Tandem Cycling - "Short" tandems

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lhbernhardt
06-17-07, 12:02 PM
Well, being a contrarian by nature, and having put many thousands of kilometers on the nearly-vintage Kuwahara tandem in the past couple of years, I am coming to the conclusion that the biggest boost to tandem popularity in the past 30 years - namely, the stretched rear compartment pioneered & promoted by US tandem builders - is oversold. Having attended a couple of tandem rallies in the Pac Northwest, it seems to my contrarian eyes that a lot of rear frame space is wasted. The stoker seems to have too much room.
This wouldn't be an issue, except that the longer rear compartment comes at the expense of a longer wheelbase, which I think most would agree is detrimental to "sporty" handling. Maybe this really isn't an issue, as I have heard that Co-Motion has the handling paradox resolved in its frame geometry.
Anyway, just as a mind exercise, I wonder how a "short" tandem would fare? By "short," what if we REALLY shortened the rear compartment, moving the stoker right up behind the driver (much like on a motorcycle). The stoker's stem would be flipped around to the front of the captain's seat post and much longer, so that it would rise up between the captain's legs. The stoker's bars would then be placed in front of the pilot and the stoker would reach around the captain to grab them. The two cranksets might have to be so close together that pedaling would have to be in phase to avoid conflict. If the tandem crashed, the captain would basically be trapped in the stoker's bars! (Or maybe protected by them...). In any event, the wheelbase could be considerably shorter, resulting in faster handling, and the stoker may not feel the bumps as intensely.
I wonder if this has been attempted/mentioned/designed?
- L.
TandemGeek
06-17-07, 12:07 PM
The stoker seems to have too much room.
How much time have you spent on the back of a tandem stoking?
dbohemian
06-17-07, 03:16 PM
I am a big proponent of the extra long stoker compartment. I learned it also from Erickson and R & E cycles.
I think the first supposition that you are making, that is a tandem would handle more "sporty" if it was 3 to 4 inches shorter in its wheelbase is not completely accurate.
IMHO, fit supersedes all other bike design considerations. A proper fitting team will produce the most amount of power available with the most comfort. The frame must be designed around this. So even though it may look like there is a lot of room available, some of that room may be used when teams stand or allow for more aerodynamic positioning of the stoker without interference from the stokers handlebars and such.
Also consider that handling is multifaceted. The overall length of a tandem only affects the turning radius of a vehicle to a small degree (exactly the extra length *PI) so this case if the tandem was 3 inches longer then I will have increase theoretical turning radius by about 10 inches. This has even less effect at speed. As long as the tandem is ridged enough to handle the extra length well everything works well.
I have considered as a design exercise an extremely short "donkey back" tandem. I see it for track use and such where the stoker pedals directly into the rear hub and the rear wheel is right underneath the rider. Even with a generous cockpit this would make for a tandem that was not a whole lot longer than a single and might allow for faster positioning in tandem track racing.
Dave Bohm
Bohemian
TandemGeek
06-17-07, 04:58 PM
I have considered as a design exercise an extremely short "donkey back" tandem.
Something along the lines of the infamous Corima tandem built for Chenoweth when he was "managing" and racing on the EDS squad?
http://images.velonews.com/images/news/1680.1687.t.jpg
Eddie50
06-17-07, 06:39 PM
How much time have you spent on the back of a tandem stoking?
+1 on that
Im in the back and there is not enough room, and to have more, I would have to go custon. not off the shelf tandem could give both of us the correct sizing.
I've piloted 3 tandem lengths and from a captains POV,the shorter tandem is less of a wrestling match.
However,the stoker greatly preferred the longest bike...
I'm guessing/betting that one of the most common options on custom tandems is a longer stoker TT/distance between BB's. They can stretch out and get low and I'm quite sure that being farther downwind from me on a hot day would be nice...
zonatandem
06-17-07, 06:49 PM
Doesn't look very comfortable . . .
zonatandem
06-17-07, 06:51 PM
here's the picture . . .
zonatandem
06-17-07, 07:06 PM
Shortest wheelbased tandem we have owned/ridden/designed had 60 1/4" wheelbase . . .
