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Mon Jan 12, 2015 4:50 pm

Hey guys! I'm hoping I can get some help with my trailing arm project. I've gone to a larger arm for more travel but I'm not sure where to mount the shocks. For that matter I'm totally lost in the whole matter of deciding what length shocks to get etc. any help would be appreciated. Thanks.

Mon Jan 12, 2015 10:59 pm

From what I see you have no IRS torsion housing. This means you are going to have to use coilovers. If you want to know the shock length measure full droop and full compression. The shocks should be at a 90 degree angle at full compression I believe. Hope this helps.

Tue Jan 13, 2015 8:23 am

And be sure to use a double shear bracket for the coilovers. They transmit way more force to the frame than a traditional torsion housing setup.

Tue Jan 13, 2015 5:14 pm

It looks like you are going to need to add more tubing to the chassis to support the top of the shock.
It would be nice to see more pictures of your chassis and what you had on there before.
Does part of the chassis extend towards the back of the engine?
A 12in travel shock is approx. 31in long extended and 19in compressed. Is there a place to mount that length of shock on the chassis?
How much travel you can get out of the rear suspension will depend on what kind of CV joints you are going to use.

Wed Jan 14, 2015 8:56 am

If it were me, I would put the CV's & Axles in it & figure out what the travel is going to be & then figuring out which shock would be easy from there. picking springs might be a tad more difficult.

As mentioned, make sure you gusset the heck out of the top mount.

thats a good looking trailing arm. where did you get it? did it come with brakes?

Bob

Wed Jan 14, 2015 10:29 am

vdub411 wrote: From what I see you have no IRS torsion housing. This means you are going to have to use coilovers. If you want to know the shock length measure full droop and full compression. The shocks should be at a 90 degree angle at full compression I believe. Hope this helps.

Or air bags.

Wed Jan 14, 2015 10:40 am

Bobalos wrote: If it were me, I would put the CV's & Axles in it & figure out what the travel is going to be & then figuring out which shock would be easy from there.

Bob

This is correct. Once you have the correct length axles installed and put your wheels back on, you can 'start' to measure axle length. Most important dimension is the distance between fully extended and fully compressed only to the point that your CV's don't start binding and making noises. This is where having the wheel on or a brake rotor helps so you can spin the axle while the arm is propped up or down. I repeated this test many times to make sure I wasn't getting binding and ended up being surprised how much travel I had gained. However, once there was a load put on the axle I noticed I should have been a little more conservative. Once you have this distance (the difference between a measurement from the floor to the lower shock mount with the arm in both positions) Then you will want to add a half inch to one inch and this number will be your shock "STROKE". The extra length gives the shock a little space so it doesn't bottom out on hard hits. Now that you have the stroke you can decide just how big of a shock you want. I went with the longest set I could for the stroke.

Keep in mind after you get done mounting the shocks you will need to add a bump stop and a limit strap to keep the suspension in it's range. Again usually a half inch less than full stroke.

Wed Jan 14, 2015 10:47 am

I should add that when you are setting up the limits you will want to center the range between where the CV's bind which would be your first stroke number and then cut it short at the ends to avoid bottoming the shock. This can get tricky when you have to set both sides the same. You may find that you get a little more travel out of one side than the other. In this case you would go with the shorter of the two. That happens because one axle is longer than the other.

Wed Jan 14, 2015 8:02 pm

Those arms are not 3x3's the look a lot longer. They look like 5x5's

Fri Jan 16, 2015 9:45 pm

A lot of great input. I'm installing 930 cvs. I figured the max operating angles and clearances for the wheels and came up with about 12" of travel is available. I like the idea of putting it together and spinning the axles. The old shocks mounted right to the rounded part of the frame. I only had 6" of travel if remember correctly. What is the best way of figuring out how strong of springs to use? Does anyone have a recommendation of who to talk to about shocks? As for a spot to mount the top of the shock, i think it can be mounted to the bar that extends up to the top of the cage. Do they make a 10" travel shock? Don't think I want to push my tolerances to the extremes...

