TheSamba.com :: View topic - Increasing rear travel/performance on a budget

Mon Dec 09, 2013 10:14 pm

Alright I'm ready to upgrade the rear suspension on my 69 baja and i've been researching alot over the last few weeks and I think I've come up with a tentative plan. The goal is to increase rear wheel travel and suspension performance for use in a desert and dune environment. I have a friend that has offered me some stock size boxed trailing arms for very cheap (maybe free) so i'd like to use those with some longer reservoir shocks attached to my yet-to-be-installed roll cage.

In all my searching, I haven't found very many people that are running a setup like this and even fewer that have listed details on things like shock length, torsion bars, and/or CV selection.

So to make a long story even longer the picture I have in my head is of boxed trailing arms with shocks mounted on top attached to the roll cage, upper bump stops remaining relatively stock and lower stops completely removed and using limit straps instead.

For shock length, I realize it greatly depends on where my mounting points are but I was thinking somewhere in the range of 10-12 inch travel. As for CVs and axles, I plan on running no less than type 4 CVs and possibly 930s if the budget allows.

So, bottom line-- my questions are:
Do you suppose I can get away with running T4 CVs?
Does 10-12inch travel shocks sound about right?
Would I benefit from running different torsion bars? (I have the long style)
Any other concerns with my plan?

Here's my build thread for background info: http://www.thesamba.com/vw/forum/viewtopic.php?t=547916&sid=7036352e6daee216e8314f2d3f53328f

Thanks alot in advance, there is alot of knowledge here but it can be hard to find when its in tiny pieces scattered throughout a million different threads.

Mon Dec 09, 2013 10:33 pm

From my experience the type 4 cvs will do well with an 11 inch stroke shock and stock x1 rear arms.But you will need different axles like aftermarket i had the type 4 but the splines are short and you will break the cv cage.

I also run 25mm SAW torsions they are the long ones.

Now to do it right and save in the long run if you need to buy new axles and cvs and stub axles just go with 930s.They will only cost a fe bucks extra overall if you shop around but you will be able to increase travel easier.(i should have gone this route).

Tue Dec 10, 2013 6:00 pm

I will tell you right now, 930 cv joints will never be worth it if you plan to keep the stock set up.

I highly recommend going type 2 or 4 cv joints, and making a 3/8 - 1/2in notch in the spring plate. That will gain you a couple inches.

If you are on a budget, this is what I have personally found to be the cheapest way to push some travel on the stock suspension.

Stub axles:

There are a few stub axle options to run 100mm cv joints. You can buy aftermarket stubs, but they are very expensive. Many people say use "thing" stub axles. These will work, but there are not many Things left that are being parted out, and off roaders are eager snap up the parts. As a result, they also tend to be on the pricy side. Every now and then You will get a good deal on them. What many people don't realize is that Porsche 924 and early non turbo 944's have the exact same stub axles as the thing. The only difference is that there are a lot more porsches being parted out, so they are more plentiful. Also, there is less demand for them because they are less known. As a result, I have found that they tend to be cheaper than the "thing" stubs...which are the exact same part. I scored a pair of '84 Porsche 944 stubs for 60 bucks! You can't even buy one aftermarket stub for that money!

Drive Flanges:

If you have a stock transmission, you have two options. New aftermarket flanges, or Thing flanges. Thing flanges are getting hard to find, and expensive because off roaders demand for them is pretty strong. Unlike aftermarket stub axles, the drive flanges are rather affordable. Go for the aftermarket flanges. 90% of the time, they will be the better buy.

Cv Joints and Axles:

Unless you have a good pair of thing or porsche 924 half shafts staring you in the face, buy new axles. Believe it or not, they are not that expensive. A lot of people run away when they hear the name EMPI, but they do make some good stuff if you know what to get. I say this over and over, but I would never hesitate to buy their axles, cv joints, and carburetors. They make a sweet half shaft that fits a stock suspension with 100mm stubs and flanges. The part number is 90-6905. They have generic 100mm cv joints, and proper length beefy axles. This will get you a stronger than stock cv joint with more articulation and plunge, which is good for more travel. Plug that number into Ebay. You will see prices from the high 50's to around 120 bucks. Buy the cheap ones. There is no difference between them and the more expensive ones...just a larger profit margin for the seller. Just watch out for the cv boots. They are the weak link. Run them until they start cracking, then replace them with better ones. Cv boots are dirt cheap and easy to replace when the time comes.

Tue Dec 10, 2013 6:32 pm

That's some good advice right there VanApple.

I don't entirely agree on the 930s not being worth it. 1600 desert racers have run 930s for decades using the +1 arms. Many have used them with stock length arms too even though the rules allow +1. 930s will allow a few more degrees of angle. Cost is sometimes almost the same between T4 and 930 when buying parts all brand new. But as Van points out, the 924/944 stubs and CV shaft assemblies can be obtained at good values.

