Drafting

Do you ride with power meters? What are your respective 1 hr MPs? What is the topography of the course? What are the prevailing winds at that time of year?

RapDaddyo said:

Do you ride with power meters? What are your respective 1 hr MPs? What is the topography of the course? What are the prevailing winds at that time of year?

We do not ride with PM. I am not sure that I know what a 1 hr MR is(I would like to know if you have time to include that bit of info), or how to measure it. The course will be moslty flat with a few gradual, rolling inclines. The winds will range from still to blustering. I know this is vague, but I greatly appreciate any information you able to give.

1 hr MP is one's max power (MP) for 1 hour. That's the relevant duration for your functional threshold (FT) for a 40K TT on a relatively flat course. If you don't have a power meter (PM), never mind. Optimal TT pacing gets about as complex as you want to make it, even solo. That's because you are dealing with two complex sciences: physiology and physics. Team TTs are even more complex, because you are dealing with physiology differences between the team members as well as the physics (which argues for using more power when the bike is slow due to hills or wind). How similar are you and your father in your max sustainable power? If you each rode a flat, no-wind 40K TT as fast as possible, what would your times be (approximately)? Are the courses out/back?

IndyRider said:

My father and I are planning on doing a couple of two man 40 km time trials next year. Does anyone have any specific information on how to most efficiently work the draft in a group of two(i.e. how long should the pulls be?)? Thanks for your input.

The individual pull lengths and team pace will depend on how closely matched the 2 riders are. You'll need to work that out during practice for the event.

If the riders are closely matched, then I'd suggest a team pace ~2mph faster than the slowest rider could do the event by himself. Set the pull duration for the weaker rider at ~1min, and the stronger rider should pull ~1-1.5 min depending upon ability.

If the riders are not closely matched, then I'd suggest a team pace ~3-4mph faster than the weaker rider could hold by himself, and a shorter (~30sec) pull duration for him. The stronger rider should then pull for ~2-3 minutes (or more if they're grossly unmatched) at a time. You'll need to tweak things from there, but the idea would be to wear both riders down equally as the race progresses.

Sounds like a fun event. Where is it going to be held?

RapDaddyo said:

1 hr MP is one's max power (MP) for 1 hour. That's the relevant duration for your functional threshold (FT) for a 40K TT on a relatively flat course. If you don't have a power meter (PM), never mind. Optimal TT pacing gets about as complex as you want to make it, even solo. That's because you are dealing with two complex sciences: physiology and physics. Team TTs are even more complex, because you are dealing with physiology differences between the team members as well as the physics (which argues for using more power when the bike is slow due to hills or wind). How similar are you and your father in your max sustainable power? If you each rode a flat, no-wind 40K TT as fast as possible, what would your times be (approximately)? Are the courses out/back?

On a course that was flat with no wind, I believe I could complete a 40 km TT in 1 hour and 6 minutes(22.5 mph). My father could complete the same course in 1 hour 12 minutes(10 mph). The course will be an out and back situation. Thank you for your information concerning the 1 hr. mp.

IndyRider

frenchyge said:

The individual pull lengths and team pace will depend on how closely matched the 2 riders are. You'll need to work that out during practice for the event.

If the riders are closely matched, then I'd suggest a team pace ~2mph faster than the slowest rider could do the event by himself. Set the pull duration for the weaker rider at ~1min, and the stronger rider should pull ~1-1.5 min depending upon ability.

If the riders are not closely matched, then I'd suggest a team pace ~3-4mph faster than the weaker rider could hold by himself, and a shorter (~30sec) pull duration for him. The stronger rider should then pull for ~2-3 minutes (or more if they're grossly unmatched) at a time. You'll need to tweak things from there, but the idea would be to wear both riders down equally as the race progresses.

Sounds like a fun event. Where is it going to be held?

Thanks for your reply. The event will be held in Monrovia, IN. It is sponsored by the Indiana Racing Series.

Indy Rider

IndyRider said:

Thanks for your reply. The event will be held in Monrovia, IN. It is sponsored by the Indiana Racing Series.

Do you have a link to the route?

IndyRider said:

My father could complete the same course in 1 hour 12 minutes(10 mph).

Do you mean 1hr 12mins or do you mean 20mph (=1hr 15mins)?

