2 road cyclist vs 1 TT cyclist

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Re: 2 road cyclist vs 1 TT cyclist

Postby rodneycc » Tue Sep 27, 2016 10:26 pm

So the longer the ride goes does the two road riders have the advantage or the TT rider has the advantage? I would of thought the two road riders would of had the advantage the longer it went?
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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Wed Sep 28, 2016 7:04 am

rodneycc wrote:So the longer the ride goes does the two road riders have the advantage or the TT rider has the advantage? I would of thought the two road riders would of had the advantage the longer it went?

If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour. Keep in mind that both "teams" are riding at their limits, and the mean maximal power duration curve is very flat over such durations.

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Re: 2 road cyclist vs 1 TT cyclist

Postby Calvin27 » Wed Sep 28, 2016 9:19 am

Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.


I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.
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Re: 2 road cyclist vs 1 TT cyclist

Postby g-boaf » Wed Sep 28, 2016 10:14 am

Calvin27 wrote:
Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.


I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.


But you are forgetting that modern high end TT bikes are really aerodynamic - they really cut through the air nicely. As long as the rider can handle that aero position for a long time, I think the benefit might be with someone on the TT bike.

TT bikes might "be a wank" (as was once said), but they are very quick. If they weren't, then pro teams wouldn't use them.

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Re: 2 road cyclist vs 1 TT cyclist

Postby Calvin27 » Wed Sep 28, 2016 10:28 am

g-boaf wrote:But you are forgetting that modern high end TT bikes are really aerodynamic - they really cut through the air nicely. As long as the rider can handle that aero position for a long time, I think the benefit might be with someone on the TT bike.


I wasn't disputing that. The TT guy could still beat the pair, sure. But I dispute that over longer distance the advantage would be greater for the TT. The advantage of the TT diminishes as the distance increases. It might still be an advantage, but it gets smaller and smaller the longer you go because the speeds will inevitably drop.

This was the statement I disagreed with:
Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.
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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Wed Sep 28, 2016 11:01 am

Calvin27 wrote:
Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.


I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.

Barely. A tiny fractional gain. Not enough to make up for anything other than the slimmest of margins over say a 40km course.

At 15% lower than threshold power, which is multi hour power, the speed drops for each team are almost identical, and the relative energy demand factors don't change all that much. Air resistance is still dominant (>80%).

e.g. 3 cloned riders but with CdA on TT bike of 0.25m^2 and on roadie of 0.32m^2.

Power for roadie pair on front 15% higher than solo TT rider. Say 300W threshold and 345W for the roadie on the front.

The roadies will be 2.75% slower than the TT rider for a threshold power race, say 40km TT.

OK so currently TT rider is winning, so how much does it tilt towards the roadies if the race is say 160km? For that sort of duration, mean maximal power drops ~15%. Since we have clones, then they all experience the same drop in power capability with increasing duration.

So if we drop to a sustainable 255W for the TT rider and 293.25W for the lead roadie then the roadies are still 2.66% slower than the TT rider. A measly 0.09% gain in relative speed over the TT rider for a quadrupling of the distance/duration.

IOW even though the race is much longer, the roadies are still not going to make up the difference just because of the tiny differences in relative energy demand factors cause by going a little slower. Of course if the power/aero difference were such that TT rider only won by a bike length over 40km, then the roadies would just pip their sibling in the 160km event.
Last edited by Alex Simmons/RST on Wed Sep 28, 2016 12:01 pm, edited 1 time in total.

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Re: 2 road cyclist vs 1 TT cyclist

Postby Calvin27 » Wed Sep 28, 2016 11:52 am

Alex Simmons/RST wrote:
Calvin27 wrote:
Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.


I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.

The speed drop when riding at say 15% less power than threshold (IOW a power maximally sustainable for many hours relative to threshold which can be sustain for approx an hour) is only ~5.5%.

The proportion of the total energy demand from air resistance only drops from ~86% for threshold speed to 83% for multi hour pace. That's hardly tilting much in favour of the roadies.


Yeah I think we agree. Maybe if I re-word - the advantage diminishes as distance increases.
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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Wed Sep 28, 2016 12:02 pm

Calvin27 wrote:
Alex Simmons/RST wrote:
Calvin27 wrote:
I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.

The speed drop when riding at say 15% less power than threshold (IOW a power maximally sustainable for many hours relative to threshold which can be sustain for approx an hour) is only ~5.5%.

The proportion of the total energy demand from air resistance only drops from ~86% for threshold speed to 83% for multi hour pace. That's hardly tilting much in favour of the roadies.


Yeah I think we agree. Maybe if I re-word - the advantage diminishes as distance increases.

I edited my post significantly since then to post an example to illustrate how small that relative gain would be.

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Re: 2 road cyclist vs 1 TT cyclist

Postby warthog1 » Wed Sep 28, 2016 1:17 pm

Calvin27 wrote:
Alex Simmons/RST wrote:If a pair on road bikes can't beat a solo rider on an more aerodynamic TT bike for a shorter ride over say 40km, it's highly unlikely increasing the distance is going to move it back in the pair's favour.


