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Should more people ride aero road bikes with full TT cockpits?
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While low base bars and pedestaled elbow pads may be the fastest/best solution for a pro time trial, I think most triathletes would be better served having their bull horn position mimic their hoods position on a road bike. It would be better for climbing hills, recovery rides, and riding in a group if you have electronic shifting.

The two bikes pictured below share the same saddle setback and pad stack and reach. The drop from saddle to pads is 9.5 cm. The saddle setback is 6.5 cm, so pretty far back considering both are short saddles. The Cervélo road bike frame is fitted with an 80mm -17 degree stem and Pro Missile integrated aerobar. The Scott has a Specialized integrated aerobar and the equivalent of a 60mm stem. The elbow pads on the Cervélo literally sit on the base bar. There are 4cm of spacers under the pads on the Scott. The chief difference is that the bull horn position on the Cervélo road bike TT conversion is about 4cm higher than on the Scott tri bike and is close to my road hoods position. The Cervélo also weighs 2.5 lbs less.

I have not tried to measure any aero deficit the road bike TT conversion may have compared to the tri bike, but I doubt it would be much. Tom Zirbel won the 2013 US Pro Time Trial title on an Orbea road frame with a HED Corsair cockpit and downward angled stem. While the road bike conversion may not be as stable as a tri bike, I have no difficulty riding a 60mm deep front wheel on the Cervélo.

I understand that those that want to ride a more aggressive position need to be able to get the front end lower and the saddle further forward, precluding using a road bike with a TT cockpit unless a downward angled stem and forward seat post are employed (which could negatively effect handling). But perusing most of the tri bikes in the transition area at a local race, most are not set up as aggressively as these two bikes. They are using high stack aero bars (at least 6 cm of pad stack) and some combination of spacers under the stem or upward angled stems to get their positions. Unless they have super bikes like the Trek Speed Concept, they are ruining the aerodynamics of their bikes with stem spacers and upward angled stems and still have a bull horn position that is much lower (and further away) than their hoods position would be on their road bike. If they want to preserve aerodynamics (no stem spacers, -17 degree stem), they end up with a bull horn position that is so low it is awkward for almost every situation except sprinting out of the saddle.

For athletes without super aggressive positions, why not offer an aero road frame that has about 4cm more stack than the average tri frame and 2cm less reach? One could then spec a low stack aerobar and zero setback post. The new Profile Design subsonic 35a aerobar and WING/10a base bar would be a good choice for the cockpit. The fit of the bike could be fine tuned using stems of varying length and angle, hopefully no higher than negative 6 degrees, and maybe up to 2cm of aero stem spacers. This would give the athlete a fast TT machine that also works decently as a road bike. The triathletes that want to ride an aggressive position can buy the pro TT bike or the more integrated triathlon model. Even triathletes with an aggressive position might be best served using an aerobar with very low pad stack or an upwardly angled base bar in order to get their bull horn position higher.

It is worth noting that both bikes below are tall and short for their respective types. The road bike has a stack of 58 cm and reach of 387 in size 56. The Scott tri bike has a stack of 54 and reach of 395 for size 54. Athletes that do not share my long leg/short torso morphology could easily choose a road bike frame with 2cm less stack and achieve similar drop to the elbow pads. If the tri bike were a Cervélo P2 in size 54, not only would my bull horns be 2cm lower (if I wanted to use a -17 degree stem), keeping the reach to the bull horn position the same would require a base bar with 2cm less reach (Vuka Bull?) or 40 mm stem, which I doubt would be advisable.





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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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I mean... at the end of the day, it's just a bike. Realistically most people don't ride a "road bike" with a full aero cockpit for convenience sake. (Most roadies buy a dedicated tt bike as a secondary bike, and I'd guess most triathletes do the opposite)

The S5 was as fast as a P4 from the paper... nothing would keep you from riding it to success. (Dean Phillips won TT nats on an S5 with aerobars a few years ago fwiw) Track riders almost always have one bike that pulls double duty with a handlebar change. It's obviously much, much easier to do with no cables of course.

