Aero/Gains Thread

[Jonny69]

I think my TT position still needs some work!

[image]

I'm thinking of moving the saddle back a bit and maybe a tiny bit higher. Unfortunately, I don't think I can reduce my stack height any further unless I replaced the entire cockpit.

I seem to remember you're not very tall are you? This is always going to put you in a slightly compromised position compared to taller riders.

However, compare your position to Quintana:

-His bars place his arms probably about 40mm lower than yours. Quite a big difference.

-He's a bit further back on the bike overall (and looks more comfortable as a result). Both saddle and elbow position are further back than yours. His elbows are slightly more underneath his shoulders than yours are which, I think, will be more comfortable.

-His head is way lower and his back flatter. Your back is a little curved. This might just be natural curvature, but I'd recommend doing some upper and mid back stretches every morning to flatten out the curve. This will straighten out your back on the back on the bike and naturally result in your head dropping.

 

[SoliD]

Just checked pressure from Monday night, 1019hpa, with 12km/h wind from the west. So not especially quick night!

 

[Shamrock]

However, compare your position to Quintana:

That is a good comparison. Quintana is 2cm taller than me according to Google.

I did wonder how Quintana rides a Speedmax CF as when I contacted Canyon they didn't make an XS Speedmax CF, hence why I bought an XS Speedmax AL. I imagine they probably do a custom one for a Pro though!

The lack of a flat back is clear but I certainly don't have a flexibility problem. I simply can't get lower at the front due to the stack height! Also, if I raise my saddle any more it is too high, resulting in me reaching for the pedals and slight knee pain.

I have been considering a new saddle to open up my hip angle a bit but I think really I need at least a new cockpit that puts me down nearer the top tube height.

It's also interesting to look at Emma Pooley who is 157cm and rides 650c...

 

[xdcx]

Dowsetts ride with power from the national TTs up on Strava.

https://www.strava.com/activities/618647917

Ah right, just the 400watts? Christ!

Just checked pressure from Monday night, 1019hpa, with 12km/h wind from the west. So not especially quick night!

I had a look on Weather Underground for a LWS in your area for that TT and yeah, conditions were pretty naff so makes it even more impressive pal, well done Weather Underground is my new toy by the way, give it a look, they have local weather stations from people all over the shop and you can see historical/forecast weather data to your hearts content. Addictive wee tool, the last thing us data lovers need! Have fun

Shamrock. Quintana.Flat Back. TT Position stuffs etc

I have spent a lot of time worrying about this recently dude. I am deciding not to get too hung up on it, I have an arched back and apparently "that is not aero" and it "should be flat!"..... But I beg to differ and think the whole flat back thing is total BS in terms of it being the being all, end all in TT'ing. Let's have a few examples:
How about the 25 record holder and 5 times Nashy TT champ?

Or the previous World and multi German nashy champ?

Or some lying cheater?

Yeah, 100% need a perfectly flat back to be fast in a time trial

 

[Shamrock]

Yes, let's not forget the real issue here besides position is lack of wattz.

 

[SoliD]

Already use wunderground. Very good site. I have an arched back. Flat back isn't possible for many riders that don't have hundreds of hours to hone positions. Just about being as small front to minimise your cda at the front.

 

[Bear]

I have spent a lot of time worrying about this recently dude. I am deciding not to get too hung up on it, I have an arched back and apparently "that is not aero" and it "should be flat!"..... But I beg to differ and think the whole flat back thing is total BS in terms of it being the being all, end all in TT'ing.

Yeah, 100% need a perfectly flat back to be fast in a time trial

Its just simple physics. You could win a TT riding on the hoods IF you were a beast and generated enough power (taking aside any technicalities of the course). Your power is what it is but you can control your aero and obviously the more aero you are, the faster you will be for a given power.

If it isn't possible for people to get into a position for optimal aero or its just not comfortable, then it is what it is. You can only do what you are capable of to perform at your best ability. To get faster you can either get more aero or train to generate more power, or optimally you do both.

 

[Jonny69]

It wouldn't take much to get Shamrock's back flatter and get his head down.

You can start simply with PUT YOUR HEAD DOWN

 

[Shamrock]

Try being 165cm

To put my head down more without lowering my stack I'd need to do a Chris Froome and ride looking at my stem!

 

[One More Solo]

I wouldn't necessarily look at pro riders for position optimisation. For a start, they are constrained by UCI regs and secondly TTing is a smaller priority for even the GT guys. The riders in the Armstrong era generally had abysmal positions - Lance included - so not surprising he could get away with his (the rounded back is one thing but his head sticks up like a massive windbreak).

Dowsett and Martin both have rounded backs, but their heads are lower than their backs and the transition between helmet and body is very smooth. Both have tweaked their bars over the last couple of years and look narrower at the front too. Narrow trumps low in my opinion but if you look like Lance you're going to struggle either way (unless you put out 500w for 10).

Edit: Dumoulin is probably the best example of how much positions have evolved over the last few years. Not many could hold that.

 

[Bear]

Narrow trumps low in my opinion but if you look like Lance you're going to struggle either way (unless you put out 500w for 10.

Narrow or low isn't better than the other, both are the same thing ultimately. It is all about reducing frontal area, how you best achieve that reduction for yourself is what matters.

 

[SoliD]

Narrow or low isn't better than the other, both are the same thing ultimately. It is all about reducing frontal area, how you best achieve that reduction for yourself is what matters.

I would suspect more is to be gained from being narrower by 2cm than lower by 2cm.

 

[One More Solo]

I would suspect more is to be gained from being narrower by 2cm than lower by 2cm.

That's what I was getting at, it's all very individual but seems to fit with a few riders I know at least.

 

[Shamrock]

Well my arm pads can't be adjusted lower or narrower so I'm screwed.

Is there anything steeper than a -35 degree stem?!

 

[Bear]

I would suspect more is to be gained from being narrower by 2cm than lower by 2cm.

Area is area, if you reduced a square 2cm in width or 2cm in height the resultant area is the same.

 

[SoliD]

Area is area, if you reduced a square 2cm in width or 2cm in height the resultant area is the same.

But you're talking about a 3d shape so is about airflow thru tha/over that shape.

 

[SoliD]

Well my arm pads can't be adjusted lower or narrower so I'm screwed.

Is there anything steeper than a -35 degree stem?!

Basically yes. New bike needed or just become normal sized. Thing is being so small you're probably fairly aero no matter what compared to a big lump and will be limited by what you can get on the market.

 

[Bear]

But you're talking about a 3d shape so is about airflow thru tha/over that shape.

The main contribution to resistance in air is frontal area. The equation for it is Power=(kph^3×fa)/77.86 where fa is frontal area. Long tail helments pointing in the air, arched backs etc all contribute as frontal area.

What is food for thought is how much you need to increase power for minor speed increases which is why aero is so important

 

[touch]

The equation for it is Power=(kph^3×fa)/77.86 where fa is frontal area.

I dont believe that. If the only variable is frontal area then there would be no such thing as "aerodynamics", it would simply be the smaller you are the faster you go for a given power.

It doesnt take drag coefficient into account?

 

[xdcx]

Very possible float night 998hpa and the warm sun is shining!
Club 10 has a hill in it.
And I have a Bambino now, I just Fairy Liquid my visor to death.
Sub 20 tonight boys.