Do Aerodynamics matter for Ultra Distance Bikepacking?

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jobro
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Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by jobro »

I'm not sure if this is relevant for this forum but I thought, if nothing else, it might be an interesting viewing.

The people in it are a tad annoying to my "old man" mentality.

https://www.youtube.com/watch?v=WcXh_oqs_Bs
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Escape Goat
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Escape Goat »

jobro wrote: Tue Mar 10, 2020 7:05 pm I'm not sure if this is relevant for this forum but I thought, if nothing else, it might be an interesting viewing.

The people in it are a tad annoying to my "old man" mentality.

https://www.youtube.com/watch?v=WcXh_oqs_Bs
Hey up, As far as frame design goes or aero luggage? Going to watch the video now - just wondering how you come about this vid.


Edit; No it doesn't matter, yes they are annoying.
Last edited by Escape Goat on Tue Mar 10, 2020 7:37 pm, edited 1 time in total.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

{rabbit hole} I think a distinction perhaps needs to be made between bikepacking and what we might consider to be 'roadpacking'.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by TheBrownDog »

Bearbonesnorm wrote: Tue Mar 10, 2020 7:29 pm {rabbit hole} I think a distinction perhaps needs to be made between bikepacking and what we might consider to be 'roadpacking'.
Oh so this. Stu wins the internet today with "roadpacking". That's a new one on me and I rather like it. I remember when we used to call it "touring" and I used to do an awful lot of it. That was back at the Tail End of the Dachshund of Time, when four panniers and a bar bag and bike built from girders were de rigueur.

I don't really give a monkey's to be honest. But for me, bikepacking is about going off road as much as possible. Mostly.
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In Reverse
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by In Reverse »

It's another thing to throw into the marginal (or maybe moderate) gains mix along with lighter gear, lighter rider, faster rolling tyres, etc.

Someone did a similar wind tunnel study a year or two ago and the results were linked on here. A bar roll made the biggest aero difference, I've never used one on an ITT since. I'm still really slow. :cool:

I don't use a backpack any more for endurance rides which is probably partly for aero reasons.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by redefined_cycles »

TheBrownDog wrote: Tue Mar 10, 2020 7:40 pm
Bearbonesnorm wrote: Tue Mar 10, 2020 7:29 pm {rabbit hole} I think a distinction perhaps needs to be made between bikepacking and what we might consider to be 'roadpacking'.
Oh so this. Stu wins the internet today with "roadpacking". That's a new one on me and I rather like it. I remember when we used to call it "touring" and I used to do an awful lot of it. That was back at the Tail End of the Dachshund of Time, when four panniers and a bar bag and bike built from girders were de rigueur.

I don't really give a monkey's to be honest. But for me, bikepacking is about going off road as much as possible. Mostly.
Agreed. I've been struggling with being a forum member for the past few months as the last bikepacking (mtb) ride I did was way back in November. I use and buy all the bikepacking kit but my main use is on the road and a few bivvies (sleeping in a ditch actually) last year were near the aide of the road.

Roadpacking (could that be classed as a paradigm shift :???: ... what a term and yes, Stu answers the Q straight on the head. I have some aero kit for ling distance on the road bike. Mainly bars (for comfort of the hands on the tops but free 1 or 2 mph whenever you get up to speed) and wheels (to be bought/built) cos once they're at speed they just make it easier to hold it. Remember though (IMO) for Roadpacking the primary aim should be comfort hence any rims I'd run would be slightly wider than standard...

'Roadpacking'... genius. Maybe we need a new sub section forum :o
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by redefined_cycles »

Oh... and like Andy says. If your using aero bars then bar rill definitely needs to be out of the question
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Dave Barter »

Is the Tour Divide bikepacking?

I was bloody glad of my aero bars on the 120 miles between Cuba and Grants. Same for the headwind filled final 65 miles.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by BigdummySteve »

Some good stuff here

https://www.cyclingabout.com/speed-diff ... g-results/

The site is heavily touring based but he’s done some really in-depth research into weight, aerodynamics, Dynamos and other factors which might affect speed, worth a dig.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

Is the Tour Divide bikepacking?

I was bloody glad of my aero bars on the 120 miles between Cuba and Grants. Same for the headwind filled final 65 miles.
It is Dave but that final section is fully paved is it not?

My earlier comment about 'roadpacking' was really referring to the video link. They talk about 'aero in bikepacking' but appear to have more incommon with an average road club run than they do bikepacking as I generally understand it.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by BigdummySteve »

If you look at alee’s research Bikepacking bags worked out 24min faster over 100km, many of the big races such as the tour divide have large sections of road/gravel. For racers it could be significant but for most of us grinding up a Welsh hill weight would be the most important factor.
A full aero gravel bike with seat pack, frame pack and no handlebar roll might possibly be the fastest setup but you wouldn’t want to do a world tour on it if you wanted some comforts.

Also you might lose the 24mins saved fitting everything back into Bikepacking bags, I used a set of front panniers on the back of my ECR when I started, much quicker to pack.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

I appreciate that bikepacking bags (in general) will help reduce wind resistance over panniers ... I always found or at least felt that fork cages held me back. Not noticable when riding across some 5mph BW but you could tell they were acting as an air brake on long fast (usually tarmac) descents.

