Posted 4/19/2017 6:39 PM (#93176) Subject: Weight distribution
So I've been asking the wrong question, or researching the wrong info, I think.
Sidecar weight should be about 1/3 of bike weight, correct?
What should weight on sidecar wheel end up being? It seems I can get close in with the 1/3 thing, but be off by a lot on wheel weight compared to some of the Harley specs I've been seeing. How heavy are Harley cars considered? Should I shoot for that as a goal? I'm going to be using a different suspension with heavier components, but I could always add more. If I have a 150# car on a 550# bike, for instance, it's a little underweight but not too far. The Harley stuff I saw is getting about 18% of total rig weight on sidecar wheel. This case it would be about 125#. I my setup, I can fairly easily lift the sidecar with one hand. I haven't weighed it yet (it's off the bike for work right now) but I'm guessing it isn't over 75#.
This is a little different question from how much ballast to use, because this weight will be added to ballast, passenger, everything, this will be minimum empty weight, with load being considered after. I guess it would be the same as ballast if you never took it out. How bad would it be to add this sort of weight unsprung? I'm guessing it would be horrible, but sidecars defy all guessing.
Is this something I should even bother worrying about, presuming I ballast it correctly? I'll always have that extra 50# most likely then, I guess, even with a passenger.
Posted 4/19/2017 7:27 PM (#93177 - in reply to #93176) Subject: RE: Weight distribution
Posts: 1778 Location: Minneapolis, Minnesota
This subject will be a seminar session and group participation exercise at the national rally. We will have electronic scales at the rally so we can weight each bike and show the actual weight on each wheel, the percentages bike to sidecar and the total weight of the rig.
You can drive yourself nuts trying to match someone else's numbers. There are so many variables that you end up doing your own testing. The "ideal" would be to have more or less equal weight on each wheel but that almost never happens. Although I generally hate "rules of thumb" there's a pretty good test. Stand on the left peg with your right foot, that means that all your weight is outside the bike side tip over line. Grab the handle bars and give them a good jerk while you lean hard to the left. If the sidecar tire comes up off the ground really easy, it's too light. In an average situation you might get the wheel to come up a bit but then it will settle right back down.
About blast... I'm anti ballast for all but the most beginning riders. If you carry ballast, you come to depend on it and if you suddenly pick up a passenger or a load of stuff, the ballast starts working against you. I've heard folks say that you can't have too much weight in the sidecar. That's not really true. The more weight you have in the sidecar the greater the inertial energy it stores. A heavy sidecar will push to the left when you try to stop and pull to the right when you accelerate. In practice, we get used to these forces and compensating for them becomes second nature. When suddenly you either add or subtract a lot of weight from the sidecar the handling changes and it's easy to forget that your sidecar's inertial behavior will change as well. Also, consider the idea that while we say that rigs don't lean, in fact they do when the suspension is compressed or relaxed. Adding weight to your sidecar will change the attitude of the rig and directly effect your lean out and that may cause the rig to pull to the right or if you set lean with weight in the car and you take it out, it could push to the left.
About now some folks say that the whole thing is just too complex and we should just stick with two wheels. It's really not nearly as bad as it sounds. Drive your rig. If you have handling issues you'll know it and then you can take steps to correct them.
Search for post number 90225 and read it. It's probably the most important thing I've ever written here.
Of course that's just my opinion, you'll hear others.
Posted 4/19/2017 7:56 PM (#93178 - in reply to #93177) Subject: Re: Weight distribution
Posts: 477 Location: Michigan - Kalamazoo
The 1/3 rule is a good back of the envelope estimator kinda thing. It's not a hard and fast rule. Just know that the heavier the bike, the more counterweight you will need on turns. If an empty car is heavy enough or maybe wide enough, then you don't need to ballast much. Similarly, if you have to carry so much ballast that you can't take a passenger or cargo, then what's the point?
As a thought experiment, a Cozy sidecar paired with a Triumph Speed Triple is a bad idea. On the other end of the spectrum, a Jawa 250 with an Astro 2+2 isn't guna work either.
