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What Lfit in GQ to fit 37-38's?

Tech Talk for Nissan owners.

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What Lfit in GQ to fit 37-38's?

Post by bigbluemav »

Yes I did search and even looked back 10 pages!!

I plan on installing a 2" body lift, so how much suspension lift to fit 37-38's?
Big Dave, Scarborough, Qld
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Post by SIM79 »

Below are 37s with a 3 inch suspension lift and no body lift
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Below are 38s with a 2-3 inch suspension lift and no body lift
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Post by Micka »

SIM79 wrote:Below are 37s with a 3 inch suspension lift and no body lift
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Below are 38s with a 2-3 inch suspension lift and no body lift
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Well I'll be damned!!!

Thank you SIM79...finally someone with a Patrol that has not done a 300" lift to fit decent tyres.

Nice chopping by the way...looks very neat.
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Post by bigbluemav »

Ta for that info all!! And, again, nice job with the guard trim!!

And it is good to see decent tyres without a mega lift!! After having a Mav' with a 4" spring + 2" body lift and STRESSING every time I saw a police/DOT car car, this time round I'll DEFINITELY be going this route this time, with 33's for road and BIGGER play tyres!!

Ta to all again.


Dave Mc
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Post by mud_runner_GQ »

yeah mate. with my truck i can fit 38's to 40's with standard springs. just depends how much you want to cut :P
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Post by BASSYK »

my shorty fit 38" swampers with 4"spring and 3" body lift

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Gu TD42t

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Post by bogged »

bigbluemav wrote:Ta for that info all!! And, again, nice job with the guard trim!!

And it is good to see decent tyres without a mega lift!! After having a Mav' with a 4" spring + 2" body lift and STRESSING every time I saw a police/DOT car car, this time round I'll DEFINITELY be going this route this time, with 33's for road and BIGGER play tyres!!

Ta to all again.
Dave Mc
suprised more people cant get past the theory of needing 29ft lift to fit tires..

or "can I get 90,000 out of swampers I wanna use them as road tires"..

2 sets or bust!
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Post by bigbluemav »

bogged wrote:
bigbluemav wrote:Ta for that info all!! And, again, nice job with the guard trim!!

And it is good to see decent tyres without a mega lift!! After having a Mav' with a 4" spring + 2" body lift and STRESSING every time I saw a police/DOT car car, this time round I'll DEFINITELY be going this route this time, with 33's for road and BIGGER play tyres!!

Ta to all again.
Dave Mc
suprised more people cant get past the theory of needing 29ft lift to fit tires..

or "can I get 90,000 out of swampers I wanna use them as road tires"..

2 sets or bust!
Agreed Bruce!! Next time, it'll be two sets, 33's for road and 37/38's for play!! And no HUGE lift!!
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Post by short ass patrol »

i have 2"spring 1.5" body and arch cut on 37s
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Post by steel »

ive measured a 38'' tyre that was only just 35'', and a 35'' that was 33''. alot of tyres dont measure up to whats written on the sidewall.
when i fitted true 37'' tyres to my gu ute they fitted no worries with my 2'' suspension lift, radius arm spacers and a little gaurd trim, i could flex it up on a trail and they wouldnt rub at all, but when i started playing harder,eg, jumping and landing hard on the bumpstops, the tyres were smashing into the top of the inner arches.
i could of extended the bumpstops but i did a body lift.
Gaurd trimming will allow you to fit 38'' tyres under a gq, but if you want to use it hard youll need a body lift or extend your bumpstops.
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Post by SIM79 »

steel wrote: Gaurd trimming will allow you to fit 38'' tyres under a gq, but if you want to use it hard youll need a body lift
If your driven hard don't use body lifts because they put extra stress on the body mounts, this why comp trucks don't use body lifts.

