justcrankn

I think you've answered your own question. 1)You like the DaVinci drivetrain 2)You're convinced a CF frame is better 3)You don't want N+1 bikes.
Get a bare DaVinci CF frame and swap over all the parts from your current bike.

bikefor2

Can you swap out that Thudbuster LT for a Thudbuster ST?? THat would save about 130g, which is somewhat significant, I would think. It will give you more options for under-seat bags, etc. too. I use the ST and it offers LOTS of "shock" protection. I actually thought the LT model was more for off-road riding, but what do I know :-)

mtnbke

If you and your stoker are finding big climbs to "ruin" your rides even when bailing out into your granny gear, I'd suggest you look at whether you have the right size cranks.

Seriously. I'm the fattest tandem captain around, probably by far at 350lbs. I use 200mm captain's cranks, and my leggy 5'5" wife wants to upgrade to 175mm cranks as the 170mm stoker cranks leave her feeling like she has NO power at all on climbs. I can't begin to convey the difference the right size cranks make for me, but I'm a complete outlier. However, I've got to believe that even for someone more typically proportioned and of a more typical stature that the difference between a "right" size crank and one too small would be night/day on climbs as well.

Just a thought.

As for weight, I think the smartest place to look is frame weight. Rather frame material, actually. A flexy steel tandem frame, regardless of its weight is going to climb like a dog being overly flexy resulting in lots of wasted energy that is not being translated to the rear wheel. Titanium, depending on the tubing/design can feel like this as well. I know people that traded/sold away their custom Sevens almost immediately upon receiving them. They were bigger cyclists, but hated the whippy loosey-goosey manner that these bikes felt. Others love their Sevens, but are smaller more typical cyclists. I personally think nothing climbs like aluminum/magnesium, but carbon fiber is a close second. To this day, I've never ever met anyone that actually prefers a steel tandem after owning something else. Unfortunately, tandems are priced as much for material as for quality. It is a reality that steel tandems are cheaper and more accessible. I always recommend that a couple purchase a used aluminum tandem from Craigslist before ever considering a new steel tandem.

As for my Topeak Mountain or Road Morph pumps, I wouldn't consider going for a ride without them. Weight be damned. My Topeak may weight a little more than a micro-pump, but it will actually do what it is being carried to do. I've never EVER used a micro pump that would actually inflate a 700x38 tire to the proper pressure.

I remember the little pump chart that Performance bike and REI used to hand out. It showed the number of "strokes" that every pump offered had to be pumped to get a mountain bike tire and a road bike tire properly inflated to 60, 80, 100, and maybe even 120 psi. I don't exactly remember. My takeaway was that almost every pump being sold was incapable of inflating a road bike tube/tire to road bike pressures regardless of how many strokes. The only "functional" pump was the Topeak Mountian/Road morph. I've bought multiples of these pumps, and converted every cyclist I've ever ridden with that has had a flat. I let them pump away for naught with their "silly" pumps until they are good and tired and then let them use the Topeak Morph "floor pump." Without fail they ALWAYS buy one following that.

CO2 just seems unnecessarily wasteful and kind of against the entire cycling ethos. Kind of like driving a Ford F350 turbo-diesel truck while living in a cul-de-sac and not owning anything that needs trailered. Just waste for wastes sake. I just don't agree with the disposable society that we've become, and quite frankly I'm astounded that places like REI even sell the silly little CO2 cartridges and inflators.

waynesulak

Agreed but l believe the OP and his stoker are fairly short. Also with age sometimes come more limited flexibility.

Agreed but not sure we would agree on what the "right" size would be for the OP.

We are your "more typical" cyclist. Team weight 290 and went through three tandems to get one flexible enough for our taste. Interestingly the flexibility is most appreciated when climbing. As you said you are an outlier. I believe the OP is much closer to our size and power than yours. In any case I recognize we too may be an outlier as many like stiffer frames than we do. Different people have different tastes.

rdtompki

OP here - I'm 6', 200 lbs, stoker 5'7", TBD lbs. I don't know where flexibility comes into play, but my seat to handlebar drop on my single is about 3": long legs, short torso, longish arms. I can take more weight off of my body this summer (10 lbs) than I can possibly get of the bike without big $'s. to recap:
1. Loose weight - best value, doesn't cost anything
2. Better, lighter pump, ditch the CO2 (done)
3. Small trunk with seat post mount for summer riding (~1/2 lb. savings) or frame-mounted Jandd bag (1.5 lb. savings)

Lighter wheels would be nice, but I'm really concerned about the roads, especially descending at speed (e.g., Solvang). Topolino's are very highly regarded, but I don't believe they have a rear tandem hub with disc mount)

mtnbke

rdtompki what is your cycling inseam (or PBH) and your stoker's?

