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Here's a link to the book of ma my faces Hirobo group , has a nice example as the title picture .
https://m.facebook.com/groups/855574807930024/?ref=group_browse

Found post on FB by previous owner of this latest restore.
Penguin are listing drivers on eBay now.
FB images prompting some mods to side panels.

It's turned into "A Tale of Two Zerdas"
Painted the penguin driver, not perfect paint job, not even good but better'n nowt.
Still some tinkering opportunities.

Happy accident...been talking about wheel track width recently so measured zerda with stock wheels and got 24cm to outside edge of tyre. By a quirk of fate the 12mm hex wheels with adapters produced the same width even with the rear being a wider wheel. Hadn't even thought of offset. Jammy or what.

Addressing the single bearing and 12 mm hex issue. I got some cheap tamiya hbx axles, found 10x15x4 bearings fit the narrow part of the cup. Can't find 5x15x5 bearings so used the zerda 6x15x5 with some spacer. Plastic until maybe some 6mm tube with .495 wall is acquired. Dadio printed some 4mm knuckle extenders to accommodate the 9mm total bearing width.
The wide part of the axle cup fits the zerda knuckle like a glove so a bit of lube and maybe a bit of sanding to relieve friction and it's like three bearings. Absolutely no jiggle and the wheel inner edge aligns with the kingpin just like zerda stock wheels.
Simple..just a bit of sanding out to relieve any friction of the widest part of the cup in the axle holder.

The final chapter on the tamiya axle,12mmhex, double bearing conversion. After an eBay seller sent the wrong size flange head screws....
Everything fits nicely with Dadio's axle holder adapter. A lot of bearing jiggle removed. Still a bit of jiggle, some related to wear in the suspension arms and pins?
Anyway a solution if you can't get hirobo axles and/or want hex with the torsion bar.

threesheds wrote: ↑Tue Dec 06, 2022 9:20 am The final chapter on the tamiya axle,12mmhex, double bearing conversion. After an eBay seller sent the wrong size flange head screws....
Everything fits nicely with Dadio's axle holder adapter. A lot of bearing jiggle removed. Still a bit of jiggle, some related to wear in the suspension arms and pins?
Anyway a solution if you can't get hirobo axles and/or want hex with the torsion bar.

I had the same reflection with the Bearcat when I applied the dual bearings mod : there is still some jiggle... And it comes from the way the arms and carriers are mounted : there is bout 0.2 mm clearance around the arms on each side, and there might be as well some clearance around the axis... That being said, it's not all bad : jiggle allows to keep the parts together : remove too much of clearance and they would break much more easier... That's a right balance to find. Last solution : print ad'hoc parts in Nylon for the bulkheads, arms and carriers with reduced clearance (and improved reliability (not sure what @Dadio kept as part clearance, at this stage my parts design have same measurements and clearance as the original parts, but I can change that later on)...

Tolerances really depend on how it's being printed , for my home stuff I usually add 0.2-0.25 mm to hole sizes for small holes , more for large holes , for Shapeways 0.1 mm everywhere.
With reference to the single or twin bearings , I've never felt any need on my Zerda , Coyote or Bulldog to do a double bearing mod but and I think it's significant that all my bearings are virtually new and have very little play in them , if they were driven hard and regularly off road then the wear in the single bearing probably would add up more quickly than a twin bearing under the same conditions .

Good ideas catch on or two minds with the same...on Facebook hirobo post

Zerda tyres or tyres for zerda...Tamiya 9805183/50344 Falcon/Terra Scorcher/Thunder Shot/Fire Dragon Tyre Set
Think I got the tip from FB group. They fit maybe a tad loose without glue and the rubber is a bit thin, will need sponge insert
But look ok

I had the Hirobo tires in my radar for a while... I'll do some once I have finished playing with Marui tires