Trying to convince myself I need a tri bike and just wondering. So I know that there are aero advantages to a tri bike but am also wondering if the different bike position allows for more power or less compared to a road bike. I have been doing tri’s for about four years now on a specialized roubaix with clip on aerobars. I have done a few HIM and am thinking of registering for my first full and as a motivation for the increased training I am thinking of buying a new bike, ie a tri. For now I have my eye on the 2014 P2, maybe a 2013 P3
I think it’s common to loss some power when first moving to a tri bike, but most people get it back when they get used to it. You won’t generate more power on a tri bike, the biggest issue is being more aero for the same power = more speed.
I generate 15-20 watts more on my TT bike. While my fit on the TT bike is very dialed, the fit on the road bike is questionable. I think fit is really what it boils down to.
Most people generate less power with an aggressive TT/Tri position, but are still faster overall because your drag is reduced so much - and that is what really matters. With adaption, you can get your power close though, but you just can’t recruit/use all your muscles as easily now matter how “open” you manage to get your hip angle.
I think it’s common to loss some power when first moving to a tri bike, but most people get it back when they get used to it. You won’t generate more power on a tri bike, the biggest issue is being more aero for the same power = more speed.
if one fully gains back any losses, then i’d say that their position is not making an optimal trade-off between power and aerodynamics.
it is perfectly appropriate for people to lose power that they will never gain back when they choose a position that allows them to go faster (reduces drag). reduce drag too much, though, and power may drop off dramatically and irrecoverably–i.e., the drag redux will be large but the power decrease will outweigh it and they’ll go slower.
i’d say that it is normal for someone who is new to an aero position to lose power and regain *some of it, *with time and practice – narrowing but not closing the gap so to speak.
if one exclusively trains in the aero position, they may feel like they’ve reduced the gap to zero vs a road position, but it actually means the more powerful road position has been neglected.
My wife is 5’10" with a CdA of around .19 while making the same power on road vs TT bike.
I am 6’3" with a CdA of around .23 while making the same power on a road vs TT bike
and this is with old school frames so giving up a little CdA there.
Some of us just can’t be bothered to care about our hip angle much. Maybe because we don’t make a lot of power? I’ve always thought that would be interesting. Do people with ~350 watts FTPs have more trouble with this than people with ~250 watt FTPs?
Did a rather small study with 5 subjects this past spring looking at road bike vs TT bike fit and power gains over a 1 month period.
While initial gains (due to off-season just ending) were there… it was noted that bigger power gains could be had cycling in a road position versus a TT position for 1 month.
As for how long does it take to transfer Road power into TT power… that is my next little study. Hopefully I’ll be able to come up with an average time needed to adapt between the two positions.
Until then, I have most athletes ride a road bike for training and switch over the weeks leading up to a TT or triathlon.
My wife is 5’10" with a CdA of around .19 while making the same power on road vs TT bike.
I am 6’3" with a CdA of around .23 while making the same power on a road vs TT bike
and this is with old school frames so giving up a little CdA there.
Some of us just can’t be bothered to care about our hip angle much. Maybe because we don’t make a lot of power? I’ve always thought that would be interesting. Do people with ~350 watts FTPs have more trouble with this than people with ~250 watt FTPs?
i’m sure you have spent a ton of time on this, but if the average rider provided the above it would suggest to me that they are leaving some gains on the table in terms of position on the TT rig or the training of FTP on the road bike isn’t as aggressive as it could be.
since it is you and your wife, i’d guess there might be a 3rd possibility – you’re as aggressive as you can be on your TT bike and you have very aero positions on the road bike that mimic your TT positions. this isn’t true for most riders, though – very, very rare to see someone with a position approaching anywhere near as aggressive on the road bike as on the TT rig. it’s often just not possible due to the geometry of road bikes most people use.
i don’t know your training history and stuff. you think you’re maxed out in both TT & road bike training?
i don’t think the drop-off is related to absolute or even relative power – for someone who is pushing their FTP on the road, they’re smart to give up some power in favor of aero gains on a TT bike, whether FTP is 250, 350 or 420.
Some of us just can’t be bothered to care about our hip angle much. Maybe because we don’t make a lot of power? I’ve always thought that would be interesting. Do people with ~350 watts FTPs have more trouble with this than people with ~250 watt FTPs?
Not that one data point means anything, but I suck and I still lose tons of power in an aggressive aero position – usually ~10% or a little less.
As for the original post, I think the only answer is that you’ve got to try it out and see how it works for you. Everyone is different. I guess I’m worse than most but maybe you will be too.
I definitely agree with some of this.
I think people get too hung up on trying to make their aero position as powerful as possible.