Use this method:

https://www.rivbike.com/kb_results.asp?ID=39

I suspect that the real problem is that your stoker is a bit how shall we say...plump? I've had lots of different stokers on my tandem and the only one that was absolutely miserable to ride with was a very heavy woman who couldn't pedal "her own weight." I've ridden with some very heavy stokers, but while they weren't "fit" in any classic sense they did ride their own singles, and were "cyclists" in some sense. We worked on climbing and giving maximum effort. I really think the problem isn't your bike. I've only had one heavier stoker that I didn't enjoy riding the tandem with. That particular one was averse to physical exercise and the harder the effort required the less she contributed. Literally I had to "pull" her up hills. She didn't ride bicycles and really wasn't interested.

Do a quick experiment. Take the tandem out without your stoker. I think you'll find that the problem ain't the bike. You could have a Paketa with carbon everything, but a plump stoker that is "coasting" is a drag, literally. It might be time to have the "talk" with your wife regarding her weight, the risk of diabetes, lifestyle choices, and really what is important to you and each other. Listen, I'm a fattie and nobody ate my way to my weight but me. However, I'm not particularly sensitive about it. However, I think when someone has food issues it might be time to sit down and take a look at what they are compensating for or what they are using food to replace in their life. I can easily imagine an older woman feigning or really being offended, but if you can't figure out to manage her weight you might not have her in your life for as long as you would hope.

This is not an indictment of fat stokers, at all. Some of the strongest stokers I've ever been with have not been...super "fit."

The first tandem I ever seriously looked at was in a shop in Rochester, MN when a guy was dropping it off (or picking it up?) after having it tuned. He was astounded how incredibly fast the bike climbed without his wife on it. He had always thought that the tandem was just a dog for climbing. This was a hard core roadie cyclist who described his wife as "fat." He commented about how strange it was that she had never lost weight while riding all the miles they had done, and he observed that she must in fact not "even be really pedaling back there." I didn't know enough about tandems at the time, but if I had that interaction with him now, I'd recommend setting the pedals up out of phase. With independent pedaling, that won't work for you.

Good luck.

conspiratemus1

Another benefit of this is that the discipline you use to lose weight will almost certainly also increase your power and stamina, which *NONE* of the other bike-and-gear gram-shedding fixes will do. Not exactly low-hanging fruit, true, but you'll feel like a million bucks. All the best wishes and encouragement!

waynesulak

I thought you were smaller. Sounds like I misinterpreted your size a little from
your little fuzzy picture.

Flexibility comes into play with larger vs smaller cranks. Larger cranks are great if the rider has the hip and knee flexibility to turn bigger circles at a good cadence without discomfort in the joints. My stoker is very fit but does have a hip and knee joint issues that require shorter cranks for her ride more than two hours comfortably.

I have found that when we go an extended period of time without riding our singles my stoker looses some appreciation for our relative contributions on the tandem. Riding singles make it obvious that tandems are a team effort and no words need be said - which is good thing.

Dean V

Crank length is a personal thing. I have a 34.5" inseam which I guess is a bit longer than average. I prefer 170 or 172.5mm cranks. 175mm I can put up with but they definitely slow down my cadence more than I gain in leverage. I actually even like 165mm which is what I have on my TT bike at the moment.
We also have two steel tandems (one is a real flexi noodle) and two C'dales. We are as fast on the flexi steel bike as the C'dale.

AllezDada

+1. Willpower. You can do it!

I don't know if weight is an issue for your stoker, but if it is I would think that she probably knows it. Even if you think it is a 'taboo' subject you might consider enlisting her in this effort so both of you can work together to lose weight. Look at this as a positive goal for the team, not a negative criticism. After all, being on a tandem is all about working together!

mtnbke

I think you meant to say that you enjoyed riding the steel tandems as much as the 'dale.

All other things being equal in terms of weight, components, wheels, bearing life (BB, hubs, etc.) it just ain't possible that a steel tandem is as fast as a Cannondale. It takes more wattage output to deliver the same wattage to the rear wheel on a steel tandem than it does on a Cannondale. There is reason that you don't see steel bikes raced in the professional peloton, and it has everything to do with the fact that aluminum and carbon are just plain faster, let alone lighter.

