Gearing question
Posted by Moto_Pig@reddit | projectcar | View on Reddit | 8 comments
Daihatsu hijet thats been engine swapped, original 660cc inline 3 replaced with an 1100cc v4 from a honda st1100
Making progress slowly but currently it runs out of gear at about 95kph which is great for burnouts but not so for cruising/traveling
Question is can you run a 2-1 reduction box backwards to make it double the gearing instead? I can look into diff swaps but width becomes the issue, along with finding matching wheels that have different stud patterns, original being 4x110 and an old hilux diff for example would be 6x139
Tango91@reddit
Woo, Pan European kei truck!
Such_Account@reddit
Are you saying you're redlining in 5th gear at 95 km/h? For a 530 mm wheel diameter, that implies a 6:1 final drive, which sounds implausibly high. Is there some other gear reduction already?
Otherwise, I think fitting a different final drive would be easier, even if you had to shorten the axle a bit. Maybe an axle from a suzuki jimny? They're also quite small, under 1400mm track width.
If you find a final drive around 4:1 you would be cruising at \~5000 rpm at 90 km/h by my calculations (assuming 530 mm wheel diameter). Not great perhaps, but are you really gonna go faster in that thing?
TA4K@reddit
You may be able to swap the diff gearset itself for one from a Terios or something, even maybe a FWD Daihatsu box if they match. Try reaching out to Daihatsu Oceania, they’re based in Auckland and may be able to point you in the right direction re diff ratios etc as he does a fair bit with Daihatsu racecars locally too
juwyro@reddit
It looks like there are different diff ratios for these. Starting there would be the easiest thing, but I don't know how hard it would be to find the axle that you want.
FalseRelease4@reddit
are those tires off a garden tractor? 😂 they dont really inspire confidence for highway speeds
Moto_Pig@reddit (OP)
Twas a farm vehicle when I bought it, wheels and tires will be done when I sort gearing, until then there's no point spending money on something ill swap out
FalseRelease4@reddit
you would get a few extra kmh from going to a larger wheel, those look kind a small
SoullessGinga@reddit
They don't make different ring and pinion gears for those rear axles? Could maybe look into UTV axles if you are trying to find something local