We have a little over 5000 miles on our Team Niobium now (purchased in January of 2006). We love the bike and I have posted some reviews of our impressions with the most recent in March at the 4400 mile mark. https://www.bikeforums.net/tandem-cycling/278514-santana-team-niobium-14-month-4400-mile-review.html We did have the experience of having the spokes loosening up on the rear wheel around mile 300 and at the time there was no posted spoke tensiometer reading so we were advised to make it like the front which was 23 on my Park tensiometer. That worked for a while but the rear began loosening up again and I tensioned the wheel up to 25 and eventually and it held that tension. Before the end of last year (but I forget exactly when) Santana posted that the spoke tension should be at 26 on a Park gauge and 95 on a Wheelsmith gauge. This past January, I went ahead and raised the tension from 25 to 26. All has been good until...

Two and a half weeks ago on a Friday we got flat rear tire about 2 miles from home. As I was sitting on the ground and putting the tire back on I saw a crack on the rim going out from both sides where the spoke goes into the rim. I could hardly believe it but looked around the rim and saw more.

When we got home, I held the wheel under a lighted, magnifier shop light and I could visually see cracks at 14 of the 16 spokes - depressing.

Well, there's never a good time for the bike to be out of commission (we have no spare wheels for our tandem) and my wife and I would be riding the 3 State 3 Mountain Challenge in Chattanooga in two weeks but I didn't think I wanted to keep riding on the wheel. I had no experience with cracked rims but I didn't want to learn through by having it fail on a ride. The shop saw it the next day on Saturday and would send the wheel to Santana by 2 day shipping and the repair would be covered under warranty using my existing hub with a new rim and spokes. I called Santana in the mean time on Monday to tell them it was coming and of course we wanted it back as soon as possible. (I had told my wife that I would tell Bill at Santana that I was in a big dog house if we didn't have the tandem for 3 State 3 Mountain - My wife said I wasn't in a big dog house but I was in a little dog house that had no windows - ouch!) Bill wanted to get me out of the doghouse and said that they would replace the rim and spokes there at the Santana shop and would be able to send it back in two days after getting the wheel. So that time frame sounded OK and LInda and I began riding the singles again...Linda and I have ridden 3S3M twice on singles but had our hearts set on doing it with the tandem this year having fallen in love with the tandem and knowing that we would be faster on the tandem (and we bought a disk brake for this ride - which is going to be the topic of another post soon)

In the meantime, I checked with Santana later in the week and found that Shimano had told Santana to send the wheel out for the rim replacement. So that messed up the timeline. I was feeling cramped in that little doghouse but the wheel did arrive back at the shop on a Wednesday, we picked up the bike that evening and gave it a test ride on Thursday and ran into Tandem Geek at the first rest stop on the 3 State 3 Mtn Ride (which he mentioned in his post on the recent Sweet 16 thread)

Last night, with 150 miles on the wheel I took off the tire and checked the trueness and the tension. The Park readings are all around 25 or 26 with the exception of one spoke which has a little bend in it that makes the Park tensiometer read low (because the bend allows the pointer to move - if you've used the gauge you'll understand) I hadn't seen this very slight bend until checking. If I move the gauge up to a different part of the spoke it reads 25 to 26. I'll keep my eye on it. I have a spare spoke I could just replace it.

I did talk to Bill at Santana about the rim failure and he said that he has only seen it on wheels where the spokes loosened up quite a bit and were ridden on for a while which allowed movement at the rim attachment point. I did have loose spokes and they were loose enough to make noise that I could hear from my seat before I realized what was up - but as I've written in my other reviews - I was under the 300 mile mark. Bill went on to say that the initial loosening that riders are seeing is not from inadeqate tension in the first place allowing the nipples to turn and reduce tension but instead its caused by the spoke attachment at the rim becoming fully seated during the initial miles. It sounds like a plausible hypothesis but I'll remain somewhat skeptical - I'll see how this rear wheel ages.

So, I'm giving the wheels another shot. I will be checking the tension closely - especially for these first few hundred miles

So updating my 4400 mile review. First impression of Sweet 16 great - second impression (300 miles) poor - third impression from 300 to 5000 great - 4th impression at 5000 miles not good - 5th impression cautiously optimistic. I should add, the cracks were not visible in January (but they could have been there and too small to notice) at about mile 4000 because I was up close and personal to the wheel raising the tension to 26 in the truing stand and installing a disk brake.

