TheSamba.com :: View topic - Confused on setting up 3x3 trailing arms?

Fri Feb 11, 2005 1:56 pm

I'm new to VW Off-road, I've been reading my Baja and Buggies book, and how to build a buggy book, and of coarse reading the web. You would think I would find my answers, but I guess I'm hard headed. :oops:

I bought a desert car frame, it currently has some boxed trailing arms that need some serious welding. So I decided to rebuild the complete rear suspension. I currently have no transaxle, and looking to buy a 3 rib bus for the lower gearing. I then think "Well since I'm buying, maybe I should buy a built transaxle with a close ratio 2-3, a stock 4 (for overdrive), super diff, and what ever else to make it stronger and more reliable. The motor I plan on using should not put over 150 hp but no less than 100hp. I plan on running 3x3 arms, 31's, and 930s.

What I do not understand is what length cv axle do I need to accommodate the 3 inch wider arms, or do bus cv axles work? I assume I do not need any adapters to connect the 930s to the bus flanges.

When I buy my new arms, is there anything I should look for, I think eagle performance tubular arms are reasonably priced?

I also not sure what is the difference between a Type II and a 091 transaxle? Do I need to stay away from one or the other? or are they one in the same?

Basically, if you could build a suspension with a bus trans and 3x3 arms (with 31s) what is the best setup for suspension travel? And best gearing for the 31s?

Any thoughts would be greatly appreciated!

Koz

Fri Feb 11, 2005 2:29 pm

If you haven't yet bought your arms and stuff you might check out Vw parts unlimited. they sell everything you need to do a 3x3 conversion for about a grand. You will need to but a heim kit if you plan on converting to coilover though. and i don't believe the 930's will bolt to bus drive flanges so you will need to change them. they do come with the 3x3 kit though.

Fri Feb 11, 2005 3:22 pm

for 930 CVs and 3x3 arms i believe the axle lenght is 19.25"

you will need new stub axles with the 930 flange, and new drive flanges on your transaxle for the 930s

Eagle arms are expensive, but the quality is top. if you were looking for something more one a budget, you could get plate steel arms. Pacific Customs in Corona, CA is also looking into importing a tubular 3x3 arm in the near future. you could call them for more information

IRS Bus transaxles came in two models, the early 002 and the late 091 which is much stronger. for your horsepower needs, you could probably get away with a stock 002.

what exactly are you asking about suspension travel setup? could you be more specific?

Fri Feb 11, 2005 8:40 pm

with 3x3's you will use either t1,t2,thing, or 930 drive flanges and stubb axles, any will work but go with the 930s then you need the 930 cv's
these come in two flavors reg or clearanced for racing apps
the clearanced ones will allow for more travel

axles are 19 3/4 but you should check after you have installed your bus trans and make sure main thing is that you measure the shortest point between your stubb axles and your drive flanges through you travel range

as for your tranny
if you can get an 091 this is a solid tranny to use and when you wear it out you will have the core you need to get a built one (core is like 500)

just make sure ou get one that has nose or center shift not side shift

02 trans will work too but not as tough as the 091

travel will be determined on where you mount your trans and the cv's you use
say you fab a custom mount for your tranny so that the angle (top view) from the drive flange to the stubb axle is almost a straight line the you only have to work with the angle from the flange to stubb side view

what i mean by this is there are two angle when doing your axles

the angle from the flange DOWN to the stubb
and the angle from the flange BACK to the stubb
hope this makes sense

anyway these angle will determine you travel available as it will be limited by the maximum angles that your cv's will tolerate

Fri Feb 11, 2005 9:00 pm

are you sure on the 19 3/4" length for 930s, 3x3s, and a bus tranny, because i searched and found this post of mine from back in december:

HamburgerBrad wrote: i went out and checked my receipt. 19.25"

http://www.thesamba.com/vw/forum/viewtopic.php?p=593773&highlight=receipt#593773

Sun Feb 13, 2005 12:35 am

if you are using 930 cvs i doubt .500 would matter. have you noticed how much these cvs slide back ond forth on the axle?

Sun Feb 13, 2005 5:56 pm

Thanks guys, you ALL have answered my questions and I appreciate the help.

If I run 31 or 32s is there a recomended ring and pinion gear or is the 091 or 002 bus trans geared low enough?

I guess I don't understand why the bus trans is ok with 31s because the bus did not have 31 inch tall tires I assume? But then agian, it might be geared numerically higher for the weight?

I have read posts here that say the bus trans is good for 31's but I would like to have a closer 3rd and keep the 4th for an overdrive so I can still do 70mph on the freeway without high rpms. The desert car will mostly be used on forest roads and propbably never on the dunes.

If I go with a closer 3rd are there any recomendations for 3rd gear raito? or even an entire ring and pinion?

Sun Feb 13, 2005 7:46 pm

I cant specifically answer for the gear ratios because I havent't driven mine with the 002 installed yet, but dont forget that the busses were designed to carry alot of weight. When you have the same transmission pushing a lighter weight vehicle, it is much easier to turn those larger tires

Wed Feb 16, 2005 12:13 pm

I run a 002 with 31" tires and it is still pretty low geared, and it works well off road, but at freeway speeds the engine is turning 4000 RPM and makes for crappy mileage.