uses 14/15 double butted Wheelsmith spokes on both sides). Since rear wheels are much more likely to break than front ones, having two identical rear wheels is much more important. Think about relative tire wear in the front and back, and double or triple that.

I ordered a new free-hub body from Amazon, and a new cone from Performance Bike Shop, who happen to remember they're a LBS, and should provide this service. They did so after a complete failure the first time (they lost all record and recollection of the order, until I jogged their memory, and then they just shrugged), 6 weeks of waiting, and then a week waiting for the re-order. When I went to pick the drive-side cone up, they informed me they couldn't sell just one - in clear contradiction to the two cones, each with their own part number, plastic bag, and price. I HATE being lied to!!!

$20, plus tax for the two cones, and $45 for the free-hub body. I'd RX getting the 2 cones along with the axle in a rebuild kit for $30 - a better deal IMHO. $65 is a lot of money to put into rebuilding a hub that didn't cost much more than that when I bought it, but the alternative was to toss the entire wheel. Nasty thing, having a nice wheel wrapped around a bad hub. In fairness to PBS, the 2nd mechanic I dealt with was very professional.

I'll see you on the dark side of the moon. Very hard to photograph. These are the best of 100+ attempts.

 When the parts came I mounted them on the custom wheel, resigned to having an expensive creaky wheel for all my trouble, but still a spare. I'm not sure if it was the new free-hub, the RnR process, the new cones, new balls, or Teflon grease, but the creak is GONE!

I now have 2 good wheels, assuming I don't find anymore nasty surprises when I repack my winter wheel, and I have replaced the stock bearings, which have G20 balls, with G10 balls I bought in bulk from Amazon.com. Btw, balls are rated according to their tolerances, so the smaller the number, the tighter the tolerances, and therefore, the better the balls. G10 is as good as steel bearings get. You can get G5 ceramic balls, and that is an advantage in having loose ball hubs. Generally though, my enthusiasm for loose balls has dissipated significantly. ;)

This looks like a spectacular grease failure. I think this was factory grease. I packed the new bearing with pure Teflon grease spread on the cups and cones, and then packed full with Finish Line grease with "some" Teflon in it. I assumed since it contained Teflon, it would be compatible with pure Teflon grease. It's usually a bad idea to mix greases.

 

 

This brings me to an important point. If you have cartridge/sealed bearings, (a misnomer, as all bearings have seals) you don't have to worry about the cups getting pitted or spalled. You replace the cups, cones, balls, and seals whenever you replace the cartridge bearing. The downside is, you're paying a lot of extra money for parts that aren't usually needed, so for any given price point, you get better quality bearings in a loose ball hub, AND, you can get them. Chris King, for example uses his own in-house mfg-ed sealed bearings - which he doesn't sell to the public.

Close to what I've been using, which I purchased at $120 an oz from an aerospace contractor, so it's MIL-Spec. This should work just as well for 1/6th the cost. Spread in zig-zag pattern across the ball path on the cups and cones before packing with the grease below to hold the balls in place while placing them in the cup. The very best grease for preventing spalling is 100% Teflon grease. Hard to find.

Good, basic bearing grease for bikes. Basically, I use it as a filler to displace water and dirt, and let the pure Teflon do the work of keeping the bearings rolling.

There's nothing very hard about replacing or repacking ball bearings, nor free-hub bodies. It pays to swap your wheels out at least once a year, and at least repack them. The G10 balls are going for a dime a piece at Amazon. There are 18 in back and 22 in front. Well worth the trivial expense in my view.

Morningstar Ball Tweezers

Highly recommended is a constant tension ball tweezers. They hold the ball with a constant force, which you relieve when you want to release the ball. This guarantees you don't scratch the ball by squeezing it too hard. It also makes holding the slippery little devils much, much easier, and allows you to press the balls into a cup's grease pack, which will hold the balls in place until you can place the axle and cone to keep them from falling out.

This one has a brass ball holder, which makes scratching a ball impossible. These are tools mechanics treasure. A source of bragging rights for those who know how easily balls can get scratched. When working with bearings, every attempt should be made to maintain a surgically clean environment. A human hair mixed in the grease, speck of dirt, metal fleck, or bit of rubber seal will degrade and/or ruin a bearing. It is absolutely essential that your tools, hands, rags, and general work area be absolutely CLEAN!

I am happy to report that the creak is gone, so almost worth the $65 bucks. Now I can focus on building up a new speed wheel in back, based on my old Alex wheel hub, DT Swiss bladed spokes, and a DT Swiss R585 30mm deep rim. With 24 spokes, and the 30mm profile, it should be slippery, and since the Alex hub is pretty light, a reasonable weight as well.

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.

Wheel Problems - Again

I bought the last Ultegra 6700 - Mavic OpenPro rear wheel Performance Bike Shop had in their warehouse yesterday for a simple reason - I need to send my custom built rear wheel back to Colorado Cyclist for a warranty inspection. It's showing signs of failure at the SUP weld joint, and I have no clue why. None of this stuff is made in heaven, so mfg defects do happen. Mavic is reportedly very good about standing behind their stuff, so I'm hopeful this turns out well.

There's an extra piece of aluminum laid on the inside of the rim, about the size of a wire bread-wrapper tie, for shoring up the weld area. You can see its "shadow" pretty well through the machined, once-smooth braking surface, in the bottom picture.

