Project "4 wheel Street Bike"

[RoosterBooster]

... Should I assume that the red and blue parts are 2 separate pieces ? Are you going to use a press brake to fold them and then weld them together ?

I probably don't need to say this but, make jigs to verify critical location points. I would at least cut out 2 of each.

as drawn the spindle is actually made of 8 pieces with two spacer tubes (at the upper UB bolts)
and a block of 6061 T6 aluminum (at the lower bolts & the balljoint)

lots of welding, but with the holes in the plates i should be able to weld them mostly on the inside,
with only a small filet weld on the outside

i do have a friend that is in the Waterjet business (and is interested to get a copy of the buggy for himself),
so cutting the parts should be not a big problem.

yes, i plan on building jigs wherever needed
however, i also plan on several areas to be "self-jigging"
like the front clip for example;

high res; http://www.supermotors.net/getfile/1036769/original/spectre7.jpg

high res; http://www.supermotors.net/getfile/1036770/original/spectre8.jpg

high res; http://www.supermotors.net/getfile/1036771/original/spectre9.jpg

it looks more complicated then it is ;
with the WJ cut plates i have all the suspension, steering and shock mounts precisely located
(as well as the radiator & fan mounting holes)
perfectly square, no measuring, no errors

this way i can also get away with minimal adjustability ;
the A-arms will be jig welded with fixed PU bushings at the frame side
chamber will be the only adjustment (Heim joint at the spindle side of UCA)

 

[theoldwizard1]

as drawn the spindle is actually made of 8 pieces with two spacer tubes (at the upper UB bolts) and a block of 6061 T6 aluminum (at the lower bolts & the balljoint)

Green on the other drawing, correct ? Are you going to sleeve the hole for the ball joint stud ?

lots of welding, but with the holes in the plates i should be able to weld them mostly on the inside, with only a small filet weld on the outside

I wonder why it had that "Swiss cheese" look ! I would love to see some pictures of the pieces and as you weld it up.

 

[theoldwizard1]

it looks more complicated then it is ;
with the WJ cut plates i have all the suspension, steering and shock mounts precisely located (as well as the radiator & fan mounting holes)
perfectly square, no measuring, no errors

Make sure the inboard A-arm mount points (blue) are a lot stronger than the arms. Swapping arms is easy compared to replacing/re-aligning those mount points.

 

[AussieDan]

Very cool concept, subscribed!

 

[RoosterBooster]

Very cool build. I like the idea of the offset drive shaft to lower COG.

imho i just cant understand how you can build (or buy) something like this ;

yeah, the suspension travel is impressive considering the size restrictions
but man, would i hate to drive it the way i like to drive things

i was never a straight line guy ... imho turning hard is where the fun is

btw
offroad.com has still one of my old pictures posted in an article about handling;

thats me in the Muggy turning around on a sidehill
low CofG and a balanced weight distribution is very important to me

 

[RoosterBooster]

Green on the other drawing, correct ? Are you going to sleeve the hole for the ball joint stud ?

yes, the green part of the spindle is aluminum

there is no sleeve needed
the purpose of the aluminum block there is that it is easier to machine (and light weight)
i used aluminum blocks in that location before and know from experience (from some "awe s..t" moments ) that the BJ stud bends before the conical stud hole deforms/elongates

if you look closely you can see the aluminum BJ blocks on this camera rig i made some years ago;

on this car (and some others) i used Coleman "modular" circle track spindles
the only "problem" i ever had with them was that the aluminum block was bolted to the spindle in single shear
(with two 1/2" gr8 bolts)
after hard use (abuse) you could see marks in the aluminum from the bolts flexing

at the spindle for this (much lighter) project i`m going to solve that by clamping the block between the two main body sheetmetal parts,
what results in a double shear load on the bolts
(the two M12 bolts that also hold on the unit-bearing)

 

[bullnerd]

What's your preferred lower ball joint and what's the rack out of?