Below are some photos of three separate cracks

Have Velocity Aerohead rims, 32H front, 36H rear. Chris King hubs, Revolution db spkes. 14,000+ miles on wheels. Not as much bling as Sweet 16s . . . minor true on back wheel once. No problems yet.
Only rims we've cracked where Mavic MA40s and they cracked at spokehole anywhere from 15,000 to 25,000 miles . . . keep an eye on them Sweet(?) 16s!

Sorry to hear and thanks for the update - I will keep an eye on the rims.

I use Velocity Aero 36H rims. Never had a problem never need truing, never need to check the tension.
I build and repair my own wheels.
I learned my lesson on my single bike, went through several Velomax wheels.
The low spoke count wheels are a bit lighter but not enough to make up for the higher cost and difficult repair. The newer Shimano wheels went away from spoke holes in the sides of rim back to the conventional center holes.

Joel

Sounds like BS to me, Bill-Speak if you will. The single bike, DuraAce version of these wheels was also quite prone to spoke hole deformation. The explanation provided by Bill seems to flip/flop the cause-effect relationship. The deformation of the spoke hole -- usually a slight bulge with cracks radiating outward -- is caused by very high bending moments. As the spoke holes deform the spokes lose tension and, while it would appear that Mr. Bill refers to this as "seating", it's not a normal function of the design. Once the spokes lose tension the tension increases on the remaining spokes in the network and, voila, more spoke holes deform, and so on. Now, in looking at your photos it appears as though there may have been a lot of spoke movement which would be indicative of Bill's suggested failure mode but, IMHO, that's not the root cause.

From a user perspective, I don't think it matters which failure mode is the root cause so long as any problem is caught early and corrected under warranty.

I know what you meant by this statement but I would like to point out an observation. Consumers seem to be O.K with substandard products just as long as they are replaced through a warrantee. I know we have all heard a rider say, “Oh it broke, but they replaced it." I think consumers should hold these products and companies to a higher standard.

Failures happen to all products. It is just a matter of keeping a very low percentage of returns. IMHO these low spoke count wheels are just not a good engineering solution to wheel mechanics. (especially on highly stressed tandem wheelsets) I have to wonder what the advantage is? Weight? no. Strength? no. Reliability? no. Cost? no. Increased rotational inertia through the super heavy rim? YES! Only thing is looks and very minor aerodynamic advantage which maybe equals .25mph on a coast down test at high speed.

Dave

P

Consumers are interesting creatures. I'd like to say that I haven't been sucked in by the allure of low-spoke count wheels but I can't. I've got three sets: Campy Eurus G3's and Mavic Cosmics that I purchased dirt-cheap a few years back and a set of Campy Zonda's that came on a second hand Calfee. These are fitted to my personal road bikes which are neither stressed by my body weight nor do they see all that much use given that at best I only ride about 2,000 miles a year on solo bikes (the tandems get the most use) and those miles are split up across four different bikes. Debbie's solo bike, on the other hand, gets about 3,000 miles of use each year is running on conventional 32h Campy Chorus hubs & Mavic CXP33 rims. The road tandems both use 36h conventional wheelsets and the only time I'd be interested in low-spoke count wheelsets is when I could buy a set for less than it would cost me to build up a set of conventional tandem wheels... which would be about 1/3 of what they're asking.

Anyway, back to the warranty coverage, that's all you can hope for and much of what you pay for when buying high-end, lightweight components. The manufacturers and retailers are all well aware of the higher than average failure rates and the pricing reflects it.

Bottom Line: If you find yourself thinking about wheel reliability when you're riding, chances are your wheels really aren't all that reliable. The only time I think about my wheels is immediately after hitting something really nasty... and that only happens about once a year.

Today we are going to do the million dollar mile ride. This 80-mile ride, I am told, takes you to a very remote area with very steep grades and no services. We will take the Edge GPS and post the ride later.

So, last night I decided to check our Sweet 16's again. My stomach felt like lead when I saw the same hair line cracks reported here in the rear wheel. Fortunately, we have the old 40-hole wheel. Unfortunately, I did not go to bed until past midnight replacing the disc, cassette, computer sensor, etc into the old wheel.

I am dreading the call to Santana tomorrow.....

So, what's happening with your wheel. I'm assuming that, like ours did, it's getting repaired with a new rim - and I hope quickly. We have a few hundred miles on the new rim now - so far so good. It never loosened dramatically like the first one did at mile 300 but I'm keeping my eye on it. I took the tire off at mile 300 and checked the tension. The spokes were near 25 on the Park guage. I raised them to 26 and it has continued to hold tension well. We'll just have to see what the future holds.

