reburns

Santana is replacing all of the S&S couplers on future travel bikes with their patented Z coupler that they had been using only on their oval bottom tubes. Opinions on a coupled tandem using these couplers vs S&S?

TandemGeek

The newer couplers are quite a bit different and far more complex from the original Z Coupler used on the ovalized boom tube. I'm not sure why, but someone has a few photos of one hosted out on Flickr: https://www.flickr.com/photos/jbirdse...santanatandem/

As with just about everything, time will tell how they fare. Bill was pretty excited about the new couplers when we visited with him at Chattanooga back in May 2011 and the development models were purportedly doing just fine.

Perhaps someone who has ridden one of the early Team models fitted with a full set of Santana's own couplers will surface and offer some impressions of how they are to use.

tkramer

...and the problem this solves is?

Lighter weight?
Fewer coupled sections?
Aerodynamics?

What am I missing? The Ritchey breakaway looks more innovative.

TandemGeek

What you're probably missing is the manufacturer's perspective... and greater control over production while achieving further product differentiation.

By designing their original Z-coupler Santana was able to use the ovalized boom tubes that it prefers over round boom tubes, noting that Santana actually used a pair of smaller coupled boom tubes before it developed the ovalized Z-coupler. While I'm not sure that a round boom tube really has that great an unfluence on how a tandem will perform vs. an ovalized tube (noting Cannondale introduced a rectangular boom tube with rounded corners in 2010 based on their CAAD modelling), Santana saw enough value in sticking to their convictions on ovalized boom tubes to successfully develop and patent a coupler in the 2002/2003 time frame that allowed them to maintain that design standard on their travel tandems. The coupler has -- from all accounts -- worked just fine and had the added feature of providing customers with a coupled tube that didn't look like it had a pair of pipe fittings or other external flanges, etc.

Assuming the photos I've found are the real deal, the new Santana round-tube coupler appears to build on the original design and adds quite a few other features that make it look pretty solid once mated with its screw-in fastners. Like the original Z coupler, it has a less obvious and more streamlined look absent the stainless steel locknuts used by S&S for its Bicycle Torque Couplings or the flanges used by Ritchey for the Break-Away. From a weight standpoint, it's certainly no heavier than the S&S from outward appearances, noting the S&S uses a pair of sleeves (stainless, aluminum or titanium) plus the stainless locknut and snap rings. As for reducing the number of couplers, that's a wash if someone is attempting to achieve the same level of disassembly using the S&S or Santana's couplers. Note that Santana, Calfee and a few others prefer to break their tandems at both ends of the stoker compartment vs. the front triangle, mid-stoker the way Co-Motion prefers to break down their Co-Pilots: again, each have their reasoning.

However, at the end of the day I suspect a significant driver remains the abilty for Santana to bring coupler design and fabrication in-house and/or to at least retain design control over its suppliers in a way that gives it more flexibility and control over its supply chain and perhaps, to a lesser extent, cost and availability. Moreover, don't under estimate Santana's desire to innovate and differentiate, since those also play into the equation.

Just my thoughts, not anything that I can recall Bill sharing during our May '11 visit and discussions.

As for the BreakAway coupler design, it has its merits. However, the first two Ritchey BreakAway tandems were built for Interbike 2003 as a way of drawing attention to the BreakAway concept. Tom & his wife have been riding one of the 700c tandems since then and the new frame that showed up at the 2011 Interbike still doesn't appear to be something that's moved forward as a standard product offering. I captured some of the original correspondence from Tandem@Hobbes on the 2003 BreakAway tandems in this blog entry: https://tandemgeek.wordpress.com/2011...rn-to-be-sure/

akexpress 

my guess is it is a cost factor. Bill recently bought the tooling and rights to build his own carbon tubes for the Beyond. He wants to have total control of the entire process.

tkramer

Perhaps -- more of a "me too!" effort if you ask me. Which product would you choose? That from the tried and true S&S who, over many years, have made thousands of units in numerous sizes and materials (and have their manufacturing processes nailed down accordingly). Or, the one that will only be made in a few hundred units, at most, for only one frame builder. I can't imagine the cost is that much cheaper for the new z-couplers, when the S&S are a commodity by comparison.

