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dumb question from newbie

hi folks.

I've ridden motorcycles most of my life and now am thinking about setting up a sidecar rig. I have absolutely no experience with sidecars so am turning to you for some advice.

I have acquired an Ariel Square Four and a CJ (Ural) sidecar which I hope I can pair. The SQ4 has 3 sidecar lugs, one near the steering head, another under the seat and a third by the rear axle.

My first question is regarding attachment. Do I need to look for mounting gear suitable for the motorcycle or for the sidecar. The hack has arms that originally attached it to a CJ sidecar. These have a clevis end. The lugs are circular and I'm assuming the adapter bolts through this? Any help greatly appreciated!

Welcome to the slightly off-center world of sidecars, Beez!

What part of the world are you in? Or in other words, are you planing a left side or right side mounting? As a general rule, you will want to use bike-specific mounts. Universal mounts fit nothing in the universe.

Am I reading this right, you are finding three attachment points on the bike, two up high and one down low? A typical three-point mount has two low and one up. The two low points should be equidistant from the ground then the bike is upright. I'm wondering if the "missing" low mount point was originally a bolt-on clamp of some sort.

A REAL expert should be along soon who can give you some solid advice specific to that sweet sweet SQ4 you have. As you can prolly tell by my user name, I love vintage bikes. Oh, and we love pictures here. You can upload them directly to this site or use one of the on-line picture storage services like PhotoBucket, ShutterFly, etc.

The fourth or "missing" mount point is usually a specialized long bolt in the front motor mount. Since I've only seen one Ariel Square Four, I'm not sure that this applies but it is a good bet.

I bet Al Olme is right

You will need a fourth lug somewhere down there, where the engine mount connects to the two downpipes under the engine.
Your frame is very soft there, so you might want to build a subframe to take this lug. This subframe should connect to both sides of the frame to allocate the force to more parts of the frame.
What I would possibly do is to make a sheet metal component of minimum .25" thick metal that is located to both sides of the front frame (on both side of the front motor mount, beeing bolted to the two upper mounting bolts and the lower one)
On the lower part of this construction I would weld a piece of strong pipe that would take the lug . (or better let the construction have eyelets to bolt the lug through with a piece of steel pipe as a spacer between the eyelets, it´s more flexible than a welded connection and doesn´t stress your frame as much)
Now you got to know that your rear axle and the sidecar axle should be appr. 11 to 12" apart (the sidecar axle should be that far in front of the rear axle). If your lugs will fit to that, fine. If not you´ll have to customize your sidecar frame a bit.
The toe-in should be around 1,57" measured on a lenght of 80", so it would be fine, if the lugs on the sidecar frame are adjustable to give the rig a correct setup. )If you do it the first time, the setup will not be satisfying at once, you´ll want to adjust over the first few months before you have found the right settings to be comfortable with, so adjustable lugs are essential in my opinon)

(sorry for my English, I dont´t use it enough and it starts to rust...)

On the early BMWs, there was one LONG bolt that supported the engine at the front/bottom. It tied into both sides of the frame lower hoops. The sidecar version of that bolt has a ball end that accepts the sidecar's "leaf collets" but there are LOTS of variations. That connection must be strong. If your Ariel is similar construction you won't need to modify the frame as the bolt already ties the two sides together and the engine makes a strong spacer. Your construction may differ, like I said, I've only seen one Square Four.

As to the toe in, Claus' suggestion is a good place to start but my experience is that each rig has it's own sweet spot for toe in. Measure the toe in the same way each time you adjust it and MAKE NOTES or witness marks on the adjusting pieces. The adjustment is usually done at the lower mounts from the bike and each time you move the lower mount you will also change your lean. At the end of the day, I find that the least amount of toe in that gives good tire wear and doesn't pull is best. Also, if your rig pulls to the curb, the first thing to adjust is the lean of the bike relative to the sidecar. Common practice is to have the bike lean slightly toward the sidecar when the rig is weighted as it will be driven. The easy way to do this is to load the sidecar, sit one the bike and have a friend secure adjustable straps [tie downs] to keep the springs compressed as they would be if you were on the bike. That lets you make adjustments as though you were riding.

Remember, all the advice you get here, including mine is just opinion. Some opinions are better than others and it's you job to sort out the wheat from the chaff. That's just my opinion, you'll hear others.

Good luck!

I'm slowly working things out...

Looks like I need to fabricate a front lower mount and a rear lower ball-end bolt. Attached are some images of the lugs and likely front mounting point. I think the SQ4 will be a good candidate for a chair. Plunger frame means added rigidity in the rear (no swing-arm). Looks like there is a mounting point off the two front engin plates. I'm guessing a strong bolt and a bush between the plates was how they went originally? Any further advice gladly accepted.

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