 

[RoosterBooster]

What's your preferred lower ball joint and what's the rack out of?

on the large cars i used the large Moog 727 as lower BJ and the smaller 772 for the upper arms.
on this light car i plan on using the 772 as lower BJ and a forged aluminum 3/4 high angle Heim as upper point

Howe and Afco make some very nice low friction precision BJ`s that are popular in circle track racing...

more $$$ , but the very low friction probably makes a noticeable difference on a light car

the steering rack is a standard circle track one
i have a Woodward like this ...

...laying around, but they all share the same mounting pattern
price of this Coleman rack is very interesting ;

http://www.colemanracing.com/Rack-And-Pinion-Heat-Treated-P4194.aspx
also available with square shaft (and even slightly cheaper);
http://www.colemanracing.com/Rack-And-Pinion-Square-Rack-P4066.aspx

great price for a strong rebuildable heat treated rack
and the available quick ratios are great
(iirc mine is a 2.25" per revolution what sounds about right for a light "non-powersteering" car)

 

[JoeFin]

Excellent thread guys - thanks for sharing

Just had a 1100cc Magna given to me - was thinking along these lines for a project

 

[bullnerd]

Thanks for the info Steph, that is a very good price for the rack.

I remember you saying you used the pinto/mustang spindles in the past, so I always keep an eye on stock car stuff.

Can you export DXF from 123 for your water jet stuff?
Can you import solids from manufacturers into 123, like McMaster or...? Like your balljoint / heims, etc..

I really need to learn how to use that program, looks really good for a freeware.

 

[RoosterBooster]

Thanks for the info Steph, that is a very good price for the rack.

I remember you saying you used the pinto/mustang spindles in the past, so I always keep an eye on stock car stuff.

Can you export DXF from 123 for your water jet stuff?
Can you import solids from manufacturers into 123, like McMaster or...? Like your balljoint / heims, etc..

I really need to learn how to use that program, looks really good for a freeware.

yeah, i got nothing but good things to say about all the Coleman products that i have used in the past.
that rack will beat the living **** out of any of the China buggy racks that you usually see in smaller buggies
(and on top of that all the replacement/wear parts are available individually)


to be honest i never checked if i can export in DXF or import any parts

i use the 3D mainly for modeling and "visualizing" ...
i actually plan to redraw the WJ parts in 2D anyway (i can take all the key measurements from the 3D drawing)

worked some more on the frame shape ;
(still missing a lot of parts)

high res; http://www.supermotors.net/getfile/1037002/original/spectre10.jpg

decided to go with large radius bends in the roof and rear side tubing
this allows me to get a lower (looking) roof ... kinda "coupe" style

high res; http://www.supermotors.net/getfile/1037003/original/spectre11.jpg

changed the exhaust to an oval muffler;
this way i can tuck it in lower next to the rear axle carrier ...
drops the CofG a minimal amount .... but every little bit counts

high res; http://www.supermotors.net/getfile/1037004/original/spectre12.jpg

instead of the previous more traditional frame with the added rollcage of the Austin concept i use bigger diameter tubing this time (but a lot less cross-bracing)
and arrange everything to form large triangles with the roll cage as an integral part of the structure.
to brake the body up into different looking panels i`m thinking to use a little trick;
the burnt orange panels are on top of the tubing (with the edges wrapped partially over the tubing)
the graphite panels are set in between the tubing.

 

[bullnerd]

Sounds good.

Looks like you need to tie in the lower front tubes?

Looks cool, I hope you can stick with it.

 

[RoosterBooster]

Sounds good.

Looks like you need to tie in the lower front tubes?

