Anyone tried a TailFin

[quixoticgeek]

Packing the sleep mat that way looks nifty, is aero and saves space, but it means you're sometimes going to be sleeping on a wet mat. But perhaps this doesn't bother some people? I recently was talking to a woman walking from Wiltshire to Edinburgh (because Covid had made her job disappear) and she was carrying her mat outside her pack. You can't walk through England for six weeks (her projected time) without encountering some rain, so I guess some people aren't bothered by a wet mat, though it kind if implies a wet bag too.

There are a few things at work here.

a) the matt if rolled relatively tightly will only have a small amount exposed to the rain.

b) You put the wetside down, so your sleeping bag is on the dry side

c) some of use use a bivvy bag on top of the sleep mat, so it doesn't matter if the mat is soaking wet, the bivvi bag keeps the sleeping bag dry.

J

[Kim]

From the distant past when I was able to sleep on the things, I recall a quick rub against some convenient doesn't-matter-if-it's-damp fabric (eg. the trousers you're currently wearing) to remove most of the water, then arranging it in the tent so it the remainder could evaporate in the time between pitching and sleeping usually worked.

[Frank9755]

It actually wasn't a great way to pack my sleeping mat.  It was a compromise because I couldn't fit it comfortably in my tail bag.  It looks ok there but, once riding, it didn't stay neatly in position, it tended to twist round so I suspect it wasn't very aero.  From an sero point of view it's always best to get things inside bags rather than strapped on to the bike.

Getting it wet wasn't a concern as it went on the ground and my bivvy bag went on top of it.  In practice I don't recall it getting wet, even in a thunderstorm, as it was rolled up tightly. 

That (half) mat went across Europe and Australia before being abandoned in the bin of an Austrian hotel two years ago, a few hours before I bumped into the OP on a train!  I still have the other half - although I've now upgraded to a Thermarest which, of course, packs much smaller so would have fitted in my rack bag.

[perpetual dan]

Packing the sleep mat that way looks nifty, is aero and saves space, but it means you're sometimes going to be sleeping on a wet mat. But perhaps this doesn't bother some people? I recently was talking to a woman walking from Wiltshire to Edinburgh (because Covid had made her job disappear) and she was carrying her mat outside her pack. You can't walk through England for six weeks (her projected time) without encountering some rain, so I guess some people aren't bothered by a wet mat, though it kind if implies a wet bag too.

I don't think i've ever put a sleeping mat inside a rucksack or bike bag. When I hiked I preferred a climbing style bag, with the mat down one side. On the bike i've always put it on top of my rack.

[Cudzoziemiec]

Indeed. Since yesterday I have remembered that I have myself carried a foam mat outside a rucksack. Can't remember now if it was on top or bottom.

Picking up on the aero point "it's always best to get things inside bags rather than strapped on to the bike" and applying this to Quixotic's latest set up, doesn't this imply that she'd actually be more aero using one small pannier each side rather than a couple of bags each side? I expect there was some reason not to do this but maybe good to know etc.

[Kim]

Picking up on the aero point "it's always best to get things inside bags rather than strapped on to the bike" and applying this to Quixotic's latest set up, doesn't this imply that she'd actually be more aero using one small pannier each side rather than a couple of bags each side? I expect there was some reason not to do this but maybe good to know etc.

I've wondered about this.  I know that smoothness is important for laminar flow, and all those straps and brackets and roll-closures are anything but smooth.  Is it cancelled out by the reduction in frontal area?  How does a pannier that isn't very full compare?  Does PVC give less drag than cotton duck?

You'd really need to do extensive wind-tunnel testing to find out, and I suspect the results are going to be very specific to individual setups.

TBH, I've always thought of bike-packing as a weight reduction/distribution thing, to make the bike easier to deal with off-road.  That endurance racers have adopted it as a way to improve aerodynamics while complying with TEH RULEZ, and the industry has decided that should be the fashionable way to carry luggage in general is a red herring.

[morbihan]

Indeed. Since yesterday I have remembered that I have myself carried a foam mat outside a rucksack. Can't remember now if it was on top or bottom.

Picking up on the aero point "it's always best to get things inside bags rather than strapped on to the bike" and applying this to Quixotic's latest set up, doesn't this imply that she'd actually be more aero using one small pannier each side rather than a couple of bags each side? I expect there was some reason not to do this but maybe good to know etc.

How important is this aero business for bike packing though?  The jury is out for me and suspect it may be over egged, particularly  for most of us non elite riders who are  trucking along at 20 kph and not in a TT position. Im not suggesting bulging panniers way wider than the rider with a coffee mug hanging off the side, but a couple of slimish panniers mostly tucked behind the legs that are moving constantly anyway. I mean what real difference does that make?  Yesterday I was riding my rig with bottles mounted on the fork cages. Standard advice seems to be that this is a no no for aerodynamics.  Aside from being super easy to reach for a drink while underway (easier than delving down into the triangle particularly with frame bags) I remain unconvinced that its a major penalty. Again they are no wider than my constantly moving pedals/legs. Ive got no data, just a hunch.

