Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

Reply
 
Thread Tools Search this Thread
Old 07-31-11, 09:08 PM   #1
rdtompki
Senior Member
Thread Starter
 
rdtompki's Avatar
 
Join Date: Nov 2008
Location: Hollister, CA
Bikes: Volagi, daVinci Joint Venture
Posts: 3,962
Achieving High HR on the flats?

When climbing the tandem I can get my HR arbitrarily high, but can sustain 140 or 145. Of course I'm using some upper body and aerodynamics are negligible. I can do this in a pretty broad cadence range, but obviously like 80+

When were in the flats I can't hit much more than 130 without spinning out my wife; If power is somehow proportional to HR, I can't generate the power at 80 rpm in the flats that I can on a climb. My hypothesis is that in the flats the deceleration as the pedals come over the top is significant and causes the torque versus rotation profile to be broader versus the profile when climbing (also, the proportionality of force versus speed is quite different). I suspect this is more pronounced on the tandem, but I'm an old, lazy engineer and I really don't want to think any harder than I already have.

Does anyone else experience this phenomenon or am I just crazy?
rdtompki is offline   Reply With Quote
Old 07-31-11, 09:20 PM   #2
gracehowler
Rod & Judy
 
gracehowler's Avatar
 
Join Date: Jun 2009
Location: Montrose, CO
Bikes: Specialized S-works e-5, Davinci joint venture, Specialized Vienna Commuter
Posts: 481
WE notice the same thing, but have no idea of why!
R&J
gracehowler is offline   Reply With Quote
Old 08-01-11, 02:00 AM   #3
PMK
Senior Member
 
PMK's Avatar
 
Join Date: May 2008
Location: Royal Palm Beach, Florida
Bikes: 2006 Co-Motion Roadster (Flat Bars, Discs, Carbon Fork), Some 1/2 bikes and a couple of KTM's
Posts: 1,151
If 80+ revs is the rpm for your stoker, or the redline rpm. Then you must work with this.

It may trash your joints but for your effort (HR) to go up at 80+ RPM, you need a taller gear.

Whatever you said about it in engineering terms sounded like the hill made resistance you don't experience on the flats.

Several possible choices...

#1, Only climb and descend.
#2, Get an ICS drivetrain and overrun your stoker.
#3, Any chance of your stoker turning more rpm?
#4, Add resistance, either less aerodynamic or less efficient rolling performance. Easiest may be a larger soft tire. Complicated maybe a switched on or off generator. A band aid approach could be a closer spaced gearset.

If you want to keep current speeds and increase HR the options are few.

Not good answers, not being a wise guy.

FWIW, #3 worked for us, along with some rides of #1.

PK
PMK is offline   Reply With Quote
Old 08-01-11, 04:42 AM   #4
swamptandem
Senior Member
 
Join Date: Sep 2010
Location: Florida
Bikes: not enough
Posts: 111
Quote:
Originally Posted by rdtompki View Post
When climbing the tandem I can get my HR arbitrarily high, but can sustain 140 or 145. Of course I'm using some upper body and aerodynamics are negligible. I can do this in a pretty broad cadence range, but obviously like 80+

When were in the flats I can't hit much more than 130 without spinning out my wife; If power is somehow proportional to HR, I can't generate the power at 80 rpm in the flats that I can on a climb. My hypothesis is that in the flats the deceleration as the pedals come over the top is significant and causes the torque versus rotation profile to be broader versus the profile when climbing (also, the proportionality of force versus speed is quite different). I suspect this is more pronounced on the tandem, but I'm an old, lazy engineer and I really don't want to think any harder than I already have.

Does anyone else experience this phenomenon or am I just crazy?
For the flats, try doing "tension drills". This is where you ride in the 53x11 and push hard for anywhere from 5 mins to 20 mins. You can do 5 min on, 5min off too. I can assure you your Hr will come up. If 53x11 is too big, gear down a notch or two. My wife and I use this to build power and simulate climbing. We live in Jacksonville, Fl, and it's flat as can be. You most likely will not exceed 80 rpm.