I'd perhaps be more interested in the findings if they'd been conducted on a mountain bike with 800mm bars, big sticky out mudguards etc because that's likely how many of us see bikepacking.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by BigdummySteve »

I’d assume the findings would hold true with flat bars, I’ve not used them for years. With drop bars there is a marked difference between the tops and down in the drops.
The biggest factor is weight, sitting in the airport coming back from Spain Craig and I were chatting, Craig’s a small unit and I weigh several stone heavier he calculated that a needed 40% more power to climb at the Same speed as him!

On the descents that stored energy plus more aero drops led to me being slow up the hills then being significantly faster downhill
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by sean_iow »

Bearbonesnorm wrote: Wed Mar 11, 2020 8:56 am I always found or at least felt that fork cages held me back.
No one has ever won the Tour Divide with fork mounted bottles/luggage so that is the proof that they slow you down :smile:
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

I’d assume the findings would hold true with flat bars,
I was thinking about the position they put you in. Riding with wide bars presents quite a barrier of efficent airflow :wink:
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jameso
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by jameso »

Aerodynamics matter on bikes full stop.
Stu wins the internet today with "roadpacking"
Aww. I used it in a post yesterday :cry: Can I have a win for yesterday?

:grin:

No distinction needed perhaps, it's bikepacking and you can do it on or off-road? at least, imho. The attitude does't change because the surface changes (the TNR is more road than off-road?). I know, I'm a pedant for this sort of thing, just the thoughts/logic that interests me. I try and save it for the internet rather than the pub or camp-outs though, honest.

I do think a distinction could be made the moment anyone says 'ultra' anything :wink: It's all relative innit. If you ride 600 or 1200km audaxes then a 1500km roadpacking race isn't that long. If you'd agree that self-supported skills come to the fore after 5 to 7 days when recovery, looking after yourself, motivation and adaptation really kicks in then why would a 10 day event be anything ultra compared to a 6 day baseline? And distance is a poor way to judge an event anyway.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by jameso »

No one has ever won the Tour Divide with fork mounted bottles/luggage so that is the proof that they slow you down :smile:
: )

I think this,
Also you might lose the 24mins saved fitting everything back into Bikepacking bags, I used a set of front panniers on the back of my ECR when I started, much quicker to pack.
the pack efficiency, is a lot of it. If you have fork mounted stuff you have more to pack and faff with. The fastest racers have figured out that it takes far less energy to save 20 mins a day in your packing/bivi process than via pedalling faster still. 20 min a day over 15 days ... it's worth 1/4 of a day's pedalling on a ride like that.
Aerodynamics will suck in the roadie-triathlete mentality (not meant as it might sound!) but a lack of bikepacking experience and efficiency will undermine those gains very quickly. Lack of faff is still the biggest gain I expect.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by faustus »

I guess aero matters if you care about speed and times or if it is how a ride is judged (= racing). Otherwise, there might be other priorities like comfort or weight that matter more, as mentioned above.

Otherwise, what jameso said ^
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

No distinction needed perhaps, it's bikepacking and you can do it on or off-road? at least, imho
Totally agree. It's attitude not terrain. However, the video uses a 'road bike' for test purposes and I wonder whether a mountain bike would behave differently if tested?

... and yes, the ability to unpack and get to sleep and pack and get going as quickly and efficiently as possible will always be a massive bonus in race / itt situations. You have to work very hard to catch a similar rider who has a 20 minute headstart.
other priorities like comfort or weight that matter more
Yep. Weight won't only require more sustained physical effort but can also increase the liklihood of physical injury and mechanical failure.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by jameso »

Totally agree. It's attitude not terrain. However, the video uses a 'road bike' for test purposes and I wonder whether a mountain bike would behave differently if tested?
I expect so - you mean the gains in aero are less as a % of the whole since the MTB has more drag to start with and av speed is slower so aero gains less effective? If they're looking at the aero savings of the bike and rider system and saying a bar bag is +/-10 watts at av road speed then (if you CBA) you could rate that down to MTB speed. Maybe aero being a concern says it's not really mountain biking - back to your orig point aren't I ; )
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Bearbonesnorm »

you mean the gains in aero are less as a % of the whole since the MTB has more drag to start with and av speed is slower so aero gains less effective?
:-bd
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by sean_iow »

jameso wrote: Wed Mar 11, 2020 11:11 am av speed is slower so aero gains less effective?
That assumes riding in perfectly still conditions? As all my rides recently seem to be into a minimum of a 40mph headwind then aero gains will be more significant :grin:

If an aero gain can be made which doesn't have a knock on negative affect elsewhere then it's free speed.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by Lazarus »

yes the argument is the slower you go the less it matters so iirc from the link 5 watts at 25 kmh is 30W [ish - he seemed to use different figures] at 50 kmh

Weight will also be a factor as a heavier bike will be slower, for obvious reasons, and he used bubble wrap in th epack on a stationary bike

All i took from it is if you want to be really fast dont use a bar bag, you will gain 1- 3 watts for this.
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Re: Do Aerodynamics matter for Ultra Distance Bikepacking?

Post by jameso »

True Sean, it's windspeed over the bike vs bike ground speed ...
All i took from it is if you want to be really fast dont use a bar bag, you will gain 1- 3 watts for this.
Same drag as a dynamo hub then, sod all.

Jan Haine's blog has testing where he shows that a trad rando bar box lowers overall drag. I could be sceptical since all his testing seems to suggest that his preferred style of bike is best, maybe it is but I think it just suggest that test methods and context can help show a desired result. In a similar way a few wheel brands have been trashed for their aero tests/claims.
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