Posted 4/21/2017 12:54 AM (#93195 - in reply to #93178) Subject: Re: Weight distribution
Posts: 2498 Location: Middleburg, Pa
Ballast is nothing more than adding weight to a sidecar that seems too light. If the structure of the sidecar itself is up to the task there is no sin in this at all, especially if one is new to sidecars. It is , however, a good idea to oractice without ballast to allow you to get the feel of things better which will help to increase your skill level. One thing that is directly related to weight bias but not too often spoken of is the track width. A light sidecar may do okay on a larger bike if the mounting system is good and the structure of the sidecar itself is up to the task if it has a wide track width. Even a fairly heavy sidecar if mounted to narrow can lose stability, especially for a new sidecar jockey. There is a lot of talk about shifting your weight and hanging off and such. This is not a bad thing but it is sad when I hear someone say they cannot ride a rig because they ar enot able to shift their weight properly. That should never be a deterrent to riding a sidecar rig if it is a well balanced outfit. I hope that Al will do a demo on the scales of how much weight is actually gained by shifting one's weight toward the sidecar whether just leaning into teh turn or actually sliding your butt off the seat The old advice,so often 'preached' by Good friend Hal Kendall PhD and one of the founders of the USCA is still a good idea. That is if you go to ride a sidecar you are not familiar with to stand on the outside footpeg,wile sitting still, grab the bars and shift your weight
away from the sidecar. If the sidecar comes up really easy and stays up it is a light rig...proceed with caution! If it comes up with some effort and stays up it is not bad and if you have to struggle to get the sidecar off the ground it is very stable. These actions can happed with a heavey or lighter sidecar depending on track width as well as weight and it's distribution.
Posted 4/27/2017 12:43 PM (#93294 - in reply to #93195) Subject: Re: Weight distribution
Thanks guys! I get it, there is no hard & fast rule, but I'm glad you understood what I meant. I'm going to go find Al's post he referenced. When you say stand on the peg and lift- I think my sidecar might flip over! Time to look for a heavier car or a lighter bike... Wait, I have a lighter bike I just bought... Hmm... The daughter didn't REALLY need to learn to ride...
Posted 7/13/2017 9:24 AM (#94127 - in reply to #93442) Subject: Re: Weight distribution
Just remember- the whole point of the question, and the conclusion from this info, is that I probably need AT LEAST 70 pounds of ballast to get it to where it should be (empty). My car is too light, or maybe set too close. It's not a show stopper, but it does make for some exhilarating rides. Like the lady who missed me when I crossed the center line when the chair lifted on a moderate right curve. Or going up the expressway embankment at 75mph. Don't take out the ballast because you feel like it, take it out because you have the skills to handle it. And be careful! That thing might fly when you sneeze!
Is it normal to be able to do 70mph down the expressway flying the chair? I'm guessing most people can't really do that for very long, I can do it all day long if I don't get too tired. (And no, completely unrelated, I wasn't doing that when I was driving on the expressway grass.)
Posted 7/13/2017 8:49 PM (#94136 - in reply to #94127) Subject: Re: Weight distribution
Posts: 365 Location: Ohio
I am mounting velorex 562 on a bmw r75/5 for a friend. He weighs over 300 pounds.
I made a 1/4 " steel plate to mount under the body and installed a car battery in the
sidecar trunk. When I am finished we will see if additional ballast is needed.
Posted 7/14/2017 12:41 PM (#94138 - in reply to #93176) Subject: Re: Weight distribution
Posts: 63 Location: NoVA
I just stumbled on this thread - not sure where I've been sleeping of the last few months.
If you drift over to the Hack subforum on advrider you'll find some discussion of a rigs wheel weight distribution - probably also some discussion of car weight versus bike weight - and lots of opinions on ballast and weight shifting in turns. All probably good subjects for chat at Corning.
FWIW with regard to rig wheel weight, most folks on adv [me included] have found that, regardless of total rig weight, wheel weight distribution seems to be pretty constant at 50% rear. 30% front, and 20% car. I got those percentages on both my old rig [a DMC + R1200GS] and my new one [EML + R1200GS]. Can't remember the weights on the old rig but on my new one the figures held from 1100 lbs [just the rig, me, and daily load] to almost 1500 lbs [me, passenger, and fully loaded for long distance travel]. All those measurements were made on truck scales.
I'm really looking forward to getting the rig on Al's scales at Rally. I wonder how rig and suspension set-up affects stuff, and whether it matters.
I hope ccjon [and Al, Claude, and Klaus] is open to letting tech session repeat/run over from Friday to Saturday.
Posted 7/18/2017 8:46 AM (#94187 - in reply to #94182) Subject: Re: Weight distribution
Posts: 477 Location: Michigan - Kalamazoo
Once your rig is assembled, stand on the left footpeg with your right foot. Grab the handlebars with both hands. Now lean your body out to the left. If the car picks up "easily" then you should consider ballast.