Very 'petite' stoker, big toeclip overlap, bent rear seattube with extremely short chainstays (so short, we had to deflate rear tire to remove wheel). Pilot's quads hit stoker's gloved hand if she was on the hoods . . . but not in the drops. In extreme tuck position, her helmet was against pilot's back. Stoker bars/stem were in the traditional position.
Quick/fast/light racing tandem . . . but it fit. We put 64,000 miles on that tandem, and yes, we loved it (but that was in younger hell-bent days!).
Contrary to your belief the shorter tandem was harsher ride for stoker (as she really sat over that rear wheel) than our later longer tandems which had/have a 63 1/2 wheelbase.
Pedal on TWOgether!
Rudy and Kay/zonatandem
NewbieIATandem
06-17-07, 08:40 PM
Hey Zona, scary that Sears would have the answer to the OP.
Fenlason
06-18-07, 04:52 AM
Ihbernhardt....I think you need to think your idea over a little more. I see some serious "issues". If the two riders are as close on you suggest... as on some motorcycles, how does either person pedal. There would not be enough room for them to move their legs in the full circles needed for pedaling. Standing on hills ... or to just get off the seat, would be totally out of the question. How would you even get on the bike and get moving? The stoker can't hang onto anything until the capton gets on. It sounds very awkward.
When I had an off-road tandem custom made. We wanted it as short as we could get it... to fit through our tight and twisty trails. Yet having the bike fit correctly ... had priority to that. The wheel base was slightly shorter [maybe an 1" or so] but the bike fit like a glove. It handled great. Of course it did not handle in the woods like a single bike... but there are some things in physics you can't get around. Besides we enjoyed the challenge of getting a "beast" of it's size through the woods.
glenn
TandemGeek
06-18-07, 06:16 AM
Hey, there's always the "Love" bike, or as it's now known the "Buddy Bike"
http://www.buddybike.com/
Seriously though, I think you need to take a contemporary performance tandem like a Co-Motion for a test ride to scratch your itch. The Kuwahara is well off the front in terms of where materials and frame design have gone since they were produced.
dbohemian
06-18-07, 06:23 AM
close, but technically a "donkeyback" has the stoker putting power directly into the rear hub and is also directly over the rear wheel. Kind of like this:
http://images.google.com/imgres?imgurl=http://www.pedalwelt.de/db_BiBici1.jpg&imgrefurl=http://www.pedalwelt.de/Spezialradverleih/spezialradverleih.html&h=72&w=96&sz=2&hl=en&start=2&sig2=VQfIQzxpikRPPvRG12snlQ&um=1&tbnid=wHQtTIOnGZN0DM:&tbnh=61&tbnw=81&ei=iXp2RoKMI5fuhAOfqt21Aw&prev=/images%3Fq%3Dbi%2Bbici%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-US:official%26sa%3DG
To make one with gearing would be a difficult engineering issue, fixed would be a little easier.
Sorry that is the best picture I could find quickly. I have seen some very old ones up close.
That one will most likely stay a conceptual idea. Can't see that there is a market for such a thing.
Dave
here's the picture . . .
Reaching for the bars in front of the captain's seat would put the stoker's face just about in the captain's.....................................................lower, lower, lower back region.
It is an interesting observation. I suggest that you spec out a short wheelbase tandem, have Dave Bohemian build it for you and see how it works. If you cannot find any stokers, you can hang it on your wall as a piece of art and it will not take up much room.
Rincewind8
06-18-07, 09:00 AM
here's the picture . . .
For some reason I have the feeling the bike was not assembled as intended by the manufacturer. I mean how would the captain of this bike pedal without hitting the stoker handle bars?!? :rolleyes:
NewbieIATandem
06-18-07, 11:23 AM
For some reason I have the feeling the bike was not assembled as intended by the manufacturer. I mean how would the captain of this bike pedal without hitting the stoker handle bars?!? :rolleyes:
Check it out, it is on the Sears website for $175 or there abouts. If you can do your own setup etc. maybe Sears is OK, but except for very light use a $175 tandem where the marketing photo is not even setup correctly...
I had thought about buying this bike as a second light duty bike but once looked at it more closely and yep, it's obviously setup incorrectly.
