Outer Limits 4x4 Board

Posted: **Mon Jan 19, 2004 3:47 pm**

I picked up from past threads that there is a rule of thumb that says for every inch up, go 1.5 inches sideways to lower the risk of sideways roll-over. Does anybody know how bigger rubber and extra height effects the possibility of end-over-end roll-overs? is there a similar rule i.e for every inch up go 1 inch longer wheel base or is it just the longer the better?

Posted: **Mon Jan 19, 2004 3:58 pm**

Hi Dawg,

I don't know about the extending the wheelbase length according to height rule, but one that i have heard about suzukis is:

"When the drivers seat is vertically above the rear wheel, the car will not climb anymore (i.e. it is too steep)... "

I don't know if this is right or wrong though - just a rule of thumb

Have a hunt around for Centre of Gravity - N*A*M recently posted a link to a jeep webpage that shows formulas for working out centre of gravity and likely-hood of rollovers at different angles etc...

Hope that helps a bit.

Cheers

Posted: **Mon Jan 19, 2004 3:58 pm**

Never really heard of a hard and fast rule for this one, but if you've got a SPOA swb zook on 35s and like hill climbs, get a cage

or a helmet! :finger:

Comp guys are hitting around 100" wheelbase these days, but unless you're running huge tyres you will be OK with 90 - 95 IMO.

BTW, i'm at about 93" at the moment and that will probably stretch out another inch or so. Tyres are 32s at the moment but I want to end up using 35s offroad.

Posted: **Mon Jan 19, 2004 4:01 pm**

basically longer is better. I'm sure this a rule of thumb but not sure what it is. A LWB will be better in this regard than a SWB. A couple of things you can do is lengthen your wheelbase by using longer springs in the front (ie rear springs like a few of us are doing), longer springs in the rear (Feroza ones like Redzook) or hilux springs like MickBJ is doing. Also fitting a stinger bar like ljextreem has done should help as this stops the car getting to the point of being on its nose.

Or you could be careful not to drive down steep drop offs

Endoes are probably less frequent than sideways flops

Posted: **Mon Jan 19, 2004 4:03 pm**

nice topic. very interesting point there. :cool:

not sure if there is any rule but there are certainly strong relationships between tyre size and wheelbase. eg 42"s at 90" would be too much, but 31"s at 110 would be not enough.

i guess it also depends on the kind of terrain you do. a lot of hill climbing would benefit from a longer wheel base; where as a lot of short course crawling, shorties have the manoeuvrability.

Posted: **Mon Jan 19, 2004 6:20 pm**

I think I have miss judged you guys (grimbo and greg)!
Your replys to this thread are quite helpfull and greg i think for us newbies we do need a bit of direction with the help of key words.
To tell you the truth without you blokes work would be boring!

And as for the rule I wouldn't have a clue because I think I have the lowest zook on this forum.

Posted: **Mon Jan 19, 2004 8:14 pm**

Damo wrote:Never really heard of a hard and fast rule for this one, but if you've got a SPOA swb zook on 35s and like hill climbs, get a cage

or a helmet! I WOULD SAY GET AND USE BOTH

Comp guys are hitting around 100" wheelbase these days, but unless you're running huge tyres you will be OK with 90 - 95 IMO.

BTW, i'm at about 93" at the moment and that will probably stretch out another inch or so. Tyres are 32s at the moment but I want to end up using 35s offroad.

Posted: **Mon Jan 19, 2004 8:22 pm**

End over end or going over backwards a very rare type of roll overs. 100' seems to be the length everyone is aiming for which isn't possible in a Zook without some major work and cutting. I guess every Zook would have a different angle at which it will go over as there are so many setups I guess when you don't feel comfortable back out.
SAM

Posted: **Mon Jan 19, 2004 10:58 pm**

You can get a Zuk up pretty high going up hill and the nose will still come down (one of the benifits of keeping the nose light .. some say a nose heavy vehicle will climb better .. but a nose heavy vehicle on the limit the front end will wash out faster .. Think of balancing a stick on its end on your finger .. now think of balancing that same stick with a weight at the top .. once it starts to go .. if it will go much faster and will need way bigger inputs to stop).

Often you will find that also that you will loose traction (when climbing) or your nerve before your likley to go end for end .. unless your going a bit hard ... then momentum is not your friend

Posted: **Tue Jan 20, 2004 8:06 am**

DeWsE wrote:I think I have miss judged you guys (grimbo and greg)!
Your replys to this thread are quite helpfull and greg i think for us newbies we do need a bit of direction with the help of key words.
To tell you the truth without you blokes work would be boring!

And as for the rule I wouldn't have a clue because I think I have the lowest zook on this forum.

we have our moments

Just don't ask what size tyre will fit an unmodified zuk :rofl:

Posted: **Tue Jan 20, 2004 8:15 am**

grimbo wrote:
DeWsE wrote:I think I have miss judged you guys (grimbo and greg)!
Your replys to this thread are quite helpfull and greg i think for us newbies we do need a bit of direction with the help of key words.
To tell you the truth without you blokes work would be boring!

And as for the rule I wouldn't have a clue because I think I have the lowest zook on this forum.

we have our moments Just don't ask what size tyre will fit an unmodified zuk

What size trye can if fit on my suzuki ... I have a swift and I want to put 17 inch mags on it :finger:

Posted: **Tue Jan 20, 2004 8:51 am**

I had a look at that Jeepoholic web site - it's american and I read the whole thing, it hurt, JEBIZ! americans can at times be painful. There is a good spread sheet on that site but I think it's a bit complicated - I'll try and work out an easier one to create some rules of thumb - I've always been worried about rolling my swift on 17"s :roll:

Posted: **Tue Jan 20, 2004 8:54 am**

DeWsE wrote:... greg i think for us newbies we do need a bit of direction with the help of key words...