I guess the question I have is... why would you want to go through the hassle of changing/cabling it every time you wanted to change setups?

My Blog - http://leegoocrap.blogspot.com
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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I watched a video on GCN or something like that (of course I can't find it now) where they did a test in the wind tunnel with a lady rider. She did a base run, run in the drops, run with hands on hoods with forearms parallel to the ground, clip-on's added, clip-on's optimized and full aero bike. The clip-on's optimized were not that far away from the full aero bike.

So basically if you can get a really nice aero road bike and optimize your fit with clip-ons I think you could be very close to a good tri set up. Might need an extra post and saddle and know exactly where to position the clip-ons without all the hassle of doing a full aero set up on the front.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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It's not only fit that drives tri bikes, it's the stability of a tri bike when ridden in aero bars.

A road bike with have 55-58mm of trail and will be very maneuverable with road bars and twitchy with aero bars. The seat tube might not be (in your case it was) steep enough to accommodate a forward saddle position and the rear wheel will be further behind putting even more weight on the front.

A tri bike will have 60+mm of trail and be very stable while riding in the aero bars but not as maneuverable on the horns.
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Re: Should more people ride aero road bikes with full TT cockpits? [jaretj] [ In reply to ]
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This ^.
I did the transformation on my road bike for my first Triathlon coming soon.
Like JaretJ says, it's twitchy.
I have to be calm and and focused to ride well.
Anyways, I never tried a dedicated TT bike, so I can't compare... :-)





Louis :-)
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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I one time toyed with the idea of getting an S5 frameset and turning it into a tri bike. With etap it wouldn’t be that horrible to switch between road bars and a tri cockpit. But the stack was too tall and I wouldn’t have been able to hit my fit coordinates

Matt
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Re: Should more people ride aero road bikes with full TT cockpits? [Morelock] [ In reply to ]
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My point was not to have one bike to do both road races and TTs. What I was trying to assert is that most Triathlon/TT frames are too low and long for most athletes. We can bring the pads back and stack them up, but where does that leave the base bars? Is the base bar position good for climbing hills, standing out of the saddle, pedaling easy, navigating crappy pavement, etc.? Why not make bikes with the base bar position close to your hoods position if you can still get the same aero position? An aero road bike frame might be a good place to start with this, assuming you can ride your aero position with a little more saddle setback and it is not a twitchy handler. The Cervélo geometry seems to work and my old Specialized Venge worked well with a TT cockpit. Don't think I would want to put a TT cockpit on a Tarmac though.
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Re: Should more people ride aero road bikes with full TT cockpits? [BMANX] [ In reply to ]
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Yeah, the (aero frame) road bike with pursuit bars was pretty close to the (uci legal) tt bike in that cycling weekly video. A good choice for those who only do the odd tri/tt.

Tri bikes are another level quite often, and good point by others regarding stability.

I am more of a “right bike for the task” type. I find the more setup or swapping i need to do, the less chance i will ride it. Thus i have my road bike, and a tri bike.
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Re: Should more people ride aero road bikes with full TT cockpits? [BMANX] [ In reply to ]
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BMANX wrote:
I watched a video on GCN or something like that (of course I can't find it now) where they did a test in the wind tunnel with a lady rider. She did a base run, run in the drops, run with hands on hoods with forearms parallel to the ground, clip-on's added, clip-on's optimized and full aero bike. The clip-on's optimized were not that far away from the full aero bike.

So basically if you can get a really nice aero road bike and optimize your fit with clip-ons I think you could be very close to a good tri set up. Might need an extra post and saddle and know exactly where to position the clip-ons without all the hassle of doing a full aero set up on the front.
Cycling Weekly, and the bike in question was adjustable enough to reach an ideal position for her.

For the OP - I say Yes! My bike (come race time) is a mutant, but with seatpost, saddle, stem, basebar and clipons (about $300 invested in mostly used parts) my position is good. A slightly longer stem would probably be ideal if I could be bothered. But it's stable and comfortable. With the right slip ons (low stack) the position is nice and aggressive. I could adjust it even lower if I wanted/needed (spacers and headset dustcap).