I had a brand new coupled Santana aluminium bike last year and the frame was, for lack of a better word, an abortion. The S&S joints began to crumble to powder at the retaining ring grooves. As the frame saw more use, the friability of the metal extended under the paint finish until it ruptured, spilling aluminium powder everywhere. The boom tube z-joints seemed to hold up fine. But I was determined not to keep the frame long enough to find out.

Mind you, according to S&S, Santana contracts them only to machine the coupler joints from provided billet and supply the steel nuts -- so, I am not contradicting myself by the first paragraph. It would seem Santana might want to get control over their manufacturing quality systems if they wish to make any of the benefits of materials/sourcing control worthwhile.

waynesulak

I believe Santana is one of the few companies that will build a S&S aluminum tandem. I would guess the reason is corrosion where the aluminum touches the steel. I suspect the issue is in the manufacture of that combination without proper segregation of the metals and probably does not carry over to Santana's other bikes. Note the position of Magnesium which makes it more of a problem than aluminum where it touches other metals.


Table From wikipeida at
https://en.wikipedia.org/wiki/Galvanic_corrosion

Galvanic compatibility The compatibility of two different metals may be predicted by consideration of their "Anodic Index". This parameter is a measure of the electrochemical voltage that will be developed between the metal and gold. To find the relative voltage of a pair of metals it is only required to substract their Anodic Indexes.[SUP][9]

[/SUP]

For normal environments, such as storage in warehouses or non-temperature and humidity controlled environments, there should not be more than 0.25 V difference in the "Anodic Index". For controlled environments, in which temperature and humidity are controlled, 0.50 V can be tolerated. For harsh environments, such as outdoors, high humidity, and salt environments, there should be not more than 0.15 V difference in the "Anodic Index". For example; gold - silver would have a difference of 0.15V being acceptable [SUP][10][/SUP][SUP][page needed]

[/SUP]

Often when design requires that dissimilar metals come in contact, the galvanic compatibility is managed by finishes and plating. The finishing and plating selected facilitates the dissimilar materials being in contact and protect the base materials from corrosion




[TABLE="class: wikitable"]
[TR]
[TH]Metal[/TH]
[TH]Index (V)[/TH]
[/TR]
[TR]
[TD="align: right"]Most Cathodic[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]Gold, solid and plated, Gold-platinum alloy[/TD]
[TD]-0.00[/TD]
[/TR]
[TR]
[TD]Rhodium plated on silver-plated copper[/TD]
[TD]-0.05[/TD]
[/TR]
[TR]
[TD]Silver, solid or plated; monel metal. High nickel-copper alloys[/TD]
[TD]-0.15[/TD]
[/TR]
[TR]
[TD]Nickel, solid or plated, titanium an s alloys, Monel[/TD]
[TD]-0.30[/TD]
[/TR]
[TR]
[TD]Copper, solid or plated; low brasses or bronzes; silver solder; German silvery high copper-nickel alloys; nickel-chromium alloys[/TD]
[TD]-0.35[/TD]
[/TR]
[TR]
[TD]Brass and bronzes
[/TD]
[TD]-0.40[/TD]
[/TR]
[TR]
[TD]High brasses and bronzes[/TD]
[TD]-0.45[/TD]
[/TR]
[TR]
[TD]18% chromium type corrosion-resistant steels[/TD]
[TD]-0.50[/TD]
[/TR]
[TR]
[TD]Chromium plated; tin plated; 12% chromium type corrosion-resistant steels
[/TD]
[TD]-0.60[/TD]
[/TR]
[TR]
[TD]Tin-plate; tin-lead solder[/TD]
[TD]-0.65[/TD]
[/TR]
[TR]
[TD]Lead, solid or plated; high lead alloys[/TD]
[TD]-0.70[/TD]
[/TR]
[TR]
[TD]2000 series wrought aluminum[/TD]
[TD]-0.75[/TD]
[/TR]
[TR]
[TD]Iron, wrought, gray or malleable, plain carbon and low alloy steels[/TD]
[TD]-0.85[/TD]
[/TR]
[TR]
[TD]Aluminum, wrought alloys other than 2000 series aluminum, cast alloys of the silicon type
[/TD]
[TD]-0.90[/TD]
[/TR]
[TR]
[TD]Aluminum, cast alloys other than silicon type, cadmium, plated and chromate[/TD]
[TD]-0.95[/TD]
[/TR]
[TR]
[TD]Hot-dip-zinc plate; galvanized steel[/TD]
[TD]-1.20[/TD]
[/TR]
[TR]
[TD]Zinc, wrought; zinc-base die-casting alloys; zinc plated[/TD]
[TD]-1.25[/TD]
[/TR]
[TR]
[TD]Magnesium & magnesium-base alloys, cast or wrought
[/TD]
[TD]-1.75[/TD]
[/TR]
[TR]
[TD]Beryllium[/TD]
[TD]-1.85
[/TD]
[/TR]
[/TABLE]

