Had a thought while taking son and dog round the forest this morning. He's got one of those electric quad bikes, runs at a decent walking pace but lacks any grunt on anything more than a slight incline. The thought hit me of doing 4wd.. hey how about something like a Land Rover? (He likes the pics too )

Sooo, I'm wondering how feasible a project this would be, I've done a rough sketch sized to account for him being 10 years old before he's too big for it (plus I could always give it more power etc as he grows) so here's my list of questions.

1. Is the front drive feasible? I'm thinking of just using a big bar connected to the smallest cv joints I can find but it that just too much weight?
2. Will a diff be needed in something of this size? (I've got a length of 1.5m and a width of 0.8m but that's flexible) because sticking a cog onto on big bar connecting both wheels would make it rather easy. If not where could I source a small rear diff and what could I do about the front? (one motor per wheel maybe?)
3. How could I do a high/low ratio? My initial thinking is a lever connected to the kind of gearing that's on a bike, is there anything better?
4. Wood fabrication. I figure plywood's fine for the panels but would some 2by4 be enough for a chassis? It's for a lad to pootle around in rather than a fast racer.
5. 12v batteries means I could use a standard car charger, but are car batteries any good for this?

Thanks all

Single motor with decent batteries and this axle, simple ladder chassis, plywood body.

QUADZILLA SMC 100 QUAD AXLE | eBay


GO KART STEERING COLUMN ASSEMBLY WITH OTHER BITS - ROTAX TONYKART ETC | eBay


350W Electric Motor 24v Bike, Scooter 24 volt Gear | eBay




Get junior involved in the build - go for it

[Edited on 14/2/12 by T66]

[Edited on 14/2/12 by T66]

I want to do a sevenesque for my son to be born based on a quad bike for running gear.

But these things are bloody too expensive in Greece and difficult to find second hand ones.

A starter motor should do the trick i would like to believe but unsure of how long it would last.

quote:

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Originally posted by T66
Single motor with decent batteries and this axle, simple ladder chassis, plywood body.

QUADZILLA SMC 100 QUAD AXLE | eBay


GO KART STEERING COLUMN ASSEMBLY WITH OTHER BITS - ROTAX TONYKART ETC | eBay


350W Electric Motor 24v Bike, Scooter 24 volt Gear | eBay




Get junior involved in the build - go for it

[Edited on 14/2/12 by T66]

[Edited on 14/2/12 by T66]

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Doesnt need 4wd - Your just being ambitious with your engineering desires.


Not sure what the gearing would be like with that axle and motor, there a re lots of karting steering setups for sale on ebay.


Some sort of pedal bike disc arrangement on the propshaft will be enough.



Get cracking ! want to see it....

Get an old ride on lawnmower and make a body for it, once you have removed the cutting deck they can be quite high,

He now wants a monster truck, so my brain's been leaking ideas in having some 13 or 14 inch steelies connected to that axle

I've found a motor in Maplins.. How powerful is 21watts?

Also does anyone know of a lightweight gearbox? I'm only after low, high and reverse really, and I'm not designing it to do any more than 10mph TOPS (well, jogging pace, he's nearly 4 atm!) I'm thinking maybe some little rwd box and blanking off the 3rd and 4th? I know this is going to start to get heavy but what the hell

Use quad wheels & tyres, so will look monstertruck anyway.



Decent motor , variable speed controller, reverse the polarity for reverse.



http://www.toylander.com/Toy_cars.php

Buy him a Jago they are dead cheap at the moment, get some blocks on the pedals and a 4 point harness and let him go, much more satisfying than faffing about with electic power!
atb
Mike
Ps I think I have plans for a scaled down land rover somewhere if you insist on that sort of thing

get your self a mobility scooter. I.ve got one off a member on here for that very purpose.