This is also a great exercise to work on your spin. You feet are moving slowly with lots of tension. You will be able to focus on your entire spin.

Have fun!
Rick
swamptandem is offline   Reply With Quote
Old 08-01-11, 07:53 AM   #5
diabloridr
Senior Member
 
diabloridr's Avatar
 
Join Date: Dec 2010
Location: Central Coast, California, USA
Bikes: Co-Motion Speedster, Calfee Dragonfly, Ancient Sun Fixie, Trek 5900, Trek 9800
Posts: 322
Just another reason why to optimize training it is usually necessary for both members of the team to spend some time on their singles.

I realize that isn't practical for some/many teams for various reasons.
diabloridr is offline   Reply With Quote
Old 08-01-11, 09:02 AM   #6
bikefor2
Senior Member
 
Join Date: Mar 2011
Bikes:
Posts: 137
I can't agree with suggestion #2 "Get an ICS drivetrain and overrun your stoker" because we have the ICS and while it will allow either of us to COAST, you still pedal at the same cadence and resistance just like a regular tandem.
bikefor2 is offline   Reply With Quote
Old 08-01-11, 09:52 AM   #7
PMK
Senior Member
 
PMK's Avatar
 
Join Date: May 2008
Location: Royal Palm Beach, Florida
Bikes: 2006 Co-Motion Roadster (Flat Bars, Discs, Carbon Fork), Some 1/2 bikes and a couple of KTM's
Posts: 1,151
Quote:
Originally Posted by bikefor2 View Post
I can't agree with suggestion #2 "Get an ICS drivetrain and overrun your stoker" because we have the ICS and while it will allow either of us to COAST, you still pedal at the same cadence and resistance just like a regular tandem.
Yes I agree. However, if the captain wants a greater rpm, with an additional effort, he could take the entire effort, raising his heart rate while the stoker is lightly spinning at their desired rpm. The end result may have the stoker with no appreciable effort at these times.

Not a perfect solution by any means.

The ideal for long flat stretches, I suppose is having 4 legs similar in rpm, with similar endurance and similar HR.

PK
PMK is offline   Reply With Quote
Old 08-01-11, 01:06 PM   #8
waynesulak
Senior Member
 
waynesulak's Avatar
 
Join Date: Jan 2008
Location: Ft Worth, TX
Bikes: 650B tandem converted from Santana Arriva, Santana Noventa, Boulder Bicycle 700C, Gunnar Sport, Trek TX700,
Posts: 1,909
We have used the tall gear workout mentioned above with some success but be careful to maintain good smooth form and avoid jerking. Start with small drills and be very careful not to hurt your knees with the new type of effort.

Usually we try to find a good 20+mph cross wind if we want the heart rate to go up. That works pretty well you get the wind hitting at 90 degrees. Lots of fun - uggg.
waynesulak is offline   Reply With Quote
Old 08-01-11, 01:39 PM   #9
rdtompki
Senior Member
Thread Starter
 
rdtompki's Avatar
 
Join Date: Nov 2008
Location: Hollister, CA
Bikes: Volagi, daVinci Joint Venture
Posts: 3,962
Quote:
Originally Posted by bikefor2 View Post
I can't agree with suggestion #2 "Get an ICS drivetrain and overrun your stoker" because we have the ICS and while it will allow either of us to COAST, you still pedal at the same cadence and resistance just like a regular tandem.
We do actually have an ICS (daVinci). I can go ahead and spin my stoker out on downhills, but on the flats I generally need her power to sustain our current speed, so if I shift down and her input goes to zero we may slow down. I'm also thinking I should look at seat height and perhaps trim to give me more power at lower RPM. I'm going to further experiment with OOP to eliminate the simultaneous "dead spot" as we go over the top.
rdtompki is offline   Reply With Quote
Old 08-01-11, 01:47 PM   #10
steve53mg
Senior Member
 