With the full cockpit and seatpost preassembled, there is no adjustment needed when converting, it just bolts straight on (well under an hour's work) and everything is already in the right position. The fact my bike has external cable routing is a big benefit admittedly.


I'll be frank, if I could justify the cost of a TT bike I'd have one, but I'm pretty happy with what I've managed to put together.
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Re: Should more people ride aero road bikes with full TT cockpits? [jaretj] [ In reply to ]
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Could the handling be fixed with a fork change? I suggest this not for the consumer, but as a way for a manufacturer to offer a tri bike with less aggressive geometry without a ton of R&D. Aero road frame, a fork that increases stability, a zero setback post, and a low pad stack TT cockpit. Voila, a nice disc brake TT bike for many that would still be nice to ride out of the aero position. I realize you cannot use an effective 80 degree seat angle on such a set up, but you might get away with 75.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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wtboone wrote:
My point was not to have one bike to do both road races and TTs. What I was trying to assert is that most Triathlon/TT frames are too low and long for most athletes. We can bring the pads back and stack them up, but where does that leave the base bars? Is the base bar position good for climbing hills, standing out of the saddle, pedaling easy, navigating crappy pavement, etc.? Why not make bikes with the base bar position close to your hoods position if you can still get the same aero position? An aero road bike frame might be a good place to start with this, assuming you can ride your aero position with a little more saddle setback and it is not a twitchy handler. The Cervélo geometry seems to work and my old Specialized Venge worked well with a TT cockpit. Don't think I would want to put a TT cockpit on a Tarmac though.
Ah OK that's your assertion.

I disagree, the problem is most "athletes" don't have a good aero bar position when they should. But you're right, if they're going to ride a crappy position then the bike itself doesn't make much difference.

Base bar position should be secondary, you should be aiming to spend the least time possible on the base bars.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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If you took 8mm of rake away from the fork the bike would be less maneuverable and ride more in a straight line.

It does not solve the problem with weight distribution or saddle position. However, it may be a good start.
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Re: Should more people ride aero road bikes with full TT cockpits? [jaretj] [ In reply to ]
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jaretj wrote:
If you took 8mm of rake away from the fork the bike would be less maneuverable and ride more in a straight line.

It does not solve the problem with weight distribution or saddle position. However, it may be a good start.
Flip widget insert on the fork dropout.
Sliding rail on the seatpost.
Problems solved.
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Re: Should more people ride aero road bikes with full TT cockpits? [MattyK] [ In reply to ]
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How secondary should the base bar position be? I could ride a Shiv TT. As long as I am racing a fairly flat TT or triathlon, it would work great, even though the base bar position would be awful. I would only use the base bar for start, sharp turns, and dismount. But what if I live where it is hilly? What if I want to go ride in the mountains? Yes, a road bike would be the better choice, but what if still want to get some time in the exact aero position I am going to race in during my 3 hour ride? A bike with a low pad stack and the base bars as high as possible will be much more palatable in those situations and give up little aerodynamically. I admit that most people cannot get 10cm of drop from saddle to pads using a road frame and ride that position with the saddle as far back as I do. But it appears many ride with 0 to 7cm of drop. I would think most of these people would be happier with a Cervélo S2 with a full TT cockpit rather than a P2.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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“...they are ruining the aerodynamics of their bikes with stem spacers...”

This seems to be a common refrain, but how accurate is it, really?

Doing some back-of-the-envelope calcs: adding a tall 60mm stack of spacers will increase frontal area by ~30x60mm = .0018m^2. At a 1.0 coefficient for a cylinder shape, the CdA increase would be about 0.0018, or 1.8 watts (using the common rule-of-thumb of 5W = 0.005 m^2 CdA at 40kph). [Note: somebody should probably double-check my work!]

