jrl@pobox.com

I've been itching to replace our Large/Medium '04 CoMotion Robusta with an X-Large/Large of some sort. I upgraded my single to an XL a few years ago based on an article about the "French Fit", and have enjoyed the change tremendously.

Go to this page, and click the "The Traditions of Road Riding and Our Three Styles of Road Fit" link (can't link directly)

I've also been thinking that the quick handling of our CoMotion may not be the best for me after speaking with a tandem dealer who suggested the fatigue I feel after riding may be partly from working harder to control the bike (not to mention my less conditioned stoker!)

We test rode a new Large/Medium Santana "Spirit" today, a 2013 model that is essentially a cross between last year's Arriva-Niobium and the Team Niobium. Nice bike, loved the stability a lot, felt very comfortable over bumps and still nimble on hills. My only real complaint is more whip than I am used to when my stoker wiggles around (assume I will get used to it?)

THE RUB: Santana says I'm out of luck finding an XL to test at ANY of their dealers.

How would the change from Large to XLarge affect this bike's ride and handling? Very scary to order a $4600 bike I have not ridden-

TandemGeek

If you can be properly fitted to the same riding position on both tandems, there should be only a very slight difference in handling associated with having your body weight a couple CM's further behind the front steering axis on the XL vs. the L. The stoker's compartment does not increase in length on Santana's tandems as the captain's compartment becomes larger and while both seat tubes become taller there isn't a significant change in torsional flex as the horizontal tubes on a Santana (as well as a Co-Motion) are pretty darn stout. Then again, you've been riding an aluminum Robusta, and Co-Motions are -- in general -- designed to have less frame distortion than Santana's frames, so therein may lie the difference.

The comment about "more whip" associated with stoker wiggles does not jive with everything else you've described, as the same difference in steering geometry that lowers the captain's work load that you're after and described as making the tandem feel more stable nulls out all but the most dramatic side-to-side stoker movements.

As for your Co-Motion making you feel more fatigued than you would be on a Santana, that may or may not be an accurate assessment. It all depends on how well you've been fitted to either bike, e.g., having your handlebars too low and/or too far forward can fatigue your upper arms, shoulders and neck on just about any bike.

That said, the basis for the claim that a Santana "could" improve your performance / comfort compared to other tandems that use more aggressive steering geometry is the reduced effort it takes to keep a Santana going in a straight line without constant steering inputs in response to left-to-right pedaling induced bike lean or excessive left-to-right stoker movements. This is because anything that moves a tandem with longer steering trail than a Santana left or right of the vertical plane will have a greater tendency to cause the front wheel to 'twitch' (it's technically a countersteering response to the lean angle of the frame) and requires some action on the part of the captain to keep the tandem moving in a straight line. For tandem teams that are "clean riders" who have smooth pedal strokes and don't shift their upper body weight around when riding, it's a non-issue. However, if someone has a stoker that moves around a lot, likes to try and look around their captain, lunges left to right or rocks on their saddle, or is just very tall... then the captain's work load on something like a Co-Motion Robusta with racing geometry (vs. a Speedster that uses a steel fork with more rake / less steering trail vs the Robusta's carbon fork) or Calfee's and just about any other tandem fitted with a 44m - 48mm fork will be higher than it is on a tandem of equal frame stiffness fitted with a 50mm (e.g., Co-Motion Speedster) to 55mm (e.g., Santana) fork.

One of the easiest ways to see just how the different fork rake / trail can influence the steering of a tandem is to push a tandem around by the stoker's saddle, much the same way single bike riders typically walk their bikes. While it's very easy to guide a tandem like a Robusta or Calfee with a 44mm rake fork around, it's nearly impossible to do with a Santana since left-to-right movements of the stoker's saddle (essentially leaning the frame left to right) has very little influence on the front wheels directional movements.

Neither of these different traits associated with the different steering geometry is necessarily good or bad; they're just different. Captain's (and their stokers) just need to figure out which they prefer and why.

Paul J

TG has given you great on outcomes of the geometry how different bikes feel with those designs. On sizing Santana doesn't give that data though someone here might have it. https://www.gtgtandems.com/ has the dimensions on older bikes which might give you a feel on the sizing differences between the L and XL captains position. It looks like it is 62 vs 68 and the tt is 58 vs 57. People who are the same height may ride a variety of frame sizes. I'm 6'2" with a 92cm inseam measurement which is more typical to someone taller so my legs are proportionally longer then mt torso so in the day of short seat posts I rode big bikes with shorter stems I'm now riding a smaller frame size with the headset stacked and a fairly typical stem length. I've ridden both a large and the XL in the Santana along with the L Co Motion and can make anyone of them work with the right amount of stack on the headset available. Good luck and I'm envious of your current ride. :-)

waynesulak

It appears that you have posed two questions. One a sizing issue and one a steering geometry issue.