Bloomington, IN

I was out of town last week. I did talk to Steve with Santana and he told me to send the wheel in to check it and he said that they will take care of it. We sent the wheel yesterday.

How heavy is your team? Do you feel that at 26 on the Park meter, the wheels, particulraly the front wheel, are sturdy under heavy loads while power climbing or sharp fast turning?

Our team rider weight is 295 pounds. The 26 reading on the Park tensiometer is with the tire off. It's lower with the tire on and at pressure (120 psi front; 130 psi rear).

I don't know how well I can assess how powerful our climbing is or how fast I'm willing to turn compared to others but I think we're pretty strong riders. We often try to work / train to make ourselves faster and stronger. We do like to go fast. We seldom get a chance to ride with other tandems but at the recent Tennessee Tandem Rally we were able to stay with the fast group a good bit of the time which included climbing and descending. We were stronger than we were last year at the same rally. We do stand frequently for climbing. I think the biggest side loads we put on the wheels are when we are standing and rocking.

Nearly all of our rides include some fast downhills. Two downhills we frequently do have a fairly sharp fast turn at the bottom and we have a set of down hill S-curves with mild rollers between that we get to do at 30 to 35 - We love those! I've always felt secure with the wheels (except when I see cracks in the rim). We have a straight downhill that we always get to 55+. Our current personal record is 58. I don't know if we are going to ever see 60 on it or not. We are going to have to spin a little faster or go find a bigger downhill ...Anyway we're not afraid of going fast.

I trust the wheels but of course I am regularly looking at the rims now.

Bloomington, IN

After three weeks we got a replacement wheel. It is a never ridden wheel... so we will have to go trough the re-tensioning routine... I guess that will be the case with a rebuilt wheel if the rim is being replaced.

Bill had the wheel for a while and it was hard to getting calls returned. When I finally talked to him he said that his best wheel builder was going to be unavailable for a couple of weeks. When I told him that I needed the wheel for the upcoming race in Oregon he suggested sending my old wheel with a new rim for me to build. He said that the old spokes and hub could be used again. What i found hard to believe was when he said that I could use the old nipples??? I did not go for that

Bill mentioned that he did not think those hairline cracks were something he would worry but that he understood if I did. He also said that this was the first such failure in the "new" rims.

We ordered a spare disc and mount from precision to keep the other wheel rerady as a spare

Amazingly 'it's only the first failure we've seen like this' becomes a standard reply!
Who me, worry about a cracked rim????!
We've cracked about three Mavic MA40 rear rims, and then only after 15,000 to 25,000 miles on the wheel. And yes, Mavic replaced them and they were surprised we got that kind of milage on one of their rims on the back of a tandem. Rear wheels of course really get torqued pretty hard. We had one MA40 front rim last 56,000 miles on the front of one of our tandems . . . and for all we know it's still in use as we sold that bike when we bought a new one.
It pays to go over the bike/components with an eagle eye every so often . .
Pedal on TWOgether!
Rudy and Kay/zonatandem

I'm glad you have your new wheel. We now have 1900 miles on the new rim and sorry to report that just 4 days ago, I found cracks at 3 spokes on the drive side. I kept a very close eye on the spoke tension on this wheel. It never got loose like the original one. After riding it 700 miles the first month (May), the tension varied from 24 to 26 and I raised them to as close to 26 as I could keeping the wheel true. There weren't any visible cracks at that time. We rode 1200 miles in June. I think we ride very hard much of the time and have been actively working at improving our times on our hilly routes and we stand on a good many hills - I don't know what the forces are on the rear wheel but the wheel apparently can't handle it.

We are going to be out of town (with the tandem) for a while so I'm not sure when I will be contacting Santana. We are going to go ahead and ride the tandem and I'll just keep checking the wheel. On the original wheel, as mentioned in my original post, we had cracks at 14 of the 16 spokes. I now have three, I'll be interested to see how it progresses over the next few weeks.

I'm assuming that this rim will also be replaced under warranty but in the meantime I have ordered another set of wheels built by Tandems Limited in Alabama (the same place I ordered our Winzip Disc Brake from). These wheels will be Phil Wood hubs, Velocity Deep V rims, 40 spokes (14 gauge).

