Ground Clearance - Basics for Newbies

Parker74

New Member
Hi All

As a newbie, there are a few questions I'd like to check out with the collective brains of 4x4 earth to check if I've got my head around things correctly.

Like everyone here, I'm guessing, I'd like to get the most out of my 4x4 (Hilux 2010 Diesel Double-cab) and would love to take a trip into the Outback and do some touring. I'm pretty much sold on the benefits of diff lockers, having seen where they are indispensable. However, I'm still not quite certain about the basics of improving ground clearance via suspension lifts, body lifts & wheel/tyre combination changes. That's where I'm hoping you good people can put me straight!

So, if I understand correctly (which isn't necessarily the case...), the only way to increase ground clearance for the diffs/wheel hubs/control arms etc is to increase the diameter of the rolling wheel/tyre combination. Now, I love the aesthetics of some chunky tyres as much as the next bloke, but I'm guessing that you can only take this principle so far before the tyres are rubbing inside the arches under suspension compression. Obviously this rubbing issue would be compounded by turning the wheels or fitting wider tyres.

So, my first question is what are the options for counteracting this? If I've got my head around this, then fitting spacers to the suspension mounts would lift the body. So, if your wheel/tyre combination diameter increases by 2", then a 1" spacer (ie. the rolling radius change) would give you back your original wheel travel. It would just need careful attention to tyre width under compression & wheel turning to avoid any fouling. Is this thinking correct, or am I missing something? (I realise the effect this has on gearing).

You could also raise the body by fitting longer suspension instead of spacers. But, correct me if I'm wrong, this only increases the ground clearance of anything attached to the bodywork. So, this would have no effect on the clearance height of the diffs, for example, but would take the oil sump farther out of harms way.

I'm struggling to visualise if there are other benefits of longer suspension. Does longer suspension give increased travel too? I could imagine this allowing the wheel to drop further into a rut, but does it also allow a greater travel over bumps too, or do you just hit the bump stops when the original suspension travel is used up? For some reason I'm having trouble getting my head around this bit!

I suppose, ultimately I'm asking for advice on what the benefits of a suspension based lift, versus a body lift plus wheel/tyre diameter change are? Presumably, the standard factory alignments are maintained with the wheel/tyre change, plus the body lift option? Whereas, I understand that CV joints have to travel through greater angles with suspension based lifts, necessitating drops kits to be used (over 2"). Are there any other pros/cons to these two different options?

As you'll gather, I'm having fun getting my head around these ideas. All pearls of wisdom gratefully received. Or if this has already been covered elsewhere, please direct me there.

Hugh
 

Les PK Ranger

4x4 Earth Contributer
G'day Hugh,

Much of your theories are correct.

I just did a small suspension lift on my IFS front / leaf rear when near new.
Lift gained was 25 front, put the lift right even on the top and bottom bumps, and doesn't bugger up CV angles etc.
Got 40 rear without it looking weird, usually carry a bit of kit in there.

Seriously thinking of winding up the HD torsions a slight bit more, and trimming bottom (?) bumps a little, then maybe adding one of my old leafs to each of the new HD leaf packs, a thin one to just give it a bit more in the rear (have canopy, towbar, going to put in drawers and fridge etc).

Going to go from ~ 28-3/4" dia tyres to 31's, should give me another good inch of real clearance overall, as well as less rolling resistance over obstacles.
I think I'll be happy with that.

That should not stuff up econ or other driving factors too much, or muck up LR gearing too badly.

A small body lift is something you could consider.
Main benefit is it's a lot cheaper than a suspension lift, but you have to consider adjusting bullbars etc (anything attached to the chassis) if body lifting more than say an inch ?
Larger body lifts also require extended brake lines and such in most cases.

A suspension lift is better than a body lift, because you do get the running gear off the deck as well as improvements to approach / departure angles and ramp over.
 

prawns

Moderator
Seriously thinking of winding up the HD torsions a slight bit more, and trimming bottom (?) bumps a little.......

I did exactly that to my Paj - Wound the torsion bars up to gain 2 inches that it had sagged in the front due to age, then cut the bumpstops in half to gain some more flex back cause it lost alot of downward wheel travel

Mind you the warning in the Paj forums were not to cut your bumpstops too much else risk the cv shaft falling out from the extra flex - but its a common mod on the older Pajs to cut them in half - and recently I did some "crossaxled" stuff where mine would of fallen out if they were going to (they didnt thank god hahahhaha :D )
 

muc the truck

Well-Known Member
Hi All

As a newbie, there are a few questions I'd like to check out with the collective brains of 4x4 earth to check if I've got my head around things correctly.