Rincewind8
06-18-07, 11:36 AM
Check it out, it is on the Sears website for $175 or there abouts. If you can do your own setup etc. maybe Sears is OK, but except for very light use a $175 tandem where the marketing photo is not even setup correctly...
I had thought about buying this bike as a second light duty bike but once looked at it more closely and yep, it's obviously setup incorrectly.
Oh, I'm not in the market for a new tandem, nor would I buy that one. It's just funny (or maybe sad) that they use a photo with the handlebars set up incorrectly.
dbohemian
06-18-07, 12:00 PM
It is an interesting observation. I suggest that you spec out a short wheelbase tandem, have Dave Bohemian build it for you and see how it works. If you cannot find any stokers, you can hang it on your wall as a piece of art and it will not take up much room.
Well, I am willing to give it a shot, just as long as the stoker fits correctly:)
Many early tandems were built super short. I think the concept may have died do to the difficulty of incorporating gear sets into the designs and the fact that you could not use standardized componenty.
IMHO bike designs are almost never optimized nor does it mean that because something does not exist now, that it did not have great merit previously.
Dave Bohm
DBC Steve
06-18-07, 01:35 PM
Many early tandems were built super short.
I am on the road (figuratively), but when I get home tomorrow I'll try to find and post a picture of a friend's track tandem from the 1968 Olympics. The picture has Peter on the bike with no stoker -- it almost looks like a single. I was the stoker for a few months on an early 1970s Paramount and my most important recollection was how tight the fit was (ok, the bike was probably too small for a 6'2" stoker with long legs).
Our 1977 Gitane had a bit more room, but nothing like the luxury of our CoMo Speedster. My stoker would stick to her single if the only choice was a short frame. In this case, the change in design made regular tandeming possible for us. YMMV....
zonatandem
06-18-07, 02:08 PM
Yup, Paramount built a 'short' tandem with drastically bent rear seattube back in the 70s. Gitanes were a bit longer. Did see a Gitane with bent rear settube. Most tandems of that time period were shorter than the current average of around 69" wheelbase.
Nothing wrong with a 'short' tandem, as long as it fits the riders properly.
That's Sears tandem, with erroneous stoker bar setup, of course was done by an 'expert' Sears certified assembler . . .
Pedal on TWOgether!
Rudy and Kay/zonatandem
I am on the road (figuratively), but when I get home tomorrow I'll try to find and post a picture of a friend's track tandem from the 1968 Olympics. The picture has Peter on the bike with no stoker -- it almost looks like a single. I was the stoker for a few months on an early 1970s Paramount and my most important recollection was how tight the fit was (ok, the bike was probably too small for a 6'2" stoker with long legs).
Our 1977 Gitane had a bit more room, but nothing like the luxury of our CoMo Speedster. My stoker would stick to her single if the only choice was a short frame. In this case, the change in design made regular tandeming possible for us. YMMV....
Sorry for hijacking this thread for a moment but DBC Steve, will we will see your tandem in a local TT race? Did you race at Dunlap?
Back to topic...I think the advances in material's strength to weight ratio allows manufacturers to lengthen bikes without turning it into noodle.
Here are two tandems that go in the other direction in pursuit of speed. One would need a miracle to make a u turn around a cone on a narrow road.
http://i170.photobucket.com/albums/u250/rallen94402/hookerTandemTT.jpg
http://i170.photobucket.com/albums/u250/rallen94402/BobJacksonTTTandem.jpg
The fastest mixed tandem team at the last Paris-Brest-Paris used a 50 year old French tandem. No bent seat tube but a super-short rear top tube. It didn't seem to slow them down and it must have been comfortable enough (1200 km in just over 2 days)
dbohemian
06-18-07, 04:21 PM
The older French tandems were very nice.
The reason old tandems were so short was that the available tubing was all sourced from singles. If you cut off the absolute bare minimum you ended up with stoker top tubes similar to what old Herse's and similar bikes had.
I don't think it necessarily held back riders but I do think it was far from optimum concerning stoker fitting.
The long stoker compartment (for a large majority of riders but not all) is the single biggest improvement in tandems in the last twenty years. I believe that strongly in it. It is only with the advent of longer tandem specific tube sets and reasonable OS tubing to retain rigidity that this has become possible.
