Drafting

Your time has not been wasted. I look forward to trying both strategies before the event next year. I also appreciate your time and offerings.

IndyRider

frenchyge said:

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.

Just to be clear, I haven't made a recommendation about rotation strategy. What I said was the direction I am leaning, based on the 15sec "free" pushes >FT and their respective FTs. But, I see three intersecting issues: (1) the half-life issue, which favors short pull durations; (2) their respective FTs, which favors asymmetrical pull durations; and (3) the time spent in rotation when both are exposed to the wind, which favors longer pull durations. As is the case with most things, there is no obvious answer because these are in conflict. I love conflict. It requires me to think.

IndyRider said:

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

What do you teach? Math or physics, I hope. How good is your math? Have you ever used AnalyticCycling.com? Do you know what NP is and how it is computed?

RapDaddyo said:

Just to be clear, I haven't made a recommendation about rotation strategy. What I said was the direction I am leaning, based on the 15sec "free" pushes >FT and their respective FTs. But, I see three intersecting issues: (1) the half-life issue, which favors short pull durations; (2) their respective FTs, which favors asymmetrical pull durations; and (3) the time spent in rotation when both are exposed to the wind, which favors longer pull durations. As is the case with most things, there is no obvious answer because these are in conflict. I love conflict. It requires me to think.

The biggest issue in my mind is maximizing the team pace without dropping the weaker rider. In this case (20 v. 22.5 mph), they are just not very closely matched. The father would probably have a hard time working 50% at *just Indy's individual pace.* Now bump up Indy's pace by 1-2 mph to account for the team synergy and the father's going to be forced to work < 25-30% of the time if he's to stay in contact. That blows the 15 second thing right out of the water, since now Indy is getting 15 sec or less of rest in between pulls. Those 15sec rests are "free" too, and don't do any good either (ie, it's like they're not there).

frenchyge said:

The biggest issue in my mind is maximizing the team pace without dropping the weaker rider. In this case (20 v. 22.5 mph), they are just not very closely matched. The father would probably have a hard time working 50% at *just Indy's individual pace.* Now bump up Indy's pace by 1-2 mph to account for the team synergy and the father's going to be forced to work < 25-30% of the time if he's to stay in contact. That blows the 15 second thing right out of the water, since now Indy is getting 15 sec or less of rest in between pulls. Those 15sec rests are "free" too, and don't do any good either (ie, it's like they're not there).

Yes, the issue is maximizing team pace (team pace implying that neither is dropped). That's why the pull durations will need to be different for each (asymmetric). But, I think their FTs are close enough that they can absolutely ride at an average power greater than either of them could sustain for an hour. Here's a quick example. Let's assume their FTs are 275w and 250w respectively. Let's further assume that their team pace is 290w and that they can draft at 220w. If the rotation durations are 2:1, say 40s:20s, then their APs are 267w and 243w respectively. I haven't worked out NP, but this is close to what I have in mind. As to your assetion that both riders are exposed to the wind during the rotation, I agree but it doesn't matter. In a 2-man TT (or any TTT), when I pull off the front, I immediately drop my power. In fact, I usually coast completely until my front hub is even with the 2nd (or last) man's rear hub, then I pick up the pace and slide over into draft position. So, I am in recovery mode instantly when I pull off the front even though I am exposed to the wind. From an NP perspective, the push duration begins when the lead man pulls off and lasts only until I pull over to let him through. The remainder is recovery duration.

RapDaddyo said:

Yes, the issue is maximizing team pace (team pace implying that neither is dropped). That's why the pull durations will need to be different for each (asymmetric). But, I think their FTs are close enough that they can absolutely ride at an average power greater than either of them could sustain for an hour.

Of course. That's what I just said by "bump up Indy's pace 1-2mph to account for team synergy." There's no "But..." about it.

RapDaddyo said:

Here's a quick example. Let's assume their FTs are 275w and 250w respectively.

You can assume that if you want, but AC.com suggests that the difference between 20mph and 22.5mph is ~60watts. That's nearly what you'll save by drafting behind someone who's down on aerobars.