People have a tendency to convince themselves of things that they want to believe anyway. Do you really believe that if you were to give a group of aspiring young domestiques your tandems and all were identically built up with the same components and wheels, and if a ticket to race professionally on a well sponsored team was on the line that these young cyclists would finish a TT or hill climb on the steel tandem with near similar times to the aluminum 'dale? C'mon.

There are steel bikes I've loved riding, that had a much more comfortable ride than my Cannondales, however, I don't pretend that they were comparable in terms of efficiency or speed. Cannondales are veritable rocket bikes, and this is more true the earlier the iteration in the CAAD evolution. There are more comfortable bikes, there are lighter bikes, but there aren't that many "faster" bikes than a craigslist Cannondale. A series 3.0 Cannondale is probably as fast as anything money can buy today, despite being considerably heavier than modern frames (interesting because the series 3.0 used to be the world's lightest frameset). Not many people appreciate the ride quality though. There is a reason that Cannondale has kept lightening their frames. They haven't made them faster, they have made them more tolerable to offset the "harsh" anecdotal campaign that was originally started by all of those that were making handmade steel frames. The funny thing is that Cannondales are still winning Tour, Giro, and Vuelta stages years after they have been optimized into a much less stiff and efficient bicycles (read slower).

For all the talk about craftsmanship and handmade, nothing steel can compare to the skill set an aluminum welder has to have. Anyone can learn to build a lugged steel bike in an afternoon. It wouldn't take but a week to make them really really well. There is a reason that welder's with facility welding aluminum and titanium don't have trouble finding work in industry. Those skills are a whole 'nother ball game.

Yes, I'm a Cannondale fan and even an apologist. I get a little frustrated with the nonsense that some of us in the cycling community put out there in terms of the steel nonsense. I think you'd find that if you were to hook up a powermeter to your respective tandems, you'd realize that it takes a significantly larger wattage output to propel the steel tandem over the same course as it does the Cannondale. As engines the human cyclist isn't putting out all that much wattage in the first place. Small variances are considerable and are magnified over time. Which is why I think your assertion that the steel tandems are "as fast" is kind of silly. They just aren't.

waynesulak

I seems to me that you are making the assumption that a bike that is the faster for pro level cyclist is the faster for all riders. I disagree with that assumption. I don't think I would hit a golf ball farther with Tiger Woods' clubs than I play with a set designed for me. I believe that I can hit a baseball farther with a bat sized for me rather the one that works best major league slugger. I bowl better with a lighter ball than a professional bowler.

You might be correct that if a motor is attached to a flexible bike and a stiff bike then the stiff bike is more efficient and therefore faster. Human beings however are not machines and how the flexibility of a bike interacts with that individuals weight, strength and coordination is an important factor just as it is for a golf club.

Dean V

I am not biased toward the steel bike. I am not on some kind of nostalgia trip. Both bikes have the same wheels and tyres.
The simple fact is that we regularly ride either bike around our regular training loops and the stop watch says that there is no significant difference. Sometimes we are faster on one, sometimes the other.

oldacura

How is it that a Cannondale is "faster" than a steel bike? I can understand how it could be lighter and thus easier to climb with but your description sounds like it is more efficient than steel. This implies that for a given amount of energy delivered to the pedals, the Cannondale transmits a higher percentage of this energy to the rear wheel than a steel bike. Am I understanding this correctly? Energy that is not transfered must be absorbed (and converted to heat) by the bike. Aside from anecdotal tales, do you have any data to support this? The only way I can think that one material is less efficient than another is if the first material flexes in a non-elastic manner such that the energy is lost to internal friction (like a rubber band). Please elaborate.

gracehowler

I like Wayne's reply, what works for you, works for you, but don't you think the "aluminum" frame is the big factor here? We are chatting about weight, I wouldn't consider aluminum low hanging fruit, but lighter, yes and stiffer, it is...might be betetr for some. We had a cannondale, didn't care for the stiff ride. Sold it and moved on.
R&J

mrfish

The aluminium frame on the tandem is neither here nor there. This is not an opinion, it's physics: Climbing speed comes from having 2 riders who produce decent power while at reasonable weights:

1) I ride carbon, steel, aluminium single bikes. I can keep up with the group on all of them. It makes a very marginal difference what bike I ride, even though one weighs <6kg and the heaviest weighs >10 and flexes much more. The 5kg difference between the bikes is a 6% difference in system weight. That means I need to produce about 2-3% more power to ride up the hill on the heavy flexy bike than the light stiff one. Like I said, no difference.

