Heavyweight vs Lightweight 4X4's

[87suzi]

I was wondering what you guys thought about weight of 4WD's while offroading cause like, weight both acts as an advantage and disadvantage for ya. The more weight placed on a tyre, the more traction it has with the ground. If the ground is soft the more weight on a tyre the more that tyre will sink which is bad. And finally while say climbing a hill, although more weight on any wheel that is driving is good because it provides more grip, the overall weight of the vehicle is pushing that very vehicle back stopping it from making it up, so in that sense you'd want the lighest vehicle possible. So yeah whats the verdict basically. I've been in situations when I've been climing up a hill spinning my wheels, and having my mate stand with a foot on each wheel arch in the back make a big difference, at least the difference between making it up or not.

[alien]

Perhaps looking at the POWER to WEIGHT ratio will give a better answer? =)

[87suzi]

When considering offroading is about traction, it wouldn't have much to do with power to weight.

[DeWsE]

When considering offroading is about traction, it wouldn't have much to do with power to weight.

Yeah your right, it's more about weight distrabution. Think weight at the wheels keep traction. The weight up high will have leverage on the front wheels causing the front to lift and loose traction.

Refer to the zuk to lux diffs thread as this is talked about a little bit. This is one of the advantages of climbing with lux diffs.

The zook is a light rig and works great in standard. But if you start to modify it with bigger tires weight distrabution will be an important factor.

My 2c

[Guy]

When considering offroading is about traction, it wouldn't have much to do with power to weight.

Yeah your right, it's more about weight distrabution. Think weight at the wheels keep traction. The weight up high will have leverage on the front wheels causing the front to lift and loose traction.

Refer to the zuk to lux diffs thread as this is talked about a little bit. This is one of the advantages of climbing with lux diffs.

The zook is a light rig and works great in standard. But if you start to modify it with bigger tires weight distrabution will be an important factor.

My 2c

Which is one o many reasons to stick with sensible sized and weighted motors ..

[alien]

power to weight i was referring to getting out of a muddy hole =) heavy and no power to drive the suctioned wheels and youre in trouble.

[roc box]

light weight is better in the rocks,its easier to drag 800kg over a rock than 2 ton.

[DeWsE]

light weight is better in the rocks,its easier to drag 800kg over a rock than 2 ton.

Hmmm sounds like you haven't seen a 1200 + horsepower monster truck hit the rocks! Makes it look like piss! have a look at the vid called hammer down.

[redzook]

light weight is better in the rocks,its easier to drag 800kg over a rock than 2 ton.

Hmmm sounds like you haven't seen a 1200 + horsepower monster truck hit the rocks! Makes it look like piss! have a look at the vid called hammer down.

the monster trucks do shit see where it gets a bit technical they cant get up it

[DeWsE]

light weight is better in the rocks,its easier to drag 800kg over a rock than 2 ton.

Hmmm sounds like you haven't seen a 1200 + horsepower monster truck hit the rocks! Makes it look like piss! have a look at the vid called hammer down.

the monster trucks do shit see where it gets a bit technical they cant get up it

They sure would. What I have seen they jump over stuff normal 4by's find technical.

Suppose this is an advantage and disadvantage of being big.

[Gwagensteve]

There is less advantage in the traction of a heavy car than you would think. My 2500kg G generates gobs of traction, but guess what? It's always trying to use that traction to push 2500kg up an obstacle. The lighter car will always be better - and I am keen to try and get weight out of the G, as I cannot think of a better way of improve its capability.

I reckon the real key is getting the right gearing/tyre under the car for it's weight and you will always be better off with a lighter car.

Many of the really light cars you see (stock sierras) are undergeared and undertyred, so they tend to make stuff look hard. As a result, you tend to associate crashing and banging + spinning wheels with a light car so you think light = no traction.

Trust me, my G with 31s on it redifined no traction. I went everywhere with difflocks on.

Greg's car, on the otherhand, never really seems to lack traction @ 1200kg, until it has to pull out a 2500kg G.[/u]

[87suzi]

My 2500kg G generates gobs of traction, but guess what? It's always trying to use that traction to push 2500kg up an obstacle. The lighter car will always be better - G.[/u]

Yes but as you know less weight pulling up a hill is better but at the same time you less downforce on the tyres meaning less traction. So the question is, does this always end up equalling out? Basically, does the drop in weight of a vehicle directly correlate to the drop in traction? It's tricky to think about isn't it?

[alien]

does a tall fat person find it harder to climb rocks that a short skinny person?

may be a better way to look at it? =) taller fatter people will likely have more strength, but need all of it to move. smaller person, not as strong, but less weight to haul up there.

sure is a noodle scratcher!