Also consider that having a long stoker compartment opens up whom you can ride with. Tandem teams don't often have other stokers out for fun but it is entirely possible with longer compartments.
Dave
zonatandem
06-18-07, 07:45 PM
Agree with TG that the Kuwahara tandem is a far cry from now-day tandems. The Kuwa was a nice/good tandem package in its day but design/tubing/components have changed drastically.
Agree with Dave B. that OS tubing, longer stoker compartments and more tandem specific components have greatly enhanced tandem usage/sales.
Believe that the tandem that won PBP was an old Rene Herse.
Pedal on TWOgether!
Rudy and Kay/zonatandem
TandemGeek
06-18-07, 08:29 PM
Believe that the tandem that won PBP was an old Rene Herse.
Jan Heine and Jaye Haworth in '03 to be specific, both are very accomplished randonneurs among other cycling pursuits. So as not to diminish their accomplishment, they were the first place mixed team and the second place team overall.
Photo and links here from a previous post:
http://www.bikeforums.net/showthread.php?p=2003618&highlight=rene+herse+jan#post2003618
Believe that the tandem that won PBP was an old Rene Herse.
<pedant mode>
It was a Herse but PBP isn't a race, so Jaye Hayworth and Jan Heine didn't win, just finished first. In any case, a male/male tandem finished before them but they were the first mixed team to finish (in record time).
</pedant mode>
http://www.rusa.org/newsletter/06-04-07.html
Edit: Too slow for TandemGeek
zonatandem
06-18-07, 09:19 PM
We've attended many events that were 'not a race' . . . PBP is an endurance event. All who finish are winners!
Just coming back from a 70-odd mile charity ride (the short route) round the hills of the cotswolds. I have to report back on the exploits of my friend Digby and wife Katy. They did the longer ride of 102 miles and 2500 metres of nasty climbs in 6h 13, beating many many road racers. I was seriously impressed with the way they danced up the hills and after starting with me dropped me and many others.
Their tandem is a knackered old Peugeot with downtube friction shifting, brake cables coming out of the top of the levers, 15 gears and 1" road tyres with tread. The moral of the story is that fitness beats flash bikes hollow so it's not worth stressing too much about the bike. Although that's not stopped me so far ;-)
NewbieIATandem
06-19-07, 05:10 AM
Back on topic. I say go for it. If you think a very short stoker compartment and shorter wheelbase will enhance your tandem experience and have the money to experiment, go for it.
If you want really fast with quick handling and your stoker agrees, than maybe a super short wheelbase is how you need to configure your tandem. If however your stoker is not in agreement, it would be a bad move.
My stoker on our first tandem was hitting her knees on the handlebars. Could we maybe have adjusted it differently? Maybe, but the stoker compartment was small. Buying a better tandem, one with room for both her and myself has made our tandem experience much better. We don't even own singles right now so making our tandem fit our bodies and riding styles makes the most sense in the equation. We go on leisurely rides of FAR LESS than 100 miles, our speeds right now flirt with 13 mph on the flats. We are enjoying being Twogether and the handling of our "long tandem" is just fine.
In other words, this is a hobby for us, not a sport. So our tandem fits that equation for us.
cat0020
06-19-07, 06:27 AM
My SO and I have ridden regular tandems, but settled on a semi-recumbent tandem since March this year.
I'm 5'10" and she's 4'11", on this tandem we could swap between captn and stoker, with enough tools even on a ride.
http://www.ilovebent.com/pic/output/_MG_0003.jpg
The overall length of the semi-recumbent tandem is shortter than a regular tandem, since the stoker's boomtube bottom bracket is adjustable, so is the overall length of the tandem itself.
frameteam2003
06-19-07, 01:55 PM
The three tandems we have are as:
Bilenky--------68" (axle to axle)--27"(CTC) stroker TT
1936 Russ-----64" (ATA)---------21"(CTC)
1950 schwinn--62"(ATA)----------21"
The schwinns first built about 1938 were listed as short coupled tandems,Claud butler also built tandems alone this design.