Looks cool, I hope you can stick with it.

yes, its still only a rough drawing
i need to tie in the front clip better and also work on the WJ cut plates that tie in the rear suspension points and diff carrier

btw here is how i plan to build the rear uprights;

high res; http://www.supermotors.net/getfile/1037036/original/spectre13.jpg

high res; http://www.supermotors.net/getfile/1037037/original/spectre14.jpg

again, a boxed structure made of fairly thin WJ cut plate.
found a brake disc that has the correct offset so that i can mount the light 2-piston DL calipers direct to ears on the outside plate.

lower H-arm will be fairly large diameter tubing to deal with the torsional load of the I&H-arm suspension.
front is a fixed PU bushing with the rear a "screw in" PU rod end to adjust toe
upper I-arm will be aluminum tubing with one forged aluminum Heim and one PU bushing rod end to adjust chamber.

i do like to use at least one PU bushing per arm;
it keeps things "quiet" (not like "metal to metal contact" Heim joints)
and i like the little "give" under extreme loads (takes away peak loads)

i just noticed that i may dont need to "lean in" the upper upright pivot point;
i did that for the narrow body Austin7S project to move the upper frame point closer to the body .... i probably dont need that on the wider body anymore
would make the upright a lot simpler to fabricate

 

[bullnerd]

"i just noticed that i may dont need to "lean in" the upper upright pivot point;
i did that for the narrow body Austin7S project to move the upper frame point closer to the body .... i probably dont need that on the wider body anymore
would make the upright a lot simpler to fabricate"

I was going to ask about that...until I read this, Ha.

 

[Bigplum]

Just a thought but would Mazda Miata or MX5 be a good source of parts?
, the front and rear subframes are nice and easy to remove and narrowing them would be a lot easier than figuring out mounting points

 

[RoosterBooster]

I was going to ask about that...until I read this, Ha.

lol
yeah... thats the problem when you take over existing drawings & details
sometimes you did things for a reason that is not relevant for the next project

anyway, i fixed the upright to straight sides and dont see a clearance problem;

high res; http://www.supermotors.net/getfile/1037045/original/spectre15.jpg

now the upright is stupid simple to build (sides can be made of strips of 1.5" flat stock)

the 17" rim in the drawing is the "street" setup,
but a 15" rim will clear as well
i plan on having a set of 15" beadlock wheels with Paddle tires for the dunes ...
actually i may even try a "desert explorer" tire for this project;

that tire seems to better tolerate short desert sections in between dunes then a full paddle ...
i intend to go to some more "mixed surface" areas with this rig

 

[RoosterBooster]

Just a thought but would Mazda Miata or MX5 be a good source of parts?
, the front and rear subframes are nice and easy to remove and narrowing them would be a lot easier than figuring out mounting points

Bigplum
yes and no

small and fairly light donor uprights would be interesting,
but the Locost and kitcar crowd wants them as well, so its hard to find them parts in a local pic-a-part yard
on the other hand there is no market for used 2002+ explorer front axles,
so they are easy & cheap to find

the rear upright is now so simple to fabricate that i gave up on the idea to look for an already made donor,
or mill them out of aluminum
the hollow steel box shape will be just as light as a solid block of aluminum

the front spindle is basically the same story ;
donor spindles usually dont have the geometry and/or the mounting points that i prefer.
by using Heim joints it is importand to me that the mounting points are double shear
milling that out of a solid block of aluminum is difficult & expensive,
so again the boxed hollow steel plate construction is kinda the most attractive DIY solution.

i do want to have the suspension and uprights kinda overbuild to take a fair amount of abuse
(compared to a "street only" rig) ...
however, not desert racing kinda abuse
i`m more of a Rally kinda guy ....
so when i talk about off-road you have to think "Ken Block" not "BJ Baldwin"

 

[holdmybeerandwatchthis]

The first thing I thought of when I read this post is the Legend Race Cars.

Check this site as a start, I don't know if it will help with your plans but everything has already been developed so might help you with some short cuts.

http://www.loosenuts.com/What-Is-a-Legends-Car-.html

 

[sac02]

... a "light" variation of the I- and H-arm IRS that i used on several other projects already.
i got it already drawn with all the pivot points established

Have you modeled that setup in a suspension kinematics program? If you have not, I have a WinGeo license and wouldn't mind inputting numbers to get you camber curves, etc. If you care about that kind of thing. (If you are building your own cars/buggies from scratch, I would assume that you would/should care).

 

[sac02]

I would use Heim Joints or thread rod ends for the inboard pivot points for simple toe-in adjustments.