Like everyone here, I'm guessing, I'd like to get the most out of my 4x4 (Hilux 2010 Diesel Double-cab) and would love to take a trip into the Outback and do some touring. I'm pretty much sold on the benefits of diff lockers, having seen where they are indispensable. However, I'm still not quite certain about the basics of improving ground clearance via suspension lifts, body lifts & wheel/tyre combination changes. That's where I'm hoping you good people can put me straight!

So, if I understand correctly (which isn't necessarily the case...), the only way to increase ground clearance for the diffs/wheel hubs/control arms etc is to increase the diameter of the rolling wheel/tyre combination. Now, I love the aesthetics of some chunky tyres as much as the next bloke, but I'm guessing that you can only take this principle so far before the tyres are rubbing inside the arches under suspension compression. Obviously this rubbing issue would be compounded by turning the wheels or fitting wider tyres.

So, my first question is what are the options for counteracting this? If I've got my head around this, then fitting spacers to the suspension mounts would lift the body. So, if your wheel/tyre combination diameter increases by 2", then a 1" spacer (ie. the rolling radius change) would give you back your original wheel travel. It would just need careful attention to tyre width under compression & wheel turning to avoid any fouling. Is this thinking correct, or am I missing something? (I realise the effect this has on gearing).

You could also raise the body by fitting longer suspension instead of spacers. But, correct me if I'm wrong, this only increases the ground clearance of anything attached to the bodywork. So, this would have no effect on the clearance height of the diffs, for example, but would take the oil sump farther out of harms way.

I'm struggling to visualise if there are other benefits of longer suspension. Does longer suspension give increased travel too? I could imagine this allowing the wheel to drop further into a rut, but does it also allow a greater travel over bumps too, or do you just hit the bump stops when the original suspension travel is used up? For some reason I'm having trouble getting my head around this bit!

I suppose, ultimately I'm asking for advice on what the benefits of a suspension based lift, versus a body lift plus wheel/tyre diameter change are? Presumably, the standard factory alignments are maintained with the wheel/tyre change, plus the body lift option? Whereas, I understand that CV joints have to travel through greater angles with suspension based lifts, necessitating drops kits to be used (over 2"). Are there any other pros/cons to these two different options?

As you'll gather, I'm having fun getting my head around these ideas. All pearls of wisdom gratefully received. Or if this has already been covered elsewhere, please direct me there.

Hugh

you got the right Idea about going for lockers . keep it perfectly legal , I have a friend who is a cop and traffic cops are going back to school about mods etc and being tested on ncop rules . He even knew to look for spot welds on doors to see a hz sedan has the correct doors fitted and defected one fellow for having a drivers side hj door fitted with no internal extrusion bars. The guy did call him a fh first but. with good shockers , tyres and lockers it will behave well both on and off road . with largest legal tyres and stronger bash plates it will get you any were you want to go.
 
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bluehilux

Banned
Your question is a good one :) But i wish i could add info but i can't.
I'm happy & lucky and like my solid 91 hilux as i don't need to do this. Sad how the 4wd have changed so much to suit the majority ..
Best of luck :)
but i agree with muc the truck if i had a vehicle of this type.
 

03gallagherj

New Member
Pretty well correct the only real other way of lifting your diff centers (which isn't exactly able to do with its) is a set of portals or hub reduction gears. Lol

Prawns yes those old paj's have that mod done alot ;) mine have fallen out a few times and when the forum refers to falling out they don't come out they still have drive etc they just unseat causing an oil leak. Push it back in and problem solved haha

Sent from my Lumia 710 using Board Express
 

abw

Well-Known Member
Good afternoon, I installed in the springs "air cylinders"

This allows me to adjust the height of the clearance
Yep, they're called airbags. Just remember that these are not designed to lift the vehicle. They are used a support or prevent sagging if you occasionally have a heavy load on the back.
 

Aaron Schubert

Moderator
Yep, they're called airbags. Just remember that these are not designed to lift the vehicle. They are used a support or prevent sagging if you occasionally have a heavy load on the back.

Yep, unless they are a kit like the second one VladHorror posted that replaces the coil altogether.

Aaron
 

Kando

New Member
Yeah good old bags, be careful with these, can end bending the dog leg on the chassis due to pivot effect and over loading of bag, think of it like putting a small stick on a log and then place a foot either end of the stick and the. You hear snap:eek:
 
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