[crispy]

Take that spanish movie that was posted up by someone cant remember who but the sierra and swb paj made it up the muddy hill whereas the old landie and rangie had no hope.
I'm with Gwagensteve I think it has a fair bit to do with gearing/tyre size and power to weight.
There are too many different variables in this situation to make a call which is actually better

[1MadEngineer]

there is no set rule on what works and what doesnt, but there are always a few rough guidelines.
Power to weight is always a big one, you really need to explain this as a few factors - torque and 'crawlability' and pure wheel speed. You need to be able to crawl over and up high traction obstacles and yet launch up and over ones that have little traction or irregular surfaces. generally a min of 150-300hp is used in most comp rigs and a crawl reduction of between 70-110:1.
Traction is another biggy. traction is a combination of vehicle weight (and mass/cg location) and tyre size/footprint/compound/pattern and suspension design. more often than not a too large a tyre is used which results in a lack of ground pressure, which limits the amount of power able to be transmitted to the ground in off camber/inclined positions. Suspension geometry is a major factor, as this must be design to utilize the weight distribution of the vehicle to an advantage.

so is lighter better than heavier, yes , if it designed properly!

[87suzi]

with gearing/tyre size and power to weight.
There are too many different variables in this situation to make a call which is actually better

Gearing/tyre size and power to weight in my opinion help in picking up momentum of your car in short distances. So for example if you had to get a run up to climb a steep hill and you only had about 10 metres, then the car with more power would be able to accellerate to a higher speed before hitting the hill, same as climbing rocks and that. But what usually stops you from making it up a hill is the wheel spin. Therefore, traction traction traction.

[roc box]

[roc box]

light weight is better in the rocks,its easier to drag 800kg over a rock than 2 ton.

Hmmm sounds like you haven't seen a 1200 + horsepower monster truck hit the rocks! Makes it look like piss! have a look at the vid called hammer down.

yeh ive got it didnt realy think the monster trucks were capable tend to agree with redzook when it got technical the wheels fell off pretty quick

[muppet_man67]

It may also have something to do with footprint to weight. a zook on 31s will have over twice the footprint to weight ratio as a large 4wd on the same size tyre. Therefore they should have much greater traction to weight. Hence the reason why zooks are able to much more easily drag themselves over obsticles. The reason I think that on a rare occasion a sierra will struggle up a muddy slope compared to a large vehicle has little to do with extra down pressure created by increased weight. and much more to do with the poor weight distribution of a swb zook on steep inclines. Almost all the weight ends up over the rear wheels where larger 4wds climb up with all four wheels taking part in the action.

I reckon if you were a maths genius you would be able to figure out a formula giving you a bellcurve with an optimal tyre size to weight ratio.

[Beastmavster]

Depends on the surface... if the surface is highly grippy, then weight isnt the issue, power to weight or even effective power to weight (read gearing) is more relevant. A S3'd zuk will win on that regard till it does a CV

If the surface is sloppy (deep mud)then more grunt and more weight will help.... it's substantially easier to clean the rubber out with more power, regardless what the power to weight ratio is.

The other issue is i suppose with more weight it's probably a bit easier to find marginal amounts of traction, and even 10% of 100kw will pull out out of mud better than 5% of 40kw.

[Gwagensteve]

I disagree. sierras will always outdo a heavier car in mud ( even with junky tyres) because they sit up on top and also have a wide usable rev range.

Yes, it is easier to generate wheelspepd with more power, but the added traction of more weight will make it harder to generate that wheelspeed. that's part of the reason why a 50kw 3b landcruiser can't generate wheelspeed but a 44kw sierra can.

as to the finding marginal traction thing - try and push an almost stuck heavy car and then push a sierra - usually, you can push the sierra out, whereas with the big car you are looking for the strap. If you have less weight to move, a very small change in the traction situation will be enough to drive it out. even changing the a lighter driver will often unstick a sierra (trust me, I weigh 70kg and have often driven cars out that 100kg drivers cant) so there has to be a benefit from less weight.

Remember the tyre to weight thing will always favour a sierra, so there are more biting edges per kg with a light car to move the car, and less force required to do it.

Lets say a "mild" sierra runs 31 10.5s, and a "mild" landcruiser runs 33-35 12.5's. to have the same ground pressure as a zuk, you'd have to have over 40's. sure, everone knows a cruiser with 40's is capable, but hardly mild, but the sums work out the same for the "mild" zuk.

except for tractor pulling, there is not one endevour in vehicle capability that is aided with more weight, except when the traction you can generate is being applied to another object, like trying to pull somone out. That's why to level out a race series etc, the #1 handicap used is added weight. EVERYTHING gets harder with a heavier car.

