Link-Pin to Ball Joint Beam changes?

[Matt Clark]

hey guys,

I was wondering if you could clarify a couple things about beams. With all the allowance of FV disc brakes, it kind of put me down a rabbit hole of thinking & digging... what exactly is needed to convert a link-pin car to a BJ beam?

I did find a bit of info on the FST page that says "When you first get your new beam you will notice that the four mounting holes are not spaced the same vertically. You can use three methods, the first is to weld a plate over the beam holes then drill the 1200 pattern into the beam. The second thing is to use the bottom holes to mount to your frame and then re-drill the upper holes in the beam. You can go one step further and modify the beam mounting holes on the chassis and change the hole location to match the ball joint mounting pattern."
http://www.formula-first.org/html/fvconversion.html

So if I understand correctly, this means the lower tube & mounting hole stays in the exact same spot, and just the upper tube & mounting hole moves upwards?
If so, how much does it move?
Are the tubes the same diameter?
Does this change the ride height of the car?
Is there a change to track width, measured at the wheel mounting face?

Like I said, it was one of those rabbit holes that makes me wonder why we can't allow BJ beams & avoid the offset bushings, etc. Might be an opportunity to make another small step forward in time.

[rgu]

Matt

Naturally we in FST (almost all of us came from Vee of some sort) love the ball joint beam and we especially love the spindles. While I’ve seen a few avid high spending vee guys in the Midwest especially criticize our beam choice its really not true to any specific degree (More on this later)

First, an answer to your question. The second hole is about an inch above the top link pin beam hole. So just add another hole in the beam upright. Simple. Next question tube diameter is a bit bigger. Not much though.

When I converted one of my cars I wasn’t that stupid to not weigh every side by side so I could get an idea about comparative unsprung weight.--- VEE vs. FST. Literally the disk $44 and the caliper, and spindle weigh just about what a drum, backing plate, wheel cylinders king pin and like pin etc weigh. I’ll keep looking for this spread sheet.

The beam itself is a tad heavier and the spring and sway bar might also be. Not much though. Once you cutoff the mouse horns etc even less.

Why we like if

1. The spindles are so much stronger and have held up to every thing. Plus they use really cheap bearings. Brand new spindles can be gotten in the $75 a pair range
2. The disks are super strong “Mystery” metal. They are available blank or with a VW bolt circle predrilled.
3. Front end alignment is a snap. Just turn an eccentric. No more spilt washer, bathing your hands in black moly grease.
4. We a considering radial R60a tires for next year. Getting the front negative camber needed for the radials is a total snap especially if you buy one of our two radial tire adapter. The cheap one can mostly just be fitted to your existing sway bar
5. In our rules shock mounts (thus brands and models are greatly expanded. Don’t get me started on shock dyno data but I have found that a $175 shock is the easy equal of famous name units costing 3X more.

You guys in CC FV are on the right path. Just keep doing the cheap, easily available thing, and you keep a winner.

One thing we are definitely doing next season is not even using a VW NOS or rip off beam but rather just using a beam made up of tubes and u channel. We have an initial estimate where the cost of a custom beam is about what a VW Brazil beam costs. I found a source for the ball joint beam roller bearing, under $30 for the pair. I have a great picture of one of these used down under. Be glad to send the pic to you via email.

I will look into your other questions and perhaps other can answer also

[rgu]

Matt

Here is SRacings BRD built in 2004. Still going strong today. Picked the BRD for this because it has a very short beam support bulkhead.

Beam bolts


Regrading right height its almost the same if you start by bolting on lower bolts and drill the new top. I would weld in your own adjuster to get final height. I have a scheme if you ever want to know. Below is a picture of Doug Seim's first BRD Vee conversion. He used to run 2.5 inches in the front and it came out exact. Picture came from car's 1st race as a FST at Nelson.


Track Just check this yourself in GCR or in VW street car spec. We use a 6" wide wheel so not applicable

[Matt Clark]

Thank you for all that info, definitely helps me understand it better.

I know there are critics of the BJ beam, but that's expected with FV vs. FST anymore. I see what is apparently needed to get disc brakes on a LP beam, and I can't help but wonder why not start looking at a full conversion. Especially with the other cost & work involved with offset bushings & such. Last set of spindles I bought years ago were $500, and those weren't even cut/quicksteer ones.

I knew you guys had the different wheels & tires, but I was more specifically wondering about the mounting faces of the LP drums vs. BJ discs. If they were basically the same, it would be a LOT easier sell to people in FV that their car didn't get X amount wider with the standard FV wheel/tire.

The other thing I know would be an issue, is the shock mounting. Obviously the moose horns don't really work with the standard FV shocks, so I would say a spec would need to be created to allow custom fabricated "hybrid" beams.
Bottom line, we need to get back to affordable parts that we can jump on a website or open a book & order. People just don't want to dig junkyards or "restore" used parts to put on their race car.

[rgu]

Matt I looked at the Clymer VW Repair handbook. The 62 VW with ball joint beam has a 51.4 front track with stock wheels. The 73 Karmen Ghia w ball joint beam with the 4 bolt wheels was 51.5 (FYI used our disks). Seems that in your Challenge Cup series you can dial in a track with wheel builders like Bart, Diamond or Basset. these guys have been really helpful. The disk is flat where the wheel mounts.

Shot me an e-mail at fst at rochester dot rr dot com. I can email pictures.