Rolle aufgrund von Hinterradplatten?
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I think I missed a few possibilities
If I understand it all correctly, the problem is not just a flat rear tire, but that the tire gets off the rim and that you then ride on the metal rim and you loose all grip. So I can see a few general solutions
1. Replace the metal with something with better grip. For example if the metal of the rim would have even a thin layer of rubber on the edge that could save your day? That would be much lighter than mounting a complete wooden ring next to the rim?
2. Another option would be something that flips down as alternative to the rim immediately the moment your tire goes flat, Daniel proposed something triggered by a bang, but that would not work if the tire goes flat without bang or if your battery is flat or so. Someone else proposed a fixed small wheel next to/behind the main wheel but that did not work for velomobiles with suspension. But we could solve that? Eg fix the wheel or support strut to the swing arm so that it follows the swing arm motions. And does it even have to be a wheel? I mean it could be even a rubber block? Lots of drag might be even wanted in this case?
3. A final option that was hinted at but I did not yet see worked out is to tie the tire to the rim so that you can never end up on the rim metal. There were references to high speed bicycle racing where they glue the tire to the rim, but this probably can be done smarter. Forinstance there could be attachment eyelets on the tire, or maybe come clamping system that makes it impossible for the tire to get off the rim in the first place. Maybe some sort of clamps that screw into place that grab the tire?
If I understand it all correctly, the problem is not just a flat rear tire, but that the tire gets off the rim and that you then ride on the metal rim and you loose all grip. So I can see a few general solutions
1. Replace the metal with something with better grip. For example if the metal of the rim would have even a thin layer of rubber on the edge that could save your day? That would be much lighter than mounting a complete wooden ring next to the rim?
2. Another option would be something that flips down as alternative to the rim immediately the moment your tire goes flat, Daniel proposed something triggered by a bang, but that would not work if the tire goes flat without bang or if your battery is flat or so. Someone else proposed a fixed small wheel next to/behind the main wheel but that did not work for velomobiles with suspension. But we could solve that? Eg fix the wheel or support strut to the swing arm so that it follows the swing arm motions. And does it even have to be a wheel? I mean it could be even a rubber block? Lots of drag might be even wanted in this case?
3. A final option that was hinted at but I did not yet see worked out is to tie the tire to the rim so that you can never end up on the rim metal. There were references to high speed bicycle racing where they glue the tire to the rim, but this probably can be done smarter. Forinstance there could be attachment eyelets on the tire, or maybe come clamping system that makes it impossible for the tire to get off the rim in the first place. Maybe some sort of clamps that screw into place that grab the tire?
wolfram
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the rim never touches the ground, so there is no need to rubber the rim.
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Es gibt den nur für 26".
Er ist sicher kein Gripwunder und er ist mit 25 bzw. 28 mm natürlich etwas nervöser als breite Schlappen.
(Weiche Gummimischungen würden mir auch zu viele Steinchen einsammeln, was gerade am Hinterrad schwierig zu überwachen ist)
Aber er hat gegenüber allen anderen Lösungen den Vorteil starker Seitenflanken, die aus meiner Sicht einen erheblich größeren Schutz gegen Aufschlitzen / plötzlichen Druckverlust bieten und auch ohne Hump für Notlaufeigenschaften sorgen.
Ich bin nicht der Einzige, der hier berichtet hat, dass er kilometerweit ohne Luft gefahren und erst nach einer Weile bemerkt hat, dass die Luft draußen war. (Ein Plattfuß nach 60T km, dünner Glasstift senkrecht mitten durch die Lauffläche)
Ich führe immer einige wiederverwendbare Kabelbinder mit, um notfalls den Mantel für bessere Demontage ins Tiefbett zu zwingen.
In meiner bisher einzigen Anwendungssituation bin ich aber mit zwei leichten, gekürzten Kunststoffhebeln ausgekommen.
(Trockenübung zu Hause hilft.)
Der Marathon Plus Evolution Line (nicht die billige Performance Line) Wheelchair ist kein Bremsanker und erträglich komfortabel, wenn man ihn bei Maximaldruck (8 bzw. 10 Bar) fährt.
Ist aufgrund seiner Konstruktion nicht für Einspurer geeignet und hat auch nicht die übliche Marathon-Laufdauer (mehr als 8-10T km sind nicht drin).
Über Erfahrungen bei hohen Geschwindigkeiten verfüge ich nicht.
Ideale Ergänzung: Reifendrucküberwachungssystem
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Am I misunderstanding something completely? I thought the problem was sliding on the metal, plus the occasional push from a derailed flopping piece of tire, that causes the danger. I would expect if something drags hard at the rear end, it will pull you back into the line of motion (as a working tire would) and thus prevent you from flipping over.
wolfram
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You think of an anchor, just try it
wolfram
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Die Führung des Hinterrades ist sehr wichtig. Deshalb sind Bremsvorrichtungen die keine Seitenstabilität aufbauen nicht gut.
Die beste Führung ist ein rotierendes Rad was sich seitlich nicht bewegen kann.
Dies muss im Notfall bestmöglich gewährleistet sein...
Aber lies den Faden mal von vorne durch dann wirst du die Problematik erkennen.
Liebe Grüße Wolfram
Die beste Führung ist ein rotierendes Rad was sich seitlich nicht bewegen kann.
Dies muss im Notfall bestmöglich gewährleistet sein...
Aber lies den Faden mal von vorne durch dann wirst du die Problematik erkennen.
Liebe Grüße Wolfram
@wolfram Thanks! If I get you right, my analysis is roughly correct but the problem with some of my proposals is that a slipping object does not resist sideways force.
Yes if there is not enough drag, then this won't help. But it still seems correct to me that if it drags hard enough (harder than the sideways pushes from the derailed tire), it still would pull your velo into the line of travel, thus preventing an overturn? I'm talking about something dragging but attached firmly to the velo straight but far behind the center of mass, eg just behind the rear wheel..
I did read from the start but it's long and there are a number of related threads that also need to be read, so it took a week or so and I'm still reading the other threads, so maybe I forgot or missed something
If I still don't get it then I indeed may have to re-read this thread again...
Yes if there is not enough drag, then this won't help. But it still seems correct to me that if it drags hard enough (harder than the sideways pushes from the derailed tire), it still would pull your velo into the line of travel, thus preventing an overturn? I'm talking about something dragging but attached firmly to the velo straight but far behind the center of mass, eg just behind the rear wheel..
I did read from the start but it's long and there are a number of related threads that also need to be read, so it took a week or so and I'm still reading the other threads, so maybe I forgot or missed something
If I still don't get it then I indeed may have to re-read this thread again...
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No!
Things are going to slide, slide in all directions.
Won't be nothing, nothing you can measure anymore.
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On a normal bike there is no problem at all if you lock the rear wheel, so it's not that simple
My first thought is that the problem arises only when you are breaking on the front wheel at the same time that the rear wheel is locked. Then it becomes a balance act between the drag force on the rear versus the break force on the front. And in this case the front wheel will win quickly because all weight goes to the front if you break.
If this analysis is right, then immediately release the (front) break should help in case of a rear flat. You would have to release the front break before your velomobile is out of track enough to roll it over.
Try what, lock the rear brake? On a velomobile? How? Throw a stick in it?