[Kim]

Quite.  I did a 200 yesterday, and swapped my usual racktop bag for a pair of lightly-loaded front-rollers, simply so I could fit a few more sandwiches in without them being crushed, and fill the water bag to full capacity.

In principle, I was carrying a couple of kilos more (mostly the water).  I don't think there's much in it aero-wise, as the panniers are tucked in behind my upper arms and shoulders, and I didn't spend much time above 20mph.  Either way, I didn't notice a difference, and my performance was mostly dictated by knee problems.

[Cudzoziemiec]

Picking up on the aero point "it's always best to get things inside bags rather than strapped on to the bike" and applying this to Quixotic's latest set up, doesn't this imply that she'd actually be more aero using one small pannier each side rather than a couple of bags each side? I expect there was some reason not to do this but maybe good to know etc.

I've wondered about this.  I know that smoothness is important for laminar flow, and all those straps and brackets and roll-closures are anything but smooth.  Is it cancelled out by the reduction in frontal area?  How does a pannier that isn't very full compare?  Does PVC give less drag than cotton duck?

You'd really need to do extensive wind-tunnel testing to find out, and I suspect the results are going to be very specific to individual setups.

TBH, I've always thought of bike-packing as a weight reduction/distribution thing, to make the bike easier to deal with off-road.  That endurance racers have adopted it as a way to improve aerodynamics while complying with TEH RULEZ, and the industry has decided that should be the fashionable way to carry luggage in general is a red herring.

Yes. And to fit in narrower ruts!

As for the aerodynamics, I don't know, just musing. I expect if you're at the pointy end of a "gravel race" it's quite important, if your version of gravel is more touring, then less so. Of course weather makes a huge difference.

[quixoticgeek]

Indeed. Since yesterday I have remembered that I have myself carried a foam mat outside a rucksack. Can't remember now if it was on top or bottom.

Picking up on the aero point "it's always best to get things inside bags rather than strapped on to the bike" and applying this to Quixotic's latest set up, doesn't this imply that she'd actually be more aero using one small pannier each side rather than a couple of bags each side? I expect there was some reason not to do this but maybe good to know etc.

Couple of things. I have one bag on each side of the tailfin, so it's not a massive amount if I was to carry panniers I'd likely end up carrying too much stuff.

How important is this aero business for bike packing though?  The jury is out for me and suspect it may be over egged, particularly  for most of us non elite riders who are  trucking along at 20 kph and not in a TT position. Im not suggesting bulging panniers way wider than the rider with a coffee mug hanging off the side, but a couple of slimish panniers mostly tucked behind the legs that are moving constantly anyway. I mean what real difference does that make?  Yesterday I was riding my rig with bottles mounted on the fork cages. Standard advice seems to be that this is a no no for aerodynamics.  Aside from being super easy to reach for a drink while underway (easier than delving down into the triangle particularly with frame bags) I remain unconvinced that its a major penalty. Again they are no wider than my constantly moving pedals/legs. Ive got no data, just a hunch.

Aero dynamics are an interesting one. IIRC Air resistance losses go up by the cube of the frontal area or some such? Meaning that the faster you go the more crucial it is. I'm hoping to average 20kph on my big rides. Meaning that aero losses are less of an issue to me than someone doing 25kph. *BUT* that assumes that air speed == ground speed. The moment you cycle in the Netherlands, and thus have a 50+kph air speed for your 20kph ground speed, then the aero matters a lot more, which is why you'll find even oma and opa have aerobars on their bikes here.

On a really long ride, that can add up to a lot of energy savings, which is why you'll find aero bars so prevalent on long races. It's why the Apidura style saddle bag is so popular.

I've wondered about this.  I know that smoothness is important for laminar flow, and all those straps and brackets and roll-closures are anything but smooth.  Is it cancelled out by the reduction in frontal area?  How does a pannier that isn't very full compare?  Does PVC give less drag than cotton duck?

I don't think at the speeds we're doing on the flat that the laminar flow and vortexes thing is a major concern. Ultimately in many cases, leaving your jersey unzipped, can have as much an impact as worrying about your pannier fabric.

You'd really need to do extensive wind-tunnel testing to find out, and I suspect the results are going to be very specific to individual setups.

Happy to do so if someone will fund it...

TBH, I've always thought of bike-packing as a weight reduction/distribution thing, to make the bike easier to deal with off-road.  That endurance racers have adopted it as a way to improve aerodynamics while complying with TEH RULEZ, and the industry has decided that should be the fashionable way to carry luggage in general is a red herring.