Rod-ends are popular for their simplicity, but they are absolutely a weak point, with all those stress risers in the threads. I have seen several fail, not good.

For A-arms I strongly recommend a clevis at the end of the A-arms, with a shimable mount on the chassis/hub for strength/durability/light weight. It's a little easier to get away with/justify a rod-end on a toe link, because the loads are less, and the adjustments are more frequent.

 

[sac02]

instead of the previous more traditional frame with the added rollcage of the Austin concept i use bigger diameter tubing this time (but a lot less cross-bracing)
and arrange everything to form large triangles with the roll cage as an integral part of the structure.
to brake the body up into different looking panels i`m thinking to use a little trick;
the burnt orange panels are on top of the tubing (with the edges wrapped partially over the tubing)
the graphite panels are set in between the tubing.

Have you run the chassis through any sort of bending/torsion model? There are several "non-ideal" things going on in that chassis, from what I can see in the limited pics available. (Suspension pickups don't appear to be "nodes", bars attaching in the middle of straight runs of tubing, etc.)

I promise I'm not trying to **** on your project, lol. I think it's awesome - just trying to contribute and make it better!

 

[RoosterBooster]

Have you run the chassis through any sort of bending/torsion model? There are several "non-ideal" things going on in that chassis, from what I can see in the limited pics available. (Suspension pickups don't appear to be "nodes", bars attaching in the middle of straight runs of tubing, etc.)

I promise I'm not trying to **** on your project, lol. I think it's awesome - just trying to contribute and make it better!

sac02
for me there is absolutely no problem when you (or somebody else) is voicing his opinions

... especially when your right
the chassis is just a "visual" raw sketch right now.
i did not really have the time to go into details like supporting any node correctly etc.

"unfortunately" i will head out for a 2 week roadtrip to Colorado today ...
no computer/internet
so there will be no progress on the drawings for two weeks

 

[autolex]

You seen any of Dennis Palatov's designs? Specifically the "DP4"?

Check this out

And the main site here...

 

[RoosterBooster]

You seen any of Dennis Palatov's designs? Specifically the "DP4"?

Check this out

And the main site here...

yes, thank you .... somebody already posted the link

... what is/was a bad thing
ended up surfing Palatov`s site for a couple days
(reading all the build logs and starring at the drawings )

i dont really like the proportions of the stubby DP4, but the DP1 gives me all kinds of stupid ideas

(image/rendering found on dpcars.net)


hmmm....

i may change the direction of my project (again )
the side mounted engine is a very attractive idea to reduce WB & size (and ultimately weight)
of the complete car

however, i just dont see me messing around with full body, chains and AWD ...

my latest "concept" would be a open wheel /long travel design
and may use a shaft driven Bike engine driving a narrow Subaru R160 LSD rear differential/IRS ....

i`m thinking about FJR1300, GTR1400, V-Max (the V4 Vmax would be very interesting due to its narrower shape)
or similar "shaft drive" high torque touring bike engine tucked tight to the driver
(for a narrower body then the DP1)

what do you guys think about that

 

[bullnerd]

"what do you guys think about that "

I think you need to stop leaving me hanging for weeks at a time with no CAD fix!

V-max would be sweet!

 

[RoosterBooster]

"what do you guys think about that "

I think you need to stop leaving me hanging for weeks at a time with no CAD fix!

V-max would be sweet!

lol .... yeah, i think a touring bike engine would be better suited for a BEC
(lower HP but higher torque compared to sport bikes)
the monster torque of the 1700 cc V-max would be ideal
... but its not really a best seller, so it is probably hard to find a donor (wrecked) bike


while thinking about the layout of the drivetrain i discovered a major "problem" ;

bike engine shafts rotate to the wrong side
to be directly compatible to an automotive rearend

a standard rear end would need to be flipped 180 degree
to bring the ring gear to the bike compatible side
doable, but may results in oiling issues (mainly pinion bearings)

forced oiling (small oil pump) would be a possibility ...

awww.... what to do ???