Sizing:

I agree with TandemGeek that getting your hand, feet and saddle in the right places is the critical aspect of fitting. That said I like how a more traditional sized frame looks and they provide better access to bottles and other accessories. I am sometimes told our tandem is too big simply because we don’t have 12+ inches of seat post showing.

The whippy feeling on the Santana appears to me to be caused by frame flex. Santana claims to make the stiffest frames but they do not. I say this as a Santana advocate but physics cannot be denied. There are two primary factors is a steel tube’s stiffness, tubing diameter and the thickness of its walls.

• CoMotion uses a larger diameter top tube and lateral tube than Santana. Santana would counter that there rear and lower frame parts are stiffer and this may be so but CoMotion’s rear and bottom tubes fall into the stiff enough category. I have done side by side comparison on this when I owned a CoMotion Speedster and a Santana Noventa.

• The Niobium tubing used by Santana in its higher end steel bikes is 7/4/7 tubing. It is great tubing but it is only .4mm thick for most of its length. CoMotion uses 8/5/8 tubing which is .5mm thick for most of its length.

In summary CoMotion’s top and lateral tubes are both thicker walled and bigger in diameter and result in a much stiffer frame. Actually too stiff for us so I sold the Speedster became a Santana lover. We are a small team however and you are a large one. I suggest that you would like the Comotion frame better. It will have less tail wagging especially when your stoker is moving or pedaling hard. You might want to check out other brands of tandems if possible.

Steering:


Steering is a complex subject with offsetting design factors that people have written thousands of words on for literally over a hundred years. Rather than turn this discussion into another on the details of that subject, I will just say that I agree with your feeling and TandemGeek’s assessment that Santana (lower trail) provide you with what you like. This should be most evident when climbing when speeds are at their lowest and riders tend to mash on the pedals rather than spin smoothly.


Given that I have suggested the CoMotion frame but Santana steering what are your options?

1. Santana does not used the 7/4/7 tubing on all its tandems. A standard Arriva used 8/5/8 tubing which will be 25% stiffer than the Niobium tubing. It is still in a smaller diameter than the CoMotion tubing but is an option you can try easily for a comparison. Santana will build a custom sized frame for an upcharge and most likely would add stiffness if requested by a large team. If an Arriva feels better you might want to see what they can do in that regard.

2. If you are ready to work at this you can do what I did and order a custom steel fork or your CoMotion. Bilenky can build you a steel fork for your CoMotion that has a 55mm rake and will result in handling like the Santana’s (I believe they boith have a 73 degree head tube angle). This is a fairly low cost/low risk option that will allow you to have a CoMotion stiff frame with Santana handling. If you decide to go this route talk to Bilenky and describe what you are trying to do so that they can build the fork that gives the desired result.

3. Go full custom. Get exactly what you want by ordering a full tandem from Bilenky or R+E cycles with a large enough frame and the handling you want. This is the scary option as far as full commitment is required without testing the bike. If you choose option #2 then you might gain confidence and be ready to take the jump on this step.

4. Lastly ride the bike that you have. We can often adapt to many things and while your current bike may not be perfect I suspect that there is a lot of good times left in it. I prefer low trail but I enjoyed our CoMotion and don’t have to have low trail to have a good time on the bike.

Good luck, Wayne

jrl@pobox.com

Wow - All very informative responses, thanks everyone for the great detail!

FYI, we are a 315-320 lb team. Still uncertain of the ramifications of my "whip" perceptions - is it basically harmless and something that people get used to?

Sounds like the whip is a normal tradeoff for the comfy Santana ride. Our CoMotion is definitely harsher riding. If the whip is basically harmless, I'd prefer the comfy ride.

When we started tandeming on the CoMotion, I was really disoriented by the whip at first on that bike since I wasn't used to any tandem. Now I am used to it.

Well, keep an eye on tandemmag classifieds in a month or so, you may see it coming up for sale!

waynesulak

Depending on the severity and your personal preference it can be a safety issue or just personal preference. I personally like a more flexible tandem than most but can see where too much can be a bad thing.

Homeyba

TG nailed this right on the nose. I hear this arguement in long distance community all the time and it is basically just a sales gimmic. I've owned and raced (ultra-distance races) on both both Santana's and Calfee with "racing" geometry and the racing geometry doesn't increase fatigue.

Carbonfiberboy 

Another thing to think about is that a new tandem may well be something that you will keep for a long time, and something that could change your lives to some extent. So take a long view. What will you want to be riding with your stoker in 5 years? What sort of rides might the two of you do on the right bike? Thus, what might the right bike be for those rides?