And that’s probably worst-case scenario given that the stack will have to be made up elsewhere with something (taller headtube, armrest risers, etc.) that has a more aero shape but doesn’t have zero drag.

Has anyone out there confirmed a similar figure in wind tunnel/Chung testing? The aesthetics might well be displeasing, but much like exposed cable/housing, I think the actual aero penalty is much less than the concern people might invest in it.
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Re: Should more people ride aero road bikes with full TT cockpits? [MattyK] [ In reply to ]
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MattyK wrote:
Base bar position should be secondary, you should be aiming to spend the least time possible on the base bars.

That's somewhat context dependent. When I started cycling, I started as a triathlete, and only had a tri bike. So my aero/horns ratio was maybe 50/50. If I was doing a group ride, or riding through a town or traffic, the base bar is by far the safer way to go. I'd only be all aero if doing a dedicated solo training ride...or possibly a TTT-like ride with some buddies. I could see the OP's comfy hood-like position being useful for this context.

Now I'm a roadie, and have a dedicated TT bike, and that ratio is like 99/1. I use the horns when starting and braking, and that's it. But then I'm only riding the bike when doing dedicated TT practice.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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https://www.youtube.com/watch?v=7lK1xC0Z5FA

I think this video which I just happened to stumble across recently really highlights that an aero position on a road versus TT bike has little difference in terms of aero savings assuming both positions are similar.
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Re: Should more people ride aero road bikes with full TT cockpits? [Amnesia] [ In reply to ]
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Thanks for the video. I had thought that shifters and hooks on a road bike were a bigger drag penalty than 3 watts at 25 mph. Given that only the most competitive athletes at sprint triathlons can average 25 mph, an argument can be made that most people doing triathlons should be on a road bikes with clip-on aero bars. Electronic shifting with shift buttons at the ends of the extension would make great set up and you could easily remove the clip-ons when you do not want them.

Personally, since I have another road bike, I will still use a TT base bar. However, I might be better off experimenting with a high hands position with standard clip-ons than worrying about having an expensive integrated aerobar or frameset. Given the data in the video, it that appears any flattened base bar with a clip on that allows me to get narrow enough would be so close to a fully integrated setup at 25 mph as to not matter. My money would be better spent in the wind tunnel.
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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One of the teams in the TdF did that a few years ago. They used Giant Propels with an aero cockpit for the TT.
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Re: Should more people ride aero road bikes with full TT cockpits? [jaretj] [ In reply to ]
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jaretj wrote:
It's not only fit that drives tri bikes, it's the stability of a tri bike when ridden in aero bars.

A road bike with have 55-58mm of trail and will be very maneuverable with road bars and twitchy with aero bars. The seat tube might not be (in your case it was) steep enough to accommodate a forward saddle position and the rear wheel will be further behind putting even more weight on the front.

A tri bike will have 60+mm of trail and be very stable while riding in the aero bars but not as maneuverable on the horns.

There's a lot of road bikes with trail in the low 60s, and a few tri bikes in the 50s. My old QR Lucero is in the upper 50s, while my road bike is 61.

One of the big differences is front-center. Most 54cm road bikes have a F-C around 580mm, while most tri bikes in a similar size are around 605mm. Putting on a longer stem and sliding my saddle forward on my road bike would put my weight farther over the front wheel than on my tri bike, and would make the handling a bit twitchier, despite the higher trail. A shorter offset fork would increase trail, but also decrease F-C at the same time, so not really an ideal solution.

Morelock wrote:
Dean Phillips won TT nats on an S5 with aerobars a few years ago fwiw

The reason Phillips rode that bike was because he had to:

Quote:
“The main reason for the Cervelo S5 VWD road frame was the big limitation of how short reach needs to be to remain UCI-legal for Masters Nationals. They now only allow 80cm maximum horizontal distance from the bb to the most distant part of the shifter, including the shift lever! At 6’3”, this is a major limiting factor for me and forces me to ride with a comparatively laid back seat position just to keep the reach to the bars reasonable. I can’t stay within the rule with a forward seat position TT specific frame"

<snip>

"This being said, the aero position on the S5 was not a particularly comfortable position (thank you UCI!); it was a struggle staying in the aerobars for even the 44 minutes at Nationals, and I’d definitely have a hard time using it for a longer event like a triathlon."