tkramer

"I believe Santana is one of the few companies that will build a S&S aluminum tandem."

Does that suggest such elementary concepts in metallurgy are not known to the builder?

TandemGeek

So....

What was their analysis / conclusion as to what happened? Did they miss a step in the coupler lug fabrication process, e.g., a heat-treat or some kind of a chemical treatment process?

How has the uncoupled Scandium model that replaced it been working out and did they make you whole on the warranty replacement?

More importantly, what kind of motorcycle is that in the background on the 2nd photo???

waynesulak

No - Santana decided to take on the challenges of mating steel and aluminum. It can be done with proper care and I would guess most Santana aluminum coupled tandems are fine. All companies make mistakes and when there are higher demands placed on quality control the error rate usually rises and there are warranty claims.

The question is how did Santana deal with the issue?

tkramer

Santana's line was to deny that they could possibly build a bad frame and blame the customer.

"You're not tightening the nuts enough".

Wrong. I always used an old 10" Hozan ring spanner to torque the nuts instead of the wimpy half-sized tool they shipped with the bike.

"Your letting sports drink drip on the frame".

Wrong again! Stoker carries water or unsweetened iced tea in her bottles. San Diego is nearly a desert. Anything that drips, dries almost instantly.

Too much other stupidity to quote.


Santana offered to re-manufacture the diagonal tube, which had the problem at both ends, but stick me with the cost of the bead blast and repaint job for the entire frame. Stoker and I figured they don't know what the hell they are doing re aluminium + couplers and decided to cut our losses, (We were riding the Scandium as a loaner already). So we are out the differential on the coupler upgrade.

If you could find an actual copy of the Santana warranty, that might be an interesting read.

In the end, it was the bike shop owner who stepped up and swapped the Scandium for the defective frame. It was his demo model and we traded all of the wear items (wheels, chain set, brakes, etc.). He even swapped the Santana travel case for a Bike Pro case he had on hand. He's stuck with covering the "warranty" work. But he thinks he can turn a modest profit when the frame comes back.

The Scandium is riding fine. The front BB is shot (Octalink cranks on a new 2012 bicycle? Seriously?!!) and when I found out that the only replacement BB is ultimately sourced through Santana, I decided I will be replacing my cranks with FSA SL-K Lights, out of spite.

That is Rolf, the 2005 BMW K1200LT. The poor thing has been languishing as a garage queen since my stoker's new found passion in bicycling. Over 20K miles two-up. But, since we got the bikes (the other is a Ventana ECdM), 0 miles. She has forsaken 2-wheeled motorsport for human power.

I understand you are also a BMW rider, TandemGeek.

TandemGeek

Sadly, that sounds way too familiar. I often wonder just how much customer good will and business has been lost due to hubris on the part of the big S.

Once again, not a unique story... sadly so.

Re: Rolf, I thought the chrome strip with reflector and rear wheel looked familiar!