Quote: So, bottom line-- my questions are:
- Do you suppose I can get away with running T4 CVs? …….Yes
- Does 10-12inch travel shocks sound about right? ………….. Yes
- Would I benefit from running different torsion bars? (I have the long style)
……Different diameter - Yes. Different length - Short torsions would allow a little larger diameter tire, but the real limiter on an otherwise limited Bug is still the body clearance. Longer bars give a smoother ride and can handle more degrees of rotation.
- Any other concerns with my plan? ………….. See below

Now, to expand on what Van has said:

- Get your arms on and CVs, stubs and axles in BEFORE you start anything with shocks or stops. The CV angle is ALWAYS the limiting factor.
- I'm not real fond of limit straps as they stretch and then let things go too far and allow breakage.
- Set your max droop BEFORE starting with the shocks.
- The shock mount bolts should always be parallel to the IRS pivot bolt.
- The shock should lean inward a little at the top, not straight above the spring plate so that as the arm swings, the shock action is in a true arc with the arm. Yes...heims will ALLOW incorrect angle, but it is STILL INCORRECT angle. Correct angle gives best action and shock wear and damage is less likely.
- If the shock is mounted to the arm above the axle, the shock travel needs to be as much as the wheel travel.
- If the top shock mount is leaned forward and in enough, and the lower mounts are forward on the arms, you can use shorter travel shocks to get the same wheel travel. But longer shocks give better performance and often cost the same.

Tue Dec 10, 2013 6:56 pm

Awesome advice! Thanks guys!

So the only reason people don't cut the lower stops is because they don't like limit straps? Personally, I'd rather take my chances with straps stretching than risk a broken spring plate. I mean, I can always use straps that are a bit short to start with and just keep an eye on them for awhile, right? But that's just what makes sense in my head, obviously I don't actually know for sure.

I'm still undecided on the CVs. I am already running a 091 trans which has flanges that use the same bolt pattern as T4 CVs right? That's why I'm tempted to stick with T4s... However, I'd also like to leave the door open for some 3x3s later on, so it might be a good idea to get 930s anyway...

Lastly, torsions: from what I understand, the torsions I already have will work best for what I want to accomplish, is this correct?

Tue Dec 10, 2013 7:15 pm

You posted while I was revising my last post...So re-read it.

Tue Dec 10, 2013 7:38 pm

Okay great, thanks dustymojave! Like you said, I have come to the conclusion that my tires hitting the body will be the limiting factor of up-travel, especially since I'm already running 31s. Do you happen to know what kind of wheel travel is actually achievable? Or know of anyone that truly has pushed stock arms to their max?

Wed Dec 11, 2013 2:47 am

10 is about the limit. Some claim to get 11... For practicality, 10 is a good number.

I like solid stops to control drop. If you have the type 3 / 68-70 bug double spring plates, you won't break them if you notch them. Just don't leave any sharp corners. Even if you have the 71 and later single spring plates, notching 3/8 to 1/2 an inch will not significantly weaken them as long as you leave a generous radius at the end of the notch. They should have no trouble with stock torsion bars. The people that crack them are running their cars extremely hard with lots of preload and/or bigger torsion bars. For the larger torsion bars, I would recommend cutting the hard stop out and using limit straps. The force on the tempered spring plate would beat the softer cast steel stop to a pulp. Stock, even if preloaded more heavily, will last longer.

Wed Dec 11, 2013 4:21 am

If you have the right size bars in there you shouldn't need the massive preload that damages spring plates/limit straps to start with - I don't use either, just let a pair of the rear dampers act as stops - many people tend to use bars that are too small and then have to run so much preload it rides like crap anyway.

Wed Dec 11, 2013 6:00 am

In this case, the right size would be stock, or type 3 bars. No need for more than that unless the original poster has dreams of driving like a class 11.

Wed Dec 11, 2013 6:44 am

Just for prespective, I will get only 8.5" with spring plate eliminators, 2.5X2.5" arms and type 2 CVs(thing stubs and 091 trans). I'd think 10 with 930s is reasonable.

Wed Dec 11, 2013 6:43 pm

Well thank's everyone for your advice and info but I found a screaming deal on a complete front and rear setup that I just can't pass up so I think I'ma go pick up this stuff this weekend:

http://kpr.craigslist.org/pts/4168222694.html

What do you guys think, good deal right? I'm pretty positive I'm going to buy the rear suspension and even though it'll be a big hit to the wallet (especially this time of year) I think it'll be cheaper in the long run if I get the front end too.

Wed Dec 11, 2013 7:04 pm

Yes you will definitely be money ahead picking it all up now. Those are some pretty good deals!!!

Wed Dec 11, 2013 7:42 pm

Try to get him to through in the axles and cv's with the rear end parts.

Ed

Fri Dec 13, 2013 12:10 pm

BUY IT ALL! lol