RapDaddyo said:

Let's further assume that their team pace is 290w and that they can draft at 220w. If the rotation durations are 2:1, say 40s:20s, then their APs are 267w and 243w respectively. I haven't worked out NP, but this is close to what I have in mind. As to your assetion that both riders are exposed to the wind during the rotation, I agree but it doesn't matter. In a 2-man TT (or any TTT), when I pull off the front, I immediately drop my power. In fact, I usually coast completely until my front hub is even with the 2nd (or last) man's rear hub, then I pick up the pace and slide over into draft position. So, I am in recovery mode instantly when I pull off the front even though I am exposed to the wind. From an NP perspective, the push duration begins when the lead man pulls off and lasts only until I pull over to let him through. The remainder is recovery duration.

It doesn't matter when you consider the pulls and recoveries to begin and end, one person's recovery is *equal to* the other person's pull. There's no two ways about that. If the off-going rider recovers much while he's in the wind, then he's going to have to accelerate again to pick up the draft, so he loses again what he was trying to save by coasting while the other rider goes by.

Anyway, my approach has been on the table for dissection since post #5, the OP has provided more info since, and I've explained the rationale twice while you're still holding the cards on your non-watered-down approach. I guess I'll wait to see what your analysis comes up with before I talk you through things too much.

frenchyge said:

Anyway, my approach has been on the table for dissection since post #5, the OP has provided more info since, and I've explained the rationale twice while you're still holding the cards on your non-watered-down approach. I guess I'll wait to see what your analysis comes up with before I talk you through things too much.

Yes, it would probably be best to see what I come up with before you shoot it down. Otherwise, you'll be like the Democrats, who object to a Republican's proposal before they even know what the proposal is.😄 😄

frenchyge said:

You can assume that if you want, but AC.com suggests that the difference between 20mph and 22.5mph is ~60watts. That's nearly what you'll save by drafting behind someone who's down on aerobars.

This is a key assumption (the drafting power delta). I plan to test this unless you have some data on this question.

RapDaddyo said:

Yes, it would probably be best to see what I come up with before you shoot it down. Otherwise, you'll be like the Democrats, who object to a Republican's proposal before they even know what the proposal is.😄 😄

More like, wait to see what your sophisticated analysis comes up with before I take you through all the issues and have you re-present my intuitive approach in your own words. 😉

RapDaddyo said:

This is a key assumption (the drafting power delta). I plan to test this unless you have some data on this question.

I save ~100w on the hoods behind someone else on the hoods. I'd guess ~75w is the number on the aerobars, but I have no data on that.

frenchyge said:

More like, wait to see what your sophisticated analysis comes up with before I take you through all the issues and have you re-present my intuitive approach in your own words. 😉

Okay, I propose a race. Here are the terms. You and I will each submit to the OP via PM our recommended pacing strategy, taking into account all variables. They will ride two training rides on the same course approximating the TT course using each of our pacing strategies (with comparable wind conditions). If your pacing strategy wins, I will post, "Frenchyge Rules!" on this thread. Vice versa if my pacing strategy wins. Deal?

RapDaddyo said:

Deal?

Nope, weather's too nice and bike is calling. 🙂 Indy should probably incorporate a mix of my suggestions and your future approach anyway. I'll stick with what I said in post #5: Team pace = 23.5mph on flat (3-4mph higher than weaker rider's pace) adjusted on hills to maintain effort level, Indy pulls for 2.5 min and his father pulls for 30 sec. If OP wants to try that out, I'd be interested to hear how it works, or if it works at all.

After you finish your analysis, how about running that plan through the works to see how it matches up?

Just so I am clear...Frenchyge, are you saying that for every three minutes of riding during our TT, I should pull for 2 minutes 30 seconds and my father should pull for 30 seconds? Does strategy change when you meet and incline?

IndyRider

frenchyge said:

Nope, weather's too nice and bike is calling. 🙂 Indy should probably incorporate a mix of my suggestions and your future approach anyway. I'll stick with what I said in post #5: Team pace = 23.5mph on flat (3-4mph higher than weaker rider's pace) adjusted on hills to maintain effort level, Indy pulls for 2.5 min and his father pulls for 30 sec. If OP wants to try that out, I'd be interested to hear how it works, or if it works at all.