[87suzi]

I disagree. sierras will always outdo a heavier car in mud ( even with junky tyres) because they sit up on top and also have a wide usable rev range.

Yes, it is easier to generate wheelspepd with more power, but the added traction of more weight will make it harder to generate that wheelspeed. that's part of the reason why a 50kw 3b landcruiser can't generate wheelspeed but a 44kw sierra can.

as to the finding marginal traction thing - try and push an almost stuck heavy car and then push a sierra - usually, you can push the sierra out, whereas with the big car you are looking for the strap. If you have less weight to move, a very small change in the traction situation will be enough to drive it out. even changing the a lighter driver will often unstick a sierra (trust me, I weigh 70kg and have often driven cars out that 100kg drivers cant) so there has to be a benefit from less weight.

Remember the tyre to weight thing will always favour a sierra, so there are more biting edges per kg with a light car to move the car, and less force required to do it.

Lets say a "mild" sierra runs 31 10.5s, and a "mild" landcruiser runs 33-35 12.5's. to have the same ground pressure as a zuk, you'd have to have over 40's. sure, everone knows a cruiser with 40's is capable, but hardly mild, but the sums work out the same for the "mild" zuk.

except for tractor pulling, there is not one endevour in vehicle capability that is aided with more weight, except when the traction you can generate is being applied to another object, like trying to pull somone out. That's why to level out a race series etc, the #1 handicap used is added weight. EVERYTHING gets harder with a heavier car.

I agree with everything you said. I think maybe we're going to get biased opinions because it's a suzuki forum and people swear by their lightweight machines. I remember my suzi on stock 205/70 R15 highway tyres used to make it up hills that my mates Ford Raider couldn't with 235/75 All Terrain's. Also my stockie suzuki outperformed a pretty well modded FJ40 Landcruiser on 31 All Terrains. I think part of that was cause of the suzuki's narrow track the wheels didn't fall all the way into the ruts.

[Beastmavster]

I'd say the opposite... based on my recently sold vitara.. With 31's even wiht a 1.6 I really struggled to clear mud from the muddies, in conditions when old landcruiserss and patrols got thru with power and at's (wit far less clearance)

I guess in some ways it was a matter of my approach speed which slowed down (to save CVs) but in the end I cleared mud from the 30's really easy but 31"s + mud equalled bogged.

As far as mud goes... my suzuki on HT's and also with stock sized a/t's would get bogged in a teacup ful of mud, even with massive RPM and second gear entry. The same stuff would be walkthrough for a L/C, Patrol, or even a for raider on 31" at's.

I think a lot of us forget how incapable a standard suzuki is in the wet since it's so long since we had one.

[Gwagensteve]

A vitara does not work like a light car. I think you wold be surprised how heavy a vit is if it ran over a weighbridge. ( my guess would be over 1300kg) In my experience you have to drive a vit more like a hilux than a sierra.

I think you are highlighting problems with the vit in relation to clearance under the front crossmember, gearing etc rather than just weight.

[Beastmavster]

Actually the vitara was 1025kg in stock form - so about 30-40kg more than a wt sierra.

After it was all kitted out it would have weighted another 100kg or so, but then so would the sierra. The proportional weight difference only gets smaller, not bigger. A 2% weight difference doesnt push a SWB vitara into a whole new weight class.

Sure gearing was definately part of the issue, but it did have the 1.6.

Anyway I was more referring to comments about how good a sierra is on 205 H/T's as opposed to say a Patrol on it's stock 31" rubber (A/t's stock on my model GQ).... and to be honest anyone who's thinks a Sierra on 205 H/T's is gonna get thru mud better has a bad memory or has their hand on it. I'll happily put my 31" A/T's back on and you can put your 205 HT's on and well make a day of it - loser buys the beer.

Clearance wasnt the vitara's issue. A vitara on 31"s has way more clearance under the front crossmember than a sierra on 31"s has under it's front diff. That's one of the benefits of IFS.

[87suzi]

Actually the vitara was 1025kg in stock form - so about 30-40kg more than a wt sierra.

After it was all kitted out it would have weighted another 100kg or so, but then so would the sierra. The proportional weight difference only gets smaller, not bigger. A 2% weight difference doesnt push a SWB vitara into a whole new weight class.

Sure gearing was definately part of the issue, but it did have the 1.6.

Anyway I was more referring to comments about how good a sierra is on 205 H/T's as opposed to say a Patrol on it's stock 31" rubber (A/t's stock on my model GQ).... and to be honest anyone who's thinks a Sierra on 205 H/T's is gonna get thru mud better has a bad memory or has their hand on it. I'll happily put my 31" A/T's back on and you can put your 205 HT's on and well make a day of it - loser buys the beer.