Have a great July of riding...

Bloomington, IN

Just for those keeping the statistical record here, our Sweet 16s have 3500 miles and no rim cracks, but we did break a spoke this Spring, presumably because I didn't know about that retensioning thing until after the spoke breakage. We're a 340# team.

Update on the cracks in our second Sweet 16 (that replaced the first one with cracks - see above) We continued riding on our Sweet 16's since my ealier post with the 3 rim cracks even after our Phil Wood / Velocity Deep V / 40 spoke wheels arrived at the beginning of August. The largest of the rim cracks appeared to be growing slowly in length to about a 1/2 inch on either side of where it enters the rim but no other new cracks appeared. With the start of school two weeks ago and the associated flurry of lesson planning and teaching we didn't ride for a week and half. We finally take a short 23 mile ride after supper Thursday - feels great. We bring the tandem into the house and I lift and turn it to line it up along the wall where it will lean. As the rear wheel touches the floor - SPROING - a spoke breaks up by the rim entry point.

This forced me to get the new wheels on so I started to switch the cogs and the rotor over to the new wheel last night. I found out I couldn't get the rotor adapter off of the old wheel so I drove up to Matthews in Indianapolis to take the rear Sweet 16 wheel to them so they could send it back to Santana and also let get the rotor adaptor off. They had another Santana in the shop with rim cracks. Their observation from the tandems they sell and see is that some are having this trouble but many are not.

I got back to Bloomington by 1:30 and got the rotor installed and caliper adjusted and we went on our 23 mile loop again with a bonus of some new pavement on what was a very bumpy stretch. I may keep the Sweet 16 on the front for a while - it has given no trouble at all.

Bloomington, IN

Our second sweet 16 rear wheel did fine for about 1000 miles. We raced on them up in Oregon last month. We really like this wheels and since the 2 year warranty was coming up we decided to keep the 16 set for special events and train and ride in the old 40h fir/hadley set.

Yes you can call my "Old school" if you like...

In the internal combustion engine world, is comun to hear "Is not Replacement for Displacement" at least in my opinion in the wheel building world (work on shops forever including wheelsmith in palo alto) "is not replacement for Spoke count".

Maybe what you need is a pair of "training wheels" with a more conventional setup, with more spokes (higher "Cross" patterns too) running on a lot less tension using rims with proper Eyelets and everything, and then leave your Fancy high performance wheels for "race day" or for "sunday rides"

Yes I know a wheel with double the amount of spokes is going to be heavier and also produce more air drag but also you also have a better "Flywheel effect".

But then again the spokes are going to be sharing the load of your team in about half the rate (specially important on a tandem), making for a far longer lasting and reliable set up, not to mention far easier to adjust and up keep and a lot less prone to suffer from catastrophic consequences if you let the spoke tension drop to dangerous levels like it hapend in your case.

Personally I have build, five front different wheels for my tandem and four rear ones (looking for more rims at the moment, in fact I have a total of about 45 wheels for the 16 bikes I own) so it puzzles me how you can pretend to have such a bike with out a back up set of wheels since tandems are famous "wheel destroyers" plus not having extra wheels end up being far costly (not going on riders, missing events, failures =>walking, taxis, time delays, etc) than the nominal cost of a nice set of wheels.


Just the honest opinion of somebody that has lace at least 500 bicycle and motorcycle wheels over the years and also destroy a few in the process from pushing my luck a little to hard and usually crashing.

Yeah, you train on race wheels and look what happens.

If I might interject... Our good friends here are merely sharing their actual experiences with these wheels.

They are all long-time cyclists and in some cases long-time tandem cyclists who have back-up wheelsets for their tandems... either by default (having upgraded to the Sweet 16's and kept the original, more conventional wheelsets) or as a hedge against problems already experienced with the Sweet 16's.

To your point about tandems & wheel durability, while tandems were in years past nortorious for being hard on wheels, most of those reliability issues were resolved in the 90's as the 145mm and 160mm rear spacing was adopted along with more robust hubs and rims designed for tandems. Thus, conventional 36°, 40° and 48° wheelsets constructed using robust rims, hubs, and spokes that are hand-built will usually be life limited by sidewall wear, crash, or road obstacle damage, more so than anything else perhaps needed a new set of bearings along the way. We've put 50k miles on three different tandems, and at least one wheelset has nearly 20k miles of problem-free performance. Others whom we ride with have similar experiences, noting that our total team weights are under 320lbs. Heavier teams riding on appropriate wheelsets will obtain similar results.