I had 2inch body lift once and two body bolts rip clean out driving on corrigations! I have learnt my leason and only lift suspesnion now.
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Post by steel »

opinions on body lifts aside, you cant fit 37''s to a gq with just a gaurd trim and any size lift. youll need to also do body lift or extend bumpstops.
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Post by bogged »

steel wrote:opinions on body lifts aside, you cant fit 37''s to a gq with just a gaurd trim and any size lift. youll need to also do body lift or extend bumpstops.
huh?


but isnt every setup different.. some say you cant fit 35's on a GU without a 7inch lift, others fit them with a 2inchlift
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Post by steel »

let me explain it like this.
imagine youve got a 100% stock GU and you pull out the springs and shocks, its now sitting on the bumpstops. if you then measured the clearance between the top of the standard tyres ( about 31'' ) and the inner wheel arch youll find theres about 50mm clearance. you must also allow about 20- 30mm compression of the bumpstops when bottoming out, so this leaves about 25mm clearance between the stock tyres and the inner wheel arches. now that measurement wont change wether you fit 2 or 8'' lift springs, unless you extend bumpstops or the coil binds up.
if you then fit 37'' tyres youre increasing your rolling diameter by 6'' or more importantly your rolling radius by 3'' or 75mm.
well as i explained youve only got 25mm clearance between the stock tyres and the inner arches when bottoming out on stock bumpstops, so how are you gonna accomodate the other 50mm?
there is only 4 ways that i know of,ie 50mm body lift, lower bumpstops by 50mm, tub the inner arches ( alot more than a simple gaurd trim) or drive like my grandma.
thats how i understand it anyway.
i think cutting and remaking inner arches 50mm higher ( tubbing ) is the best option but it wasnt an option for me.
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Post by Nelso »

steel wrote:let me explain it like this.
imagine youve got a 100% stock GU and you pull out the springs and shocks, its now sitting on the bumpstops. if you then measured the clearance between the top of the standard tyres ( about 31'' ) and the inner wheel arch youll find theres about 50mm clearance. you must also allow about 20- 30mm compression of the bumpstops when bottoming out, so this leaves about 25mm clearance between the stock tyres and the inner wheel arches. now that measurement wont change wether you fit 2 or 8'' lift springs, unless you extend bumpstops or the coil binds up.
if you then fit 37'' tyres you're increasing your rolling diameter by 6'' or more importantly your rolling radius by 3'' or 75mm.
well as i explained you've only got 25mm clearance between the stock tyres and the inner arches when bottoming out on stock bumpstops, so how are you gonna accomodate the other 50mm?
there is only 4 ways that i know of,ie 50mm body lift, lower bumpstops by 50mm, tub the inner arches ( alot more than a simple gaurd trim) or drive like my grandma.
thats how i understand it anyway.
i think cutting and remaking inner arches 50mm higher ( tubbing ) is the best option but it wasnt an option for me.
But if you put a 2 inch lift in and 2 inch bumpstop extensions you still have the same amount of up travel. By running longer shocks with your 2 inch lift and minimal uptravel you can get a lot more down travel which will get you your articulation. I don't understand why so many people are against bumpstop extensions, I would much prefer this than lifting the body. I agree that tubbing the wheel well is the best option and there is plenty to be gained in a Patrol from this, unfortunately it is a big job.
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Post by steel »

most 2 inch lift kits use shocks that are the same length or only slightly longer than stockers, so extending bumpstops tends to leave you with a little less wheel travel.
the reason im not keen on bumpstop extensions is this: most of us know that as your suspension extends( travels down) the angle of all your suspension links increases which can compromise ride characteristics and flog out bushes.
the further your suspension extends the worse these angles become and the worse it will handle.
in other words the flatter ( and longer) your suspension links are the better your truck will ride and handle.
so in my opinion it seems a shame to eliminate 2'' of travel from the top of its cycle (compression) where the suspension links are operating at such favourable angles
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Post by badger »

you dont need lift you need a grinder
1hd-fte 5 speed tiptronic 105 series
78 series troopy for work
gu ute play truck For sale
FTE 80 series sahara Sold

i think i have a problem
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Post by steel »

yeah i used my grinder to cut my siezed body mount bolts ha
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Post by Nelso »

steel wrote:most 2 inch lift kits use shocks that are the same length or only slightly longer than stockers, so extending bumpstops tends to leave you with a little less wheel travel.
the reason im not keen on bumpstop extensions is this: most of us know that as your suspension extends( travels down) the angle of all your suspension links increases which can compromise ride characteristics and flog out bushes.
the further your suspension extends the worse these angles become and the worse it will handle.
in other words the flatter ( and longer) your suspension links are the better your truck will ride and handle.
so in my opinion it seems a shame to eliminate 2'' of travel from the top of its cycle (compression) where the suspension links are operating at such favourable angles
You don't but a 2 inch kit, you should buy and run longer shocks. Fit your springs, cycle your suspension with the bumpstop extensions, measure it all up and fit the longer shocks. You don't have to eliminate two inches of up travel, if you fit the right length shocks you will have the same up-travel but with more down-travel.