We are a smallish team, though not that light. We are what TG describes as "clean riders." Our medium/small Speedster is none too stiff. At first, it was tiring because it's really different from a single and requires adaptation. But after 5 years we can do double metrics, etc., on it. We've been taking a spin class for years in one of those rooms with mirrored walls. I can see that my arm and shoulder development has improved. It just takes more effort to control a 350-400 lb. machine and I don't see that there's much to be done about that. Muscles associated with shifting were one of the things that needed the most upgrading, don't know why, maybe cable drag, maybe braking effort. When I get on my single now, which is rare, it's like, "How do I keep this thing on the road, anyway?"

professorbob

Speaking about whip, we're a heavy team, almost 400lbs. We've got an Arriva and bought it for the comfort over a Primera. Both very good bikes, by the way. I was feeling a bit of the stoker induced whip and decided that that was one of the aspects of tandeming and accepted it. Then my wife stoked for a more experienced captain, who explained that if she kept her weight on an even plane with the frame of the bike and did not lean into turns the ride would be smoother. She picked up on that pretty quickly, and now the whip is gone.

ksisler

+5 for all the learned and experienced input contributed...and agree with essentially all of it. Well reasoned.

- I have a XL/LG Santana Rio that I bought used and we love it. It is our primary ride (with OEM flat bar, brifters, 26" 48-spoke wheels {I replaced the originals**, upgraded to an Ultegra Crankset, 1 3/4" Schwalbe Marathon Plus tires).
- The four or five other major brand modern tandems that I own or have owned or ridden which were sized to fit us were universally excellent, imho. The differences between all of them was very minor except the Cannondale which I felt rode with a different feel that I didn't cared for so I sold it off for a small profit.
- The six to eight other major brands that I own or have owned or ridden which were not sized to fit us, such as "not quite big enough" were universally still not bad at all, but I noticed the more cramped Captain's quarters, mostly in terms of a slightly shorter top tube, usually solved easy enough with a bit longer stem. When I had finished adjusting the sizing by stem change, the resultant bikes felt right to me and certainly acceptable.
- With respect to any whippiness, I think the last time I felt any was on a tandem from before the modern era (a Bob Jackson made of single bike tubes and a Motobecane Mixte of high tensil steel). Since I have become "associated" with modern tandems (aka; the happy times), I will honesty offer that my stoker just doesn't contribute enough effort to help me cause it, especially when she pulls off the pedals and puts her feet up on the lateral tube! Thus I no experiental data to offer on that aspect.

Hope that helps a bit...
/K

jrl@pobox.com

Great feedback all - thanks very much for your input.
I spoke with Steve from Santana at length this morning, very helpful. His comments confirmed most of what was said here. I'm left with the following conclusions:

1. Just go with the XLarge frame. Santana gave "delta" measurements to my dealer (see below), which are the dimensional differences between a Santana Large and XLarge. I measured the large Santana last weekend, so I can extrapolate that they put the bike at nearly the same dimensions as my Cervelo RS XLarge single bike which fits like a glove.
2. Don't worry about the "whip" - we'll get used to it. And even if a new Santana is flexier horizontally than our current CoMo, there will still be less input to the steering
3. Focus on picking our favorite ride quality between the steel and aluminum bikes - in this case 2013 Santana Spirit (niobium steel) and 2013 Sovereign (scandium aluminum). We will have a chance to try a large Sovereign this weekend, which should be a fair comparison with the large Spirit we rode last weekend. AFA I'm concerned, we are probably not interested in another CoMotion. The Santana's clearly handled more to my liking. Even if the CoMo Speedster is designed as more stable than other CoMo's, it still has 5mm less rake than the Santana, and I expect won't feel as stable as the Santana. If the shop has a Speedster, I would like to try it just to be safe.

However, the Sovereign tester that is available is NOT a scandium. Steve described the difference simply as: similar ride comfort, lighter, slightly stiffer. I imagine trying the non-scandium should give us a close enough idea.

If you're wondering why my stoker isn't mentioned in all this decision making, it's because she doesn't care! (ideal stoker huh?) She doesn't notice these subtle ride characteristics, mostly because we have her all gussied up with a super thick saddle and thudbuster. Her main comments: "I love the bullhorn bars", "I love the granny gear", "I love that Aloha fade color", and "Whatever you decide honey". Okay!

