Post by Uralee on Mar 7, 2023 8:58:38 GMT 10
When I get home from an “interesting” ride, wifi wonders why I am mentally drained. Well, I told her it is the thought process I go through for every turn on the track……
With regard to braking, on rigid-mounted setups:
The rear wheel is on the centre-line of the bike and most of the outfit’s mass is in front of -although not all in line with- its contact-patch. With regard to turning the whole caboodle away from the chair, the effect of braking at that wheel is far more pronounced . This is (more) easily understood if one is to consider the applicable moments of force around what is, effectively, the pivot-point afforded by the rear wheel’s contact-patch itself. MO=F.d, for those that like such. Here, the Force applied is due to the acceleration of the un-braked Mass of the chair (broadly), as it seeks to overtake the braked Mass of the bike. (‘d’ being the distance between the Force and the pivot.)
Considering, now, the effect of braking at the front wheel, we can see that there is far less Mass in front of that wheel. This means that there is far less kinetic energy available in front of the pivot-point (f/wheel contact-patch) to be effective in turning the whole plot away from the s/car. This is why, with such braking, there is tendency for the front wheel to ‘crab’ sideways. It is true that some, small turning effect will be evident in use: however, when compared to rear-wheel braking in the same scenario, far less effect is derived.
Also: in turns away from the s/car, by progressively tapping the front brake, an incremental movement in the direction of the turn can be achieved. . . but again; not as much of, nor as immediate a turn is achievable as with using the rear brake only. There are, however, times when this technique can be useful.
All that having been said, steering and braking by (mostly) throttle control and, sometimes, gear-changing alone is preferable, if only to make the whole process simpler . . by virtue of needing to monitor and use only one -and sometimes, two- control device(s). One always has one’s hand on the throttle: it is the most immediate way to influence both speed and direction.
In the case of linked brakes:
With rear+sidecar linked brakes:
Her, the only option for brake-assisted turns away from the s/car is using the front brake. This is because in such a turn, the s/car wheel must increase rotational speed in order to ‘go round’ the bike; braking on that wheel inhibits this. For reasons mentioned above, comparatively little directional control is available with this method. Such control as exists is enhanced with added throttle reduction. . .. as are all turns away from the s/car.
With front+sidecar linked brakes:
It is not an option to use this kind of configuration to enhance turns toward the s/car; as is possible using fully independent braking configurations (with s/car-wheel brake), at the lower speeds and when that wheel has (preferably) its greatest loading. The front wheel must increase rotational speed in order to ‘go round’ the pivot-point (s/car-wheel contact-patch). Application of front brake inhibits this. In any event, it is rare that one would require to brake whilst turning toward the s/car . . with the exception of relatively low-speed manoeuvre-ing. It is also not an option to use this configuration in attempting turns away from the s/car. This is because, here, the s/car wheel needs to increase rotational speed. The s/car brake inhibits this. Also, comparatively little directional control is facilitated by front-wheel braking.
Overall, it is desirable to have braking available on all wheels.
The main case for this is to do with straight-line and/or emergency stopping. Especially with a heavy and/or heavily laden chair, the tendency for same to continue along the line of travel, and to influence that line, is more pronounced under heavier braking. Also, all of this is amplified when towing.
The secondary case is that the more (isolated) control one has over the individual wheels, the more precisely can one position and direct the vehicle. And the more options one has for control and positioning.
One more thing which may not be immediately evident to the novice is that, in an emergency, a very pronounced reduction of speed can be achieved -with minimum directional penalty- by savagely using both steering and rear brake to pitch the caboodle violently sideways, with the sidecar first in the line of travel. This introduces a maximum amount of friction between tyres and road, thusly washing off speed in a hurry! . . and, hopefully, avoiding whatever it is that one wished to avoid! A loose or slippery surface makes this technique . . quite exciting! Worth rehearsing on such a surface, however, at the lower speeds: not only for fun but as an investment in technique! (On a personal note, have needed to do this but once: not a comfortable experience at speed but the bacon was saved ! )
All-in-all, throttle, brakes, weight-distribution changes and gear-changing can all be appropriately used on any outfit to achieve directional control under brakes or throttle. How it is all managed depends upon the existing configuration and setup . . . and operator skill / experience !
Also: with Earles’ or leading-link f/ends (each similar, but different) designed to rise under braking it is sometimes useful, in turning toward the chair, to be able to tap the front brake (whilst applying appropriate ‘body english’) in order to set the s/car wheel back on the ground in the case of unwanted / unexpected lofting. With a f/brake+r/brake-linked configuration, this is not an option because it slows down the rear of the outfit which is not desired when turning toward the chair. All we're looking for is a short, sharp rise in the front. This technique is not for the faint-hearted nor the novice and is not often needed. . . just another in the unique bag of tricks pertaining to the eccentric vehicle which is The Outfit !
(Stolen in part from FB).
