Need some parts for sidecar project:

[HankPfister]

I'm building a sidecar rig with a 1984 R100RS. My problem is installing wider bars, they interfere with the RS fairing. I think I need a set of bar back risers. Anyone have an extra set? I have a set of RT bars, but I think a set of bars that are wider than RS bars, but not as high as RT bars would be good. Like maybe R100R Roadster bars? Or someone suggested K75C bars, but I don't know how wide they are.
I also need a lower ratio final drive, preferable one with the ribs on the side, from an R80. A 32/10 or 37/11.
You can check out my project here:
http://pfestus1.smugmug.com/gallery/412601

Thanks for any help!

[larrylarry75]

I'm building a sidecar rig with a 1984 R100RS. My problem is installing wider bars, they interfere with the RS fairing. I think I need a set of bar back risers. Anyone have an extra set? I have a set of RT bars, but I think a set of bars that are wider than RS bars, but not as high as RT bars would be good. Like maybe R100R Roadster bars? Or someone suggested K75C bars, but I don't know how wide they are.
I also need a lower ratio final drive, preferable one with the ribs on the side, from an R80. A 32/10 or 37/11.
You can check out my project here:
http://pfestus1.smugmug.com/gallery/412601

Thanks for any help!

Hank, You may want to send an email to my bud Gene Fitch, he's a sidecar nut and has several laying around in bits & pieces that he wants to find a new home for. I don't know what all he has but he's owned BMW's, currently pilots a Ural. His email address is cafeboy@verizon.net. Best, Larry

[pmdave]

I used some K75 bars on my R100/Ural rig. They are narrower, with good rise.

I suggest the 11/37 final drive ratio. Of course, changing the drive also changes the speedo ratio, so now you can brag about driving the outfit at "110 mph." I have several rear drives on the shelf, and if you can't find an 11/37 elsewhere, Email me.

I suggest you use a subframe for the sidecar attachment. Dauntless Motors in Covington WA can provide. Their subframe wraps around under the RH muffler and connects to the LH side of the frame for better lateral support.

I also suggest you add a cross tube to brace the frame. Those lower holes in the frame under the seat frame bolts provide a good place to attach a tube. I used a heavy wall SS tube, threaded to accept R100 clutch bolts. The tapered heads allow for some misalignment. You can either punch holes in your tool box, or remove it. I carved a slot in the box and glued in a U shaped piece of plastic so the toolbox can be removed without having to remove the cross brace.

pmdave

[pmdave]

Addenda:

You may be thinking of wider bars to get better leverage for steering, which is a good idea if you intend to keep the stock front end. Bars about 48" wide would be about right.

Or, if you want to run narrower bars that allow you to hang off either side in corners, better start thinking about a leading link to reduce steering effort.

And, if you haven't taken the Sidecar/Trike Education Program, I'd highly recommend you locate one before heading out on the street with your new rig.

pmdave

[HankPfister]

PM Dave,
All your advise is exactly what I would tell someone to do, and is in fact the exact tract I am taking. Check out my gallery on smug mug and see the subframe that Gary Haynes built. He also modified a set of EML leading links to fit. Gary is quite the sidecar subframe fabricator. He did an awsome job on my rig. He has a shop in Buchannon W. VA, the Sidecar Majic Shoppe, where he does custom sidecar mounting. And he is quite reasonable. His subframe cost about the same as I could have bought one from Dauntless.
I do anticipate that I will need to lower the final drive ratio. I have a 32/9 rear end on my R75/5/Dnepr rig and it does real well for the 750 (from a R50/5). If I return the /5 to solo duty, I may try that rear in this R100RS rig, but it might be too steep. I was thinking a 37/11 or a 32/10 would be good. My /5 rig has a subframe, and a modified triple tree set from Perry Bushong in Fort Worth TX. He builds sidecar rigs mostly on Airhead Beemers, with Russian hacks. His triple trees move the forks out about 1 3/4" to reduce trail. Works pretty good, look real good. Thanks for the input.
http://pfestus1.smugmug.com/gallery/412601
My R75/5/Dnepr:
http://pfestus1.smugmug.com/photos/43760268-S.jpg

[pmdave]

Gary knows what he's doing, and is the "other half" of Hack'd magazine, having moved back to Buckhannon WV.

The EML leading link looks very sturdy. IMHO, stronger and more flex-resistant than the Unit fork, and much, MUCH stronger than the old /2 "Earles" forks some folks think about converting from /2 to /7 duty.

I would suggest a target of about 0.75" trail for the R100. That will result in relatively easy steering (with the stock 19" front wheel) Stock trail on most airheads is about 3.75" An inexperienced sidecar driver would find such very short trail to be "twitchy", but it results in easy steering even with narrow bars.

If you can devise an adapter that will center a laser pointer in the hole in the bottom of the steering stem, it's easy to locate the center of the steering axis on the ground. A square positioned touching the inserted axle (on both sides then divide by half) will determine the center of the contact patch (behind the center of the steering axis) The difference is the resulting trail.

You can also run an 18" wheel on the front, with the LL. There is a wider variety of 18" tires around. A "rear" tire can be run on the front, mounted with the "drive" arrow pointing backward. Of course, spoking up an 18" rim requires a /6 "spoked" hub.

Given a choice, use Brembo calipers rather than ATE. EBC has semi-floating rotors that bolt right up to BMW hubs.

Ain't sidecars fun?

pmdave