I agree with running longer arms to improve suspension geometry but that is beyond the average bolt on modifier. The original question asked how to get 38s to fit and the simple fact is you can run a two inch lift and trim your guards to do it. You don't have to fit a body lift. By fiting the right length shocks you can still have plenty of articulation for the weekend warrior. By changing links and shock mounts you can get more than enough articulation still utilising just a two inch lift, but that's another issue entirely.
What's the difference between ignorance and apathy? I don't know and I don't care.

I am an insomniac dyslexic agnostic. I often lay awake all night wondering if there really is a Dog.
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Post by steel »

yeah Nelso i know what your saying, and you know what your talking about.
I just wanted to make it clear to those that don't, that if they fit 37'' tyres with just a gaurd trim then they are gonna have clearance problems.
there's way to many people giving the impression that trimming gaurds is the answer to all " big tyre fitment problems." ;)
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Post by ROGQ »

Nelso wrote: But if you put a 2 inch lift in and 2 inch bumpstop extensions you still have the same amount of up travel. By running longer shocks with your 2 inch lift and minimal uptravel you can get a lot more down travel which will get you your articulation..
Ok..this is where i get lost. Hopefully some of you guys can clear this up for me... Nelso, you keep talking about extending the bumpstops. Now if you were to put 2 inch bumpstop extensions in, this would limit up travel. As the diff is hitting the stops sooner prevented upwards movement. You then go on to say you can have minimal or the same up travel, and a lot more down travel. I don't see how this works. I picture it like holding a broom stick in my hand and imagining it's an axle. For one end to go down, the other end has to go up. So therefor by limiting uptavel wouldn't you be limiting down travel. I mean the axle is solid, it can't flex. :?
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Post by Nelso »

ROGQ wrote:
Nelso wrote: But if you put a 2 inch lift in and 2 inch bumpstop extensions you still have the same amount of up travel. By running longer shocks with your 2 inch lift and minimal uptravel you can get a lot more down travel which will get you your articulation..
Ok..this is where i get lost. Hopefully some of you guys can clear this up for me... Nelso, you keep talking about extending the bumpstops. Now if you were to put 2 inch bumpstop extensions in, this would limit up travel. As the diff is hitting the stops sooner prevented upwards movement. You then go on to say you can have minimal or the same up travel, and a lot more down travel. I don't see how this works. I picture it like holding a broom stick in my hand and imagining it's an axle. For one end to go down, the other end has to go up. So therefor by limiting uptavel wouldn't you be limiting down travel. I mean the axle is solid, it can't flex. :?
Say the standard suspension has 100mm between the axle and bump-stop and then you fit a coil that lifts the suspension another 50mm (2 inches) you will now have 150mm between the axle and bump-stop. You still only need the 100mm of up travel (unless you are going to do high speed work or jump your car) so you extend the bump-stops to keep up travel to 100mm. Now when your tyre goes up into the wheel well you have an extra 50mm above the tyre so you can increase the tyre radius by 50mm (diameter = 100mm increase) which is the difference between the standard tyres and a 35 inch tyre.

By increasing the length of the spring you have now moved the lower shock mount 50mm (or so, we're not going into trigonometry for this explanation) away from the upper shock mount so you can fit longer shocks. Measure the distance at ride height and take away your 100mm for your up travel and you have your compressed shock length. The longer shock will give you more down travel.