………Well, I am not exactly inexperienced nor faint-hearted but I am telling you the “tap the front brake” technique is extremely dangerous unless accompanied by a “quick flick of the steering “ away from the chair……😳
With regard to braking, on rigid-mounted setups:
The rear wheel is on the centre-line of the bike and most of the outfit’s mass is in front of -although not all in line with- its contact-patch. With regard to turning the whole caboodle away from the chair, the effect of braking at that wheel is far more pronounced . This is (more) easily understood if one is to consider the applicable moments of force around what is, effectively, the pivot-point afforded by the rear wheel’s contact-patch itself. MO=F.d, for those that like such. Here, the Force applied is due to the acceleration of the un-braked Mass of the chair (broadly), as it seeks to overtake the braked Mass of the bike. (‘d’ being the distance between the Force and the pivot.)
Considering, now, the effect of braking at the front wheel, we can see that there is far less Mass in front of that wheel. This means that there is far less kinetic energy available in front of the pivot-point (f/wheel contact-patch) to be effective in turning the whole plot away from the s/car. This is why, with such braking, there is tendency for the front wheel to ‘crab’ sideways. It is true that some, small turning effect will be evident in use: however, when compared to rear-wheel braking in the same scenario, far less effect is derived.
Also: in turns away from the s/car, by progressively tapping the front brake, an incremental movement in the direction of the turn can be achieved. . . but again; not as much of, nor as immediate a turn is achievable as with using the rear brake only. There are, however, times when this technique can be useful.
All that having been said, steering and braking by (mostly) throttle control and, sometimes, gear-changing alone is preferable, if only to make the whole process simpler . . by virtue of needing to monitor and use only one -and sometimes, two- control device(s). One always has one’s hand on the throttle: it is the most immediate way to influence both speed and direction.
In the case of linked brakes:
With rear+sidecar linked brakes:
Her, the only option for brake-assisted turns away from the s/car is using the front brake. This is because in such a turn, the s/car wheel must increase rotational speed in order to ‘go round’ the bike; braking on that wheel inhibits this. For reasons mentioned above, comparatively little directional control is available with this method. Such control as exists is enhanced with added throttle reduction. . .. as are all turns away from the s/car.
With front+sidecar linked brakes:
It is not an option to use this kind of configuration to enhance turns toward the s/car; as is possible using fully independent braking configurations (with s/car-wheel brake), at the lower speeds and when that wheel has (preferably) its greatest loading. The front wheel must increase rotational speed in order to ‘go round’ the pivot-point (s/car-wheel contact-patch). Application of front brake inhibits this. In any event, it is rare that one would require to brake whilst turning toward the s/car . . with the exception of relatively low-speed manoeuvre-ing. It is also not an option to use this configuration in attempting turns away from the s/car. This is because, here, the s/car wheel needs to increase rotational speed. The s/car brake inhibits this. Also, comparatively little directional control is facilitated by front-wheel braking.
Overall, it is desirable to have braking available on all wheels.
The main case for this is to do with straight-line and/or emergency stopping. Especially with a heavy and/or heavily laden chair, the tendency for same to continue along the line of travel, and to influence that line, is more pronounced under heavier braking. Also, all of this is amplified when towing.
The secondary case is that the more (isolated) control one has over the individual wheels, the more precisely can one position and direct the vehicle. And the more options one has for control and positioning.
One more thing which may not be immediately evident to the novice is that, in an emergency, a very pronounced reduction of speed can be achieved -with minimum directional penalty- by savagely using both steering and rear brake to pitch the caboodle violently sideways, with the sidecar first in the line of travel. This introduces a maximum amount of friction between tyres and road, thusly washing off speed in a hurry! . . and, hopefully, avoiding whatever it is that one wished to avoid! A loose or slippery surface makes this technique . . quite exciting! Worth rehearsing on such a surface, however, at the lower speeds: not only for fun but as an investment in technique! (On a personal note, have needed to do this but once: not a comfortable experience at speed but the bacon was saved ! )
All-in-all, throttle, brakes, weight-distribution changes and gear-changing can all be appropriately used on any outfit to achieve directional control under brakes or throttle. How it is all managed depends upon the existing configuration and setup . . . and operator skill / experience !
Also: with Earles’ or leading-link f/ends (each similar, but different) designed to rise under braking it is sometimes useful, in turning toward the chair, to be able to tap the front brake (whilst applying appropriate ‘body english’) in order to set the s/car wheel back on the ground in the case of unwanted / unexpected lofting. With a f/brake+r/brake-linked configuration, this is not an option because it slows down the rear of the outfit which is not desired when turning toward the chair. All we're looking for is a short, sharp rise in the front. This technique is not for the faint-hearted nor the novice and is not often needed. . . just another in the unique bag of tricks pertaining to the eccentric vehicle which is The Outfit !
(Stolen in part from FB).
………Well, I am not exactly inexperienced nor faint-hearted but I am telling you the “tap the front brake” technique is extremely dangerous unless accompanied by a “quick flick of the steering “ away from the chair……😳