I disagree. The longer distance will inevitably have a lower speed. Lower speed means the impact of drag actually reduces, tilting slightly to the two roadies.



Brave 8)
But foolhardy :P

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Re: 2 road cyclist vs 1 TT cyclist

Postby Calvin27 » Wed Sep 28, 2016 2:00 pm

warthog1 wrote:Brave 8)
But foolhardy :P


Lol school me back on TT haha!
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Re: 2 road cyclist vs 1 TT cyclist

Postby warthog1 » Wed Sep 28, 2016 3:07 pm

I am no expert I only ever was a club level hack.
My schooling might be more like finger painting :oops: :lol:

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Re: 2 road cyclist vs 1 TT cyclist

Postby queequeg » Thu Sep 29, 2016 2:20 pm

Hmm...I did the Nowra State TTT Championship. We had 4 riders. Three of us were on standard road bikes, the fourth was on a TT bike.
I don't need to imagine, the guy on the TT bike was killing the three of us, particularly on the downhill. One of the other guys now has a TT bike, so if have the same team next year it will be 2 with and 2 without. Damn that's going to hurt!
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Re: 2 road cyclist vs 1 TT cyclist

Postby warthog1 » Thu Sep 29, 2016 2:38 pm

You can get some of the benefit with clip on bars, skin suit and aero helmet. Not a huge outlay in the scheme of things.
You'll need to run the saddle up and forward depending on where you have it now, to get a nice fit with low frontal area. Maybe a shorter saddle, ism adamo etc, if you can find one cheap, then time in the saddle. You might get the bug if you can find a few tts around your area.

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Re: 2 road cyclist vs 1 TT cyclist

Postby g-boaf » Thu Sep 29, 2016 3:16 pm

queequeg wrote:Hmm...I did the Nowra State TTT Championship. We had 4 riders. Three of us were on standard road bikes, the fourth was on a TT bike.
I don't need to imagine, the guy on the TT bike was killing the three of us, particularly on the downhill. One of the other guys now has a TT bike, so if have the same team next year it will be 2 with and 2 without. Damn that's going to hurt!


You could set up your S5 as a TT bike if you needed to. I've seen that done before -

https://s-media-cache-ak0.pinimg.com/23 ... d45883.jpg

It should be lighter than the P5 too, I think.

The TT bike will be much faster downhill, that's just how they are. I know from comparing my P5 on 65mm wheels with the Giant TCR Advanced SL I also have. I'm on a very aggressive position on that Giant, so I'm not sitting up too high, but the P5 kills it for speed downhill or even on the flat. The P5 is incredibly fast downhill.

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Re: 2 road cyclist vs 1 TT cyclist

Postby warthog1 » Thu Sep 29, 2016 3:25 pm

The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.

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Re: 2 road cyclist vs 1 TT cyclist

Postby London Boy » Thu Sep 29, 2016 10:23 pm

Is it relevant that Chris Boardman had two goes at the hour record, once on a TT bike (a very special TT bike) and once on a regular track bike. He did 56.3km and 49.4km respectively, a difference of around 14%.

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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Fri Sep 30, 2016 8:02 am

London Boy wrote:Is it relevant that Chris Boardman had two goes at the hour record, once on a TT bike (a very special TT bike) and once on a regular track bike. He did 56.3km and 49.4km respectively, a difference of around 14%.

Yes it is relevant. The difference between Boardman's coefficient of drag area (CdA) for the two set ups was of course even greater than the speed difference. Keep in mind the 56.375km mark was set using a now prohibited "Superman" position, although the aerodynamics that permitted are not massively better than is possible with existing bike regs and tech. As an example of that, he set the world 4km pursuit record (4:11.xxx) at around the same time as the hour record and with same bike set up. Jack Bobridge broke that record in 2011 with a 4:10.xxx ride under more contemporary bike regs.

The power to CdA ratio require to ride 56+km/h on the track at sea level is ~2200W/m^2.
For the 4:10 4km pursuit, it's ~ 2700-2800W/m^2

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Re: 2 road cyclist vs 1 TT cyclist

Postby g-boaf » Fri Sep 30, 2016 8:06 am

warthog1 wrote:The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.


Yes - and this is the image I was trying to find:

http://i0.wp.com/www.beyondaero.com/wp- ... TBuild.jpg

S5 with aerobar and base bar setup. I have seen adjustable stems for the S5 as well used for this purpose. Don't use the bottle seen in that photo, they are flaming useless. They fly out of the cage over even moderate bumps taken at speed.

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Re: 2 road cyclist vs 1 TT cyclist

Postby queequeg » Tue Oct 04, 2016 12:39 am

warthog1 wrote:The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.