After you finish your analysis, how about running that plan through the works to see how it matches up?

IndyRider said:

Just so I am clear...Frenchyge, are you saying that for every three minutes of riding during our TT, I should pull for 2 minutes 30 seconds and my father should pull for 30 seconds? Does strategy change when you meet and incline?

That's what I'm saying. At 23.5mph (on the flat) you'll be slightly above your 1hr power, and he will be close to his while following you at 3.5mph faster than he could ride on his own. When he pulls through for those 30s, he will be way above his, but only briefly to give you a chance to stretch out, get some water, etc.

When you meet an incline, the team pace will have to slow to the speed that he's able to climb -- any more and you'll drop him. To be safe, you should pull up any noticeable hills. He should pull through on the descents, and let the pace rise to whatever level he's comfortable pushing. Wind is going to present the same problem as hills.

I'd look to Rapdaddyo for the overall team pacing. He's as good as any at pacing strategies, but the challenge will be for you 2 to follow the plan with just speed to rely on. It's very tough to accurately assess your output when the road fluctuates or wind blows.

One piece of new data. Although it is based on a short test, I have a small amount of data on the power relationship between pulling and drafting at ~25mph. In a test of different rotation durations, I experienced a 300w/208w relationship between pulling and drafting. Average power varied of course based on the duration ratio of pulling and drafting. I tested 30s:15s, 40s:20s and 30s:20s rotations. The main problem with the short pulls is the frequency of the short bursts to get hooked on after pulling off. It's only about 2 secs but I averaged 400w for those 2 secs each rotation. My training buddy has only ~225w FT and he said it was a piece of cake at 30:15 and only slightly more effort at 40:20. The only time he worked was when we did the 30:20 rotation. He said, "This is fun. Can we ride like this all day?" I was doing a little huffing and puffing, but could have gone a long time.

Cool. What riding position? Aerobars?

frenchyge said:

Cool. What riding position? Aerobars?

Nope. Just in the drops. I was mostly interested in my power numbers when drafting, since I already knew what it takes to pull from the front at that speed. But, I was really dumbfounded by my training buddy's unsolicited enthusiasm for what we had just done. I mean, he wasn't even sweating, yet he was pulling 300w on front -- albeit for only 15-20sec. He didn't have a PM, but my instructions to him were to maintain cadence and speed, whatever it was when I pulled off.

RapDaddyo said:

Nope. Just in the drops. I was mostly interested in my power numbers when drafting, since I already knew what it takes to pull from the front at that speed.

Yeah, 100w delta is what I typically see. I think the aerobar delta will be smaller, mostly due to a lower Cd and pulling power.

RapDaddyo said:

But, I was really dumbfounded by my training buddy's unsolicited enthusiasm for what we had just done. I mean, he wasn't even sweating, yet he was pulling 300w on front -- albeit for only 15-20sec. He didn't have a PM, but my instructions to him were to maintain cadence and speed, whatever it was when I pulled off.

I expect his enthusiasm will change when he gets closer to the P/D curve. 😉

Thank you both for you suggestions so far. Would a cadence monitor help in the monitoring of the information that you are giving me? If so, that is an upgrade that I might be able to make. Thanks.

frenchyge said:

Yeah, 100w delta is what I typically see. I think the aerobar delta will be smaller, mostly due to a lower Cd and pulling power.

I expect his enthusiasm will change when he gets closer to the P/D curve. 😉

IndyRider said:

Thank you both for you suggestions so far. Would a cadence monitor help in the monitoring of the information that you are giving me? If so, that is an upgrade that I might be able to make. Thanks.

If you have a speedometer that measures speed to the 1/10th mph, you should be able to use that for pace management. If your speedometer measures speed rounded to the nearest mph, I think cadence would be helpful for pace management because of the higher precision (~1/100th vs. ~1/25th). Personally, I use cadence to manage pace, but that is largely because of the data source (crank magnet vs. hub). But, a wheel magnet-based speedometer should be sufficiently precise for pace management.