Join Date: Dec 2009
Location: Long Island, NY
Bikes: Serotta Legend Ti, Santa Cruz Heckler, Santana Visa TAndem
Posts: 198
Rick, I could be looking at this wrong, but it seems to me that you might be over-engineering this. It sounds to me like you are aerobically more efficient than your stoker. If you need to train harder, perhaps you should consider spending a greater portion of time on your single, where you can spin to your heart's content. I also find that I work less on the flats, but the balance tips toward me on the climbs and acceleration, when the added mass of the tandem comes into play and the advantage of halved wind resistance is exponentially less at these slower speeds. For this reason, I find that I get a harder workout when we ride along with and try to match pace with singles.
Unfortunately, the very nature of the beast, is that most of us are combining 2 riders of different sizes and condition. Because of this, most of us will never match our workout numbers exactly, but for the most part the tandem does take the best of both riders, in the long run.

Last edited by steve53mg; 08-01-11 at 01:56 PM.
steve53mg is offline   Reply With Quote
Old 08-01-11, 03:24 PM   #11
waynesulak
Senior Member
 
waynesulak's Avatar
 
Join Date: Jan 2008
Location: Ft Worth, TX
Bikes: 650B tandem converted from Santana Arriva, Santana Noventa, Boulder Bicycle 700C, Gunnar Sport, Trek TX700,
Posts: 1,909
Let us know how the OOP thing works for you. As you know cadence is the hardest adaptation for a tandem team. Like most teams we had that problem but my stoker adapted to a higher cadence and me to a lower one. Now we like churning at the same speed.

If I were in your situation I would be tempted to use the Davinci to really go OOP with a smaller chainring for the captain. Probably have to change the captain's cranks to accomplish this. Sugino's square taper tandem cranks are good and cheap and would fit right on your existing bottom bracket.

I know this approach is frowned upon but you can easily change back.
waynesulak is offline   Reply With Quote
Old 08-01-11, 08:52 PM   #12
DubT
Senior Member
 
Join Date: Sep 2009
Location: Central Illinois
Bikes: Trek Speed Concept 9.9, 2011 Calfee Tetra Tandem
Posts: 1,037
If YOU will work harder your heart rate WILL go up. Your wife can ride however hard she wants to ride. If you ride with someone else who is faster than you are and try to stay with them your HR will go up even on the flats. I know this from personal experience.

Wayne
DubT is offline   Reply With Quote
Old 08-01-11, 10:52 PM   #13
Carbonfiberboy 
just another gosling
 
Carbonfiberboy's Avatar
 
Join Date: Feb 2007
Location: Everett, WA
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Posts: 10,993
I've given up on the theory that our tandem can get faster by just the captain getting faster. All that's done is make it easier for me to blow out my stoker. I've rethought it as a team effort. Thus, I simply don't ride my single anymore. We do take a spin class together and we will use our rollers and trainer for recovery rides and the occasional training when it's raining, and we also lift weights at the gym, but not so much in the summer.

What we've done is to ride the tandem on ever longer and more difficult rides, plus do some ordinary 20 mile moderate loops. This program has made a huge difference. We are both lighter and the tandem team can go further and faster uphill and on the flat. We can both easily spin up to 100 or so and have gradually gotten good enough to do longish anaerobic stands. So that's what's worked for us.

As you already know, the way to get your HR up on the flat is high cadence, 90-100 is good for duffers like Stoker and I. If your team must ride low cadence on the flat, then I also suggest long climbing intervals at low (50-55) cadence, at a few beats below LT. The way to achieve these HRs at that cadence is to pedal perfect circles, not stomping. The pull up on the back will be weak, but once you get the hang of it, you won't be able to tell if you are IP or OOP. It's a matter of both team members keeping constant torque on the BB, which doesn't mean keeping constant torque on each crankarm. You can tell if you are doing that if you have no upper body motion and little force on the bars.