Clearance wasnt the vitara's issue. A vitara on 31"s has way more clearance under the front crossmember than a sierra on 31"s has under it's front diff. That's one of the benefits of IFS.

Well in some cases my suzi on stock 205 H/T did outperform bigger cars on 31" A/T's. I don't know about in the mud so much, but think about it heavier cars will sink more. Anyway as I said, this one time the FJ40 got stuck in the mud while mine made it through rather easily. I don't know whether this was to the narrow track of the sierra which stopped it's wheels falling into the ruts.

[Gwagensteve]

Actually the vitara was 1025kg in stock form - so about 30-40kg more than a wt sierra.

After it was all kitted out it would have weighted another 100kg or so, but then so would the sierra. The proportional weight difference only gets smaller, not bigger. A 2% weight difference doesnt push a SWB vitara into a whole new weight class.

Sure gearing was definately part of the issue, but it did have the 1.6.

Anyway I was more referring to comments about how good a sierra is on 205 H/T's as opposed to say a Patrol on it's stock 31" rubber (A/t's stock on my model GQ).... and to be honest anyone who's thinks a Sierra on 205 H/T's is gonna get thru mud better has a bad memory or has their hand on it. I'll happily put my 31" A/T's back on and you can put your 205 HT's on and well make a day of it - loser buys the beer.

Clearance wasnt the vitara's issue. A vitara on 31"s has way more clearance under the front crossmember than a sierra on 31"s has under it's front diff. That's one of the benefits of IFS.

The lightest sierra I have ever seem on a weighbridge as 1060,( with a 70 kg driver) and that had no trim, no bumpers, no cage, and #$% all else.

Most vits will be 1300kg across a weighbridge. Most of the kerb weight figures I am seeing for a vit are in the 1200kg range. There is no way a vit is only 40kg heavier than a sierra. I wasn't even talking about a whole different weight class, rather that with the combination of heavier car with similar power and torque and taller gearing in a vit leads to a car that can no longer be compared to the performance of a genuinely light car, in a sierra.

Sorry, I am only talking from experience whent I talk about stock sierras and mud ability, but I'm in vic, where all we have is rock and hilux axles, so what would I know.

[Beastmavster]

The lightest sierra I have ever seem on a weighbridge as 1060,( with a 70 kg driver) and that had no trim, no bumpers, no cage, and #$% all else.

Most vits will be 1300kg across a weighbridge. Most of the kerb weight figures I am seeing for a vit are in the 1200kg range. There is no way a vit is only 40kg heavier than a sierra. I wasn't even talking about a whole different weight class, rather that with the combination of heavier car with similar power and torque and taller gearing in a vit leads to a car that can no longer be compared to the performance of a genuinely light car, in a sierra.

Sorry, I am only talking from experience whent I talk about stock sierras and mud ability, but I'm in vic, where all we have is rock and hilux axles, so what would I know.

Couple of things here. Do the math, a w/t sierra has taller overall low gearing than a vitara.

Both have 3.652 first.

Low Sierra 2.268 x 3.73 diff = 30.9:1
Low Vitara 1.816 x 5.125 diff = 33.9:1

Scary huh? Vitara has lower stock gearing AND a 25% bigger engine. And I keep hearing here this stuff about how sierras have heaps lower gearing.

Even a 1 litre tcase only brings the sierra level at 34:1 (the sierra is actually about 1-2% ahead then).

Not lower gearing at all unless you have a rockhopper. We'll ignore nt utes for the moment Chris

The weight differential is hardly suprising... the alloy front end weighs heaps less than the sierra equivalent and the sierra block actually weighs more than the vitara one too.

Later vitaras did lard out though - while my SWB was a light 1025 (88 model) by about 1993 they weighed in at 1200kg. Yeah it's a kerb weight figure, just like supplied by suzuki for the Sierra at just under a ton.

I stand by my comments, the proportional weight difference will be smaller in real life than it is on "kerb weight". Really we're both agreeing with each other....

Add 70kg for a driver, 50 litres in liquids, another 100kg for muddies, another 100kg for other crap and the weight difference stays the same, but the percentage weight difference goes down.

Add the same stuff in on a Patrol and it makes a lot less difference.

One benefit of the slightly higher GVM means we can put a bigger engine in the Vitara legally Here in QLD once it's over 1100kg GVM they change the way max capacity is calculated

[Gwagensteve]

We are saying the same thing, except that In my experience vitaras drive perform more like heavy cars than a sierra.