All that said, we return our focus to one of three low-spoke count, paired spoke aerowheelsets which have been popularized in parallel with the single seat road bike markets fondness for go-fast goodies.

The underlying "sales pitch" and rationale behind the Sweet 16's is that they are purportedly more durable, while at the same time lighter and more aerodynamic, than Santana's conventional 40° wheelsets. Again, our good friends (and others on Hobbes) have been kind enough to offer their experiences with these wheels because their results have not been consistent with the marketing pitch and their expectations.

If you haven't seen it, here is what Santana says about their wheelset...

The text in red typeface, above is what I find somewhat interesting.

Again, Santana does not market these as race wheels: they are purportedly designed as an equivalent replacement for their standard 40° wheelsets. While you (and I, for that matter) may disagree, that is in fact the premise: take note of their comments in the blue typeface, above. As a Santana customer, there is clearly an expectation that these wheels will be as trouble free as the conventional wheels they replace. Our friends comments clearly indicate their expectations were not met.... and they are not alone.

Interesting story behind the wheels.

Regarding the 40h test vs the S16, they say they simulated endless out of the saddle sprinting and climbing. That would suggest that there was some sort of off-plane force applied to the wheels while rolling. Given the left-right spoke crossing, I'm sure the Sweet 16s would favor that kind of use. Unfortunately, a lot of out-of-saddle sprinting and climbing is not a good simulation of the forces on a wheelset under normal tandem use.

It's true that lateral loads are always the toughest on a set of wheels, but it appears that Shimano may have ignored the standard usage model. Seems like a good test would be to throw 500 lbs on in the same plane as the wheel and let that roll for three weeks at 20mph (~10,000 miles).

I would be surprised if they did actually neglect to do an on-plane test, but that's what the text infers...

It's time for another update on our Sweet 16's one year after the original post. We have about 11,000 miles on the tandem and the front Sweet 16 at this point (approx 5000 miles per year on the tandem). As mentioned in the August 2007 post, we received our second warranty replacement on our rear wheel for cracked rims. While waiting for the replacement we started using a Phil Wood 40 hole with Velocity Deep V rim for the rear wheel while keeping the original Sweet 16 on the front. I transferred the rotor and we kept the rear disc brake installed (Winzip - 10 inch rotor - originally installed for 2007's 3 State 3 Mtn descent), so we have not ever used the second Sweet 16 rear replacement wheel.

We just returned from a great time at the Tennessee Tandem Rally. Yesterday morning as I was wiping the front rim, I saw a crack on the rim. I was surprised - the front wheel has been fine from the beginning. I looked at the rest of the spoke / rim junctions and found a second smaller one on that side and one on the other side of the rim. With a magnifying glass I found two more smaller ones on the side with the larger one I saw originally. One can see what these sorts of cracks look like in my original post in this thread (photos of cracks on the rear rim).

I checked the tension with a Park tensiometer - still at 26 on that gauge. The front wheel spoke tension has been stable since the beginning. The front wheel never loosened up in the two and a half years we've been riding. The original rear wheel did loosen up but the first replacement rear wheel was never allowed to loosen up (and when Santana finally published the Park tensiometer setting of 26, the tension was raised to 26 on the rear and the front).

I would just keep riding it around home but we are leaving for the Bicycle Tour of Colorado next week so I will put on our Phil Wood 40 hole front wheel which has been sitting in reserve. I don't want to worry about the wheel on that trip. We're five months past the two-year warranty so I'll have to see what the cost will be to replace the rim and decide if we want to do that or not. I believe the aerodynamic improvement of the front Sweet 16 is noticeable but we'll be fine without.

Bloomington, IN

What I'm taking out of this thread is to keep a close eye on our rims. We weigh 50 lbs less than you folks but ride more.

Don't want any sort of wheel problems on the tandem. I was thinking about getting a second set of wheels (with rotor, cassette and tires) for non-speed use. 36 spoke Hadleys ought to be fine.......

Nothing like being guinea pigs for 'ShimTana' wheelsets! Eventually they'll get it right.
Unlike other tandem builders, Bill only uses the very best.
You have our sympathy!

You'll probably see some big descents on your Colorado ride. Losing 1/16 spokes when rolling at 50 mph could be very serious. I want to have as much peace of mind as possible when rolling that fast. If a component is going to fail, it is most likely to fail under the greatest loads.