Anyway, if you can reach those HRs at 50 cadence climbing, you'll be able to reach them at 80 on the flat. The downside is that at 80 your legs won't last as long as they would at 90-100. To make the tandem go faster, you should do these drills as a team, which requires commitment from Stoker.

Stoker and I both wear coded HRMs and from time to time report our HRs to each other, so we keep our personal efforts in sync. Even if I'm putting out much more wattage than Stoker, she's working just as hard for the team as I am. We happen to have similar LTHRs. Teams which do not would have to have some comparison that they both just know.

As many others have reported, one of the best ways to make a tandem faster is to synchronize pedal strokes between the team members so that one team member is not trying to accelerate the legs of the other. I think the simplest way to achieve this is the idea of constant BB torque for both team members.
Carbonfiberboy is offline   Reply With Quote
Old 08-02-11, 04:10 AM   #14
PMK
Senior Member
 
PMK's Avatar
 
Join Date: May 2008
Location: Royal Palm Beach, Florida
Bikes: 2006 Co-Motion Roadster (Flat Bars, Discs, Carbon Fork), Some 1/2 bikes and a couple of KTM's
Posts: 1,151
Quote:
Originally Posted by Carbonfiberboy View Post
I've given up on the theory that our tandem can get faster by just the captain getting faster. All that's done is make it easier for me to blow out my stoker. I've rethought it as a team effort. Thus, I simply don't ride my single anymore. We do take a spin class together and we will use our rollers and trainer for recovery rides and the occasional training when it's raining, and we also lift weights at the gym, but not so much in the summer.

What we've done is to ride the tandem on ever longer and more difficult rides, plus do some ordinary 20 mile moderate loops. This program has made a huge difference. We are both lighter and the tandem team can go further and faster uphill and on the flat. We can both easily spin up to 100 or so and have gradually gotten good enough to do longish anaerobic stands. So that's what's worked for us.

As you already know, the way to get your HR up on the flat is high cadence, 90-100 is good for duffers like Stoker and I. If your team must ride low cadence on the flat, then I also suggest long climbing intervals at low (50-55) cadence, at a few beats below LT. The way to achieve these HRs at that cadence is to pedal perfect circles, not stomping. The pull up on the back will be weak, but once you get the hang of it, you won't be able to tell if you are IP or OOP. It's a matter of both team members keeping constant torque on the BB, which doesn't mean keeping constant torque on each crankarm. You can tell if you are doing that if you have no upper body motion and little force on the bars.

Anyway, if you can reach those HRs at 50 cadence climbing, you'll be able to reach them at 80 on the flat. The downside is that at 80 your legs won't last as long as they would at 90-100. To make the tandem go faster, you should do these drills as a team, which requires commitment from Stoker.

Stoker and I both wear coded HRMs and from time to time report our HRs to each other, so we keep our personal efforts in sync. Even if I'm putting out much more wattage than Stoker, she's working just as hard for the team as I am. We happen to have similar LTHRs. Teams which do not would have to have some comparison that they both just know.

As many others have reported, one of the best ways to make a tandem faster is to synchronize pedal strokes between the team members so that one team member is not trying to accelerate the legs of the other. I think the simplest way to achieve this is the idea of constant BB torque for both team members.

Yes...these low rpm high effort posts are already making my knees hurt.

Riding the single can make you stronger, which will allow you to pull more gear, the thing is though, you are trying build this strength and get your HR on the flats while not over running your stokers input.

The comment from the op needing his stoker to maintain speed is valid, and this will happen as the captain tires and his HR has to recover.

As a team it took us a while to sort this out. The primary factor being both riders need to be able to comfortably turn a similar rpm range. With that, and monitoring HR of both riders, the output is there to be seen, the speed falls where it may. The ride distance is also a factor, knowing the distance is longer, you will settle into certain rpm and HR ranges that get the job done, these would vary compared to a 100% effort / high rpm sprint as in a short distance race or effort to catch a group in front of you.