My hunch is the post-weld rim was bulging out, so the machining to make the braking surface smooth again cut away too much material, making the rim wall too thin. With 32 spokes pulling with 30 lbs of force, there's almost a half-ton of pressure trying to crush the rim - mashing the ends together at the weld.

The danger, aside from outright wheel failure, is the brake grabs at the point of the weld. This will tend to lock the rear wheel on a descent, resulting in a sideways-skid, and causing you to lose control. 
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On paper my 2 rear wheels will be almost identical, but I have heard the Performance wheel uses cheap spokes and nipples, and ships out of true. Good to have a neighbor with a pro wheel-truing setup who owes you favors! As long as it can stand in when I need a spare it's done its job.


If Colorado Cyclists does rebuild the wheel, especially on warranty, I am going to ask them to use DT 14/15 double butted spokes on the drive side. I love my DT Revolution 14/17 super-butted spokes, but they are a bit too flexy on the drive side at my weight and power, and I don't like asymmetrical flexing out back.

I also realized that any serious commitment to training, especially a 2X Century, requires enough spare gear to stick to a training program - and a spare set of wheels is #1 on any such list. As it was I got a killer deal on the Performance wheel, and didn't have to pay shipping as they shipped it to a local store. (tip: if a company has a physical store in your state they are required to collect state sales tax, BUT, they will almost always ship to that store for free if you ask, and most advertise they will do just that. The cost of shipping and tax are usually the same)

I need a new seat, and maybe seatpost too, as my seat just doesn't work for the TT position, and is too old and spongy to make a good 2x Century saddle. I will ride the seat the rest of the winter and keep an eye out for a deal on the Specialized Romin (the spelling has Caesar rolling in his grave, I'm sure), as spongy has a way of getting nice and hard in the cold of winter.

The linked review is pretty thorough, with lots of price and weight info, but I do wish every last reviewer would stop insisting that "The Romin has a cut-out section that runs the length of the saddle..." Clearly, from the picture, anyone can see it does NOT!

I had to make a trip to REI to exchange a pair of Novara Road Gel shorts (the best warm-weather chamois on earth) for a new pair, as the stitching that holds the chamois to the short was coming loose. It's times like these you really love that NQA return policy at REI! While there I looked at the new Shimano 6700 compact crank.

The entire area between the 34T and 50T is covered by a smooth piece of black, ABS plastic, so the chain has nowhere to go but between the gears. Sweet! I am very concerned though about those very, very thin teeth wearing well. The replacement cost of the outer ring is a whopping $277 street! OMFG! Not gear for 2X Century training rides - unless they start using ceramic coatings, as Middleburn has done.

A call has gone out for 2X Century training partners at our bike club. I am going to suggest regular face-2-face get-togethers, maybe with slide shows and such, because there are just so many questions to be answered.

Sneaking in a Ride

I finally got out the door today, after taping some SpaceBlanket stuff over my shoes to keep the wind out and the heat in, gathering up all of my cold-weather gear, long-fingered gloves and such, and finding my Gatorade back. It was mostly cloudy, but not that all-day bone-chilling cold kind of day. In fact, it felt pretty warm, around 50 I think, and when the sun shone through it was gorgeous. My feet were toasty warm, and being warm and comfortable is a sure way to find the joy in a sunny day.

It wasn't a long ride. I didn't want to get caught too far from home if the sky opened up, and it was the first time out on a real ride with my new back wheel, so I wanted to be a bit cautious. About that. I have a very serious suggestion for anyone contemplating buying a new bike. Buy some good custom-built wheels for your old ride first - or if not that, put your old wheels on any new bike you are thinking of buying and go for a ride. Most of the difference in ride quality between a $2,000 msrp bike and a $5,000 bike is the wheels. Really. No bull. It's just amazing.

The difference in ride quality between my old and new rear wheel is more than the change from my steel bike to my carbon one. I can't even feel the roughness of the road now except for my POS radially spoked front wheel. It's going to get replaced as soon as I get through Christmas. If the hub were better quality I would just re-lace the wheel with DT Revolution spokes and ride on, but with only 20 spoke drillings, there just isn't much that can be done with them.

The rear wheel performed better than even I had expected on the return home today. There is a sharp left turn at the bottom of a hill where the asphalt is really torn up and wrinkled. I normally have to slow down to 10-12 mph to take the turn, and then add a lot of power to climb back up the hill to the left. I was a bit cautious today, but I carried 15-18 mph into the turn and knew immediately I could have carried far more speed into it if the front wheel had been more compliant. I cannot feel any harshness at all coming from the rear wheel. Only the front.

The freewheel hub's ratchet is almost silent. No one will ever know when I am tired and coasting. I'm the stealth rider now! The bluish tint on the Ultegra hub is very nice in outdoor light too. I am just chomping at the bit to get the front one ordered now. I will get it with the Mavic's CD treatment to reduce rim wear on the braking surface up front, as the front wheel takes 4-5X the braking wear as the rear. The micro machining on the new rear rim was very sticky, completely homogeneous, and that was in wet, sandy conditions. Very impressive.

I only wish I had bought custom wheels this spring. It would have made the training miles so much easier.