The web site is a bit sketchy about the course, but I think it goes west from Monrovia on SR42 to ~Eminence (SR142). If so, it is indeed largely flat. See the course profile for the outbound leg below (I think). The chart makes the hills look larger than they are because of the vertical axis scale. The total vertical scale is ~275' so the climbs are modest. There are a couple of climbs near Eminence that you will want to plan for. The average wind speed is ~10mph in May, decreasing a bit into the summer. Prevailing wind direction is probably from the west or southwest. So, you're probably looking at net headwinds on the outbound leg and tailwinds on the return leg. I'm not quite in synch with frenchy about pacing because I don't think he is exploiting the half-life physiological response phenomenon. So, I would argue for shorter pulls, but unequal in duration (your pulls would be longer than your father's). I need to run some numbers to come up with the specifics. But, I'm thinking about <30sec pulls for you and ~15sec for him. I'll get back to you on the rotation strategy. Also, if there is much wind, it would be fastest to have unequal pacing outbound/inbound. More later.

I did mean 20 mph avg above. Sorry for the typo. That is the course that the event is held on. Thanks for the extra work.

IndyRider

RapDaddyo said:

The web site is a bit sketchy about the course, but I think it goes west from Monrovia on SR42 to ~Eminence (SR142). If so, it is indeed largely flat. See the course profile for the outbound leg below (I think). The chart makes the hills look larger than they are because of the vertical axis scale. The total vertical scale is ~275' so the climbs are modest. There are a couple of climbs near Eminence that you will want to plan for. The average wind speed is ~10mph in May, decreasing a bit into the summer. Prevailing wind direction is probably from the west or southwest. So, you're probably looking at net headwinds on the outbound leg and tailwinds on the return leg. I'm not quite in synch with frenchy about pacing because I don't think he is exploiting the half-life physiological response phenomenon. So, I would argue for shorter pulls, but unequal in duration (your pulls would be longer than your father's). I need to run some numbers to come up with the specifics. But, I'm thinking about <30sec pulls for you and ~15sec for him. I'll get back to you on the rotation strategy. Also, if there is much wind, it would be fastest to have unequal pacing outbound/inbound. More later.

RapDaddyo said:

I'm not quite in synch with frenchy about pacing because I don't think he is exploiting the half-life physiological response phenomenon.

No, I'm not. I'm keeping it simple because it's unlikely that you'll get full MMP curves from IndyRider and his dad.

RapDaddyo said:

So, I would argue for shorter pulls, but unequal in duration (your pulls would be longer than your father's). I need to run some numbers to come up with the specifics. But, I'm thinking about <30sec pulls for you and ~15sec for him.

I recommend longer because with 2 people rotating that quickly, I think you'd spend as much of your time side-by-side as you would front-and-back. A somewhat longer pull give you a chance to get in a rhythm on your pull, and a chance to catch your breath during a rest. You're right though, nothing scientific about my suggestion. Just my two cents worth.

frenchyge said:

No, I'm not. I'm keeping it simple because it's unlikely that you'll get full MMP curves from IndyRider and his dad. I recommend longer because with 2 people rotating that quickly, I think you'd spend as much of your time side-by-side as you would front-and-back. A somewhat longer pull give you a chance to get in a rhythm on your pull, and a chance to catch your breath during a rest. You're right though, nothing scientific about my suggestion. Just my two cents worth.

Well, it's a fascinating question. I have never done a 2-man TT, but recently had to make a decision about 2-man rotation strategy in the final 10K leg into a 25mph headwind where I found myself on a 2-man break with a rider in a different age division. I was the more experienced rider and he looked to me for guidance. I put us in a 15sec rotation at about 120%FT. We rode that way for the entire 10K and did sustain the break (actually, we steadily increased the gap), but I have no hard data to compare different rotation strategies with. Clearly there is a tradeoff between longer pulls to minimize the time that both riders are exposed to the wind and shorter pulls to exploit the acidosis response half-life. I need to do some work on my computer and on my bike. I wonder if there is anything written about TTT rotation strategies, taking into account the riders' FTs and the acidosis half-life question. Interesting.😕

I'd expect rider experience/proficiency to play a part here as well. Very proficient riders can rotate quickly and naturally without surges, and minimize the time they spend side-by-side, slowing/accelerating, etc. (finding their rhythm). Developing a good rotation pace and technique will be part of the training process, but we really don't know how practiced the team will be in terms of working together.

frenchyge said:

I'd expect rider experience/proficiency to play a part here as well. Very proficient riders can rotate quickly and naturally without surges, and minimize the time they spend side-by-side, slowing/accelerating, etc. (finding their rhythm). Developing a good rotation pace and technique will be part of the training process, but we really don't know how practiced the team will be in terms of working together.

