Suspension tuning with a sidecar

Some years back I was privileged to attend an highly informative suspension clinic conducted by Dave Sallberg of the Honda Sport Touring Association. What I discovered was that sport bikes and grandpa rigs are entirely different critters. As a service to other three wheel road pilots, I will try to explain some of the fine points of tuning for maximum road handling ability.

Toe-in and lean are two critical issues in sidecar handling, followed by fork suspension travel and rear shock adjustment. All of these contribute to making the sidecar experience one of joy or one of sheer terror. In an effort to alleviate the latter, I offer the reader nearly 35 years of my experience in sidecar tuning.

Having the right tools is essential. Because alignment of the sidecar is so critical it is imperative that precise methods are used to set the toe-in. I have found that a well calibrated set of steel bed rails is the best device for taking initial measurements. If you have a spare set, that would be the best way to go. If you have to remove a set from one of your childrens beds, you will want to try to get them back before the evening which can make this whole process a little rushed. In fact, you probably just want to explain to your son or daughter that they will be sleeping on the floor for a few days.

As for calibrating the bed rails, you will want to make sure that they are straight and true within .001” over their entire length. If you know someone who has a coordinate measuring machine, that would be very helpful. If it is determined that your rails are out of tolerance, place one end in a vice and yank on the other end until you feel some give and then have it re-measured. You may have to do this a few times until you get everything into specification.

Next you will require a good box end wrench or crescent wrench for loosening the attachments between the cycle and sidecar. Be careful if using a crescent wrench so that you do not round over your nuts. Worse still, if the wrench slips completely, you could damage your nuts. Ouch!

It is not necessary that your measuring device has a metric scale if you are more comfortable with inch readings. This is personal preference. A calibrated, digital tape measure is recommended, but there are other alternatives. In a pinch you can tape together two yard sticks making sure that the mating ends are sanded square. Use duct tape if you can to join the two and make sure that you carefully re-mark the tape where you have covered up the scale markings. You may need the markings under the tape. You will want to have paper and pencil at hand to record the measurements you will be taking.

The place to begin this whole process is with some initial measurements. Your rig must be on a flat surface, i.e. the garage floor. Place one of your calibrated bed rails on the floor and against the front and rear wheel of the cycle. Take the other rail and place it against the sidecar wheel. Next, measure the distance between the two rails, first from the rail at the front wheel of the cycle and then between rails at the rear wheel. This is your toe-in dimension. I have found that 3/4”-1” of toe in is a good starting point. All rigs are different and each will be set to what is best on an individual basis.

Assuming that your toe-in measurement needs adjustment, you will have to loosen the struts that connect the sidecar to the bike. In my case, there are two fixed upper mounts and two ball and socket lower mounts. The lower mounts can be moved in or out as necessary and the upper mounts can be lengthened or shortened by screwing them in or out. You will probably find that each mount will have to be adjusted to get the proper setup.

A word of caution is due here. If you disconnect the upper struts in order to adjust the lower ones be careful that you do not lose control of the situation. Should the bike decide to fall inward you will be left looking at something akin to a folded up pita sandwich. Run quickly to the house and look in the mirror, you do not want to miss the expression on your face. This is the voice of experience speaking. If you have dumped your solo bike and had to lift it off of the pavement, you know that it can be a bit of a strain. Try lifting it back up with a sidecar attached and the sidecar wheel dragging against every effort you make. Better still get a ratchet type cargo strap and attach one end to the bike and the other end firmly to one side of the garage or other fixed point and start ratcheting. Do not remove the cargo strap until your upper and lower mounts are once again firmly attached, unless you enjoyed the previous experience.

Assuming that by this time you have set all of your attachments for toe-in, next you must consider lean. Ideally the cycle should lean away from the sidecar by about 1/4’. A carpenters square against the rear wheel is a good way to determine this measurement. Tighten all of your connecting hardware and proceed to a static test of spring compression. You will need a second person to help you here. Place yourself on the saddle while your partner stands behind you. No need for your friend to hang on to anything, you are not going to fall over, Duh! Your friend is there to visually determine whether you need heavier rear shocks or less ass. If it is a good friend, heavier springs will be recommended. You do not want your shocks to bottom out by virtue of your just sitting there. If that happens, I recommend a trip to your favorite cycle supply.

The front suspension may or may not have adjustments. Mine does not. If the front end feels like it wants to dive to the limits when you apply the brake and throw your weight forward, you may need new springs, you may not have any fork oil, or the oil may be of the wrong viscosity. Check the owners manual and head for your favorite cycle supply.

Now the moment of truth has come. After all of your efforts, a road trip is in order as a reward for your hard work. If everything is aligned perfectly your riding will be effortless. Fat chance! Did you really think that you would get it right on the first try? You may be experiencing a tendency for the rig to pull one way or the other. This makes riding very tiring as you constantly fight to keep tracking in a straight line. You will also eat up your rear tires at an alarming rate. You will have to return to the garage and tweak the alignment a bit more until you feel comfortable that the tracking is straight down the road. Ultimately, your tire wear will be a great indication of whether you have things right or not. The wear should be even across the width of the tire. If it is not, you will have to keep on tweaking the alignment. Eventually you will come to a compromise where you find that everything is as good as you can make it or you are just not willing to mess with it anymore.

