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# how many times faster is a tandem bike with 2 people than a regular bike

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# how many times faster is a tandem bike with 2 people than a regular bike

03-17-07, 11:11 AM
#1
dty
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how many times faster is a tandem bike with 2 people than a regular bike

on average?
03-17-07, 11:19 AM
#2
cornucopia72
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Wild guess:

- Flat terrain: Tandem 10% faster that the average of the two riders on singles.

- Down hill: Tandem 20% + faster than.....

_Up hill: Tandem 5 to 20 % + slower than.... depending on how well the team works.
03-17-07, 11:24 AM
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TandemGeek
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From a previous response to a similar question:

All things being equal except for the bike, (and despite myths to the contrary) a tandem road bike with two riders is between 30% to 50% less aerodynamic than a a solo rider on a road bike. Therefore, in order for a tandem to maintain a constant speed that is as fast (or faster) than a solo rider, the team must produce a net power output that is at least 30% to 50% greater than a solo rider.

Moreover, consider if you will that power production on a tandem is not necessarily linear since either one or both of the two riders on a given team may at any given time fall victim to poor form, individually or collectively. Put another way, even if you have two strong cyclists (1+1), they will lose some efficiency due to the nature of a tandem and, if they are not able to work well together, their efficiency will fall way off. So, in reality what you will often times find with a tandem is that you have two riders of different abilities who can produce variable levels of output which may or may not be as high as they are able to produce when riding alone. This is why some tandem teams who are weaker riders individually than a team comprised of two strong riders are often times as fast (or faster) than the stronger couple when both teams ride their tandems. The place where a team's combined efficiency level is most obvious is when they get to the hills where you have the same math problem with percent grade being substituted for headwind MPH and the added factor of team weight having more importance than aerodynamic drag. Less I digress...

So, to answer your question, if you have a team who can produce at least 30% to 50% more power as a team on a tandem they should be able to keep up with a solo rider. However, if a tandem team can produce a net power output above what is required to compensate for increased drag, the tandem pulls the train.
03-17-07, 11:47 AM
#4
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Originally Posted by TandemGeek
From a previous response to a similar question:

All things being equal except for the bike, (and despite myths to the contrary) a tandem road bike with two riders is between 30% to 50% less aerodynamic than a a solo rider on a road bike. Therefore, in order for a tandem to maintain a constant speed that is as fast (or faster) than a solo rider, the team must produce a net power output that is at least 30% to 50% greater than a solo rider.

Moreover, consider if you will that power production on a tandem is not necessarily linear since either one or both of the two riders on a given team may at any given time fall victim to poor form, individually or collectively. Put another way, even if you have two strong cyclists (1+1), they will lose some efficiency due to the nature of a tandem and, if they are not able to work well together, their efficiency will fall way off. So, in reality what you will often times find with a tandem is that you have two riders of different abilities who can produce variable levels of output which may or may not be as high as they are able to produce when riding alone. This is why some tandem teams who are weaker riders individually than a team comprised of two strong riders are often times as fast (or faster) than the stronger couple when both teams ride their tandems. The place where a team's combined efficiency level is most obvious is when they get to the hills where you have the same math problem with percent grade being substituted for headwind MPH and the added factor of team weight having more importance than aerodynamic drag. Less I digress...

So, to answer your question, if you have a team who can produce at least 30% to 50% more power as a team on a tandem they should be able to keep up with a solo rider. However, if a tandem team can produce a net power output above what is required to compensate for increased drag, the tandem pulls the train.

What he said!!!!

Two individuals on a Tandem and it is hard work. Get those two working as a Team and I would say that cornucopia is somewhere near right. As we have found out- You put your advantages to use so if you have a Kami-Kaze pilot Then you can gain downhill or on corners. If both of you like hills- then you can stay with the solos.
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03-17-07, 02:03 PM
#5
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All things being equal (which is never the case in cycling), on a single I maybe average ~ 16 mph over a given loop, my wife averages ~ 11 mph, and together we average ~ 15 mph. We do well on the flats, but wind and hills really hurt us. That said I did a short ride with my Dad once, I'm guessing we would be + 16 mph, he is a lot more powerful then my wife.
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03-17-07, 04:27 PM
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cornucopia72
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Originally Posted by TandemGeek
the team must produce a net power output that is at least 30% to 50% greater than a solo rider.
Particularly when working against cross winds
03-17-07, 07:38 PM
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Speed primarily has to do with efficient use of power . . . on a single or on a tandem.
So why do singles like to draft a tandem . . . 'cause they're slower?
04-02-07, 11:13 PM
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WishYouWasMe
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well is these a luxury road bikes or what?

