Leaner Sidecars – Minimal Modification Required
Why build a Leaner Sidecar?
Are there any issues with a Rigid Hack Sidecar combination?
The answer is yes. This article will address the Pros and Cons of a Leaner Sidecar and the benefits of building this combination rather than the more common Rigid Hack.
If you are not sure what a Rigid Hack is, then perhaps read Rigid Sidecars (Hacks) – Neither Sidecar or Motorcycle Lean first and return to this article.
Here is discussed the attachment of a sidecar to a motorcycle as a Leaner Sidecar Combination.
Leaner Sidecars are very unique and quite rare. This method of sidecar combination is very safe, due to the motorcycle counter-steering as designed by the manufacturer.
- Minimal Modification: No need for Leading Link modifications or Steering Damper.
- Safer cornering with counter steering
- Cannot accidentally “Fly the Chair”
- Experienced solo riders can easily ride a Flexible, Parallel or Leaner sidecar
- In many designs, easy removal of sidecar to allow solo riding
- In Width: In the case of a Leaner Sidecar, the sidecar must be mounted further away from motorcycle to allow for lean. This is not a disadvantage for the Flexible Sidecar
- Drivers of “Hacks” will need to re-learn to ride a leaner sidecar (counter steering)
Leaner Sidecar in Action
A demonstration of a beautiful BMW K1600 Sport Leaner Sidecar
Manufactures – Past and Present
Following is presented an explanation of leaner sidecars, manuals explaining the construction/attachment and links to past and present leaner sidecar manufacturers.
What makes leaner sidecars unique is that the sidecar remains straight while the motorcycle leans.
As pointed out above, this is the preferred method of attaching a wheelchair accessible sidecar to a motorcycle.
With this design, (unlike a Flexible Sidecar) we are able to keep the occupant close to the ground.
Leaner Sidecar Videos
Proof you can’t “Fly the Chair”
Watch a Leaner in Operation
Another Leaner in Action
A Clear Video of the Pivots
Thank you Shahn for posting this video on YouTube. This video provides a clear view of the Leaner Sidecar attachment and the raised Front Mount. To see photos of the bike and read about the build, look for Shahn’s comment on this page: https://haulnride.com/about-haul-n-ride#comment-79
Leaner Sidecar Manufacturers
Armec Sidewinder Leaner Sidecars
Below is a video of an Armec Sidewinder Leaner Sidecar.
Armec Sidewinder Sidecars are located in Switzerland.
Kalich Leaner Sidecars
Here is a clear video of a Kalich Leaner Sidecar in action.
More Kalich Leaner Videos: Click Here
Kalich is a manufacturer of Swing – a Leaner Sidecar in Germany.
Sauer Sidecars are located in Germany
Leaner Sidecar Attachment
The fore and aft Pivot Mounts on the motorcycle are to be placed on its center-line.
The front Pivot Mount is simply placed slightly higher than is that of the rear.
This then “steers” the sidecar wheel slightly as the motorcycle is steered to the left & right.
The front Horizontal Mounting Bar has a slight upward bend near the Pivot Mounting Point, while the rear one is straight.
Compare the slight difference in the height above the road between the front and rear Pivot Mounting Points on this BMW:
As the motorcycle leans the front Pivot Mount moves further outboard than does the rear Pivot Mount.
This will steer the sidecar wheel as the motorcycle is leaned over. The higher front Pivot Mount steers it in the direction of travel. Think of the arc the pivot points are traveling on as the bike is leaned in and out. The center of this arc is the ground. Claude
Source: Click Here
Please watch the following video for further understanding:
Photographic Examples of Sidecar Chassis, Horizontal Mounting Bars, Pivot Brackets and Pivots
Example 1 Sidecar Chassis, Pivot Bracket and Pivots
Example 2 Pivot Bracket and Pivots
The pivots need to be inline with the center-line of the bike so the load is directly down.
Otherwise, just like standing on one foot peg, a motorcycle is going to fall over. So to mount on one side of the motorcycle frame, you would be fighting that effect all the time while riding.