Here are the measured differences between a Santana Large and XLarge:

Seat tube:
Captain: +3.5 cm (57.5 --> 61)
Stoker: +2 cm (50 --> 52)

Top tube:
Captain: +1 cm (58 --> 59)
Stoker: +0

Standover height:
Captain: +2.6 cm (81.7 --> 84.3)
Stoker: +2.1 cm (75.6 --> 77.7)

Paul J

Hey JRL did they say or did you get a sense if these are top of the seat tube measurements or center on center? As we plan toward the future I'm trying to decide which direction I should go on frame size. We re-measured inseams and my legs are longer then I was remembering at 94cm which fully puts me in the XL range but were riding a shorter top tube. I wonder how I should measure the tt on our Cannondale to compare? When I measured it along the top tube it measures 55cm and we are riding a 120 stem. We're going to need to ride a few bike when we are really in the market. My wife informed me that was 2014 on our ride today, I can live with that. :-)

bgross

Excellent points, and, IMO, goes to the heart of the matter: the combination of 1) the ability of the captain to deftly handle whatever bike, and 2) the possibility of the stoker ("the stoker makes no mistakes") becoming more proficient/efficient in the saddle.

You are indeed fortunate to have a stoker who enjoys the ride and is willing to let you make the equipment decisions. I am similarly blessed, and over time our communication has improved to where any 'adjustments' in riding position (wiggling) is coordinated verbally. Along with that, my bride has perfected the art of sitting up to take photos - and I barely notice. Her pedaling never changes!

Best of success in deciding.

jrl@pobox.com

They didn't specify. What I did was measure using my own method with a level and straightedge, and compared it to the same measurements on my own bike. Then I only needed to compare the deltas supplied by santana to get a close enough estimate.

Now that top tubes are slanted, it is difficult to compare frame geometries between vendors, so I have my own method which simply looks at the horiz rectangle formed with the bottom bracket and top of steerer at its corners.

To answer your question, I would guess that

seat tube is center-to-top,
Standover is floor to top, and
top-tube is center to center (it should be along a horizontal line but not sure what Santana does there).

You could call them, I have found them quite helpful over the phone, which perhaps contrasts some of the negative spin they seem to get (the need to even ask frame measurements is befuddling, the dealers can't even answer these questions).

bgross

I forgot to mention that I recognized part of your problem from my (our) own experience.

We bought our C'dale new. It is a VERY stable ride with its oversized AL frame and 26" wheels.
When we added the vintage Santana to our stable about 18 months ago, it was scary: the more compliant steel frame and 27" wheels really forced us to step up our riding skills! "Stoker steer" had a totally different effect on the more 'flexible' frame.

We enjoy both, and learned to appreciate the unique qualities of each. Not 'right' or 'wrong', but 'different'.

ksisler

Should you need such; I noticed on Peter White's site that he has newly available 27 inch rims in 48 spoke; specifically for vintage tandem needs...these rims have been unavailable for quite a few years. If you are going to ride the old S_bike much, might be a good time to have Peter lace up a replacement dynohub based front wheel and you would gain a free spare rim complements of the old wheel.

jrl@pobox.com

Thanks for the affirmation, good to hear.

We went to another Santana dealer last Sat and once again rode both a niobium Spirit and an AL Sovereign. This time the Spirit was a med, the Sovereign a large.

Impressions: Spirit had beautiful ride quality, little harder over bumps than I remember the large, but the whip was less. Probably as you would expect. I would expect an XL to be even smoother over bumps, but with more whip. Interesting thing though. Mentally I was ready for the whip this time and liked it. The niobium steel is really lively, it feels that even though there is some give to the frame, it springs back returning the energy. My riding quickly shifted to respond to this springiness, and I experienced the bike as very responsive.

The Sovereign struck me as efficient but harsh riding. This was a non-scandium. We did not like it as much.

waynesulak

Amen to that. Many don't feel the same by I am hooked by that feeling. I have been told that some high end carbon bikes feel that way as well but have not tried any of those. "Lively" is a great way to express the feeling. The bike feels alive as it seems to leap forward.

-Wayne

jrl@pobox.com

Yes. It was really noticeable when standing. I could rock the frame subtly and if I used the right rhythm, the frame would spring back in the opposite direction in sync with my pedaling. The spring back felt like it was helping me. More noticeable than on a single bike because of all the extra weight in back (forgive me honey!). Ive been riding carbon and aluminum singles for 12 years, forgot that steel is pretty cool stuff. The Niobium has a very refined feel.

waynesulak

It is my understanding that all steel alloys have the same flex and it is not the Niobium alloy but rather that it is 7/4/7 butted tubing which is more flexible than 8/5/8 tubing used on most tandems. Just like a golf club you have too little or too much flex. The key is to get the right amount of flex for the team weight and style.

Keep in mind many will think we a completely wrong about flex being a good thing - ever. That ok with me as long as I have the bike that is the most fun to ride.

Wayne