Are they good bikes I dont know lol.
04-03-07, 06:04 AM
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TandemGeek
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Originally Posted by WishYouWasMe
well is these a luxury road bikes or what?

Are they good bikes I dont know lol.
04-03-07, 06:14 AM
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ElRey
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Go out and see. This is not a theoretic issue.
04-03-07, 07:17 AM
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Trsnrtr
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Originally Posted by cornucopia72
Particularly when working against cross winds
Correct. My wife and I rode with two singles last week on a ride where the winds at completion were being given by the Weather Channel as 30 mph with gusts to 44. When we were riding in a straight-on headwind or tailwind, the other two were drafting, but on even the slightest crosswind, we were suffering big time.

Still, all in all, I'd rather be on a tandem than a single on that ride.
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04-03-07, 07:41 AM
#12
asu_gt
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We have a little data on the road with our power measuring tandem.

One road trial (48Km..24 out and back), total climbing 1754 feet.

tandem ride:
Ave speed: 21.5 mph
capt. power: 272(96) mean(sd)
stoker pwr: 149(66)

I rode the exact same course two days later under nearly identical conditions, with my single:
Ave speed: 21.6
Pwr: 276(111)

two equal efforts from me in terms of mean power and similar speeds for the single and tandem ride. I must note that after the tandem effort I felt much better and could have continued on for a longer ride. Inspection of the raw power data revealed that both the stoker and and captain could take "mini-breaks" that appeared to serve as recovery periods.

gotta run.
jay
04-03-07, 08:42 AM
#13
cornucopia72
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Originally Posted by asu_gt
We have a little data on the road with our power measuring tandem.

One road trial (48Km..24 out and back), total climbing 1754 feet.

tandem ride:
Ave speed: 21.5 mph
capt. power: 272(96) mean(sd)
stoker pwr: 149(66)

I rode the exact same course two days later under nearly identical conditions, with my single:
Ave speed: 21.6
Pwr: 276(111)

two equal efforts from me in terms of mean power and similar speeds for the single and tandem ride. I must note that after the tandem effort I felt much better and could have continued on for a longer ride. Inspection of the raw power data revealed that both the stoker and and captain could take "mini-breaks" that appeared to serve as recovery periods.

gotta run.
jay
The big question now is what your stoker speed and power output would be? Also, can you graph the results by elevation change?
04-03-07, 11:05 AM
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cowtandemstoker
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measuring tandem power

Jay,

I am interested in how you were able to measure your power for both stoker and captain on the tandem? Please advise.

Pat & Gabrielle
04-03-07, 11:54 AM
#15
Hermes
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Originally Posted by cowtandemstoker
Jay,

I am interested in how you were able to measure your power for both stoker and captain on the tandem? Please advise.

Pat & Gabrielle
04-03-07, 12:54 PM
#16
asu_gt
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Pat,

Here is a video of the bike in action:
https://www.wkyc.com/video/player_hea...id=63410&bw=hi

We will most likely do a few more tests on the road, on the weekends when the bike is not being used for the study.

I will try to generate a graph that also includes elevation..though I am working on a couple grants at the moment so time is tight.

I do need to another single test with the stoker, I just need to take the time to swap her crankset with a SRM.

My next fun project will be to examine frame properties and overall power loss using a customize rear PT hub. I have a co-motion robusta, Paketa and Calfee dragonfly (en route) for the testing. should be interesting.

jay

Originally Posted by cowtandemstoker
Jay,

I am interested in how you were able to measure your power for both stoker and captain on the tandem? Please advise.

Pat & Gabrielle
04-03-07, 01:22 PM
#17
WishYouWasMe
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Originally Posted by WishYouWasMe
well is these a luxury road bikes or what?

Are they good bikes I dont know lol.
04-03-07, 04:47 PM
#18
Hermes
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Originally Posted by TandemGeek

One of your best posts...not saying anything negative about your other stuff which is excellent. Where did you get that GIF?

Let's send the active ingredient to Washington.

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