Having the front Pivot Mount higher than the rear Pivot Mount makes the sidecar turn/steer in the direction of the corner when you lean. As the front Pivot Mount being higher it has a longer arc radius than the rear Pivot Mount which pushes or pulls the front of the sidecar across more than the rear Pivot Mount does. Pete-NZ
Source: Click Here
Example 3 Pivot Bracket and Pivots
Armec Sidewinder Leaner Sidecar Measurements
Edwards, mentioned above, was kind enough to send in some measurements of the Pivot Points on his Armec Sidewinder Sidecar. Thank you Edwards 🙂
Rear Pivot Mount is 6.75 inches from the floor to the center of the bolt.
Front Pivot Mount is 10 inches from the floor to the center of the bolt.
Front Pivot Mount from a different angle.
Sidecar Wheel Lead
Sidecar wheel lead refers to the sidecar wheel hub being forward of the motorcycle rear axle. Average Wheel Lead is between 8 to 12 inches (200-300mm). To understand why Wheel Lead is important, imagine a sidecar/motorcycle combination without Wheel Lead, (the sidecar wheel hub is in line with the motorcycle rear axle),
Now imagine you take one of the front wheels off a car. If you turn too fast, or reduce speed suddenly, you will raise the rear wheel off the ground and nose dive the front of the car toward the ground, (on the missing wheel side). This is why Wheel Lead is important.
The more Wheel Lead is forward, the better weight distribution, the further toward the rear, the less scrubbing of tyres on turns. Therefore, Wheel Lead is placed slightly forward of the motorcycle rear wheel to find the best compromise between reducing scrubbing and safety.
Early Harley Davidson rigid hacks did not have wheel lead, whereas racing hacks designed for the track have very large wheel lead.
Extracted from the Sidecar Manual2003: http://www.cyclesidecar.com/pdfs/Sidecar Manual.PDF
Tow In Adjustment Guide
Image Source: Click Here
The sidecar wheel should be angled slightly toward the front of the motorcycle.
An incorrectly aligned sidecar will drag the motorcycle to either side, which will not only make the combination difficult to handle, but also cause excessive tire wear. Alignment is best accomplished on a smooth level floor.
Toe-in is checked by placing a straightedge along the motorcycle wheels and a straight edge along the sidecar wheel. This creates two parallel lines. The solid straight edges form a measurement line parallel to the center-line of the motorcycle and a measurement line parallel to the sidecar wheel.
The spacing between the straight edges at front and rear determine the toe-in. Measurement points are below the front and rear axles of the motorcycle. Take care to measure along a line perpendicular to the straight edge, and to keep both straight edges in contact with the tires.
Recommended toe-in is 3/8 inch (9.5 mm). That is, toe-in is correct when spacing between the two straight edges at the front axle is 3/8 inch (9.5 mm) less than that at the rear axle.
Again, this is only a starting point but will get you close. After this, it is trial and error to try to get the rig (motorcycle) so that it does not pull left or right when braking or accelerating. The process can be a little frustrating the first time, but some patience will go a long way. After the first time it will be much easier. Time spent aligning the sidecar is time well spent.
NOTE: When making toe-in adjustments, make corrections in small increments, then recheck. Very small adjustments in position of the Rear Pivot will have large results in toe-in.
CAUTION: Tighten all bolts securely.
Unlike a Hack (Rigid Sidecar), a Leaner Sidecar does not need Lean Out adjustment prior to road testing.
The true test of toe-in adjustment is the road test, preferably on a smooth, straight, level, paved road with typical camber slanting off towards the left (in Australia). At a steady speed of 40 mph (65,km/h), the motorcycle should not pull to either side while running at normal road speed.
Extracted from the Year 2000 Ural Repair Manual: http://www.sidecarafrica.co.za…
These pictures are an example of a replacement motorcycle stand on a Leaner Rig and Outfit.
Proposed Leaner Sidecar Project Steps
These Steps are a Guide only, Please Use Common Sense 🙂
1. Inspect Sidecar Welds If necessary, re-weld any messy welds on the sidecar chassis.
2 Locate the Lead and Clearance
To locate the Lead, place the sidecar wheel hub 8-12 inches (200-300mm) forward of the motorcycle rear wheel axle.
To locate mirror and handlebar clearance, place the motorcycle beside the sidecar. Using chain blocks, lower the bike towards the sidecar between 45 to 50 degree lean.