2) On the tandem if you sit in the saddle and pedal relatively smoothly at 90rpm, the forces at the pedals are small. The frame stiffness makes very little difference to steady-state pedalling efficiency and thus speed on the flat, up hills,... Where the stiffness does matter is if you sprint out of the saddle or ride fast through corners. I do agree that riding a noodle in these situations is a dangerous, not just inefficient.

3) An unfit novice rider produces maybe 120W for an hour. A moderately fit club rider like me maybe 230-250W. A cat 1 rider 320W. Lance 400W. You don't have to be a mathematician to see that step 1 on the route to going fast up hills is to go from developing 120W to developing 200W, which is an increase of 67%, rather than buying light parts.

4) As the power goes up, most people's weight will go down of its own accord (if it doesn't, it's worth a serious look at nutrition). Benefit there depends on one's starting point, e.g. 80kg to 75kg = 6%. 120kg to 80kg = 33%.

mrfish

P.S. 200mm crankset - How do you get round corners?

oldacura

I think Mr Fish's tale agrees with a well-known rider who maintains "It's not about the bike".

Carbonfiberboy 

Absolutely agree on the weight vs. watts thing. Training is the hammer. Everything else is a feather.

However the frame material/construction thing I'm not so sure on. I have two stiff aluminum singles of greatly differing weights, a carbon single, a flexy steel single, and a steel tandem. The two alu singles climb about the same, with a slight nod to the lighter and stiffer CAAD 9. The carbon single is by far the fastest, seeming to continually accelerate as long as I put power to the pedals. The flexy steel single is a power thief.

We've extensively test ridden a C'dale and two other steel tandems. I didn't notice much difference in speed between them, although it does seem like our Speedster goes pretty good when we put the power to it. I have test ridden other people's steel singles and have found a great difference between them in both speed on the flat and climbing. Some bikes just don't seem to transfer the power from the pedals into the road. Others do. I have no idea why that is. They feel like one is pedaling on melted asphalt, and that's not subjective. I get dropped. Some people say that the stiffer the frame the faster. Others say that a certain amount of flexibility is faster. I don't know who's right there, either. But something is definitely going on there, and that thing is much more important than weight. Frame? Wheels? Tires? The combination?

DoubleDiamonDog

mtnbike - I have to say that your experience with steel bikes being more comfortable than aluminum is consitent with mine.

However, one could make an aluminum bike less stiff, but that would seem to be going against the advantage of the material. On the other hand, when people refer to steel bikes as noodly I think they need to try a different bike. Steel tubesets have continued to evolve and lightweight efficient frames, even for tandems, are possible. There are people who still buy the lugged steel frames that you referred to but they form a very small sampling of the steel frames sold today.

Ideally a bicycle frame material will be chosen based on the rider(s) and intended purpose. It is clear that you believe that for your size and riding style only aluminum and only as made by cannondale will work. Most other people are correct in believing that they may choose from a broader range of frame materials when searching for a suitable bike.

As for the fact that "People have a tendency to convince themselves of things that they want to believe anyway" as you say, I believe it to be possible that Dean V is "as fast" on a steel bike as on a cannondale. But could it be that becasue of you are "a Cannondale fan and even an apologist" that you have convinced yourself otherwise?

Brad Bedell

I Specified rack mounts on *our* Cyfac. I don't have it dressed super light, but still tips the scales under 26lbs *ready to ride* (bottle brackets, computer and pedals). Didn't want to clutter up the frame for the 'top ones' as I'd just use a derailleur clamp on mount and use the seat post. for the front rack attachment. While I tend to subscribe to the 'racer' mimalist mentality, I didn't want a frame that was obsolete if I wished to do some light touring in the future. It's been mentioned above, arm/leg warmers in the pockets. *OR* just plan on being a little chilly until you warm up.

https://bedellracing.smugmug.com/Othe...led-089-XL.jpg

That said, wheels/tires would be the only place I'd spend money to save weight on the above setup. (especially if you wish to use a rack/bag) I have a set of 36 spoke Comotion wheels with velocity hoops that are adequately light over the set seen in the first photo.

waynesulak

Lots of good points are being mentioned here. I think most would agree:

- Motor is most important and everything else is much less a factor to climbing speed.
- Light will climb faster than heavy, everything else held constant
- People can fool themselves if they are not scientific in their approach

I will point out that I do not equate steel with flexy. The stiffest single I ever rode was a modern steel bike with very fat tubes. Just the opposite of a steel bike with thin tubes. Both frames are steel and weight almost the same and made in the same factory but they ride very differently.