 

[RoosterBooster]

hmmm....

thinking about flipping the Subaru R160 IFS diff carrier

here is a pic of the R160 carrier in the correct orientation;

...and here it is flipped over to reverse rotation;

i "think" the factory oil passages should be adequate to splash-lubricate the front bearings ...

ring gear would run on the weaker "heel" side, but i guess thats probably not a big problem with low bike engine displacement/torque

i still like the kinda "shifter cart" offset engine layout ....
the FJR 1300 engine would be a nice fit (narrow left side cylinder head for more knee room);

this could be a very compact car
(probably sub 80" wb and under 105" overall length)

heck, if i could keep it at 102" overall length i could load it sideways onto my truck

 

[bullnerd]

Yeah, engine availability could determine the design.

I have a pic somewhere of a guy from MBN that did a cool side engine, I'll see if I can find it.

I like the explorer axle more...but for no real reason.

 

[RoosterBooster]

found a Locost 7 replica with a FJR 1300 engine in it :

imho i just dont really like the proportions,
especially with a compact bike engine in it.
seating position is too far back for my taste and the WB & hood is way too long
(lots of wasted space)
and the lack of travel and a solid rear axle is definitely not suitable for the rough roads that i plan to hit

however, the comments of the owner about the first driving impressions give me hope that i`m on the right track with my BEC concept
here is a quote;

"The clutch will take a bit of getting used to, but contrary to what people have said about BEC's it is surprisingly driveable.
It didn't help that my knees were shaking! "

"Engine was great - never skipped a beat. Once I got used to the clutch it wasn't hard to drive.
No shortage of torque either.
It is hard to get anywhere close to the bike engine redline -
common sense makes you want to shift at 5K when really there is another 5K left to go!! "

 

[RoosterBooster]

I like the explorer axle more...but for no real reason.

right now i`m kinda looking into two different rear diff directions
one would be the offset type (single seat car ... but limited travel)
or the center mounted diff (probably two seat car with significant more rear travel)

if i continue on the shaft driven engine (what makes the most sense)
i would need to flip the rearends
the Explorer axle could not be used due its fixed mounting bosses,
but a Jeep Liberty axle (that is also a Dana "super 30") would work.
plus side is that there is a torsen true trac available for the Jeep D30

the Subaru R160 is very small & narrow;

what would result in a lot of possible rear wheel travel (probably an easy 16+ inch )
but used LSD ones are not as common (but several aftermarket LSD`s are available)
strength (when turning the "wrong" direction) as well as oiling of the loooong pinion shaft is maybe questionable

another very interesting diff would be the R200VLSD out of late 350Z/G35
its a viscose LSD that is inexpensive and easy to find (lots of them on e-bay)
the un-equal half shafts are interesting
(pinion/driveshaft would remain centered after flipping):

but probably heavier then the smaller R160 (larger housing & 200 mm ringgear compared to the 160 mm of the R160)

definitely overkill and probably bombproof behind a 1300 cc engine

 

[bullnerd]

I don't know how you know so much about whats available from stock autos?

What about a big turbo ,CVT, Snomo engine to the subi rear? No shifting!

Heres the pic from MBN. Onlyguy, I think his name is. Doesn't come around any more but was really slick, you'd like him. Did a nice conversion on a WRX trans to a bike engine.

Hope the pic works, not very good.

 

[Playwme]

What about MX5/ Miata diff? They're pretty small, reasonably strong, and should be plentiful.

I've got one I found at the dump. It's a pretty basic one so assuming it was leftover from an upgrade. Seems to spin ok. I've got a couple of Carbon Monoquoqe FSAE race car chassis' and a GSXR1000 motor for future projects.

 

[RoosterBooster]

I don't know how you know so much about whats available from stock autos?

What about a big turbo ,CVT, Snomo engine to the subi rear? No shifting!

Heres the pic from MBN. Onlyguy, I think his name is. Doesn't come around any more but was really slick, you'd like him. Did a nice conversion on a WRX trans to a bike engine.

