Originally written by Stout on 2/2/2007 4:05 PM
I've been pondering how to address the ease with which the sidecar wheel comes up on my rig with my light passenger (apart from adding ballast - I'd rather make setup improvements first) and would also like to thank contributors to this thread - it has been most helpful. I think my rig is running considerably more lean out than required. I also think the chair could be lower and further out than it currently is - have been thinking these two for a while, but it was great to hear some more experienced thoughts on all this.Stout
What sidecar and bike do you have Stout?
The factory recomendation for my Dnepr MT-16 is zero lean out and 1/4 to 3/8 inches of toe in. Because of its full time two wheel drive, it has less lead than the MT-11, about 6", the lead is not adjustable.
With the driven/braked sidecar wheel, it doesn't pull one way or the other, when accelerating or braking and it seems immune to road camber.
I have a windshield on the sidecar, but not on the tug. A headwind just slows the rig down, it doesn't push it one way or another.
Of course it has a top speed of only 60 mph, maybe if it went faster, I would notice it pulling one way or another at speed.
Dave
It's interesting that you have a full-time two wheel drive. Does it have a differentlal in the drive unit?
Yes, it has a differential. It also has a rather elaborate system of two planetary gear boxes and a spring steel shaft to the sidecar to allow for sidecar wheel lead and adsorbing the shock of the hack wheel bouncing and grabbing for traction on rough surfaces. The driveshaft to the sidecar wheel turns in the opposite direction of the wheels at about twice the wheel speed.
Flying the car is a very temporary thing with the two wheel drive, when the hack wheel comes off the ground, all the torque is diverted to the wheel in the air, the rig slows and the wheel comes down.
Dave
Very good.
I read the recent article in Cycle World by Peter Egan about the trip he took with his wife in a Ural. It has a selectable 2WD but there is no differential. Therefore, he was advised by the distributor that he should only use the 2WD on soft ground, not on the pavement.
Your system sounds more sophisticated.
Thanks.
GNM109
THanks for posting this, Tod. This may be the clearest explanation i have seen yet. I am saving it to consider more thoughtfully and perhaps play with a bit.
"There are several factors not addressed in this thread that affect the amount of toe and lean required for a given rig and the effect that adjustments will have on the way a rig handles...(concise and astute observations snipped-read previous post by tkpinsc)"
Originally written by RedMenace on 2/4/2007 11:36 AM
THanks for posting this, Tod. This may be the clearest explanation i have seen yet. I am saving it to consider more thoughtfully and perhaps play with a bit."There are several factors not addressed in this thread that affect the amount of toe and lean required for a given rig and the effect that adjustments will have on the way a rig handles...(concise and astute observations snipped-read previous post by tkpinsc)"
Ditto Tod, good post and a lot of stuff to think on. YOU SHOUDL POST MORE OFTEN!
Claude,
I have a '77 BMW R100RS with a California Friendship II. I have uploaded a couple of images to my album on this site.
Stout
Originally written by Stout on 2/6/2007 4:23 PM
Claude,I have a '77 BMW R100RS with a California Friendship II. I have uploaded a couple of images to my album on this site.Stout
Stout, I had asked you what your rig was because you had concens of the wheel coming up easily. Looked at you pics, very very nice lookimg rig! What kind of track width are you running? This means from center of rear bike tire to center of sidecar tire. I like to run between 48 and 52 inches with the wider preferred. Never could see any advantage to a narrow track as it does nothig for satbility and also can make working on the biek a hassle, especially with an airhead. Another factor is sidecar wheel lead. On our personal outfits we usually run a little more lead than many. This adds stability in left handers for us. It will also allow the sidecar wheel to come up easier which was your complaint to begin with. Keep in mind that everything is a compromise and what is 'right' for you may not be for someone else. It depends on riding style etc. I typically run a lot of twisty roads and prefer to run a sidecar on the heavier side with more lead. This gives it a good stability factor in left handers and also makes it behave well in right handers due to weight alone. We sometimes run a swaybar as well which makes a ton of difference but that is another story. Ballast? Al ballast is is a way to make a sidecar that may be lighter than it shoudl be a litttle heavier. Witha good suspension on th ehack a 'ballasted sidecar' can actually run better than a sidecar that is the same weight. This is because th eplacement of added ballast can be where it will be to your advantage. This is to th erear and as close to the outside as possible. Never add ballast in the nose!! Some speak lowly of adding ballast and I cannot understand why. If th esidecar is too light for you make it heavier as long as the suspension can handle it of course. There are no bragging rights in be able to run a ligth sidecar over a heavy one if it is not handling well. Nothing macho about creeping arond right handers or having to be a world class gymnist to get through the twisties. All in all..widen the track width if possible...add balalst if needed..and practice a lot. Your rig should be a decen thandler in time after a little tweaking here and there. From that point it can always be made even better through suspension mods and maybe a swaybar. Hope this made some common sense. Others may think otherwise but that's okay. Let's go run some twisties :-)...........................................................Sorry that there are no paragraphs in my posts. For some reason they never show up on thsi site recently.
