Baja Frame head help - Extend & Caster?

[thevarmit]

Hi there - Building a baja in the UK and struggling as I am new to VWs.

The car started as a rust free 1303 and I have converted the pan to a proper frame head.

I have just recieved this kit in the post:

http://www.dansperformanceparts.com/off-road/off-r...t-1sr.html

Unfortunately we did not realise that there were two types of beam suspension when the project started and have fitted a ball joint head instead of a link pin head! I now have the correct head and am about to begin cutting it up again when I have finished swearing at it!

My question is - Should I extend the frame head by 1.5 inches to match the extended trailing arms while I have the chance before it gets tied into the cage? This doesn't seem common with most builds unless the arms are much longer but it might make sense while I have the chance??
Also - how much caster would you guys recommend for this set up - I am looking at running a 35'' wheel max. Or should I leave it stock and shim it afterwards?

Thanks in advance for any help. We run a fab shop over here so making anything isn't a problem - just the lack of VW knowledge! Cheers.

[oldschool5er]

I am only mentioning this to give you another option although it is something that I won't use and don't like the setup. Many people use this as it is a cheap way in theory to get around having to replace the pan head. They make a solid aluminum adaptor block with a matching pattern on one side for ball joint pan head and on the other side matching the link pin beam. It also adds to the wheelbase as you asked about, I think it is 2" not sure since I don't use them. If you already have the link pin pan head and want to weld it in, for me that is the preferred method. The final method is if you plan on putting in a full cage front to rear in the car then because you would be tying the cage into the front beam top and bottom you can just cut off the pan head and use the cage to mount the beam, that is typically what we do in building a full on Baja bug for off road if we want a longer wheel base and clearance for running big tires, we also run stronger combo spindles other than the spindles your kit has. If you didn't need to add wheelbase you could keep the pan head but with the size tires you want to run I think you have to add wheelbase. Be aware those size tires will add stress to the arms and spindles. You have to also consider what your running in the rear. you can go with a 7.00x15 tire in the front at 33" tall (Yokohama as example)(correct to 28" not 33" for Yokohamas see below) but because it is narrow unlike a 35" it will be less stress on the arms etc. and if you run 33" in the rear the car will be more level. When you run 33" as example in the rear you need lower gearing as in a bus trans and some HP in the motor to pull them. 35" tall tires are a whole different beast and it takes more than a recreational Baja bug to get them to work well IMO. 33" in my opinion is the max you should shoot for and that making sure you have got the HP and gears to pull it all.
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HRE in Westerville,Ohio

Full machine shop with all types of CNC. Rapid prototyping available, CNC Plasma cutting, 3D printing and Laser engraving.

[veeweeman]

Minimum. ...I would push the heat out 6 inches...I have the same beam but 4" over stock arms...you have1.5" longer arms now, but as you know we VW guys like to keep changing stuff 6"s will give you plenty of room to grow and running 31-35" tires.

As for caster, all I can say is my street legal rail had a ton of caster designed right into the frame and I hated the way it would steer on the street and freeway speeds, wow!...on my project build I left it stock. ..a lot of guys run heavy caster for better off road handling. ..if you plan to drive 50% or more on the street, I wouldn't put more than 10 degrees of caster but that IS just my personal opinion, you have to remember that the steering rack you have is 3/4 turn from center to lock both ways. ..the more caster you do the touchier your steering becomes. ..good luck with your front end and we hope you will post some pics.

VeeWeeman

[thevarmit]

Thanks for the replies - much appreciated.

It's going to get a fair amount of abuse this car definitely going to weld it all in but thanks for the option I didn't know that even existed.

Ive already built the cage for the car - just need to tie the front in once the beam is in and add the shock mounts at the rear.

The car is for a customer and will be used for classic endurance rally - it's never going to want for any more travel than its going to have with these arms. It will spend a lot of time on the road as well so I was thinking more along the lines of 5 deg added in when I swap the head over. Does that sound reasonable?

