Sidecar Design Formula - IMPORTANT!

[PPCLI-Jim]

Wow I am glad I am doing my research. I see I can buy a frame for 1200 US +shipping. but I am a fabricator so should be able to build one for less . But I need the info about how it will change the balance and steering of my bike. A DR 650 . with all the good stuff here I should be able to wade into this project with no real issues . If this goes ahead I will take pics,vids and post end results. if anyone has really good leads info I will accept all info in a PM onto the winter build season . but as I live in Victoria winter is more of an extended fall rain squall season.

[Kyler]

Originally Posted by PPCLI-Jim

Wow I am glad I am doing my research. I see I can buy a frame for 1200 US +shipping. but I am a fabricator so should be able to build one for less . But I need the info about how it will change the balance and steering of my bike. A DR 650 . with all the good stuff here I should be able to wade into this project with no real issues . If this goes ahead I will take pics,vids and post end results. if anyone has really good leads info I will accept all info in a PM onto the winter build season . but as I live in Victoria winter is more of an extended fall rain squall season.

read these threads

http://www.advrider.com/forums/showthread.php?t=571308

http://www.advrider.com/forums/showthread.php?t=691705

I'm at the end of a DR650 project myself - the above two threads were priceless and boxertwin is very helpful.

[dogtiredRAT]

Started reading, 5 pages in so far, it would be 2 pages if you took out all the shit fights...
Back to page 6.

[ANKOF]

it was discussed some earlier in the tread. how much lean in on the sc wheel is appropriate? is there any drawbacks?

[DavePave]

You want the side car wheel (tire) to toe in and the bike to lean out (away from the sidecar).

I have read that most people use about 3/4" of toe in and about 3 degrees of lean out.

FYI, I have a 57" wheel base and about 10" of wheel lead.

When I set mine up, that's what I started with. It was a great starting point. I ended up having to lean mine out more so it would track straight - maybe about 5 degrees. I also later adjusted mine to a little less toe in, but believe I will have to go back to about 3/4" as I now get a bit of wobble (head shake) where I did not previously.

The drawback with "lean in" on the bike is that it will always want to turn right - you'll end up fighting it.

The drawback with "toe out" is very unstable and dangerous steering. The bike wants to crab down the road.

Good luck!!!!!

If you are truly referring to sidecar wheel lean in - mine doesn't ave any. Those that I have seen, have no lean in. Though I have seen motocross bikes on line that have a huge amount of sidecar wheel lean in.

[ANKOF]

no I mean lean in on the sc wheel, found this on page 10 but but maby I missunderstod.

>>one trim setting that is largely ignored is chair wheel "camber". Lean-out is a camber adjustment to balance the drag of the chair. Chair wheel camber can help too. Chair wheel lean-in can reduce toe-in and lean-out requirements. With lean-out, the camber hurts turns into the chair, you would like to have lean-in. With chair wheel lean-in the driving and steering wheels are more upright for turns into the chair the lean-in is "good" camber for turns away from the chair.<<

[XL-erate]

I know you're new around here and I don't want to chase you off in any way. Unless you use the proper term of 'Camber' instead of 'Lean' nobody is going to know what you're talking about, because Lean isn't Camber and Camber isn't Lean. Proper terminology helps everybody including you and incorrect terminology can make a real mess of things. Of course it's not just you by any means! One of my pet peeves though...

I know that all these different terms can be real confusing and I'm just learning myself, so hang in there, it starts to make sense after awhile....

[ANKOF]

thanks for the comment. I mean negative camber on the sc wheel.

I normaly have problems expressing my sely clearly doing small talking with my wife. being clear about technical stuff in english to people on another continent is bound to be a problem.

[XL-erate]

Originally Posted by ANKOF

thanks for the comment. I mean negative camber on the sc wheel.

I normaly have problems expressing my sely clearly doing small talking with my wife. being clear about technical stuff in english to people on another continent is bound to be a problem.

Hey, wives don't count! I'm convinced they're not just from another continent, they're from a different planet.

