Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles Sidecar with bull neck frame

Sidecar with bull neck frame

Moderators: Curt!, Pa

Post Sun Apr 26, 2015 7:21 am

Posts: 161
Location: Radolfzell, Germany
Hi there

I'm running now my 46FL for a while with a sidecar and never was really happy how it behaves particularly at low speed. You need almost Arnold's arms to keep the biest on a straight line. Now the question. Did anyone out there try a rig with a bull neck frame and an inline frontend? Would that make a difference?

Thanks and best regards

Klaus

Post Sun Apr 26, 2015 4:11 pm
GuS

Posts: 368
Location: Bergen, Norway
Klaus.
46 i assume springer. Inline i assume one of the different springer setup with different trail?
Yes if this is reducing the frt wheel trail, it will help reducing the force needed to turn the handlebars on your sidecar rig. There are several important things that need to be correct if you shall have a reasonable and safe rig. In my view the side car toe in is more important than the frt wheel trail. You need to get this correct first. Side car wheel lean and trail compared with bikes rear wheel also play a role. Frt wheel Trail should be less than a solo rig. Very important to have a friction bolt through the steering neck when trail is reduced. Old sidecar outfit like the BMW R50/2 had one. A steerin damper will do the job. A sturdy fork is a must. Springer look cool and i love it on my solo bike. But it should never be fittet on on a sidecar rig. For a sunday trip all right. But thats your choice. But dont expect much if you stay with the springer. Earles fork like the said Beemer is the best. Hydra got one with an adjustabel steering head for sidecar use if you need to stay with factory parts.

How to install, adjust and test? Try this page.

http://www.sidecar.com

Good luck

GuS

Post Tue Apr 28, 2015 1:46 am

Posts: 161
Location: Radolfzell, Germany
Thanks Gus

Don't really want to change the front end since the bike is pretty much all original. Just wonder if Harley shipped their sidecar rigs in 1946-48) with the Standard offline Springer frontend or if they equipped them with the pre46 inline setup. No problem to get the Biest around a corner, my issue is more to keep the handelbar straight when going at lower speed (and yes, the steering damper is at Max)

Thanks
Klaus

Post Tue Apr 28, 2015 3:57 am
GuS

Posts: 368
Location: Bergen, Norway
Klaus, I see your point.
If you can adjust the sidecar toe-in, there is a lot to gain. Straightedge along the front and back wheel and a straightedge along the sidecar wheel will tell you the toe in.
GuS

Post Tue Apr 28, 2015 1:04 pm

Posts: 3134
Location: Central Illinois, USA
Klaus!

You might try running minimal tire pressures.
Mine wanders everywhere if close to solo specs.

.....Cotten

Post Wed Apr 29, 2015 11:44 am

Posts: 161
Location: Radolfzell, Germany
Thanks Guys

Tried all. I measured the toe-in yesterday and both wheels (bike and sidecar) are exactly parallel ... anyway, I wouldn't see how I can adjust it.

Best
Klaus

Post Wed Apr 29, 2015 12:44 pm

Posts: 2687
Location: Los Angeles, CA
BAVARIAN_KNUCKLE wrote:
I wouldn't see how I can adjust it.

Best
Klaus



Read the book. It really isn't Toe In. It is having the top of the wheel further from the bike than the bottom. Done by adjusting the frame brace. 2 degrees is the suggested amount.

Post Wed Apr 29, 2015 2:40 pm

Posts: 3134
Location: Central Illinois, USA
Klaus!

Actually "lean" is different from "toe-in", I think; Chris refers to how the bike and hack wheels should be straight up and down when the machine is fully loaded. So when empty, the hack and bike lean away from each other an arbitrary couple o' degrees.

Adjustment occurs at the two 'pillow' clamps upon the beam that bends up to the headstock mount.
Chokeing up closer to the bike increases toe-in. Of course, the other mounts need attention at the same time.

Onc't I spaced out at the rear with a compliant mount, only because I only had a spare late assembly when I needed a round swingarm mount.
It worked;
It worked well.
And it wasn't even PEEK.

....Cotten

Post Thu Apr 30, 2015 10:48 am

Posts: 2687
Location: Los Angeles, CA
Most sidecar newbies make the mistake of bolting the rear mount directly to the frame. When properly mounted there are nuts between the mount and the frame.

Post Thu Apr 30, 2015 11:39 pm
GuS

Posts: 368
Location: Bergen, Norway
Sidecar wheel lead.
This you can not do anything with without rebuilding all the fasteners. I suspect you have close to zero. Sidecar wheel some 5-10 inches ahead of the rear wheel improves handling, easier to turn and safer. If you have close to zero, please be aware that hard left turns and loaded sidecar can surprise you by the whole rig flips over the line between bikes frt wheel and sidecar wheel.

Bike lean.
This is dufferent from who you ask. Some say lean the bike a couple of degree out from vertical. Ive tried both veratical and lean out. Doesnt make much difference. I got my rig set up with no lean

Sidecar wheel lean.
This is built in an cant be adjusted. Different manufacturer claim different effect. My Watsonian rig had a terrible lean out. I first thought the frame was deformed. Finally called watsonian who told in the old days the QC was sloppy and it was suppoed to be vertical. I used re-brazed the mount to a vertical wheel position. No different in handling, but it looked much better. Before it looked as if the wheel was about to fall off.

Toe in
Staight edge as you have done. If using wood planks please flip them over to check if they are truly straigt.
Both the staightedge along the bike and the one along the sidecar wheel should be the length of the bike. Measurement between the staightedges in front shoul be +/- 1 inch shorter than the rear. This you must adjust by testin. You staded 0. This is no good. Here you have to figure out a way to adjust. Chimming, longer bolts, clamps etc. Please be aware what you may believe is an original part may have been modified by somone sometime. The fixtures were made to be adjustable.
Testing is the way to go. When driving in 50 kmph and steady increasung speed to 80 kmph wih a person in your sidecar without havig to wrestle you are there. Acid test is a longer trip with a passenger and your arms feel all right afterwards. On my rig i ended with 25-30mm toe in.

Front wheel trail
Measure through the steering head. Compare with vertcal point from front wheel axel. Solo riding 1-2,5 inch behind steering head line. Sidecar ridig close to zero. Going straight makes no different. If you arm hurts and you have to wrestle, it's the toe-in thats wrong. But a close to zero lead may lead to crazy wobbling and you need a steering damper. Making turns, sharp curves and rounding corners is far easier with less trail. So if your arm hurts because you have a loaded sidecar and are fighting city traffic turning corners you shuold be looking to do something with the fork/frame.

But first you need to get the toe in corrected

GuS

Post Fri May 01, 2015 12:37 am
GuS

Posts: 368
Location: Bergen, Norway
Klaus.
If possible you could also play with the lean out an see if it helps you.
It didnt help me, but your rig is different and it might help you.

God luck.
GuS

Post Fri May 01, 2015 5:49 pm

Posts: 2687
Location: Los Angeles, CA
Notice the nuts between the sidecar mount and the frame.
Image

Post Wed May 06, 2015 12:16 am

Posts: 161
Location: Radolfzell, Germany
Thanks Chris for the photo. Exactly the way my rear mounting braked is fixed to the frame.


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