Fri Jan 16, 2015 9:51 pm

https://www.thesamba.com/vw/gallery/pix/1302388.jpg

Fri Jan 16, 2015 9:53 pm

Oops. Lol got it right this time.

Thu Jan 22, 2015 7:25 pm

With those arms and 930 CVs I see no reason why you could not get nearly 20" of travel.

One of the 1st things I suggest doing is to hold the arms so their CV flanges are precisely level with the trans output flanges, then measure from trans output CV flange to trailing arm CV flange on both sides of the car to make sure the trans is mounted so the output CV flanges are centered in the frame...NOT the engine and the trans case. In a VW 002 or 091 trans, the output flanges are not centered in relation the the trans case centerline. So if the trans is centered, the axles will be different lengths on the 2 sides.

The swingaxle trans that frame was designed for was equal from one side to the other.

Thu Jan 22, 2015 8:01 pm

lol.
20" of travel is not going to happen.
That's like what a Class 1 car pulls.
3x3 Arm with conventional vw stub axle your looking at somewhere in the neighborhood of 12-14 inches of travel.
If anyone's claiming more it's likely to be a bluff.
My car pulls 12 3/4'' of travel (bumped and strapped) with 3x3 conventional arms. 26* of cv angle. preped cv's. cv stars have recessed back cuts so that the cut out slides over the c-clip on the axle. Car has ground clearance at full bump.
See for yourself :D

Thu Jan 22, 2015 8:50 pm

turbodon1776 wrote: lol.
20" of travel is not going to happen. I had a friend that got 32 inches of travel out of his bug....although it was the original trophy bug that he bought from kreger fab.

Thu Jan 22, 2015 9:23 pm

BDR Loves Baja wrote: turbodon1776 wrote: lol.
20" of travel is not going to happen. I had a friend that got 32 inches of travel out of his bug....although it was the original trophy bug that he bought from kreger fab.

Nearly 3 feet of travel per trailing arm :shock:

Thu Jan 22, 2015 9:46 pm

Highly unlikely pal :D
Sorry.
Here have a look.
Here are the specs on a Jimco Class 1 and Class 10 race car.
Jimco builds state of the art championship winning cars...
20'' rear travel for Class 10
22'' rear travel Class 1 (bigger tires= more ground clearance=more travel)
Very big trailing arms, outboard hubs, super long axles, etc.

http://www.jimcorace.com/race-vehicles/jimco-class-1-car/

http://www.jimcorace.com/race-vehicles/jimco-class-10-car/

Thu Jan 22, 2015 10:31 pm

Yep...
1st off...Those are bigger than 3x3 arms he's showing in those pics. That's why I suggested that near 20" is feasible.

And many Class 5-16 racers get 16-17" with micro stub hubs and 930 CVs on 0x1 arms...on torsion bars.

Crumco Class 5 Open cars are built for 20" travel with micro stubs and 930 CVs.

What's limiting the travel on turbodon1776's Baja is the bodywork, shock travel and the upper shock mounts. More bump is the ticket to more travel.

A friend of mine has a 4 seater he built in the late 90s with 5x6 arms and VW hubs and 930 CVs that gets 20" of travel... With Rancho shocks for cryin' out loud!!!

Thu Jan 22, 2015 11:23 pm

Wrong.
My car bumps 3" off the ground with 33" tires.
How much lower would you bump?
I could let it slam on the ground and then claim 16" of travel... but that's not the way you do things.

my 3x3....

Posters arm sure looks the same....

I'm really doubting these big numbers being thrown around.
But hey everyone always has more horsepower and travel on the internet :lol:

Sat Jan 24, 2015 10:18 pm

Turbodon you should be more travel than what your getting, dustymojave is right 5/1600 are getting 16"of travel but there a lot work that goes into it like lowering than 3"from stock location, modifying the torsion housing,and raising the fenderwells and modifying and maxing out Cv joints.