OK fellas, the faster I ride the harder she pulls to the right, what gives...under thirty no pull at all, from 35 to 80 pull increases relative to speed. Tony
Typically it is too little lean out. Another thing can be flexing mounts.
Feel free to call Tony. I am home tonight.
you do know that is sorta what they do?
You can use the lean out to set it up to be fairly neutral at a given speed on a given road surface, but above that speed it will pull right and it will still tend to pull right under accelleration. Road camber will affect this too.
A wide rig will be more prone to this than a narrow one, particularly on a heavily cambered road.
Toe out or having the sidecar wheel leaned out will also cause it to pull right.
Vernon is correct of course. A rig needs to be setup for the road surfaces (road camber wise) that it will typically be running on and the speed it will typically be going. Softly sprung rigs that pitch and roll from side to side will be affected more than one with a stiffer suspension. This is why the various tilt adjusters on the market are popular as they allow the driver to compensate for different road cambers, going up a hill, wind forces, heavier loads in the sidecar etc. In other words they allow the compromise' to be narrowed with a simple on board adjustment. An anti swaybar will automatically compensate for these same effects up to a point. Some outfits are much more sensitive to road camber changes than others. I would assume , from my experience, that yours being a highly sprung GS with a russian sidecar on it would be affected quite a bit. In fact some of the dual sport rigs are pretty scary in left handers on the street. One notable and long established sidecar rigger will not even construt a dual sport rig due to this. I have done a fair amount of them usually GS (OILHEAD OR AIR HEAD) rigs but have also done a KLR 650 outfit and they can be made into nice runners on the pavement. You can also play with body english and hanging off which will make some difference. These gymnastics can get a little ridiculous and tiring if you are assulting the twisties though. On an oilhead GS/Ural rig recently tested after the addition of a swaybar I was able to break loose the front end or the rear on the pavement in left or right hand turns at will when riding hard and still maintain good predictable stability. The effects can be dramatic. Bottom line is that any rig should be setup to run straight and not be tiring under the conditions it will normally be run under. The addition of things such as a tilt adjuster or swaybar or both can make the road conditions less of a factor as the rig can be adjusted to suit or in the case of a swaybar will adjust itself to a certain degree.
Alright, I will set it up to track straight as possible for 90% of my riding (which is actually back and forth to work). And Claude, it won't be long before I touch base with you...Tony
Tony, you mentioned in another thread you centered the bike on a chalk line and used a straight edge on thesidecar wheeel to check your toe in. I never had much luck using this method.
Just for giggles, recheck your toe in using a straight edge against the bike's rear wheel too. You probably got a good measurement with your method, but it doesn't take much error to change toe in to toe out. Since you are having some handling issues it wouldn't hurt to recheck using a different method.
set up and alignment can be fussy work...
Another thought is to check the sidecar wheel fro runout. Like Vernon said a little makes a lot of difference when checking toe in. Maybe jack the wheel slightly off the ground and hold a screwdriver or something next to the side of it and spin it slowly to see how much run out you have. Then when you check the toe in mark the wheel some how so you can always meausre in the same place. That way you have a baseline to work from. Not perfect but a start. You did say you had a Dnepr right? 🙂
Damn, (oops sorry) I mean jeeze, you guys can come up with some good ideas...Thanks Red and Claude...I will try both suggestions.
Could part of the correction be as simple as folding down the windshield? Whether the windshield was up or down made a big diference on my R1100GS/Ural at higher speeds. I've now raked the steering (reduced the trail) so don't notice any pull under just about any condition...danny
Originally written by Danny on 12/17/2006 7:45 PM
Could part of the correction be as simple as folding down the windshield? Whether the windshield was up or down made a big diference on my R1100GS/Ural at higher speeds. I've now raked the steering (reduced the trail) so don't notice any pull under just about any condition...danny
Danny, Making the steering easier by reducing the trail is typically a good thing but it will not correct a problem of the setup being off. The only way to monitor setup is by keepng an eye on tire wear. Not saying yours is off just saying that easy steering and setup concerns are not all and the same in all cases.
The comment that the pull gets harder at faster speeds is the key to the problem.
The weight of the rig and the distance from the bike will have an affect during braking and accelleration but minimal at a constant speed.
First if you have proper toe set to correct for the amount of flex and slop in your bearings and frame it will not have any affect on your pull left or right.
Improper toe will have considerable affect on the tire wear.
Your rigs lean angle towards or away from the chair is how you adjust to track straight at a given speed. The lean required changes considerably as the speed and camber of the road changes.
The camber of the road is somewhat obvious as the amount of slope the rig is on will change the actual lean of the bike in relation to the road. The lean you are measuring is in relation to the road, not the chair. The camber of the road will not change the pull to right or left in relation to speed.
The wind resistance will vary considerably in relation to speed. The less aerodynamic rigs and wider rigs will be more affected then narrow sleek rigs.
The wider the rig the more leverage the wind resistance will have on the bikes effort to go straight.
The more you lean the bike away from the pull created by the sidecar, the harder the bike will try to go straight and correct for the side car.
The faster you go the more pronounced the wind resistance becomes, as resistance goes up as a square of speed. ( I know these numbers are not exact but illustrate the principle)
load factor (not a real number, you would need to know the frontal area, where the frontal area is positioned on the lever (sidecar frame) and other stuff about the rig to calculate this) but an example of squared numbers
20 mph x 20 mph = 400
30 mph x 30 mph = 900
40 mph x 40 mph = 1600
50 mph x 50 mph = 2500
60 mph x 60 mph = 3600
70 mph x 70 mph = 4900
as you see doubling the speed from 30mph to 60mph puts 4 times the wind load on the rig. A 20 mph increase from 50mph to 70mph also doubles the load.
Remember also, if the load is 2 ft from the bikes centerline, the wind resistance will be half what it would be a 4 ft from the centerline.
As you can gather from this it is near impossible to set leanout to be correct for all conditions. A shorter trail gas the affect of adding power steering so the pull is less noticeable at the handlebar, but does nothing to eliminate the pull. A variable leanout adjuster is the only way to set a rig up to compensate for pull at all speeds and camber.
This is not to suggest you have to have one, I don't on a wide russian sidecar with a lot of pull, I do however have what appears to the uninformed a considerable amount of lean so I can travel comfortably at 70 mph on the interstate.
Numbers are for illustration, and a scientific type can probably give more accurate numbers then my example, but the principles remain.
Good point pinsc...I've have her to where she just barely pulls to the right but the bike is definitely leaning again. Is there anyone who might be able to post a picture fo their bike from the rear? I know that every bike is diferent but I would like to see a few pictures just to compare to mine...Thanks, Tony
As I answered in your other post, Check Hack'ns Hacks in the Albums section for rear pix of sidecar rigs. you will find severalthere.
Lonnie
