Outer Limits 4x4 Board

had a late night brainstorming session last night (thanks MADZUKI) and came up with a lightweight rock buggy. Should be cheap to build and run.

Use a motorcycle engine like an XR650

All chain driven (make it real easy for gearing)

Independent suspension (make this a class rule )

Use motorcycle rims with trials bike tires

You could use heaps smaller tube for the frame

Have a maximum length and width to keep things more even

Be heaps of fun and make things really interesting and cheap

hmm, might need to up the CC limit for ppl with beer guts etc >_<

just put in big ass 20 cogs

I like it, have been thinking there has to be a cheaper option to compete. would be heaps lighter to tow around to comps & small enough to store when not being used. Also easy to machine up your own parts from scratch when you have small hobby lathes & mills etc.

Bring it on

Only problem being, it must weigh a minimum of 1000Kg's.

Therefore power will be an issue.

Pete

TEAM OPW wrote:Only problem being, it must weigh a minimum on 1000Kg's.

Therefore power will be an issue.

Pete

Why does it need to have weight restrictions if we start a new comp class all together?
Cheers

Ingenious-Eng wrote:

TEAM OPW wrote:Only problem being, it must weigh a minimum on 1000Kg's.

Therefore power will be an issue.

Pete

Why does it need to have weight restrictions if we start a new comp class all together?
Cheers

That's exactly what I was thinking. you could easily use motor cross shocks for this as well. I might build one just for the fun factor.

or just get a trials bike

there are already comps at club, state, national, and international levels. you'll be able to get over some pretty amazing rocks, its cheaper, and you'll also get all the lightweight, easy tow and storage, etc... advantages you mentioned.

if you want to build something different go for it. but if you expect a class to be formed, that'll take some convincing.

N*A*M wrote:or just get a trials bike

there are already comps at club, state, national, and international levels. you'll be able to get over some pretty amazing rocks, its cheaper, and you'll also get all the lightweight, easy tow and storage, etc... advantages you mentioned.

if you want to build something different go for it. but if you expect a class to be formed, that'll take some convincing.

I don't have the balance to do trials. Besides, how does any class of motorsport start????

I agree... it would be quite impressive what you could achieve.

Designing the class would be half the fun.


You could potentially even run a 4wd system with chains (there's been 2wd bikes after all).

Certainly bigger shaft drive motorbike motors could easily turn a suzuki tcase. Kinda removing the fun factor though, and getting too much like a quad bike anyway.


Your limitations that I can see.

How do you actually intend to set up reverse gears? I'm guessing a reverse down, forward up arrangement would be easiest, although it could be possible to have some kind of forward/reverse transfer box.

Driver safety. How do you prevent parts being poked outside of the cage in the event of an accident? I guess making the cage a little bigger and having netting alround would be possible. In the event of a big rock poking through the cage though you're kinda screwed.....


Tyres? Would you want to use trail bike type rims and tyres? To be honest they're very skinny and not gonna be much good for rocks.

Trials tyres maybe.

Perhaps ATV wheels and tyres, but much more expensive to get big ATV rubber.




Overall I see the concept kind of like the old Honda oddysey buggies, but designed for 2wd rockcrawling. It's something I've thought about myself.

With less and less places available, and less and less space, and more traffic damage on the remaining places, doing something like this does have some merits.

N*A*M wrote:or just get a trials bike

there are already comps at club, state, national, and international levels. you'll be able to get over some pretty amazing rocks, its cheaper, and you'll also get all the lightweight, easy tow and storage, etc... advantages you mentioned.

if you want to build something different go for it. but if you expect a class to be formed, that'll take some convincing.

I'd love to do trials, but due to the ageing process I don't heal so well any more, so time I build a full exo cage around the bike to protect me (being a complete newbie at the sport) it aint going to get very far up any rock! & don't tell me they don't get hurt as I was at the the top comp just recently & one of the top A class english riders took a fall that would have put me in a wheel chair for life

Bring on the micro buggy class

I want to make alloy twin steer mini portal axles with micro air lockers & alloy tube frame, around 350 total kg's would be good.

these things would be as much fun as the pit bikes are at the moment.

C'mon toughnut pull your finger out & make it happen

im thinking something akin to sandrails interms of weight, engine go the old Vdub's, not as long but single seater useing that size of tyre.

in my mind this both works cheaply and sounds awsome.
I know there must be some CAD guru's hideing here im sure someone can knock up an idea of what it would look like

Beastmavster wrote: You could potentially even run a 4wd system with chains (there's been 2wd bikes after all).

That's what I meant by chain driven. Probably run a central shaft and then a chain to the front and rear axels

Beastmavster wrote:Certainly bigger shaft drive motorbike motors could easily turn a suzuki tcase. Kinda removing the fun factor though, and getting too much like a quad bike anyway.

Though of this but then things would be become heavy and up the costs

Beastmavster wrote:Your limitations that I can see.

How do you actually intend to set up reverse gears? I'm guessing a reverse down, forward up arrangement would be easiest, although it could be possible to have some kind of forward/reverse transfer box.

You could set an engine capacity and maybe use quad bike motors that have reverse in the gearbox. You don't need to go fast so you could get away with slightly less power and just gear it right down with the cogs.