Tyres are definitely going to be in the 31-35'' range - whats the minimum amount of extension I will need to get the clearance needed?

The engine set up is still being debated but will 100% be air-cooled and boosted. Gearbox choice seems to be a minefield - will need some help making a choice soon enough as I need to work out driveshaft angles before I commit to the rear shock mounts.

I'll grab some photos of where we are at now. Cheers for the help.

[veeweeman]

5 degrees sounds good but still need 6" extention to clear 35" tires...if you're not sure than mock up with 35" tire and no shocks with full turn.

VeeWeeman

[oldschool5er]

I think 5 deg is fine but Max I would go. As far as wheelbase normally with a 6" wider beam and only 1.5 added in arm length you would be good but VeeWeeman has a good point to build it with more wheelbase but I think in terms of a Rally race conditions like curving forrest roads slower speed 100" stock wheelbase or high speed more straight you would need 105" or 106" probably. In the rear you are limited to 31" unless you put in short torsion bars any thing bigger will require wider and longer arms to keep the long stock torsion bars. It also brings up a whole bunch of decisions you have to make on the rear end when you go above 31". Just curious about the Rally conditions because it seems to dictate how you would set it up, is this slow speed stuff or high speed straight rolling hills? is it possible for the car to catch air?.
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HRE in Westerville,Ohio

Full machine shop with all types of CNC. Rapid prototyping available, CNC Plasma cutting, 3D printing and Laser engraving.

[dustymojave]

I agree with OldSchool5er that 35s are WAY too big for a Baja bug. And my Yokohama 7.00-15s are NOT 33" tall. Mine are 28".

Even on a full race full tube chassis Baja Bug with a 14" over beam and 4" over arms, 10 over wheelbase and rear arms that are 7x5s....35s are too damned BIG.

Or maybe somebody's been watching too many Redneck Yacht Club videos on YouTube and doesn't understand Baja bugs at all.
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Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet.

[thevarmit]

Thanks again. The car really will have to be an all rounder of all conditions as the rallys are up to 9000miles over 30+days.

Currently mocking up with 33s and looks spot on. dustymojave your car is not at all what we are looking to achieve.

Running 3x3 rear arms and full coil-over 12'' travel rear so should be all good for a big tyre.

Front end will be mocked up today - should be back with a verdict on the extension shortly.

Cheers.

[veeweeman]

Can't wait to see some pictures

VeeWeeman

[oldschool5er]

[quote="dustymojave"]I agree with OldSchool5er that 35s are WAY too big for a Baja bug. And my Yokohama 7.00-15s are NOT 33" tall. Mine are 28".

You are right Richard lol, I had 33" on the brain, I kept thinking about the rear end.
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HRE in Westerville,Ohio

Full machine shop with all types of CNC. Rapid prototyping available, CNC Plasma cutting, 3D printing and Laser engraving.

[dustymojave]

[Dark Earth]

I thought if the front beam is supported by a cage the frame head isn't needed anymore. Don't people cut the frame head off flush with the firewall, plate over the tunnel, and run tubes from it to the lower beam tube when extending the from beam forward ?
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My Build: '69 Baja - Dark Earth Version

~I'm almost done. I just lack finishing up.~

[oldschool5er]

[dustymojave]

[Dark Earth]

[thevarmit]

Hi - Holy thread bump - haven't been on this site since last in this thread but thinking of another project has brought me back.

Few asked for pictures which I never got round to. The beetle was finished and delivered in 2020. Here are a couple of pics all done. Have loads of other pictures happy to add if anyone is still interested in this.

Thanks for all input with the frame head was a big help.

Cheers.

[QRP]

We are always interested in more pics.

[tripicana]

Are those rear fenders home made or bought? Link?
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[Crogg]

I used the link pin conversion blocks on one of my bugs. If you are tying it all together with a tube frame... use the link pin. My other bug is welded head 4 inches out for 4 inch arms.

[thevarmit]