I agree. That's why I intend to frame my suggestions in the form of, "This is what I would do, because it is the optimal pacing/rotation strategy. But, I would practice it in advance and here's a fallback strategy that requires less skill and concentration." But, I'm not going to water down my recommended strategy on the assumption that the OP and/or his father can't do it. They can decide for themselves.

RapDaddyo said:

But, I'm not going to water down my recommended strategy on the assumption that the OP and/or his father can't do it. They can decide for themselves.

Yep, I'm not going to water mine down either. That's what I'd do if it were me and my dad. 🙂

Rapdaddyo, I greatly appreciate the time and effort you are putting into answering my question. My father and I train together no less than 4 times per week...weather permitting. I am confident in the fact that we will be able to practice the strategies you give us and utilize to our greatest potential next year in our TT. Thank for not "watering down" your approach. I am here only to learn from other more experienced riders, not have them tell me what they think is best for my level of rider.

IndyRider

frenchyge said:

Yep, I'm not going to water mine down either. That's what I'd do if it were me and my dad. 🙂

IndyRider said:

Rapdaddyo, I greatly appreciate the time and effort you are putting into answering my question. My father and I train together no less than 4 times per week...weather permitting. I am confident in the fact that we will be able to practice the strategies you give us and utilize to our greatest potential next year in our TT. Thank for not "watering down" your approach. I am here only to learn from other more experienced riders, not have them tell me what they think is best for my level of rider.

Good. Well, I can tell you right away that you are at a significant disadvantage if you don't have a PM, especially if there is much wind. Given that it is a relatively flat course, if there is no wind you can manage your pace pretty well with your speedometers. But, you can't develop a strategy on the assumption that there will be no wind. Actually, if I were making a plan I would assume a strong wind. PMs are a pretty big deal financially ($1K+) and with a limited budget they compete with wheels and other aero equipment. But, you should know up front that pacing with a PM is an advantage. I plan to frame my suggestions under both assumptions, that you do or that you don't have PMs (or at least one PM).

IndyRider said:

Rapdaddyo, I greatly appreciate the time and effort you are putting into answering my question. My father and I train together no less than 4 times per week...weather permitting. I am confident in the fact that we will be able to practice the strategies you give us and utilize to our greatest potential next year in our TT. Thank for not "watering down" your approach. I am here only to learn from other more experienced riders, not have them tell me what they think is best for my level of rider.

IndyRider

I'll try not to take your comment the wrong way, but don't take my previous ones the wrong way either. My suggestions were not a 'dumbed-down' approach, despite the strawman comments that RDO has thrown out. As is obvious by now, neither of us can direct you to a study that gives you the specific detailed information you asked. If you train in tandem 4 times a week, then you probably have more experience in what you're doing than either of us. Have you guys experimented with different rotation strategies to see what works best for you?

RDO's suggesting 15-30 sec pulls based on physiological response half-lives, and I discounted that approach for a 2-man team in favor of maximizing the draft benefit and rhythm of two unmatched riders on such a long ride. If your team is spending a lot of time riding side-by-side, then you'll be riding at the speed of your slowest rider, or the stronger rider will end up pulling the weaker to the finish. Longer pulls also give you a better opportunity to monitor the status of the weaker rider before he cracks completely.

Anyway, I've given my suggestions based on my experience. They're not dumbed down or an affront to you and your father's capabilities. I considered the things that RDO is talking about, and felt there was more benefit to my approach. You now have 2 suggestions and the rationale behind them. It won't bother me if you don't use my suggestions or if they turn out to be unhelpful, but don't think that I wasn't serious when I spent my time offering them. Good luck.

I can tell you for sure that a PM @ $1000+ is not even remotely in this married, single income teacher with a child's immediate future. LOL

RapDaddyo said:

Good. Well, I can tell you right away that you are at a significant disadvantage if you don't have a PM, especially if there is much wind. Given that it is a relatively flat course, if there is no wind you can manage your pace pretty well with your speedometers. But, you can't develop a strategy on the assumption that there will be no wind. Actually, if I were making a plan I would assume a strong wind. PMs are a pretty big deal financially ($1K+) and with a limited budget they compete with wheels and other aero equipment. But, you should know up front that pacing with a PM is an advantage. I plan to frame my suggestions under both assumptions, that you do or that you don't have PMs (or at least one PM).