"I'm thinking of a number between 1 and 10, and I don't know why!"
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Re: Should more people ride aero road bikes with full TT cockpits? [Warbird] [ In reply to ]
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Yes, I do agree that front/center makes a difference as well

The road bikes I've seen in the low 60's have been small bikes that have had the head tube shallowed and the manufacturer did not spec a new fork to get that trail right. I've only ridden the small bikes (700C) with a lot of trail and did not like them compared to something like a Felt F5 with 61mm of trail.

For example (from a few years ago): a small Specialized Ruby had 68mm of trail...terrible for a road bike but that would likely work well as a tri bike. Likewise a small Cannondale CAAD 10 had 66mm of trail. The older Lucero (650C) had 54mm of trail with a FC of 572 which is huge for that size of bike, that must have been an interesting bike to ride.

For a tri bike, my Cervelo P2 (650C) has 59mm of trail and that bike is twitchy compared to my Felt DA which has 65mm. The newer Felt IA has 60mm of trail just like the NP2, both would be on the more maneuverable end of the tri bike range.

There are bikes on both sides of the spectrum. My experience is with small bikes but if I was researching bigger bikes for a friend to have a dual purpose I'd be looking at a longer FC and trail like you eluded to.
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Re: Should more people ride aero road bikes with full TT cockpits? [louisn] [ In reply to ]
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louisn wrote:
This ^.
I did the transformation on my road bike for my first Triathlon coming soon.
Like JaretJ says, it's twitchy.
I have to be calm and and focused to ride well.
Anyways, I never tried a dedicated TT bike, so I can't compare... :-)





Louis :-)




What frame is that?
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Re: Should more people ride aero road bikes with full TT cockpits? [wtboone] [ In reply to ]
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I think the premise that having the bull horns mimic the hood position on a road bike would be beneficial is not correct. The problem its that you ride a bike differently when on the aero bars than when on the hoods. A bike (and saddle) which are optimised to function well when riding in the extension will be very suboptimal when on the bull horns/hoods. This is the same problem with using shorty bars in ITU racing. You are can not have the bike set-up so its great in both the normal position and on the extensions.

Fundamentally if you have the front end set up to use the aerobars you want the bull horns to be usable without adjusting the saddle. This is typically a very low position, to account for the fact you have rolled your hips forward, and certainly lower than where you would have the hoods. If you start by setting the front end so the base bar its like a road bike you are going to end up with a super high front end.

The super aggressive position preferred by world tour riders may well contradict the above statements. At the highest level the pros are riding so low that they ride their road bikes close to what many AGers ride TT bikes. So if you give a typically triathlete a world tour bike and slap aero bars on it the fit may be near correct but that's an odd comparison.
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Re: Should more people ride aero road bikes with full TT cockpits? [Fishbum] [ In reply to ]
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Fishbum wrote:
louisn wrote:
This ^.
I did the transformation on my road bike for my first Triathlon coming soon.
Like JaretJ says, it's twitchy.
I have to be calm and and focused to ride well.
Anyways, I never tried a dedicated TT bike, so I can't compare... :-)





Louis :-)





What frame is that?


NOrco CRR SL 2010 road frame size M. Pain was stripped. (74 STA should look more like 76-78 with the seat topper in reverse position - 72 HTA )

LOuis :)
Last edited by: louisn: Aug 20, 19 5:12
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Re: Should more people ride aero road bikes with full TT cockpits? [louisn] [ In reply to ]
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Would the handling be less twitchy if moved the saddle back a couple of centimeters and either moved the pads back the same amount or swapped out to a shorter stem? This would put his weight more over the center of the bike. Do not know if he could produce same power and be as comfortable with the saddle back a bit.
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