Hope the pic works, not very good.

bull
i do hate CVT`s with a passion
one of the reasons why i play with the BEC idea is that i like manual sequential transmissions

What about MX5/ Miata diff? They're pretty small, reasonably strong, and should be plentiful.

I've got one I found at the dump. It's a pretty basic one so assuming it was leftover from an upgrade. Seems to spin ok. I've got a couple of Carbon Monoquoqe FSAE race car chassis' and a GSXR1000 motor for future projects.

yes, the miata would be interesting as well,
but gearing and availability (of LSD units) is maybe an issue.

i still try to wrap my head around the final gearing i would need in the axle to work with a shaft driven bike engine
but gut feeling tells me that i probably need something around 3-3.5 : 1
iirc miatas are mostly 4.10 : 1

i kinda lean towards the 350Z/G35 R200 differential, mainly for its price & availability
right now there are at least 10 3.5 :1 geared VLSD ones on e-gay at ~$400 each ....
that is a sensational cheap price for a complete LSD rear carrier.

i guesstimate the complete R200 (with half shafts) to be ~ 50-60 lbs heavier then a subaru R160 ....
but the subaru is only a "supplement" AWD diff (iirc torque split is only 35% to the rear)
the torque of a FJR1300/ ZG1400 could be too much for the inverted axle
(definitely if i happen to find a 1700 cc V-max engine)

so i probably rather compromise on a little extra weight then questionable strength

the R200 also has the advantage that the pinion is short and there is a "bolt on" flange:

with the rear inverted i should have room to may mount a ring gear & electric reverse to the pinion flange
(as well as a possible parking brake)

if i go this way i will probably blow my target weight ,
but most likely never have to worry about the diff, half-shaft or CV strength

 

[bullnerd]

"bull
i do hate CVT`s with a passion "

LOL, I hear ya'

I love the CVT in the Briggs, but I mostly use it in tight trails...no time to shift...just steer.

Sounds like a good option for a diff, like the bolt on flanges.

 

[RoosterBooster]

... Sounds like a good option for a diff, like the bolt on flanges.

but unfortunately the 350Z diff will not work

i finally found the gear ratios for the ZG and FJR;
ZG final drive gears are 32/10 (3.20:1), FJR are 33/9 (3.66:1)
each uses a 190/50ZR17 (26.5" tall) rear tire

so if i want to run something like 225/55ZR17 tires
i would need a shorter ratio then the iirc 3.56 of the 350Z
possible dune trips are an even bigger problem;
smallest paddle tire i can think of (that would work with my weight&HP) is a 28 x 15 x 14"
(~25.5" without counting the paddles)

i also need to gear the BEC shorter to compensate for the extra weight...
and i guess i dont need a 160+mph top speed

....


so i started looking again

Miata diffs are just too expensive (large demand for them)
and the housing/mounts are goofy (hard to invert)

but i think i found the perfect donor;
the high reving rotary RX 8
4.44 gears, many with factory LSD (iirc torsen, what i would prefer over visco)
and also fairly inexpensive @ under $300

the housing has a bunch of mounting points ...

... that could ease the fabricating of the electric reverse.
i also like the pronounced "sump" (the pic is of an inverted diff)
i think the sump will greatly aid in pinion splash-oiling in reverse rotation

 

[b-bop]

Love this thread Rooster, found you over here after seeing some of your posts on the HAMB. Damm you build some cool stuff. Found some new motor-vation for you instead of the V-Max which I have always loved. Kawasaki is coming out with a new H2R. 300 HP. I would guess with that kind of HP, there should be a couple donor bikes quite quickly as well as organ donors.

"With its supercharged, 998cc, inline four cylinder engine, the H2R will make 300 horsepower." As quoted by a bike magazine.

 

[nine4gmc]

Rooster, have you checked the "you pull" salvage yards around there? I used to frequent the ones here but it's been a few months since I was regular. There is all kinds of cars available with the rear diffs. Think Lexus LS400, SC300/400, BMW's, Mercedes, Chryslers, Suburu's etc. If you can narrow it down to a couple that would definitely work, I would not mind checking around here for you as well.