The sidecar experience can be quite rewarding once these few minor adjustments are made. Just do not expect that once they are made they are permanent. Unfortunately things loosen up and move. You will know when that happens as your arms and shoulders begin to strain at the effort of keeping things on a straight line. Do not despair, by now you have gotten good at aligning your rig and you will certainly be the envy of all of your two wheel friends who constantly risk falling over at stop lights when they forget to put their foot down. Eventually you will make the decision to permanently weld your brackets in place so they cannot move.

2010 Schedule of events I will be present at.

My vendor schedule this year includes the following event: Please stop and visit with me if you can.

1. April 23-25, AMCA meet at Oley Pennsylvania.

2. June 11-13, AMCA meet at Rhinebeck New York.

3. July 16-18, AMCA meet at Wauseon, Ohio

4. Sept. 12-15, AMCA meet at Davenport, Iowa

5. October 6-9, AACA meet at Hershey Penn.

So you think you want a sidecar

So you think you want a sidecar
By: Jerry Hooker

Around thirty five years ago, I started looking at sidecars as a means of transporting my growing family. With a wife, an eight year old daughter and a one year old daughter, the solo BMW was definitely not “family” transportation. Not wishing to reduce my riding time, a sidecar made good sense in terms of total family enjoyment.

I began looking at sidecars in 1974 and had inquired about the Bender Florin which was being manufactured in Denmark. It was a remake of the original Bender’s made in the 1950s and used all of the original sheet metal dies and tooling.. It's suggested retail price of $942.50, was well beyond my means. In October of 1975 I received a letter from the manufacturer indicating that because of the soft sidecar market, a few units left in California were being sold at the attractive price of $ 630.00 each. I could not resist.

With the assurance that comes with ignorance, I looked at attaching my new sidecar to my trusty 1972 R75/5 BMW. I was able to purchase a sub-frame from a company in Iowa, called the Iowa Sidecar Company. The sub-frame has provided very stable attachment points for the sidecar. It's main purpose is to distribute the stresses to both sides of the frame to minimize any harm to the bike. It has worked well. The BMW seems to have been a good choice for the sidecar even though BMW no longer makes cycles for sidecar use, nor do they warrant them with a sidecar. With a stock steering damper, good front end control is maintained. I changed my rear shocks to Koni, with 150 lb. springs which have provided better suspension. I also replaced the fork springs with heavier ones.

I was totally ignorant about sidecars. I knew no one who owned one or had ever driven one. I was on my own. Learning to drive the rig was a long and often exasperating experience. I chewed up rear tires at the rate of about every 1000 miles. Alignment was all trial and error. I am now very comfortable that my alignment is as good as I can get it. I judge this by even tire wear, but mostly by straight tracking down the road. It is effortless. Handling is great on the straight-aways and cornering is extremely stable. I have found that alignment is all about compromise. There are many factors including whether there is a passenger, the surface and crest of the road and not to discount the torque of the Beemer engine which wants to pull everything slightly to the right. I usually ride solo so my setup favors that condition, but adding a passenger does not change things much, other than acceleration and gas mileage. Solo, I get 35-40 MPG. I haven't checked it with a passenger lately, but it has gone as low as 25 MPH fully loaded, in up and down terrain. I usually and easily cruise the expressways at 65-70 MPH.

Piloting a sidecar rig in the twisties is all work. There is no lean or effortless flow through the corners. The arms and shoulder muscles take a lot of abuse since it is all about steering the front end into the corners. The straight stretches of road are effortless often requiring only gentle pressure on the bars. The corners can get a bit frightening with a sidecar, but more than a few solo riders have also entered corners and had the fear put to them. Left hand turns are great since our friend, centrifugal force helps to keep the sidecar down and tracking through the turn. Right hand turns are an entirely different matter. If one’s speed is too great, the sidecar is likely to rise up precariously creating a condition know as the dirty underwear syndrome, which all new sidecarists experience. With a passenger or ballast in the sidecar the right hand turn lift effect is reduced, but not eliminated.

So why would anyone want a sidecar rig? From my own experience, I would like to offer the following pros and cons:

Hey this sidecar thing is great!

1. Very few people you know have one
2. Sidecars are as old as motorcycling and an integral part of it’s history.
3. You get lots of smiles and no one gives you the finger.
4. For the most part, even a poor rider does not fall over.
5. You don’t need bungee straps, just throw everything in the hack.
6. The sidecar provides great visibility unlike a solo machine.
7. When the wife gets bored, she can read a book.
8. If you ride a lot, you get good at changing tires.
9. In desperation you can sleep in the sidecar.
10. If the ladies don’t find you handsome, at least they will know you’re handy.

Hey this sidecar thing sucks!

1. Forget about leaning into the corners and feeling the rush as your knee scrapes the
pavement.
2. Don’t even think that you are going to squeeze into the smallest parking place.
3. There are times you definitely wish that you had a reverse gear.
4. How the heck are you going to fit a truck a car and the rig into the garage this
winter.
5. If you ride a lot, you change a lot of tires
6. If you have old fashioned drum brakes you need to start thinking about your next
stop after you leave your last.
7. What do you mean, the drive spline is worn out again, and the clutch is slipping?
8. It seems like I just stopped for gas and now I’m on reserve again.
9. When caught in a storm, can you say bathtub?
10. If the ladies think you’re handsome it’s a lie, they just want on your rig.