Sorry if I sounded harsh. You have a good excuse but with some people it's just pure lazy, "You do my thinking for me, okay?" NO, it's NOT okay

Hope the best to you with your sidecar/hack adventures!

[YOUNZ]

I built my own sidecar from scratch and I decided a prerequisite was a fully adjustable sidecar suspension, camber and toe in. Not extremely difficult to implement and very advantageous.
Just attach the car fundamentally, set basic toe in and camber, road test, pull over, make quick adjustments, proceed.
No need to adjust the entire rig in order to track properly.

[XL-erate]

Originally Posted by YOUNZ

I built my own sidecar from scratch and I decided a prerequisite was a fully adjustable sidecar suspension, camber and toe in. Not extremely difficult to implement and very advantageous.
Just attach the car fundamentally, set basic toe in and camber, road test, pull over, make quick adjustments, proceed.
No need to adjust the entire rig in order to track properly.

Precisely what I have in mind! I cannot imagine any better way to do it, matter of fact. Also we have a great advantage in building it ourselves by knowing every nut & bolt and what they do! Hope the best for you in your build project!

Say, I don't suppose you have a running commentary of that build posted up anywhere? I'd be interested to see it, thanks!

[ANKOF]

yes YOUNZ, it would be interesting to see how you made it.

[Old Mule]

I like seeing design solutions and have been wondering, what is the effect of the great height of the off road sidecars I see on this board? The long suspension travel and high seating postion makes a high and variable c of g...
I've never ridden a modern off road sidecar, strictly a street driver. But I remember years ago I put some effort into lowering my machine. Just taking two inches out of the seat foam lowered the 175 pound rider's center of gravity. Only four inches of suspension travel on the bike and 2 inches on the sidecar wheel. A "vintage" machine, obviously.
When a rider and passenger sit on a modern high-clearance off road sidecar outfit that's realy high to begin with, doesn't that make for a overly high c-of-g and high polar moment of inertia?
Wouldn't handling and braking be better if the machines were much lower?

[DRONE]

Yes.

But a hole in your crankcase takes all the fun out of backcountry trips. Forces me when hanging off to try to get my butt down lower than the seat height.

What we really need is an adjustable on-the-fly air suspension that gives us 3" of clearance on pavement and 12" when off. They've got stuff like that don't they?

[claude]

Originally Posted by Old Mule

I like seeing design solutions and have been wondering, what is the effect of the great height of the off road sidecars I see on this board? The long suspension travel and high seating postion makes a high and variable c of g...
I've never ridden a modern off road sidecar, strictly a street driver. But I remember years ago I put some effort into lowering my machine. Just taking two inches out of the seat foam lowered the 175 pound rider's center of gravity. Only four inches of suspension travel on the bike and 2 inches on the sidecar wheel. A "vintage" machine, obviously.
When a rider and passenger sit on a modern high-clearance off road sidecar outfit that's realy high to begin with, doesn't that make for a overly high c-of-g and high polar moment of inertia?
Wouldn't handling and braking be better if the machines were much lower?

Yes handling would be best on most roads with a lower CoG no doubt. However, the adventure bike crowd wants ground clearance. How much is needed? For most conditions not as much as many have. However most want the ground clearance anyhow and that is fine. Everything is a compromise to some extent between road surface requirements, road surface handling and of course 'the look; that seems so important to many even if they seldom if ever go off road. It wasn't that long ago that world touring was done on /2's and such..Face it a corvette and a Jeep are good in certain elements and awful in others if pitted against one another.

With all of that being said the dual sport adventure type outfits can be made to scoot around pretty good on hard surfaces and still do okay off road. We have experimented with various suspension designs and feel that the anti swaybar is a great asset to any sidecar outfit but they really do shine on the adventure bike based outfits. They can be deactivated easily if one gets into th ereally harsh rocky type terrain but few ever actually unhook them.

Body english can go to a point too as Drone mentioned. I seldom do that myself too much and can get around quite well on hard surfaces, dirt or paved. Actually all it does is transfer some weight over to the inside of the turn and, as mentioned, it can lower the weight slightly too.