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ZCI 4mm shaft gears

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I'm starting to stash bits for my next build (budget 35+rps) and I'm looking at the newer ZCI gears, both the solid shaft 4mm items and the ones with the removable shaft where the gear runs on a bearing. I'm a little dubious about running a sector gear on a pair of bearings, let alone a single one housed within the gear itself. Has anyone got any experience of using the ZCI stuff, or just stick with the tried and tested SHS 13:1 set?

And as an aside, how about running bearings on the spur gear and non side load face of the bevel with solid bushes on the sector and the loaded side of the bevel? Worth it or not with a  M120 spring?

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No - SHS 13:1 will suffice


Where are you going to get:


fine ranges of shims 0.1, 0.15, 0.20, 0.25 etc.....

yes I know 0.1 + 0.15 = 0.25, but also sometimes a wide outer diameter will suffice - eg under spur gear

but other times a smaller outer diameter shim of same thickness might be preferable - eg bearing

So where will a good range of 4mm shims come from - yes they supply some but betcha want one in between

The G&G DSG HC05 had a mix of 3mm & 2 x 5mm axles on spur & sector

wot a PITA trying to reshim due to no thinner 5mm shims about

Plus they used 9mm not 8mm holes - got some SHS 9mm bearings with 3mm axle or ID's

As well as sourced some 9mm 5KU 9mm bushings - but what a pain tbh

(so yeah sod these unique/bespoke/odd ideas I feel)


4mm bushings/bearings to fit into gearbox - yes they might supply but options of solid/cross/bearing etc.. will be limited


As pointed out - bearings on shaft inside gears - hmmm mixed reviews & I'd be worried more about spur gear in middle

Also - have you broken a SHS 3mm axle yet ???

G&P might have had weak axles but not SHS - OK some clones or bad batches existed

but usually I'd say the bevel's 10 teeth would strip off first if you had a mash up under stress

(must have a spare compatible 3mm bevel in ya box - where would get a 4mm axle bevel from ??)

A 3mm bevel - just pick one that looks decent and meshes ok with pinion & spur

So yeah 4mm axle stuff - hmm maybe not tbh


Like them sector gears that have a bearing to draw the tappet plate back...

Sounds good having a rolling bearing to reduce wear of tappet fin

But if you want to add a delayer - you can't


Think I'd stick with ol' school stuff, seems to work OK, easy range of bits - shims, bearing/bushings etc....

Until the ar$e falls out I'm happy to stick to decent 3mm axle gears I think


make sure you use a bushing under spur gear - see this clip


what you do after that is up to you

I personally do bushings under all 3 gears then add bearings on top of spur

The other two I place what ever works ok, if I have a bearing that I feel is robust I will use it on bevel

(give it a bit of free running maybe)

The sector - well not bothered tbh as it turns the least out of the 3 gears

the bevel will turn 6.25 times on 18:1 gears or 4.25 times on 12:1 to 1 rotation of sector gear

(so no real biggie what goes on top of sector really imho - if it rolls nice then a bushing or bearing maybe) 

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