That's odd. I get on without any trouble. Rolland gave me the web site link when he and Daniel were here at my house a few years ago. If you'll email me at tewells99029@gmail.com, I'll send both of them your info and ask them to invite you. The reason I put my e-address on here is that it's published elsewhere on this site and in the Sidecarist magazine.
editor or myself messed up - sorry for this.
Chris
Quote from ChrisK on September 29, 2020, 11:05 amBack to the actual topic of this thread.
While I was initially willing to shrugg off Jan's and my different approaches to riding styles and risk-taking as a mere matter of personal preferences, Jan's vehement, even passionate advocacy of the LPR method kept me thinking.
And then it occurred to me, that the true meaning of "passion" by its roots in latin and greek language is actually "suffering". Could that be the case? At least there are some hints as to that:
In an earlier post, Jan stated that:
"As you can atest, riding a motorcycle is you and the machine against the road. However on three wheels it is the machine and the road against you."
That doesn't actually sound like fun to my ears. Rather, I picture Jan trying to ride a feral dragon through enemy country. While I look at the road as a playground, which I enjoy using a recreational vehicle, pretty much like I would be riding the slopes of a ski resort on a snowboard.
Could it be, that Jan's rig is significantly different from mine?
Perhaps the most telling and tangible hint at this is his following statement:
"My current BMW/EZS rig is very planted and stable on all curves at posted and above posted speed limits even with no passenger."
Now it's getting interesting! Meet my benchmark-curve, which is around 5 miles away from where I live and which is also covered by Google Street View:
As we are talking about right curves, read this from right to left. I evaluated the radius of curvature at the inner edge as 35.4 meters, and at the center line as 39.8 meters. Hugging the center line as close as possible, without letting any part of my rig cross it results in a radius of curvature for the combined center of gravity of my Ural cT rig plus myself at somewhere between 38 and 39 meters. Hold that figure for a minute.
With the other relevant data of my rig, like chassis dimensions, individual wheel loads, tipping angle plus my personal mass and position, my Interactive 3D Sidecar Simulator indicates a centrifugal acceleration at the tipping limit in right curves of 0.4 g (see bubble arrow below):
In order to experience a 0.4 g centrifugal acceleration in my benchmark curve (see above), I must drive at a speed of approximately 44 km/h. A value, which I was able to validate during extensive test rides.
Alas, my benchmark curve has an official speed limit of 60 km/h assigned to it.
On this occasion, having presented the sidecar simulator's view of the Ural cT, please note, how extremely asymmetricalthe "target" covers the supporting green triangle surface, with a "heavy overhang" at the left side, making the Ural cT extremely (by comparison) susceptible to chair lifting, while on the other hand providing almost perfect safety from tipping over in left turns. I'd say, that the Ural cT will rather go into skidding mode (exceeding the limits of friction), than tipping over in left turns. Which also allows for a lot of braking in left turns, before crossing into the desaster zone.
If we take Jan's statement of his rig being stable at street legal (and above) speed at face value, his rig should be able to sustain this benchmark curve without tipping at a centrifugal acceleration in excess of 0.7 g. This is what it would look like in my diagram, with the vertical blue line marking the radius of curvature of my benchmark curve (r = 38.5 meters):
Clearly, Jan's rig must have a weight distribution which is significatly different from that of my rig. I played with the individual wheel loads in my simulator, leaving all else equal, to achieve a tipping limit of 0.7 g. In doing so, I allowed a 30 kg higher empty weight for the BMW / EZS rig, as my Ural cT is a light, bare-bones, maybe even primitive rig, and the BMW / EZS is probably a little heavier all around.
So I came up with the following:
In looking at this evaluation of Jan's BMW / EZS rig, it strikes me how extremely well-balanced and symmetrical the coverage of the green supporting triangle by the target is. As a result, Jan's bike is considerably more resilient against accidental lifting of the chair, while on the other hand having become more susceptible to tipping over in left turns. As always, there's no free lunch 😉
As a preliminary conclusion, I'm happy to admit that my understanding of Jan's take on riding a sidecar has considerably grown in the process. With what I initially called "personal preferences" apparently having a solid foundation in measurable differences in the properties of our individual rigs.
I have also gained some intelligence into the effects of these differences on the respective steering effort required. Which I am not disclosing just yet 8-p I think this has been a long lecture already.
In any case, thanks for your attention this far.