All you really need to care about is making it as FAST as possible. With a consideration for comfort/race distance.
There is also the other consideration in that an aero position that has a more open hip angle may result in the recruitment of more running muscle, such as the hip flexors/psoas.
In a race you are going to want these pretty fresh for the run, so being sat up and using them to eek out a little more power in the deadspot may result in a slower run time/race.
IMHO the best aero position for triathlon is one which predominantly utilises the quads and glutes, with minimal input from the hip flexors, hamstrings and calves.
This can actually be achieved through a lower position, with cleats as far back as possible (to stop use of the calves) a lower saddle, to again stop the use of the calves. and of course good hip extension/glute activation.
One of the keys to this is relaxation, NOT pulling up at all on the upstroke and allowing the inertia of you and the bike to carry through the deadspot prior to the big push down, which is actually more hip extension coming from the glutes.
IF your glutes aren’t aching a little after a hard ride in aero position I would question whether you are really using them!
Same power for tri and road bikes
jaretj
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My wife is 5’10" with a CdA of around .19 while making the same power on road vs TT bike.
I am 6’3" with a CdA of around .23 while making the same power on a road vs TT bike
and this is with old school frames so giving up a little CdA there.
Some of us just can’t be bothered to care about our hip angle much. Maybe because we don’t make a lot of power? I’ve always thought that would be interesting. Do people with ~350 watts FTPs have more trouble with this than people with ~250 watt FTPs?
I’ve wondered this as well. I lose ~20W at FTP in my aero position vs pursuit position on my tri bike, which is outweighed a few times over by improved CdA. The interesting thing is that this discrepancy is not constant across all power levels, something that has taken me a lot of time and testing to realize. It’s as if the two positions have distinct critical power curves that are equal until ~85% FTP and then begin to diverge reaching a difference of ~20W at FTP and even more into the VO2max zone.
So testing FTP in the pursuit position significantly over-predicts the power I can hold for Sprint/Oly (90-98% FTP), but it is spot on for 70.3 (~85% FTP). If I were a short course specialist, it might be better to go with a slightly less aggressive position, which is counterintuitive.
Has anyone else experienced this? Or is my fit just crappy…
I always thought (perhaps wrongly) that a very forward position with saddle location gave a mechanical advantage in terms of power. It seems that Tri bikes for the top pros are setup with a very forward position. At least as far forward and they can legally get. It also seems that the top TT riders even then slide forward. All of this would support a proposition that “forward” is best/fastest. This is separate from “low” as the aero advantages are/ seem to be dialed in regardless. That being the case, how does a road position provide greater power potential ? Honest question as it seems counter intuitive to me. There must be a power advantage (as well as aero) from pushing the peddles from a forward position.
i think that was a controversy in the early days of tri - are steep angles more aero, or more powerful? i wanna say that someone like boone lennon argued for more power. the intuitive explanation is that when you need more power on your road bike, you scooch forward a bit.
i think lennon or one of those guys had what was called a ‘ouija bike,’ with a seat angle you could adjust on the fly, and try to find which geometry was most efficient for you.
-mike
I too am one of those that does not lose power in TT vs road. I am also not more aero by going lower. that said, going a bunch lower does eventually cause power drop and at the same time increases drag.
now, I will say I was about 3% down on my short 1min intervals last night in aero, but I did 1min instead of 2 because I wasn’t feeling it from the get go.
I ride my road bike at zero setback(cuz I am as of yet unable to get the AR4 seat clamp to work with my ARES saddle)as I lose power sliding back(road or TT)
I am well adapted to my TT position and lose about 10w of FTP versus my road position.
I think it’s common to loss some power when first moving to a tri bike, but most people get it back when they get used to it. You won’t generate more power on a tri bike, the biggest issue is being more aero for the same power = more speed.
if one fully gains back any losses, then i’d say that their position is not making an optimal trade-off between power and aerodynamics.
it is perfectly appropriate for people to lose power that they will never gain back when they choose a position that allows them to go faster (reduces drag). reduce drag too much, though, and power may drop off dramatically and irrecoverably–i.e., the drag redux will be large but the power decrease will outweigh it and they’ll go slower.
i’d say that it is normal for someone who is new to an aero position to lose power and regain *some of it, *with time and practice – narrowing but not closing the gap so to speak.
if one exclusively trains in the aero position, they may feel like they’ve reduced the gap to zero vs a road position, but it actually means the more powerful road position has been neglected.
I am finding that I am generating more power on the tri bike than on the road bike. Part of the problem is that I can’t get really low on my tri bike due to a neck injury. Perhaps if I could get lower, I’d be in the scenario you describe.