You obviously haven't read many of my posts dewse - most of my keywords are "thingy", "thing-a-me-jig" and "type-thing"... :oops:

Posted: **Thu Jan 29, 2004 6:56 pm**

Dawg wrote:I had a look at that Jeepoholic web site - it's american and I read the whole thing, it hurt, JEBIZ! americans can at times be painful. There is a good spread sheet on that site but I think it's a bit complicated - I'll try and work out an easier one to create some rules of thumb - I've always been worried about rolling my swift on 17"s

Any news???????????

Posted: **Thu Jan 29, 2004 7:17 pm**

overkill wrote:End over end or going over backwards a very rare type of roll overs. 100' seems to be the length everyone is aiming for which isn't possible in a Zook without some major work and cutting. I guess every Zook would have a different angle at which it will go over as there are so many setups I guess when you don't feel comfortable back out.
SAM

Yup....there are very rare Sam... :armsup:

I came close but luckily it didnt go over

Posted: **Thu Jan 29, 2004 7:42 pm**

I've gone about 6" higher and 6" wider - cant remember for sure but it's something like that and I AINT putting it back to measure

I think the biggest risk of rollover is due to me planting the boot during u turns with the CIG rear......

Moose where are you? :oops:

Seriously if you never wanna risk rolling it no lockers is a good place to start..... so is having no testes.... :finger:

Posted: **Fri Jan 30, 2004 8:16 am**

Yeah, the Dawg has been a bit busy (lazy) lately but I'll hook it up this weekend and post on Monday.

Hey Viagra, try your testes on this one baby! I don't need lockers to roll :cool:

Posted: **Fri Jan 30, 2004 8:40 am**

Dawg wrote:Yeah, the Dawg has been a bit busy (lazy) lately but I'll hook it up this weekend and post on Monday.

Hey Viagra, try your testes on this one baby! I don't need lockers to roll

Yeah .. but thats a landcrusier .. they can fall over in a coles car park with the motor turned off and the handbrake on

not one of our super stable Zuks

I am kidding ..

Posted: **Fri Jan 30, 2004 9:07 am**

that's cool Love_Mud, my old cruiser was so lifted it probably would have - hence the up and coming rule of thumb

Posted: **Sat Jan 31, 2004 8:12 am**

Dawg wrote:Yeah, the Dawg has been a bit busy (lazy) lately but I'll hook it up this weekend and post on Monday.

Hey Viagra, try your testes on this one baby! I don't need lockers to roll

So you have testes but no locker.....

Howver it's clear you have no brain instead of no testes - for owning a toyota :finger:

Dawg, this just goes to prove if you don't wanna roll something, zuks aren't necessarily the least stable. Maybe this is why you want a Zuk instead of another Cruiser

Luxes and cruisers aren't much different for stability either.

Bit concerned about how you managed to roll there.... :shock:

it's not like the terrain looks particulraly steep or challenging.

Posted: **Sun Feb 01, 2004 9:49 am**

I reckon this is stable

Posted: **Sun Feb 01, 2004 8:09 pm**

[/quote]

Yeah .. but thats a landcrusier .. they can fall over in a coles car park with the motor turned off and the handbrake on

not one of our super stable Zuks

I am kidding ..[/quote]

Try a Rangie, roll it in the carpark and still keep the tyres on the ground, suspension by slinky

Posted: **Mon Feb 02, 2004 9:48 am**

There there Viagra, It was raining and I slid sideways over a water run off :oops:

Now, the rule of thumb is as follows:

What we are trying to do is work out:

1) how many inches sideways you have to go for each inch up and,
2) how many inches longer you need to go for each inch up

The general rule can be applied to any car except Vitaras as they can't be lifted anyway so nobody cares :lol:

NB: Since we are working out a ratio, somebody needs to do this on a bog standard zook first, to get the ratio that everybody else can use. It is pointless doing this on a lifted 4by because it will just give you the ratio for that car, and have no relevance to any other car (i.e. the ratio will be wrong)

Sideways

1) Measure the height of the centre of gravity off the ground. As hard as this sounds, for a good approximate just measure from the ground to the centre of the base of the drivers seat. Car manufacturers will generally try to position the CoG as close to the drivers position as possible to give the driver maximum feeling of control over the vehicle. So, Hcog = Height from ground to centre of base of drivers seat.

2) Measure the wheel track (WT) from the outside of each tire

3) divide WT by Hcog = ratio.

4) example: WT = 60 inches, Hcog = 40 inches therefore ratio = 1.5

So, in this example, for every inch up, you need to go out sideways by 1.5 inches

End-Over-End

Same rule as above except replace the WT measurement with the Wheel Base of the car

Other stuff about roll-over angles

Since the CoG is off centre of the vehicle (i.e. closer to the drivers side), it's easier to roll your 4by on the drivers side than the passenger side.

For the same reason it's also easier to roll your 4by frontwards instead of backwards.

Every inch up results in ABOUT 1 - 2 degrees worse roll-over angle (sideways).

According to the american spreadsheet, lengthening your WB results in a reduction in side rollover angles - no idea why, it's just what it says

Hope this helps - can somebody do the actual measurements on a standard suzi and find out the real ratios please?

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