Tod
I appreciate your explanation of tracking before, during, and after the "head shake" period. It helps me grasp at some issues.
I have an complete EML Tourist T conversion on a '81 Wing, and the one thing that stills boggles me is rear drive tire wear. I have about 2* outward lean (loaded with 180# sand bags on the mule), which is very significant lean, but is an increase from my previous set ups. Toe in is about 3/4". One of the issues I'm concerned about is that my rear tire wears on the sidecar side of the tire. It seems a little less with the increased lean, but time will tell. I still don't understand, with even 1* outward lean, why the tire would wear on the sidecar side. Most of my miles are at highway speed, so I'm crabbing most of the time. I'd think the left side of the drive tire would wear faster than the sidecar side.
One issue I have in suspect is that my sidecar wheel has lean to it, lean away from the sidecar and mule. This might be an issue, but I'm not sure if/what it will do to the performance or tire wear. The sidecar wheel lean wouldn't be difficult to change, with some shims. My rig has two plates and six bolts on a plate where the sidecar suspension mounts to the sidecar frame - used for toe in adjustment. I can have tapered shims manufactured and placed between these plates. I'm not sure if this is a critical issue or not. It's suspect because logic says the sidecar wheel lean should contribute to pull to the right. Maybe my strange drive tire wear is effected by this, but I don't understand how.
I'm interested in any input on these issues.
Mike wrote:One issue I have in suspect is that my sidecar wheel has lean to it, lean away from the sidecar and mule. This might be an issue, but I'm not sure if/what it will do to the performance or tire wear. The sidecar wheel lean wouldn't be difficult to change, with some shims. My rig has two plates and six bolts on a plate where the sidecar suspension mounts to the sidecar frame - used for toe in adjustment. I can have tapered shims manufactured and placed between these plates. I'm not sure if this is a critical issue or not. It's suspect because logic says the sidecar wheel lean should contribute to pull to the right. Maybe my strange drive tire wear is effected by this, but I don't understand how.====================================================Sidecar wheel lean is very seldom mentioned bu tit can be an advantage or a disadvatage. The sidecar wheel should be vertical as a rule although leaning it in towars th esidecar at th etop can be advantageous. The only one I have seen mention it here has been Vernon Wade. I have built a couple of rigs and purposely leaned the sidecar wheel in slightly and ,yes, it does take pull away, allows less leanout to be run and you can reduce toe in a little more dependant upon the geometry of the sidecar swingarm and it's pivot. I may be wrong but if you were to make that wheel vertical or lean it in some I think you could run less toe in and less leanout than you have now. It probably will get rid or you rtire wear delima too. Don't hurt to try and at least on that EML you can do it without it being a major deal.
Claude,
According to my notes from some very rough measurements I made a while ago, the track of my rig is 46-47" and the sidecar wheel lead about 13". I haven't actually measured lean out yet, but believe it must be 3-5 degrees without me on the bike. I made a rough measurement with a square against the front tyre and found 0.5-0.75" difference between top and bottom (19" wheel) I only had a 2' long straight-edge handy at the time, but measured the toe-in as 0.25" over this length. It all tracks nice and straight with no adverse tyre wear in the 1500 miles I have done so far, but as I mentioned, it comes up a little too easily for my liking. I'm a fan of ballast and like to move weight from the bike to the sidecar wherever possible - I put a larger, SLA battery right over the sidecar wheel in my first rig and removed the one from the XS11 hack. I also used to carry 5 gallons of fuel in the trunk, which usually came in handy riding an XS11 with only a 4 gallon tank! I also already have a couple of gallons of water in the trunk of the Friendship II as an interim measure, but I'd like to get the basic geometry as good as it can be and I don't think this rig is there yet - I had already identified the width and height of the sidecar mounting position as areas for improvement, but had not realised the contribution lean out makes to lifting of the sidecar wheel until reading this thread. I have always thought (just from the feel of the rig as the wheel lifts) that sidecar suspension travel is part of my problem - it just seems to keep on pushing the bike up. I've therefore been following the sway bar discussions with interest for some time, but again, I want to sort the basics out first. I know you (and others) manufacture custom sway bar installations, but I'd be interested in where to get raw materials to do it myself if you wouldn't mind sharing this info - it can be tough trying to find stuff in a foreign country 😉 I'd also be interested in an indicative price to manufacture and ship a bar kit if I provided you the measurements - could you send me a PM with this please?
Appreciate the responses. Sometime in the next few days I'll snap a few images of the rig to record what how everything looked before I started making adjustments (to complement the detailed measurements I'll also be making) and I will post before / after shots in my album.