Beastmavster wrote:Driver safety. How do you prevent parts being poked outside of the cage in the event of an accident? I guess making the cage a little bigger and having netting alround would be possible. In the event of a big rock poking through the cage though you're kinda screwed......

It'd be easy to have the same setup as the buggies do now. You could just run mesh with some of the panels removable to get in and out.

Beastmavster wrote:Tyres? Would you want to use trail bike type rims and tyres? To be honest they're very skinny and not gonna be much good for rocks.

Trials tyres maybe.

Perhaps ATV wheels and tyres, but much more expensive to get big ATV rubber.

The idea is to use the trials type tyres and bike wheels to keep the tracks a bit more user friendly. You wouldn't have to make the tracks as extreme then because the buggies simply wouldn't be as capable.

most(all?) 2wd bikes use a hydraulic from wheel drive system dont they?

Shadow wrote:most(all?) 2wd bikes use a hydraulic from wheel drive system dont they?

Yamaha do. Some concept bikes used a realy strange chain and shaft drive

I dunno how capable the buggies would be. Obviously without the years of development it would be well behind the car 4wd scene.

But using the example of a standard trailbike wheel, you're probably looking at about these sorts of figures:

Suspension: IFS/IRS. Solid axles would be possible, even with chain drive, but weight is a key factor.

50 Hp (650cc trailbike engine - or more with other engines)

Dry weight - approx 250-300kg
(2 and a half times what a trailbike weighs)

27" tyres

Ground clearance: With IFS + IRS you're probably looking at the driveshafts on about an downward angle of about 30 degrees. So if the vehicle was say 3 feet wide (bloody narrow even for single seater).

Since the most sensible spot for engine mounting is either front or middle, and chain is to the left of the engine I'm guessing you might stretch it to 3 1/2 - 4 feet

Rough off the top of my head guess says you'd be looking at least 6" higher in the centre than the middle of the tyres, so about 20" ground clearance front and rear, and more in the middle (maybe 30").


Gearing.... Obviously as short as you want it to be, but dependant on available sprocket sizes. Guessing the shortest you'll easily source will be something like 17/31 for final drive.

If you had a seperate reverse/reduction box you can go way lower.


Effective power to weight - ample considering light weight and gearing combos.


Diffs locked by default (chain drive)

Left hand drive (chain output on left of most bike engines, meaning a middle chain needs rightmounted engine).

HHMMM thinking single sided swing arms for portal hubs facing slightly rearward at the rear and vise versa for the front. This would keep the steering and axels all nicely tucked up out of the way

Sellout..there goes our R&D advantage

With the swingarms that would skyrocket the price..there would be better easier ways to do portals

make our own portal/swing arms

toughnut wrote:make our own portal/swing arms

SSSHHHHHH!!!!!!

was thinkin something along those lines myself but with a harley motor through a zook t case

Due to the high cost of motor cycle tyres I'm thinking it would be cheaper to run 235/75/15 on 15x7 steel rims, as this tyre wheel combo can be bought for less than $150.00 brand new, thats how much just one cheap trials tyre cost. Tyres are the part thats cops the biggest hiding on a buggy as a consumable item so they need to be cheap & second hand tyres are usually free/or cheap in this size. (It's the size tyre we use on most 4x4 camper trailers)
For the outlaw mini buggy class they could be allowed to run up to 31/10.5/15

We gotta keep it cheap then it will be the biggest class of all as everyone can afford to do it!

Like others have said it is just as much fun making up the rules as it will be to build & compete

What will it be called?

Toughnut class

http://cgi.ebay.com.au/eBayISAPI.dll?Vi ... 0009455201

sierrajim wrote:http://cgi.ebay.com.au/eBayISAPI.dll?Vi ... 0009455201

You couldnt help yourself, could you


Mock

We should cap the engine size as that could get out of hand pretty quickly, but i think it would be cool to leave the tranmission of power from the engine to the wheels as anything goes, as it would allow some awesome new ideas to be born. One idea I've got is to run 4 x cheap belt driven car power steering pumps of a honda or briggs & stratton engine with each wheel having a modified power steer pump in it through a reduction unit of your choice, this could do away with brakes as the hydraulics could power & brake the wheel at the same time, also gives the ability to skid steer on its own axis if required, also frees up clearance issues for suspension/articulation, weight distribution as you dont have to worry about chains or drive shafts passing through or around the cab area.

Cheap way to try out new ideas to see how wheel they work before fitting them to the bigger comp trucks

would a power steering pump even work as a hydaulic motor? Dont think it would.

Shadow wrote:would a power steering pump even work as a hydaulic motor? Dont think it would.

They are usually just a cheap vane type pump, which in theory can be turned into a vane type motor similer to those used in air tools, pump operating pressure is only around 1500 psi which is half of what normal hydraulic systems run at. it would be costly to try & do this setup on a full size comp truck but for the elcheapo light weight micro toughnut class it should work a treat.

call it 'LilRock'

interesting idea with the power steer pumnp. Only problem i can see is that the low pressure side of the pump may not be able to handle the full pressure as in the high pressure side? i guess experimentation is in order >_<


If you got 4 4wd pumps for the wheels, and a big ass truck power steer pump attached to the motor, you could then also run all your steering etc from hydro aswell.

I wonder how much torque a power steer pump would have before you blow seals in the pump.