Now, when one tyre goes up and hits the bump-stop there is nothing stopping the other wheel from continuing to go down as it is not fixed at a single pivot point. When you lift the whole car off the ground both sides drop at the same time after all, and will continue to do so until the shocks reach their limit. The same will happen when you articulate the diff. One side will go up until it hits the bump-stops and the other will continue to drop until it reaches the limit of the shock.
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Post by steel »

Nelso wrote:
ROGQ wrote:
lso" wrote: But if you put a 2 inch lift in and 2 inch bumpstop extensions you still have the same amount of up travel. By running longer shocks with your 2 inch lift and minimal uptravel you can get a lot more down travel which will get you your articulation..
"

what nelso is saying is that he still has the same amount of compression stroke as standard (100mm in his example) because he has lifted springs as much as he's lowered bumpstops, but he could of had 150mm compression if he hadn't lowered bumpstops.
he still has the same or better than stock travel by making changes to shock length.
as i mentioned before i prefer not to lose that 50mm of compression from lowering bumpstops because of the favourable susp link geometry when working in that last 50mm of compression.
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Post by ROGQ »

Thanks for the explanation... I understand what your saying with the bump stops and shock mounts. My main point/question was that by limiting up travel you would restrict down travel. I still can't get my head around the if the axle stops upward movement one end, that it can continue to go down on the opposite side of the axle. I thought the bumpstop on the compression side would be the limiting factor of down movement on the extension side, not the shock. I will have to go flex it up need weekend and have a good look under there... Cheers
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Post by steel »

[quote="ROGQ"]when the suspension on one side reaches the bumpstop it does not stop the suspension on the other side from continuing to travel down.
what happens is the compressed bumpstop works like a fulcrum and the axle pivots on it.
hope this makes sense mate :)
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Post by steel »

just read your previous post again where you mentioned your example of holding the broomstick in the middle with one hand and pivoting it up and down.
well in this example the broomstick is pivoting from the centre which is what your axle does untill it reaches one of the bumpstops. it then pivots around that bumpstop.
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Post by bigbluemav »

Hi All

Thanks for the responses. What I was trying to work out was, can I have a (relatively) legal vehicle and run 33's on road, and still have 37-38" play tyres.

Last time I had a 4" spring and 2" body lift, and was ALWAYS paranoid about police and transport dept stooges. This time round I'd like a 3" spring (nearly legal and bullsh*table) and legal 2" body lift.

I'm no suspension engineer, but will a 3" lift have comparable flex to my old 4"? (Swaybars were removed, and will be again!!)

Sorry about the blonky query, but your help/SIMPLE explanations would be greatly appreciated.
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Post by coxy321 »

Its been done a hundred times this week, but my personal opinion is to pick your lift (not 6 or 8 inches, four is PLENTY), pick the right shocks that will allow some decent down travel, limit your compression by extending your bumpstops.

Albeit a different car, i ran 31's daily on my old MK ute, and 37's for play. The car had no spring lift, just 2" bodylift (and yes, body lift sucks b@lls), and cut guards. The only issue i had was the 37's ripped out the front indicators all the time (the ones under the headlights). The 37's fit due to my bumpstops. Looking back, i should have fitted some decent shocks to allow more down travel.
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Post by bigbluemav »

coxy321 wrote:Its been done a hundred times this week, but my personal opinion is to pick your lift (not 6 or 8 inches, four is PLENTY), pick the right shocks that will allow some decent down travel, limit your compression by extending your bumpstops.

Albeit a different car, i ran 31's daily on my old MK ute, and 37's for play. The car had no spring lift, just 2" bodylift (and yes, body lift sucks b@lls), and cut guards. The only issue i had was the 37's ripped out the front indicators all the time (the ones under the headlights). The 37's fit due to my bumpstops. Looking back, i should have fitted some decent shocks to allow more down travel.
I agree!! I must admit that I find it disturbing/amusing hearing about and seeing (spring) lifts of six and eight inches. As I said, previously my old truck had a 4" spring but was TRYING to make it a bit more legal.

If there is DISTINCT and CONSIDERABLE real world difference in offroad performance between a 3" (as I said previously, at least BLUFFABLE that its legal) and 4" lift (the absolute maximum I would EVER go to).

Simply put, what are the advantages of a 4" spring lift over a 2" spring and 2" inch body? I think that frames the question in such a way that I'll get the technical type of answer that I'm chasing!! :D :D :D
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Post by twodiffs »

For a start you won't have the issues that appear with a body lift.
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