Double A-arm suspension

[pure55vw]

Progress has been disappointingly slow due to other commitments, but so far: The suspension has been on the car about 3 months (car is an otherwise bone-stock '74 beetle). Subjectively, the ride is better, but needs some tuning with the adjustable front and rear shocks it has. Steering is very light (almost too light), which causes it to "dart" slightly with any bit of steering input. May need more caster (has 3 degrees now). Still looking at roll angles and intial turn-in feel of the steering, and I'm considering a stiffer anti-roll bar although I can't do too much with the skinny stock tires. Nothing seems to be wearing out too fast, but I'm still planning to replace the urethane a-arm pivots with OEM-style rubber bushes. I promise to post later with more info as it comes in and those always-popular pictures!

Jay

[volkdent]

I'm glad to hear its still on the go. How come stock rubber bushings vs PU? I made some serious progress tonight. I bolted on the complete suspension chassis mockup(wood) and it fit like a charm. One snafu though, it looks like I may have to raise my ride height a bit so the input shaft for the steering rack will be able to make a decent angle with the stock steering shaft. We'll see.

Jason

[Vincent]

you could always use a steering knuckel like in some modern cars to fit the angle. I rember when we put a new front end in my grandfathers 1959 International truck we had the same problem and just put in one of the universial joints to make the angle worked pretty slick.

[volkdent]

Universal joints don't work at severe angles, which is the situation I'm in now. I'm planning on using 2 high angle joints, but at this point I think the angle may be too much. The input shaft is inboard quite a bit, as well as being very high, almost the same level as the stock steering shaft. So, we're talking about an abrupt 90 degree turn, no universal joints can handle that!!

Jason

[volkdent]

I recieved a MkII non-powered rack universal joint today, so I can hack off one end and see what its max limit for angulation are. I did some more brainstorming, and I figure that if I put the second UV joint up inside the tube the steering shaft is in, it will give me some more room to work with and shouldn't effect much of anything.

Jason

[pure55vw]

Jason, going to try rubber bushings for the same reasons the OEM's do: less maintenance, less suspension friction (good in a light weight car like this), and less cost! Since my lower A-arm pivot doesn't have to "twist", I can use a stiffer bushing to keep the radial stiffness high (though not as much as PU). I've done the "wooden mockup" thing too, so I know what that's like! I solved the steering U-joint problem with wide spaced A-arms allowing the rack to sit closer and further forward on the pan. The tie rods are at a slight angle in the top view, but not bad. Since T-III knuckle steering arms are bolt-on, they're easily changed or shifted to adjust the Ackerman. With the second ujoint inside the steering tube, you'll need to put another through hole in the firewall, something I also considered

[volkdent]

Actually, it looks as though I'll be OK with the steering tube just trimmed down till it is just meets the rubber grommet in the bulkhead. I've had a Teflon bushing made to reside inside the steering tube, and I've ordered a Flaming River 5/8" - 5/8" U joint. Here's a peak at what I've come up with thus far. This was designed by Bob Frost-Stevenson at Rorty Design in Melbourne AU.

Suspension View