The Russ is a double gents racing frame(not to be confused with a track racer)more alone the lines of a club racer
the wife likes the Bilenky the best--it is the newest of out bikes and the easest to ride
But the hardest to handle when off the bike.
DBC Steve
06-19-07, 07:09 PM
Sorry for hijacking this thread for a moment but DBC Steve, will we will see your tandem in a local TT race? Did you race at Dunlap?
Photo of Peter's 1968 Olympics tandem attached. Dunlap? Yep -- we enjoyed it from the deck of Steady Eddy's in Winters, coffee drinks in hand. No amount of coaxing in advance could convince my stoker, but a spin back to our place on Road 95 (and a view of those great Dunlap tandem shots) convinced her that we gotta try TT sometime soon. We will do Dunlap next year, but may try the DBC Wednesday night time trials on Putah Creek Road sometime this summer. Not all that great for a tandem -- it is an out and back course, meaning that you have to take a sharp 180 in the middle of PCR after five miles. Still, price is right (free) and it would be fun. It also starts 4 miles from home.
This thread also mentioned a Kuwahara several times. I took a nice pic of one at Folsom Lake a few months ago -- wild paint job, nice bike.
zonatandem
06-19-07, 08:45 PM
The Kuwahara's did have an eye-appealing paint scheme. Most tandems at that time were single color or with a contrasting color panel. None of the fancy fade schemes that abound now.
Have seen primarily white, but also one blue, Kuwa and they had a nice wide band of rainbow colors to contrast the paint job.
Talking about Olympic tandems: our friend and now retired custom framebuilder Colin Laing, built several tandems for the Russian Olympic team . . . He built many tandems/singles as what he called 'brown wrappers' . . . no decals. Even had one of his 'brown wrappers' ridden to a win in the Tour de France.
If someone needs/wants a short wheelbased tandem, custom will be the logical choice.
TandemGeek
06-19-07, 09:00 PM
The Kuwahara's did have an eye-appealing paint scheme.
Indeed they did. I had a Kuwahara Cougar rigid mountain bike that looked sensational... unfortunately the Ishiwata triple butted tubing and lugged construction added up to a 30lb beast of a bike. Never mind the biopace chainrings and U-brake: what WERE they thinking!
http://www.thetandemlink.com/kuwaharapnt.jpg
lhbernhardt
06-19-07, 09:59 PM
My Kuwie tandem was from before they started doing the fancy paint jobs. It's your basic medium blue. The Subaru WRX blue touchup paint is a pretty good match. I've never been tempted to upgrade to a "current design;" I'd just get caught up in this vicious circle of materialism, and all the tandems today look the same anyway. Somebody's got to have something that looks a little different.
Anyway, I'm glad to see there's agreement that the longer stoker compartment is one of the keys to greater tandem popularity, and that older tandem designs are not the limiting factor in how a team performs.
I don't think I'd ever try building a really short tandem; as I said, I was interested in a thought experiment, or to see if any of you experts out there had ever seen a tandem as short as I'd envisaged.
- L.
Photo of Peter's 1968 Olympics tandem attached. Dunlap? Yep -- we enjoyed it from the deck of Steady Eddy's in Winters, coffee drinks in hand. No amount of coaxing in advance could convince my stoker, but a spin back to our place on Road 95 (and a view of those great Dunlap tandem shots) convinced her that we gotta try TT sometime soon. We will do Dunlap next year, but may try the DBC Wednesday night time trials on Putah Creek Road sometime this summer. Not all that great for a tandem -- it is an out and back course, meaning that you have to take a sharp 180 in the middle of PCR after five miles. Still, price is right (free) and it would be fun. It also starts 4 miles from home.
This thread also mentioned a Kuwahara several times. I took a nice pic of one at Folsom Lake a few months ago -- wild paint job, nice bike.
The Dunlap TT was the best run race, course and facilities this year. It was a lot of fun and we will definitely be back next year.:)
DBC Steve
06-20-07, 06:55 AM
I had a Kuwahara Cougar rigid mountain bike that looked sensational... unfortunately the Ishiwata triple butted tubing and lugged construction added up to a 30lb beast of a bike. Never mind the biopace chainrings and U-brake: what WERE they thinking!
Here it is! Note also OOP and those all-important fenders.
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