If the op knows the available rpm range his stoker enjoys, and his knees can handle it without then turn the taller gear. Might expect some shorter distances doing this until you are acclimated to these efforts for the long haul.

So knowing the op is on an ICS machine, I am curious, are you planning to lock the driveline at 90 oop, or allow it to settle there? Like a dynamic damper, I would expect that this setting will creep until things get smooth by feel, which would be sort of an optimum phase angle.

PK
PMK is offline   Reply With Quote
Old 08-02-11, 12:26 PM   #15
gracehowler
Rod & Judy
 
gracehowler's Avatar
 
Join Date: Jun 2009
Location: Montrose, CO
Bikes: Specialized S-works e-5, Davinci joint venture, Specialized Vienna Commuter
Posts: 481
No one has tossed in the possibility of different length crank arms?
R&J
gracehowler is offline   Reply With Quote
Old 08-02-11, 03:13 PM   #16
rdtompki
Senior Member
Thread Starter
 
rdtompki's Avatar
 
Join Date: Nov 2008
Location: Hollister, CA
Bikes: Volagi, daVinci Joint Venture
Posts: 3,962
Quote:
Originally Posted by PMK View Post

So knowing the op is on an ICS machine, I am curious, are you planning to lock the driveline at 90 oop, or allow it to settle there? Like a dynamic damper, I would expect that this setting will creep until things get smooth by feel, which would be sort of an optimum phase angle.

PK
We've tried riding the daVinci OOP, but my stoker is so automatic about getting in phase that she could consistently get OOP. What I might try next time wer'e on the flats is delaying for a fraction of a pedal rotation to allow the stoker to get a bit "ahead". I think this would help smooth out the dead spot when both of us are going over the top. I might buy the two pieces I need to convert the daVinci to non-ICS, but just for the purpose of experimenting with phase. We've ridden non-ICS briefly and it was a bit wierd
rdtompki is offline   Reply With Quote
Old 08-02-11, 03:21 PM   #17
waynesulak
Senior Member
 
waynesulak's Avatar
 
Join Date: Jan 2008
Location: Ft Worth, TX
Bikes: 650B tandem converted from Santana Arriva, Santana Noventa, Boulder Bicycle 700C, Gunnar Sport, Trek TX700,
Posts: 1,909
On a non ICS tandem, putting the stoker a couple teeth in front of the captain works well with stokers with slower cadence.
Your stoker looks fairly short. Does she have short cranks? That helped my stoker get her cadence up to my speed. She is 5' 6" and uses 165mm cranks.
waynesulak is offline   Reply With Quote
Old 08-02-11, 05:19 PM   #18
Hermes 
Elite Rider
 
Hermes's Avatar
 
Join Date: Oct 2006
Location: San Francisco Bay Area
Bikes: Too Many
Posts: 9,657
We started racing our tandem in 2007 in local time trials. We used HR as an indicator of effort. We had no problem raising our heart rates to threshold level or slightly above. Typically, we climb at 70 to 80 rpm and 90 to 95 rpm on the flats. We ride OOP stoker leading.

We did a couple of state championship 40K TTs on the tandem on flat terrain and had no problem establishing and maintaining threshold heart rates. And we did one 40K ITT in phase and it was okay but we prefer OOP.

Some riders can push themselves hard and some cannot. I found that my individual time trial performance improved when I got my power meter. I found that I did not push hard enough on the slight down hill. So even on single road bikes, it is harder to keep power up on flat to rolling terrain than climbing but it can be done and requires training and concentration.

Also, low cadence power intervals do not raise the heart rate as high as 10% higher cadence intervals at the same power. So know that if you are climbing and the cadence is 50ish the HR is going to be lower. What happens is you will use more strength and different muscle fibers and more than likely fatigue the legs sooner.