Same thing with carbon. A friend of mine had an old Trek carbon bike with fairly narrow tubes. The bottom bracket came loose and he got a free new frame from Trek which had much bigger tubes. I don't know about the speed of either bike but he didn't enjoy the new bike and lamented the loss of the old one. He claimed that his new bike felt "dead" compared to the old one. He is not a big guy which probably makes a difference.

mtnbke

You make good points. However, while some drivers are better driving some cars and there are variances involved, an Andretti in a Ford F-150 just ain't gonna be faster than me in a Porsche.

People race on steel because of sponsorship deals, because of budget constraints, and maybe even because of comfort or an affinity for something vintage or the cult and ethos of steel, but no one rides steel because it is "faster." The poster didn't communicate that steel was faster, but as fast, and I'm just trying to keep the conversation in the realm of reality. It just ain't so, all other things being equal.

mtnbke

Good points. However, motor is a constant regardless of which frame cyclist is on. Parasitic wattage loss due to frame inefficiency does not allow steel tandems to perform the same as other materials.

However, it has been stated on this forum and needs to be stated again, that not all materials ride the same for all riders. Keith Bontrager made, according to some, some epic steel mountain bikes. When I went to buy a Bontrager Privateer around ~ '94 I couldn't believe how much bottom bracket flex there was on the frame. I was young and didn't know better, but believe it or not my cheapo $300 Trek 830 was a stiffer "faster" frame, for me then (competitive basketball player ~190lbs with strong legs). I rode my first Cannondale and fell in love. When we went to buy our first tandem we bought into the Santana propaganda and marketing material hook, line and sinker. However, the Santana tandems we rode didn't reconcile with the great ad copy that is the Santana literature. Every Santana we rode was flexy to the point of being disconcerting. We almost gave up, before the sales fella said that we should try a Cannondale tandem. Again, it was love at first ride (aside from the tandem being way too small, but it was the largest made, Jumbo captain's compartment).

I guarantee that there are plenty of tandem teams that are faster on their steel tandems than we are on our aluminum tandem, but that ain't saying much!

As expensive as tandems are, and as cheap as you can find nicelly equipped and upgraded Cannondale tandems on Craigslist that often times have less than 1000 miles on them, I just feel inclined to make the point. I just think that all other things being equal, no one put those drinking the Kool-Aid would ever "want" a steel tandem if they could alternatively have an aluminum one, let alone a magnesium, titanium, or carbon tandem. Well, maybe if they wanted a break apart with couplers for travel to third world countries. Then the steel tandem would be faster because all the other tandems might be cracked and broken after rough handling on lorries! There are benefits and not to everything under the sun.

In the context of this thread, even in light of my stated opinion the steel tandem ain't the problem. I strongly suspect that our captain realizes that his plump bride ain't even coming close to pulling her own weight. A high zoot Calfee or Paketa or even just an aluminum Co-Mo or my beloved Cannondales aren't going to make much of a difference.

Speaking as a fat cyclist, grams saved are not the problem when the problem is being overweight by 100+ pounds. Just to locate the conversation back into context. To the OP, good luck with that. I have a hesitant stoker who doesn't "love" cycling, but is game for physical activity at least (ex multi sport athlete, but way past prime plus two kids). It certainly takes the joy out of cycling when a partner just isn't "into it." As for stoker's that won't even give effort to pull their own weight. I've ridden with one heavy stoker like that once, I'd rather ride the tandem alone, thank you.

Dean V

I have no doubt that a stiffer frame will handle differently and feel different to the rider and may even feel to be faster. But is it?
Where is the data or tests to back up what you say that a more flexi frame is slower and more power is gone in parasitic losses?
As I said previously in my experience I have not found it to be the case.
Going back to the C'dale 3.0 you mentioned. When this came on the scene did it dominate the steel bikes in performance? Were the riders of these out sprinting, climbing, etc the competition because of the much increased stiffness in the frame? I don't think so.
In fact going in the other direction there is always Sean Kelly on his Vitus which is the ultimate in noodly bikes and he seemed to do ok.