The Xt400 side car (winter project)

RAGBrian

New Member
Re: The Xt400 side car (winter project)

I'm in on this thread and watching for ideas. Good work so far!

phat fingered on my phone with Tapatalk
 

MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
So, while i'm looking for materials I might as well start planning some of the other stuff I need to figure out.
1) Chassis design,
2) What is the best way to figure out toe in. Should I make the chassis square and make the toe in out at the wheel or at the point where it attaches to the bike.
3) Since I am using a swing arm setup for the wheel/suspension, should I use both shocks or just one.
4) any ideas for a tub(body)? I would like something somewhat enclosed because my 3.5yo son will be riding in it from time to time.
Im sure i will think of other things but that is all I have for now.
 

crazypj

Split personality, I fake being smart
British bikes had a ball and socket type fitting around the swing arm pivot area and sliding joints on the swan neck and other mounting points.
May be easier to send PM to Erskine as he had to figure everything out (although I did point him in the right direction a few times)
 

Erskine

New Member
crazypj said:
May be easier to send PM to Erskine as he had to figure everything out (although I did point him in the right direction a few times)
Quite honestly, if I hadn't listened to the advice from yourself and Beachcomber I would not have the sweet handling bundle of fun that resulted! :) :)
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
MILLENNIUM FALCON said:
So, while i'm looking for materials I might as well start planning some of the other stuff I need to figure out.
1) Chassis design,

LIGHTWEIGHT AND SIMPLE RECTANGULAR SQUARE BOX SECTION WITH DIAGONAL BRACE WILL WORK - KISS. I'M ASSUMING THE WHOLE RIG WILL BE A FEATHERWEIGHT LIKE ERSKINE'S PLOT ?

2) What is the best way to figure out toe in. Should I make the chassis square and make the toe in out at the wheel or at the point where it attaches to the bike.

DUE TO YOUR ANGLE STEEL CONNECTOR [ VERY GOOD BTW ] AND THE FACT YOU'RE GOING WITH A SWING ARM, IT MAKES SOUND ENGINEERING SENSE TO MAKE ALL THE ADJUSTMENT AT THE WHEEL. MUCH SIMPLER AND EASIER TO ADJUST. KEEP THE SWING ARM AS SHORT AS POSSIBLE - EVEN THOUGH YOU MAY REQUIRE MORE SUSPENSION MOVEMENT THAN WITH A PURE ROAD MACHINE [ I'M ASSUMING THE ODD OFF ROAD EXCURSION ? ]

3) Since I am using a swing arm setup for the wheel/suspension, should I use both shocks or just one.

ONE SHOCK IS GOING TO BE MORE THAN ENOUGH ON SUCH A LIGHWEIGHT OUTFIT, BUT MAYBE FIT A HOOP BRACE AT THE WHEEL SPINDLE END - LIKE A LARGE MUDGUARD MOUNT - IN FACT IT COULD DOUBLE UP FOR JUST THAT.

4) any ideas for a tub(body)? I would like something somewhat enclosed because my 3.5yo son will be riding in it from time to time.

AS FAR AS DESIGN IS CONCERNED - THAT'S VERY SUBJECTIVE - HOWEVER, WITH YOUR MOST PRECIOUS CARGO RIDING IN THE CHAIR, I'D INSTALL SOME KIND OF INNER PROTECTION BY WAY OF A STEEL LOOP ACROSS THE LEG AREA AND ANOTHER BEHIND THE SEAT INCORPORATING A CAR TYPE ROLL BAR. MAYBE EVEN A BELT HARNESS. DOESN'T HAVE TO BE HUMUNGOUS IF IT'S SUITABLY BRACED.

AS YOU'RE LOOKING AT A SWING ARM MOUNT FOR THE CHAIR WHEEL, YOU COULD VERY EASILY INCORPORATE THE ADJUSTMENT FOR THE TOE.
 

MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
Here is a quick sketch. This was just an idea. Originally I was planning on using round tubing, but I think this would work too. What do you guys think. Beachcomber, is that kinda what you were thinking?
 

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MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
I was reading back through our Pm's but couldn't remember what you said would be a good track width. I think you said yours was around 1 meter, correct?