 

[RoosterBooster]

Love this thread Rooster, found you over here after seeing some of your posts on the HAMB. Damm you build some cool stuff. Found some new motor-vation for you instead of the V-Max which I have always loved. Kawasaki is coming out with a new H2R. 300 HP. I would guess with that kind of HP, there should be a couple donor bikes quite quickly as well as organ donors.

"With its supercharged, 998cc, inline four cylinder engine, the H2R will make 300 horsepower." As quoted by a bike magazine.

thank you

darn.... that H2R sounds interesting ... need to check it out

Rooster, have you checked the "you pull" salvage yards around there? I used to frequent the ones here but it's been a few months since I was regular. There is all kinds of cars available with the rear diffs. Think Lexus LS400, SC300/400, BMW's, Mercedes, Chryslers, Suburu's etc. If you can narrow it down to a couple that would definitely work, I would not mind checking around here for you as well.

nine4
yeah, i`m surfing e-gay mostly for comparing prices and demand/availability
this is intended as a low buck project, so i try to pulling parts myself
however, there are a couple already pulled RX8 LSD rear ends on e-bay for a price that is hard to beat
especially if you consider fuel, labor and pain of pulling the parts yourself

looked at a lot of pics yesterday
i think the RX8 rear is just about ideal (if only the housing would be aluminum)
the axles are non-symetrical so even when i invert the rear end i still end up with a centered pinion
(what is important for a small driveshaft tunnel)

the housing is fairly narrow and the one piece halfshaft/stub axles save space & weight
there seems to be a lot of possible wheel travel
the track dimension (59.3") is also perfect for my project

one seller listed the shipping weight as 35 kilo ... definitely not ultra light weight ...
but "peace of mind" compared to the lighter but considerably weaker Subaru rear



i had also some ideas for the uprights/knuckles
instead of re-inventing the wheel (aka fabing them myself) i probably also just dip into the OEM parts bin

there are several aluminum uprights that would be interesting,
like for example the T-bird irs knuckles;

or the Lincoln LS ones;

or the Mazda RX7 ones;

the RX7 would be a direct fit (but a little hard to find)
the others would require that i turn down the RX8 wheel hubs a little to fit
(RX8 hub OD is 1.7716, LS & T-bird bearing ID is 1.653")
but thats easy compared to building an upright from scratch

i guess i just need to make up my mind on what spindle to use
(each has it pros and cons on how the control arms and links are shaped & mounted)

 

[RoosterBooster]

guess the single seater idea is death

i actually gave up going the "super lightweight" direction anyway,
when i decided to make this thing "dual purpose" (street & mild offroad)

my target is now to make this a better "barbie jeep" ...er... UTV

looking at the RZR 1000 EPS Desert Edition ...
http://www.polaris.com/en-us/rzr-side-by-side/rzr-xp-1000-eps-desert-edition/specs
... i was surprised at how much the RZR grew in size and weight (and height ) over the older versions.
LxWxH is 123.5" x 64" x 76" with a WB of 90"
estimated dry weight of 1651lbs
so "only" a 1000 cc/110 hp engine does not sound overly exiting to me

re-drawing my concept to two seats and the transverse mounted FJR 1300/ ZG 1400 engine
i came up with the following dimensions;
LxWxH of 112" x 70" x 50" (in street trim with "only" 7.5" ground clearance)
WB would be 84" ... and i`m shooting for ~1200 lbs
engine output would be 145 hp and 99 ft-lb

for comparison i may add the 2014 Mini Cooper specs;
LxWxH is 146.6" x 66.3" x 54.4" and 98.2" WB
published curb weight is 2535 lbs
engine is a 1600 cc I-4 with 121 hp and 114 ft-lb torque

 

[wyo george]

In regards to the drive shaft rotation, both options are available depending on the bike. I've had three shaft drive Honda motorcycles and two of them had right drive while the other had left drive. You just gotta pick the right engine/transmission for your final drive. (or go the Subaru route)