Stout
I'll give it a try Claude. It may be the html button in your settings
Joyce
Stout wrote:>><According to my notes from some very rough measurements I made a while ago, the track of my rig is 46-47" and the sidecar wheel lead about 13". I haven't actually measured lean out yet, but believe it must be 3-5 degrees without me on the bike...SNIP.... (I)had not realised the contribution lean out makes to lifting of the sidecar wheel until reading this thread.<<<
Stout, From what you wrote above I feel all of it is a contributor to a light feeling sidecar in right handers. No surprize that it tracks straight but that is not your main concern. I would suggest you widen the track width. I wrote previously that 48- 52" is typical for me when we set up a sidecar and that I lean toward the wider of the two. We have done wider ones than 52" also. To get an idea about what track width does for you hold a heavy object with one hand close to your chect and pick it up...easy right? Then hold it at arms length and pick it up...harder to do because of the leverage working against your efforts to lift it. Also, think of a sidecar rig if it had , say, a track width of 18", pretty absurd right. But it would be very unstable in both directions. Now think of one with a track width of 10 feet and the idea begins to make sense. Some HP sidecars are almost as wide as they are long.
13" of lead with the narrow width you have is also working against you in right handers. Good in lefties as it moves the so called tip over line forward but in right handers it allows the sidecar wheel to get light easier.
3 to 5 degrees of lean out is quite a bit too. If this is without you on the bike it is really a lot as when you get on the bike, the suspension will sag and the whole rig will tilt over to the bike side. This in essence creates even more leanout so to speak. Yes, lean out is definatley a consideration to instability in right turns. Think of it in a way as having the rig set up so it is already trying to pick up the sidecar wheel when standing still. Oversimplification? Probably, but who cares.
Overall I would do a re setup on the rig by first widening the track width. Then try it out and you will see some difference, maybe a lot. From there I would reduce leanout and add ballast if you want to.
A stiffer shock on the rear of the bike may be a benefit. If yours has high milage on it just replacing it with a stock one may help. Beemerboneyard is a good souce price wise. (Google them)
As a last thing possibly reduce wheel lead. You have a bike that is not real heavy and this sidecar shoudl work pretty good on it. Due that the rear of the bike does not carry a lot of weight itself I would try and get it working with the lead you have.
Due to the fender design on the California sidecars you will only be able to lower it so much and reatain clearance for wheel travel. It has been done and some have even converted them to a rigid suspension that allows one to set the body down onto the wheel very close. Does nothing for ride comfort though unless body is suspensded and then we are right back where we started in a way. We have converted soem of the California sidecars that had the small leaf torsion bar suspensions over to a real torsion bar with a manual tilt adjustor built in. This works well but isn't a real necessity to get the thing handling okay. Dauntless offers a conversion to a coil over shock deal that had a heim end supported and pivoted tube running across the sidecar with the shock mounted on the left of the body. I have no experience with this setup. Swaybars are a huge improvment on any rig. Quite a bit has been written here on the as you mentioned
I disabled HTML.
We will see what happens.
Thanks Joyce
Hi Mike.
My r100rt rig wears the same pattern on the tread. More and faster on metzler k-block then on the Avon sm. The wear is from the rig crabbing down the road. The sidecar side of the rear tire is the trailing edge if you think about how the rig travels. The wind pushing backwards on the sidecar pushes the rear of the bike outwards against the forward motion of the rig. The toe in on the sidecar also tries to bring the sidecar backwards to make the tire track forward. I think it is the trailing edge of a tire that takes the most wear, not sure. I mostly live with the residual wear, after striving to setup the rest of the rigs paramenters best I can. If the rig is properly setup, to reduce wear futher you need to lower the wind resistance of the sidecar, and/or move the center point of resistance closer to the bike by reducing the track width of the rig. Of course some would say that slowing down would help prolong tire wear, but that has never seemed like a viable option to me. I don't know how to make a significant change in the drag of a chosen chair, except to remove the windshield, and I prefer to reap the benefits of a wider track, even at the price of shorter tire life. If you look carefully at your tire you should see slivers of rubber kinda rolling off the edge that is showing the most wear. You should also see a mirror image of the wear, though less pronounced on the sidecar tire.
I run a slight inward lean to my sidecar wheel with the idea it will help track straight, similar to leanout on the bike. I think it helps more then excessive toe in, but not much, as the sidecar tire has less traction to work with then the bike's tires. I would get rid of any leanout on the sidecar wheel. Possibly aim at verticle when at rest, then when you climb on you will have a slight lean in as your weight is added to the bike. I trust 3/4" is over the length of the rig, and not the length of the wheel?
Any toe in excess of the minimum needed to take up slop in the bearings, mounts, suspension etc. to insure there is never toe out, is excessive and will contribute to tire wear in the pattern you describe. On an EML it should not take very much toe in as the EML rigs I've seen are all very stout and seem to have very little built in flex.
As I mentioned in the beginning different tires will wear markedly different with the same rig setups, so depending what you are using it might pay to try a different rear tire.
I think if I was to experiment I'd try to straighten up the sidecar wheel, and probably cut back a little on the toe-in and try it out.