Mine has the single position post, and the saddle is already as far forward as it can go.
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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Tue Oct 04, 2016 8:53 am

g-boaf wrote:
warthog1 wrote:The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.


Yes - and this is the image I was trying to find:

http://i0.wp.com/www.beyondaero.com/wp- ... TBuild.jpg

S5 with aerobar and base bar setup. I have seen adjustable stems for the S5 as well used for this purpose. Don't use the bottle seen in that photo, they are flaming useless. They fly out of the cage over even moderate bumps taken at speed.

Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.

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Re: 2 road cyclist vs 1 TT cyclist

Postby warthog1 » Tue Oct 04, 2016 9:00 am

queequeg wrote:
warthog1 wrote:The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.


Mine has the single position post, and the saddle is already as far forward as it can go.


Mine can easily go further forward than is legal.
You might only get an approximation of a good set up then. Can you get an old post?
Depending on your handlebars it is still worth trying some clip on aerobars. They may not fit on some S5 handlebars in which case forget it.
If you lived anywhere near me I'd give you a run on my old P2. It's old, but still heaps faster for me than the S5

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Re: 2 road cyclist vs 1 TT cyclist

Postby queequeg » Tue Oct 04, 2016 12:00 pm

warthog1 wrote:
queequeg wrote:
warthog1 wrote:The S5 is a fair starting point with its' dual position seat post. My old one does anyway.
May need a -17 stem to get the clips-ons low enough with its' tall head tube.


Mine has the single position post, and the saddle is already as far forward as it can go.


Mine can easily go further forward than is legal.
You might only get an approximation of a good set up then. Can you get an old post?
Depending on your handlebars it is still worth trying some clip on aerobars. They may not fit on some S5 handlebars in which case forget it.
If you lived anywhere near me I'd give you a run on my old P2. It's old, but still heaps faster for me than the S5


Mine is a 2015 model with the Cervelo Aerobars, so no clip-ons. I'd have to change them over. The only TT I have ever done is the Club Champs (yep, not even a training ride lol). I certainly couldn't justify a TT bike, and even converting the S5 into a full time TT bike would seriously restrict it's usage. Clip-ons might be a happy middle ground if I am just going to do the occasional ride.
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Re: 2 road cyclist vs 1 TT cyclist

Postby g-boaf » Tue Oct 04, 2016 12:50 pm

Other than that, scan the pro team websites near the end of the season to find any of them selling spare framesets or race-bikes. That's the cheapeast way to get one. And then only to satisfy the N+1 rule.

Alex Simmons/RST wrote:Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.


I wasn't aware that they'd clamped down on it even further than before. I knew there were certain rules regarding the shape of them, how they could be carried on the bike, etc. Certainly they were getting away from the proper purpose of the bottle and more as aerodynamic improvements to the bike. The Arundel (which I think is what was pictured, despite the Camelbak branding) came in two versions, a first version (became illegal) and a second version that was apparently compliant for the time it was introduced.

What's the point of it when you are at risk of the thing flying out and running over it. I've done that once and narrowly avoided running over the bottle twice - fortunately without incident each time. After that, no more.

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Re: 2 road cyclist vs 1 TT cyclist

Postby Alex Simmons/RST » Tue Oct 04, 2016 2:26 pm

g-boaf wrote:Other than that, scan the pro team websites near the end of the season to find any of them selling spare framesets or race-bikes. That's the cheapeast way to get one. And then only to satisfy the N+1 rule.

Alex Simmons/RST wrote:Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.


I wasn't aware that they'd clamped down on it even further than before. I knew there were certain rules regarding the shape of them, how they could be carried on the bike, etc. Certainly they were getting away from the proper purpose of the bottle and more as aerodynamic improvements to the bike. The Arundel (which I think is what was pictured, despite the Camelbak branding) came in two versions, a first version (became illegal) and a second version that was apparently compliant for the time it was introduced.

What's the point of it when you are at risk of the thing flying out and running over it. I've done that once and narrowly avoided running over the bottle twice - fortunately without incident each time. After that, no more.

Not sure why you want a bidon for TTs of less than an hour anyway, unless it's filthy hot.

As for the bidons, I may have over stated a little. Don't have to be cylindrical, but they do have minimum cross sections:

1.3.024 Bottles shall not be integrated in the frame and may only be located on the down and seat tubes on the inside of the frame and cannot be integrated to the frame. The dimensions of the cross sections of a bottle used in competition must not exceed 10 cm or be less than 4 cm and their capacity must be a minimum of 400 ml and a maximum of 800 ml.
(article introduced on 1.10.11; text modified on 1.01.13)

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Re: 2 road cyclist vs 1 TT cyclist

Postby DaveQB » Wed Oct 05, 2016 1:02 pm

Alex Simmons/RST wrote:Those non standard shaped bidons are not permitted in events run under UCI regulations in any case.


Really?
But this is ok?
https://goo.gl/images/LDVHcH
I use this ^ and saw it in use in the Vuelta (ITT) this year.
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