Rotate the handlebars to ensure there will be enough clearance.
3. Make Pivot Bracket (Shadow Frame) and Pivots
Use some tie downs to hold the motorcycle straight upright and use other tie downs to compress the motorcycle shockies to simulate a rider sitting on the motorcycle. This will give the correct distance between the road and the motorcycle lower frame.
Manufacture a Pivot Bracket to connect to the motorcycle frame.
Do not drill or weld the motorcycle frame if it is oil filled.
Attach Pivots to this Pivot Bracket. These Pivots will be located in the centreline of the bike, one to the rear, underneath the frame and the other slightly higher in front of engine as per the above examples.
The Pivots are to have a rotating bush or ball joint at one end to allow free rotation and a threaded rod on the other end to connect to the sidecar chassis allowing Tow In adjustment.
Place the rear and front of the motorcycle side of the sidecar on stands to ensure the sidecar is sitting level.
Pump the sidecar tyre to manufacturers recommended pressure.
Place 150kgs (to represent an electric wheelchair and occupant) into the sidecar to confirm correct shocky compression.
If after pumping up the shocky, it is not suitable to support this weight, replace the shocky.
5. Manufacture Leaner Horizontal Mounting Bars
Extend the sidecar chassis to create Leaner Horizontal Mounting Bars which will be used to attach to the Motorcycle Pivots. (Ensure the motorcycle stand will still operate and also check that you are still able to put your left foot down at stop signs without the Leaner Horizontal Mounting Bars getting in the way). Relocate the motorcycle stand if necessary. Refer example mentioned above.
The front Leaner Horizontal Mounting Bar will bend upward to reach the higher front Motorcycle Pivot.
The Leaner Horizontal Mounting Bars will have a nut welded on the motorcycle end. This will allow the Motorcycle Pivot’s threaded rod to adjust Tow In.
6. Install Brakes
Install the disc brake and assembly to the sidecar.
Connect motorcycle rear brake to the sidecar brake via a proportional valve.
Test brake operation.
7. Test Ride and Adjust Tow In
Test ride the Rig (motorcycle) and Outfit (sidecar) by counter steering the motorcycle.
Adjust Tow In as required.
Summary of the Problems with a Rigid Hack Sidecar Combination
- The need to convert the front end to Leading Link and add a Steering Damper (expensive and requires an engineer and modification approval)
- The danger of Flying the chair on a bend will steer you in a straight line until you can return the sidecar to the ground to regain steering control which could collide you with oncoming traffic (You would have to steer toward the oncoming vehicle to lower the chair)
- More effort to steer, I know because I steer my 650kg Rigid Hack (in comparison counter steering is effortless)
- Turning scrubs the sidecar tire (the sidecar tire does not steer)
- Tow-in and Lean-out are required to be adjusted every time the combination is separated and rejoined
Transport Authority Deny Approval of Leaner Sidecar
Unfortunately, I was denied the right to build a Wheelchair Accessible Sidecar and was only given the option to build a Rigid Hack. The decision to deny was based on overall width on Lean-Out. Although the maximum allowable width was 1850 mm, with full lean out, my mirror was outside this restriction, making a width of 2700.
Extract from the Modification Application
This could be solved by building a sidecar from the ground up, rather than converting an existing tub. A motorcycle tire on the sidecar would reduce width significantly, as a car tire and wheel guard add extra width.
Also, if the sidecar was fabricated closer to the ground and a non solid tub was selected, the motorbike could be mounted closer to the tub, without the left hand-grip hitting the tub.
The Leaner Sidecar Provides Solutions
- Effortless Counter Steering
- Sidecar tire steers with the motorbike
- No Leading Link or Steering Damper modification necessary
- Flying the chair is not possible
- Tow-in and Wheel Lead only needs to be setup once. Lean Out is not necessary
- Sidecar can easily be removed and replaced to allow solo riding with minimal adjustments on replacement
Share Your Project
Submit Your Leaner, Parallel or Flexible Sidecar Project: Visit the webpage below and leave a comment indicating you would like your project included on Haul N Ride. Other builders would love to see your project. 🙂
To take a look at more Homemade Leaner Sidecar Combinations and to Submit Your Project:
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Thank you for visiting Haul N Ride. Dave