Erskine said:
Quite honestly, if I hadn't listened to the advice from yourself and Beachcomber I would not have the sweet handling bundle of fun that resulted! :) :)
 

crazypj

Split personality, I fake being smart
Wider is more stable
Do you intend to stay on tracks or go 'exploring'?
Narrower is better to get places but tends to tip over easier
 

MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
Most of the road/trails I will be on will be big enough for jeeps. So I would rather keep it more on the stable side. Especially for my first Hack.

crazypj said:
Wider is more stable
Do you intend to stay on tracks or go 'exploring'?
Narrower is better to get places but tends to tip over easier
 

crazypj

Split personality, I fake being smart
Leading link forks cope with side loading a lot better than tele's, plus, it allows you to adjust trail so it's easier to steer
 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
MILLENNIUM FALCON said:
Here is a quick sketch. This was just an idea. Originally I was planning on using round tubing, but I think this would work too. What do you guys think. Beachcomber, is that kinda what you were thinking?
Spooky - almost like you read my mind !!

Exactly so. I'd also add a diagonal brace from the main diagonal [ top right to lower left in the sketch ] at right angles and into the bottom r/h corner - that would give you a nice triangulation, and assist with spreading the load when the bike / chassis diagonals are added. Due to the weight of the outfit none of these members need to be Forth Bridge construction - the triangulation will give you the necessary strength. If you're not too familiar with force diagrams - think of the "flow" of forces as water through pipes. If the flow comes to a sudden halt or has to take two different paths - nitch gut. That becomes a point of high stress that isn't being radiated away.

That is a gross oversimplification of 12 months of my life as an engineering graduate - but serves the purpose.

In the car design game - I always made the structures a little on the heavy side on the prototypes and then trimmed down as and where for the production runs. Unlike Colin Chapman - who made everything lighter and smaller until it broke ! Sometimes with dire results for his drivers.

Ditto to the width and the leading links - although perversely on off road / light side G outfits, teles soak up the lumps and bumps - especially where more suspension travel is required
 

MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
Ok.....I finally got some work done on the bike. I built my hinge and made some pins. I got the main part of the frame built. I will be adding more to it once I figure out how I want to build the body. I set it up with 10" of lead and 38" track width. Does that seem about right? I mounted the swinger. I still need to fab up a swing arm brace/fender mount. and The shock mounts. It acts like a leaner right now since I dont have any struts on it yet. I rode it around the house like this................that was creepy feeling! I dont think I would like a leaner. I hope to get some more time to work on it this week.







 

beachcomber

TJ - Beachcomber
DTT SUPPORTER
I love watching stuff take shape - keep the pix coming. So far it's looking great.

I realise it's early days, but just a consideration [ you probably have this for the next phase of construction ] - you have a point of high stress where the swingarm mount member joins the main chassis "square".

At the very least it needs a couple of triangular brackets welded in to spread the load and / or a curved tubular member from the outside edge of the s/a member picking up on the parallel [ to bike ] member. Maybe that could tie in with whatever you're using for the top mount for the coil over.
 

Erskine

New Member
Bloody hell that's brilliant progress, really nice work, although I'd not have expected anything less from you :)
What track and toe in did you settle for?
Email to follow.
 

MILLENNIUM FALCON

Active Member
DTT BOTM WINNER
thanks guys! I have some more work to do to the chassis. I am going to add some bracing as I go. As far as track and toe.........Right now the car wheel has about 9.5" inches of lead which is around 13% of the bikes overall wheelbase. The track width is about 38" And when I run a straight edge across both of the the bike wheels and the car wheel, It is about 1/2" tighter at the front wheel, when compared to the rear wheel. The picture kinda makes it look like it is going the other way but the tape measure says otherwise. Do these number sound right? It wont be too hard to change things at this point. Is 38" wide enough? I was going to make it a little wider but i already thought it look way to wide for what I plan to do with the bike. But I still wanted it to have some stability. Erskine, I will respond to your email shortly. Thanks again.
 

Erskine

New Member
Hey, I'd say 38" is the absolute minimum width. Is that spokes to spokes? 40 - 42 would be preferable, because your bike is so tall, with the added height of a rider, you may be surprised by the leverage that will be exerted!
 

crazypj

Split personality, I fake being smart
It may well be worthwhile setting 'bike side' of swing arm pivot lower than 'outside' so wheel isn't vertical
 

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