This is true... I've been riding motorcycles since I was 13, mostly Honda MX and then sport bikes. I switched to the boxer back in 2008 after a Ford Expedition totalled my CBR1100XX and have been riding an '03 R1100S Replika pretty much every day since then as my commuter: it's how I get weekday's started and finished with a s--t eatin' grin. We had an '04 R1150RT that ended up suffering the same fate as your friend Rolf. Sadly, I sold the RT after loosing my moto-mojo for a brief period. I even had the R1100S on the block but came to my senses before closing on a deal.



What can I say: I like bikes... Cars and trucks are a means to an end.

Here's hoping your tandem-troubles are behind you.

tkramer

My first motorbike was a Honda 75cc trail bike @ 14 years old.

I sometimes think about selling Rolf. But the only valid reason to do so is to make space. At this point, the space it frees up isn't worth the potential regrets. It's paid off and still has many miles ahead.

They're just things, but it's the relationships that those things facilitate that puts true value on having them. Some who make those things don't seem to understand that. It just dawned on me after typing that last sentence that the gist of Co-Motion's tandem marketing is essentially the human relationships engendered.

waynesulak

Disappointing story. Looks like a warranty claim was justified to me. Sounds like you have a good local shop owner. Care to share his name?

TandemGeek

Indeed it is.

sixtiescycles

The new design begs the question, "So, what was the problem with the original design?" S and S Machine have many years of experience--with a high degree of success, both in terms of performance as well as reliability--that sets a pretty high bar for someone hoping to improve on their design. I'd be very interested in hearing the analysis, pro and con, of the Z Coupling vs. S and S.

reburns

My understanding is that the z couplers are lighter and visually cleaner. And the tool required is just a hex wrench.

TandemGeek

My gut tells me what I've already suggested... N.I.H. + differentiation + design & process control

I'm a little old school and I always thought the pointed & polished "old style" couplers on our '02 Erickson S&S tandem were like jewelry on that frame.



I never saw them as an eye sore and they along with the more utilitarian S&S coupler installation on our Calfee tandem never ever gave us a lick of trouble. Of course, the Calfee's Ti four very large S&S couplers added $2,975.00 to the cost of the frame.

I don't believe there have been any reported problems with the original oval-shaped Z-Coupling and I've been "told" that the fixing screws were getting positive reviews from folks who even had lots of experience with the threaded BTCs. Hard to know without getting my hands on a bike that has the new couplers and doing some real world testing. The coupled Beyond we rode in May '11 for 3 days around Chattanooga, TN, had only the boom tube Z-coupler and four S&S BTCs on the internal and top tube. The only thing that stuck me about the Z-coupler was a feeling that I'd want to have a spare grub screw or two around in case I lost one in transit or while building up the bike. It's kind of hard to lose any parts off an S&S coupled bike since the only moving part is the coupler nut and it's held on the frame by a snap ring.

Frankly, I think it's all a rather moot point. I can't imagine making a decision on a tandem builder based on what type of coupler they used. You either buy into a builder's design philosophy, material choices and reputation or buy based on brand name recognition. It would appear that if Santana otherwise suits your tastes and expectations you'll end up with their coupling system. If you go with Co-Motion, I'm going to take a wild-ass guess that they won't abandon the S&S couplers unless Steve Smilanik decides to close up shop without selling the the rights to his BTCs to someone else as part of his machine shop or separately to someone. Remember, BTCs are a very small product line for S&S; it's not what they do to keep the fires burning, as best as I can tell from my previous discussions with Steve... one of the nicest guys you'll ever meet.

reburns

Right now the pertinent decision is between a Santana with S&S couplers or a Santana with Z couplers, as Santana are offering a discount on S&S bikes until they clear their inventory.

tkramer

Nice! A naked metal Erickson is definitely on the short list of what bike to get next, some day. A trip to Steamboat Springs being the bonus.

After hand assembling the top and lateral tubes, it was nice just having to offer up the boom tube from the bottom without fidgeting to get another pair of coupler teeth aligned. I always thought the fastener bolts should have been captive. I was always mindful of losing them or having them fly through the air into the storm drain a la Ralphie in A Christmas Story.