Riding a tandem is similar to dancing with someone. One can be a great dancer but when two great dancers try to dance as one, it takes practice to move with efficiency, grace, power and speed with the proper steps in time with the music. Stepping on toes is a no no. However, I think that some tandem teams step on each others toes or both try to lead. YMMV.
__________________
We are what we repeatedly do. Excellence, then, is not an act, but a habit. Aristotle

Cat: Killer
Hermes is offline   Reply With Quote
Old 08-02-11, 09:10 PM   #19
rdtompki
Senior Member
Thread Starter
 
rdtompki's Avatar
 
Join Date: Nov 2008
Location: Hollister, CA
Bikes: Volagi, daVinci Joint Venture
Posts: 3,962
Quote:
Originally Posted by waynesulak View Post
On a non ICS tandem, putting the stoker a couple teeth in front of the captain works well with stokers with slower cadence.
Your stoker looks fairly short. Does she have short cranks? That helped my stoker get her cadence up to my speed. She is 5' 6" and uses 165mm cranks.
My stoker is 5'7" (I'm 6'0") and she uses 170mm cranks. I might give 165mm. If they don't work I can keep them in reserve for my grandsons.
rdtompki is offline   Reply With Quote
Old 08-03-11, 07:42 AM   #20
DubT
Senior Member
 
Join Date: Sep 2009
Location: Central Illinois
Bikes: Trek Speed Concept 9.9, 2011 Calfee Tetra Tandem
Posts: 1,037
While on our morning ride I had a thought about your inability to get your HR up on the flats and it prompted some questions.

* What gear do you typically pull on the flats 54/17 or what at what RPM?
* What cassette are you running, wide ratio or close 1 tooth jump or 2/3 teeth.

If you are running a close ratio cassette, my suggestion is to shift up one gear and for you to concentrate on working harder. That is what I have to do. If you have a wide ratio cassette then I can see how you would have an over spin problem.

I certainly would not start changing cranks etc.
Wayne

Last edited by DubT; 08-03-11 at 07:43 AM. Reason: Added
DubT is offline   Reply With Quote
Old 08-03-11, 10:42 AM   #21
waynesulak
Senior Member
 
waynesulak's Avatar
 
Join Date: Jan 2008
Location: Ft Worth, TX
Bikes: 650B tandem converted from Santana Arriva, Santana Noventa, Boulder Bicycle 700C, Gunnar Sport, Trek TX700,
Posts: 1,909
Quote:
Originally Posted by rdtompki View Post
My stoker is 5'7" (I'm 6'0") and she uses 170mm cranks. I might give 165mm. If they don't work I can keep them in reserve for my grandsons.
Shorter stoker cranks solved our cadence issue, but I have known others that used shorter cranks for the stoker and also longer cranks for the captain than he would use on his single. This tends to slow down the captain and speed up the stoker.

Good luck.

Wayne
waynesulak is offline   Reply With Quote
Old 08-03-11, 10:56 AM   #22
Hermes 
Elite Rider
 
Hermes's Avatar
 
Join Date: Oct 2006
Location: San Francisco Bay Area
Bikes: Too Many
Posts: 9,657
Quote:
Originally Posted by waynesulak View Post
Shorter stoker cranks solved our cadence issue, but I have known others that used shorter cranks for the stoker and also longer cranks for the captain than he would use on his single. This tends to slow down the captain and speed up the stoker.

Good luck.

Wayne
Our Santana came with 175 mm for the Captain and 170 for the Stoker. Even though the cadence will be the same for both, the leg speed (at the pedal or tangential velocity) required for the captain to maintain the same cadence as the stoker will be greater. I was a little annoyed with the 175 since I wanted to standardize all my bicycles to 172.5 mm cranks.
__________________
We are what we repeatedly do. Excellence, then, is not an act, but a habit. Aristotle

Cat: Killer
Hermes is offline   Reply With Quote
Old 08-03-11, 03:27 PM   #23
tredlodz
Senior Member
 
Join Date: Dec 2009
Bikes:
Posts: 134
The best way I've found to get heart rate up is to ride with someone just a little faster, or try to catch someone ahead. It's the competition that does it.
tredlodz is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:18 PM.