Something I like about the bike packing approach is everything is in the plane of the bike. I find this makes the handling a lot nicer. It also means that in off road I have less things to worry about fitting through a gap.

I am sure there are better ways of carrying what I have on my bike for this coming trip. But I am adapting a setup I had picked specifically for one event in very different conditions. Hence a dry bag strapped to each leg. The adaptability of something I already have is great.

Had I done my intended event this summer, all I'd have on the legs of the tailfin is the extra water. A sleeping bag would go where my extra food bag has gone for this trip. And I wouldn't have all the cold weather stuff in the main bag, so more space there.

J

[Cudzoziemiec]

Cube of speed, I think. A physicist or googler will be here in a minute.

[grams]

“I’m a slow rider, I don’t need to worry about aero” doesn’t make sense, because except at very low speeds and when climbing, the thing slowing you down is almost entirely aero drag. So if you can significantly reduce drag you’ll go faster.

Whether rearranging luggage can have a significant effect is the question to ask. I suspect not given how much of the drag comes from the rider.

[Paul H]

Whether rearranging luggage can have a significant effect is the question to ask. I suspect not given how much of the drag comes from the rider.

Even if it can, I doubt it's simple to work out.  I've always tried to keep rear luggage as far forward and as close into the bike as possible, all the air between the rack and the bags on quixoticgeek's set up look wrong to me, but I have no idea if there's any basis for that.

[Kim]

“I’m a slow rider, I don’t need to worry about aero” doesn’t make sense, because except at very low speeds and when climbing, the thing slowing you down is almost entirely aero drag. So if you can significantly reduce drag you’ll go faster.

The other exception is off-road or otherwise technical terrain, where the thing slowing you down is TEH FEAR.

That said, slower riders benefit more from better-rolling tyres, as the rolling resistance makes up a greater proportion of their power use.

Whether rearranging luggage can have a significant effect is the question to ask. I suspect not given how much of the drag comes from the rider.

See also: "Would an equivalent recumbent make you faster?", to which the answer is more obviously yes unless it's all uphill, or rolling and downhill speed is limited by technical conditions and/or TEH FEAR.  Recumbents go faster because humans are much more aerodynamic in a laid back orientation, and aerodynamics always wins.

(In the real world, the sticking point is 'equivalent recumbent' - once you get away from touring bikes, it's not always easy to achieve the same weight, and the rider would have to train differently to make effective use of it.  And you can forget about UCI compliance or technical off-roading.)

"Should you rearrange your luggage?" is like "Should you zip your jacket up?" - yes, unless the aero benefit is going to be cancelled out by other effects (faffing to get to things, overheating, thinking too much about luggage and not going for a training ride, that sort of thing).

[Nick H.]

I would love a real time drag measurement display. Garmin are thought to have one in the works https://the5krunner.com/2021/07/08/garmin-vector-air-soon-hints-that-its-coming/ There's also one by Notio but it requires an iphone, and I don't do Apple products.

[Kim]

I would love a real time drag measurement display. Garmin are thought to have one in the works https://the5krunner.com/2021/07/08/garmin-vector-air-soon-hints-that-its-coming/ There's also one by Notio but it requires an iphone, and I don't do Apple products.

That would be impressive, if it actually works.  And doesn't make uselessly restrictive assumptions about what you're riding in order to do so.

[quixoticgeek]

“I’m a slow rider, I don’t need to worry about aero” doesn’t make sense, because except at very low speeds and when climbing, the thing slowing you down is almost entirely aero drag. So if you can significantly reduce drag you’ll go faster.

Whether rearranging luggage can have a significant effect is the question to ask. I suspect not given how much of the drag comes from the rider.

Yes, but at lower speeds, the changes are less significant. Someone doing 25kph rather than my 20kph, is going to have to have to put in twice the power as I do. Meaning that any saving from aero is more significant the faster you go.

“I’m a slow rider, I don’t need to worry about aero” doesn’t make sense, because except at very low speeds and when climbing, the thing slowing you down is almost entirely aero drag. So if you can significantly reduce drag you’ll go faster.

The other exception is off-road or otherwise technical terrain, where the thing slowing you down is TEH FEAR.

That said, slower riders benefit more from better-rolling tyres, as the rolling resistance makes up a greater proportion of their power use.

Yep. I've noticed that even tho I lack power, I can make substantial gains over some people through bike handling, and because I'm running wider tyres, This was stark on a 300k from Groningen a couple of years back when the 23, 25, 28mm tyre clad riders I was with were left behind the moment things got bumpy.

"Should you rearrange your luggage?" is like "Should you zip your jacket up?" - yes, unless the aero benefit is going to be cancelled out by other effects (faffing to get to things, overheating, thinking too much about luggage and not going for a training ride, that sort of thing).