TandemGeek

Sort of... Our's are/were Erickson tandems by Glenn Erickson. We sold the one in the photo to help pay for our Calfee S&S. We still have an '08 that's not coupled.

You're thinking of the Eriksen tandems by Kent Eriksen, founder of Moots. Although... there ARE two titanium Erickson-branded tandems out there that were designed by Glenn Erickson and fabricated by Kent Eriksen along with a few Erickson by Eriksen titanium singles! Yes, it can be confusing.

But yes... a bare, titanium Eriksen tandem would be a beautiful thing. I talked with Kent & Katie about doing one but given the costs involved it was hard to justify in a stable that already has the coupled Calfee.

Philly Tandem

We have a Santana Cabrio triplet that has regular S&S BTCs on the top and lateral tubes and the Santana Z-couplers on the bottom tubes. Since it's a triplet, we have three of the Z-couplers and six BTCs on it. We also have an older Santana Fusion S&S tandem that has the dual bottom tubes with S&S couplers (8 BTCs total). Rounding out our S&S-equipped bike stable are three Co-Motion single bikes (Co-Pilots) with two couplers each. So, with five coupled bikes with 20 total S&S BTCs and 3 Santana "Z" couplers, I guess I can say I'm pretty familiar with the couplers in question!

Some thoughts:

1. The Z coupler is definitely much cleaner looking and, when it works right (see below), a lot easier to couple/uncouple than the two bottom-tube setup with S&S on our older tandem. Without a doubt, the single, oval bottom tube with Z couplers is lighter than the two-tube bottom tube setup with four couplers. I've never weighed them in comparison, but after many trips hefting both types I can say that pretty definitely.
2. The only weak point to the Z coupler, in my experience, is the hex bolt/retaining snap ring setup. But I wouldn't say it's a deal-breaker by any means. The way it works is that as you loosen the hex bolt the bolt head pushes against the retaining ring, pushing the two pieces of the frame apart (much like a self-extracting crank bolt would). The snap ring is not just there to keep the hex bolt from falling out, but is an integral part of the design. The snap ring is pretty small, and is fitted into a small machined groove inside the coupler. I've had snap rings pop out on me five or so times when loosening up the bolt. Sometimes they are bent and can't be reused, sometimes they are ok and I can pop them back into the machined groove. This is usually due to too much tension on the joint, either from it being dry/not lubricated fully (if it's been a while since we last disassembled) or possibly if the frame is still under tension somehow. I guess this would fall into "user error" to a degree, and I'm sure Santana would say so, but it's just something to be aware of. I include and extra snap ring or two and one bolt in my repair kit when we're touring or traveling with this bike. I wouldn't hesitate to buy another tandem with this setup, though. I haven't seen the new Z couplers, and would be curious to see if they have changed this at all, like maybe using a more robust snap ring that can handle the pressure better (and making a deeper groove to keep it seated under pressure).
3. Steve from S&S is GREAT to deal with, and has helped answer a few questions for me over the years, including calling me personally in response to an e-mail. Great customer service.

tkramer

Our boom tube z-couplers had no such retaining rings. You loosened the two bolts at each end and they dropped out onto the floor. Maybe Santana decided to abandon that design. (or our frame was an outlier in more ways than one).

Philly Tandem

Are you sure they weren't just missing? Are you the original owner? Peer inside the hole where the bolt goes and see if you there is a small, machined groove 1-2mm down from the outside. If so, that's where the snap ring would go.

tkramer

Yes, original owner.

lf they were missing, it would not have surprised me considering the shoddy workmanship that frame was obviously built under. The fastener bolts were fully threaded with no shoulder or circlip groove. I don't have the frame any longer, (see the above tangent in this thread). It might be just as well that they discontinued the feature. Probably too many requests from the field for replacement parts. Judging from the crappy treatment I and the reseller rep received from Santana, customer relationship management is at the bottom of (if even on) their priority list. So, if they could "engineer" a solution to avoid it, they probably would.