ST2 LT In Progress - Help me overcome its flaws :)

[Daniel Dk]

Hi Guys

I've finally started my build of a Badlands ST2 LT. I know it is not the best buggy but as far as i can see it is more suited for a complete noob like me

I will try and document my progress as i go along. Unfortunately i can only spare one day a week for this project so prgress may be slow .

A little about me: I'm 26 and work as a Systems Administrator in a hosting company. I amsomewhat mechanically inclined (sp?) But I have NO experience in building buggies so please be patient with me if i don't get this metal working stuff right away. oh and Please excuse my poor spelling as English is not my first language

As far as i can read on this forum, the ST2 have some weakneses. in particular the rear drive and the lower front a-arm. So i've been researching different solutions and i think i may have come up with something but, i definately need you guys approval..

I'm building my frame out of 35mm tubing with a 2mm wall thickness. Oh yeah i'm in metric-land Denmark Scandinavia so thats 1.38 inch diameter tubing .0788 wall for you guys suspension and other high stress areas are 2.5mm (.0985") wall.


i think is coming along pretty nicely and im getting ready to get my plates cnc-cut.. i drew em all in autocad (which was another first for me) . The file is attached in this post....


After 6 daysO'work this is my progress:


As you can see i've beefed up the leading edge of the lower a-arm and made them 100 mm (4") longer to give me a bit more travel and to keep the front end wider than the rear. i've also put in 1½ degree of rake? so the wheels moves a little backwards when the suspension goes up.


As for the rear drive, I've drawn something up in solidworks (again a first - be gentle that may work but let me know what you think. Because theres not enough room between the seat and the rear arms the engine has to me mounted higher and with a jackshaft. I've hinged the plates for the main bearings and the jackshaft off axis so they may be used to tighten the chain. Anyhow heres here's a screenshot:

















UPDATE 14. april 2009:

Did a little more on the Cart

Heres the rear drive:



Mounted the caliper(used one of the front calipers from the suzuki sv1000), disk, and sprocket in the box:


added bushings and a-rms all the way around :


I need to make the rear a-arms longer.. the buggy looks a little wierd with such a narrow rear axle. These a-arms are made to fit the driveshafts from the porsche 924 - i need longer driveshafts and a-arms but i need to find a source...

[TrollBro]

Howdy Daniel,
The buggy's looking good. I am also ready to start building an ST2LT for my son as soon as we finish refurbing his FL350. I've attached the plate kit CAD file that I received from Bruce at Badlands. Keep up the good work and keep us posted, I'll be watching intently for your innovations.
Larry

[Daniel Dk]

Hi Larry

I didn't know they were willingly giving them out had i know i would propably have modified theirs insted of drawing every thing from scratch

[crazyawesome]

looks like you have a good start. Your doing a fine job, For not knowing this " metal working stuff ". Keep up the good work...

[Gene]

Welcome to MBN!

The lower A-arm appears as though it will creat negative spindle inclination because the lower are seems shorter than the upper arm.

Play with this suspension calulato to see the effect of arm length and mounting points at the frame and spindle. Try to get negative camber change throughout suspension cycle. Try minus 1 to 2 at full droop and minus 1 to 2 at full bump. If it gets to zero as it swings up or down it whold be all right. Positive camber is not good.

Racing Aspirations - a Formula 750 constructors diary (Fiat FIRE 1108) - Suspension Geometry Calculator

[plkracer]

A simple rule..... A shorter upper arm induces negative camber during droop. Closer mounting points at the frame induce negative camber on compression. When you mount them close though, you will induce positive camber on full droop unless your static camber is extreme at normal ride height. Because of this, you need to shorten the upper arm to cancel that effect. Just for reference, the upper arm on my barracuda is almost 5 inches shorter than the bottom arm.

[Daniel Dk]

Originally Posted by Gene

Welcome to MBN!

The lower A-arm appears as though it will creat negative spindle inclination because the lower are seems shorter than the upper arm.

Play with this suspension calulato to see the effect of arm length and mounting points at the frame and spindle. Try to get negative camber change throughout suspension cycle. Try minus 1 to 2 at full droop and minus 1 to 2 at full bump. If it gets to zero as it swings up or down it whold be all right. Positive camber is not good.

Racing Aspirations - a Formula 750 constructors diary (Fiat FIRE 1108) - Suspension Geometry Calculator

Hi Gene


Thanks for the link! i've put in the measurements for the front suspension ( well i've shortned them both by 4 inches (100mm) cause they wouldnt fit in the window. heres a link with my settings :linky

As you can see from link, the upper a arm is actually 2" shorter than the lower.

[daaboots]

Looks great so far!

[Daniel Dk]

Whee the postman came bearing gifts - pun intended

SKF-PF90, PF52 to be exact. Seen here with a CV-cup from a vw golf II - (mentos butted in for the photoop)



The CV-cups from the VW jetta, Golf ,and some buses fits the Type 4 cv joints. CV Joints 101
And they are stubless with 33 internal splines, making for easy (dis)assembly.I'm gonna use a cut-down 33 spline driveshaft from a porsche 924 as the center drive shaft. It will hold in each CV cup with a circlip and groove cut into the splines.

a close-up of the cup:




:cheers:
oh and thanks for the kind remarks!

[ErwinBnl]

Looking very nice!
I'm also planning to build an ST2 Long Travel too... And i am also an noob at Buggy's..
I'm an ICT student

Very nice that you live 'near by'.. I'm from The Netherlands. Here we also use the metric system so it's very handy! I allready calculated the sizes of the tubing into metric but haven't ordered it yet.
Good that you use 35mm tube with an thickness of 2mm. I'm gonna order that too.

Good luck with your build! I will follow this topic and hopefully start my own very soon!

Erwin