Exactly, if I lose 10 minutes twice a day when I have to find, then stow my leg warmers, cos my bags are badly packed, that could easily swallow the watt or so of saving I got from the more aero setup.

Ultimately, like most things in cycling, if I lost some weight, I might be more aero. The meat sack between the saddle and handlebars is always going to have a bigger impact than the collection of fabric above the rear wheel.

J

[Kim]

Yep. I've noticed that even tho I lack power, I can make substantial gains over some people through bike handling, and because I'm running wider tyres, This was stark on a 300k from Groningen a couple of years back when the 23, 25, 28mm tyre clad riders I was with were left behind the moment things got bumpy.

It's been observed that a HPV Streetmachine with 40mm Marathons is faster than an Optima Baron with 28mm Duranos, given the same rider in various circumstances, including comedy-off roading (you can ride, rather than walk) the Derbyshire Pie Run (immunity to skoggy lanes cancels out extra weight on the climbs) and descending Welsh mountains (better view of the road surface and less FEAR of DETH in the event of a pothole).

Race tracks, fenland hills and threading the needle through Silly Sustrans Gates™ are another matter...

Exactly, if I lose 10 minutes twice a day when I have to find, then stow my leg warmers, cos my bags are badly packed, that could easily swallow the watt or so of saving I got from the more aero setup.

It's a truism that the easiest way to get faster at things that involve time off the bike is to spend less time off the bike.

Similarly, the easiest way to get faster at things that involve navigation is to get your navigation right the first time.  As evidenced by the sportive-types that you plod past on the first half of any 100k audax.

[Cudzoziemiec]

Exactly, if I lose 10 minutes twice a day when I have to find, then stow my leg warmers, cos my bags are badly packed, that could easily swallow the watt or so of saving I got from the more aero setup.

This may or may not be important depending on the type of riding though. If you're "touring with a sense of urgency" then time and especially time lost multiply over several days is important, particularly at the pointy end. If you remove that sense of urgency then taking 20 minutes longer each day becomes fairly meaningless but having a bit of extra energy to battle the headwind, conquer the final climb or to dance the night away becomes more important.

[Kim]

Exactly, if I lose 10 minutes twice a day when I have to find, then stow my leg warmers, cos my bags are badly packed, that could easily swallow the watt or so of saving I got from the more aero setup.

This may or may not be important depending on the type of riding though. If you're "touring with a sense of urgency" then time and especially time lost multiply over several days is important, particularly at the pointy end. If you remove that sense of urgency then taking 20 minutes longer each day becomes fairly meaningless but having a bit of extra energy to battle the headwind, conquer the final climb or to dance the night away becomes more important.

If it's less urgent, then the time spent faffing can be time spent resting and digesting which fortifies you for that climb or headwind.

[Cudzoziemiec]

Or there can be time for faffing and fortification. You might even decide to change route to avoid the hill or delay until the wind has subsided.

[Frank9755]

Some misconceptions above - aerodynamics are very important, even - or especially - for slow riders.

The main thing you are working against, over the course of a long ride, is wind resistance. 

Aerodynamics becomes significant when you are moving at 20+km/h vs the air.  As QG says, air speed isn't always the same as speed vs the land, as winds exist.  So if you ever ride into a headwind, then aerodynamics matter.

Also, if you ride at an average speed of 20km, or 15km, or whatever, you don't go at a steady speed but your speed varies, mostly according to hills.  So, on a long ride, as well as a chunk of time at very low speeds, you will spend a fair amount of time at high speeds.

Finally, while fast riders receive a larger % benefit from aerodynamic improvements, slower riders receive a greater absolute time benefit over a given distance than faster riders, because they are in the wind for longer.   

[Nick H.]

Similarly, the easiest way to get faster at things that involve navigation is to get your navigation right the first time.  As evidenced by the sportive-types that you plod past on the first half of any 100k audax.

Speaking of which, Nicolas Roche said on Eurosport today that about half the grand tour riders have a GPX file of the stage route for their head unit, showing dangerous corners and all sorts. Nobody is yet known to have crashed on a dangerous corner because they were looking at their screen.

[Andrew Br]

I see that TailFin have brought out the extended top stay. I have to confess that I was expecting an extension to the saddle mounting rather than a complete top piece.
That would, I imagine, cost less than the new component ............

[felstedrider]

Does my bum look big in this?



J

Sorry, digging this thread out from a while ago.

I have my Tailfin now installed.   I have used the supplied light bracket to fit one rear and have just bought 2 * Omnis.   I note you have yours ziptied on.   Is this a belt and braces approach or did you have a bad experience with the tilfin bag light mounts ?

Thanks


Rob