[suzi-fan-22]

what are all the diff ratio's that will fit in a sierra wt 89 model
doing a centre swap cause its like reduction gears

[JrZook]

suzi-fan-22 wrote:

what are all the diff ratio's that will fit in a sierra wt 89 model
doing a centre swap cause its like reduction gears

Easiest and most available is the NT 3.9 centers. What tyres do you run? Unless there excessivily big transfercase gears are the way to go both on/off road

[Bruce]

It's nothing like fitting reduction gears. But better than nothing.

[suzi-fan-22]

bout to ru 30's have worked out need 4.1:1 ratio what diff centers are these?
i allready know that 1lt diffs fit
but i cant find any anywere

[303zuke]

suzi-fan-22 wrote:

what are all the diff ratio's that will fit in a sierra wt 89 model?
bout to run 30's have worked out need 4.1:1 ratio.
i allready know that 1lt diffs fit
but i cant find any anywere

If you know that 1.0lt diffs will fit in your 89 WT, then it's no point anyone on here telling you THEY WON'T!

If you think swapping diffs are just like fitting reduction gears (only more expensive and less effective), then you shouldn't consider 4.16 gears (1.580 Hi, 4.16 Lo). Put those figures in your calculator compared to 4.11 diffs.

[inbits]

1 ltr diffs dont fit only the rare maruti wide track 4.1 centers fit.
you can fit front vitara gears they come in 4.6 and 5.12 not sure but i think thers 4.8 aswell

[Gwagensteve]

Diff gears are nothingnothingnothing like transfer gears.

Diff gears can be used for correcting a tyre size on road, but will add very little to your off road gearing.

You can use 4.1 diff gears in a WT sierra, from the rear of a jimny ( which are apparently made from glass) or a late model Maruti (apparently)

But you don't want to. You want 4.1 transfer gears. Leave your diffs stock.

Steve.

[suzi-fan-22]

righto great advise from EVERYONE thanks!
decided to go for 4.16:1 reduction gears
but how much and where from just some guesstamtions or rough figures would be great.

i live in ipswich QLD so just anywhere close to that would be lovely


thanks! heaps

[303zuke]

Lowrange Offroad will post to your door. Just ask for cheapest shipping option, takes about a week to 10 days.

[joeblow]

Gwagensteve wrote:

Diff gears are nothingnothingnothing like transfer gears.

Diff gears can be used for correcting a tyre size on road, but will add very little to your off road gearing.

fuck you dribble shit a lot of the time.

diff gears will correct on road gearing and give you heaps better off road gearing too, not as much as t/case gears gears but plenty enough for you to drive off road with confidence. diff gears also don't have a tendancy to shag t case mounts out and other driveline components in a hurry.

[Fatzook]

[Gwagensteve]

Lets look at some figures.

Speed @ peak torque in 1st low with 26's and stock diff gears = 13.18km/h

Speed @ peak torque in 1st low with 30's and 4.1 diff gears = 15.2km/h

Cruise revs 26" tyres, 3.7diff gears, 100km/h, 5th= 3475rpm

Cruise revs with 30's, 4.1 diff gears, 100km/h, 5th= 3337rpm


So a sierra with 4.1's in the diffs and 30's is taller geared both on and off road than stock. That's not really an improvement in my opinion.

The next available next diff gear step is 4.3

@ peak torque in 1st low with 30's and 4.1 diff gears, speed = 14.5km/hr
Cruise revs with 30's, 4.3 diff gears, 100km/h, 5th= 3500rpm

Gearing is still taller off road, but spot on on road.

Above that, it's diminishing returns for off road performance.

Just to prove the point:

4.6 diff gears,

@ peak torque in 1st low with 30's and 4.6 diff gears, speed = 13.55km/hr
Cruise revs with 30's, 4.6 diff gears, 100km/h, 5th= 3744rpm

4.88 diff gears

@ peak torque in 1st low with 30's and 4.88 diff gears, speed = 12.77km/hr
Cruise revs with 30's, 4.88 diff gears, 100km/h, 5th= 3972rpm

and finally, 5.12

@ peak torque in 1st low with 30's and 5.12 diff gears, speed = 12.17km/hr
Cruise revs with 30's, 4.88 diff gears, 100km/h, 5th= 4168rpm

I don't think diff gears are a good way of improving off road gearing, and that's why. To gain slightly improved off road gearing once tyres are taken into account, your cruise revs are murdered, and car becomes less useable.

Anyway, to compare with stock diffs and 4.1 transfer gears:

Speed @ peak torque in 1st low with 30's and 4.1 transfer gears = 9.08km/h
Cruise revs with 30's, 4.1 transfer gears, stock diff gears 100km/h, 5th= 3313rpm

You be the judge of where the money is better spent.

Steve.

Never mind though, I'm just dribbling shit.

[suzi-fan-22]

Gwagensteve wrote:

Lets look at some figures.

Speed @ peak torque in 1st low with 26's and stock diff gears = 13.18km/h

Speed @ peak torque in 1st low with 30's and 4.1 diff gears = 15.2km/h

Cruise revs 26" tyres, 3.7diff gears, 100km/h, 5th= 3475rpm

Cruise revs with 30's, 4.1 diff gears, 100km/h, 5th= 3337rpm


So a sierra with 4.1's in the diffs and 30's is taller geared both on and off road than stock. That's not really an improvement in my opinion.

The next available next diff gear step is 4.3

@ peak torque in 1st low with 30's and 4.1 diff gears, speed = 14.5km/hr
Cruise revs with 30's, 4.3 diff gears, 100km/h, 5th= 3500rpm

Gearing is still taller off road, but spot on on road.

Above that, it's diminishing returns for off road performance.

Just to prove the point:

4.6 diff gears,

@ peak torque in 1st low with 30's and 4.6 diff gears, speed = 13.55km/hr
Cruise revs with 30's, 4.6 diff gears, 100km/h, 5th= 3744rpm

4.88 diff gears

@ peak torque in 1st low with 30's and 4.88 diff gears, speed = 12.77km/hr
Cruise revs with 30's, 4.88 diff gears, 100km/h, 5th= 3972rpm

and finally, 5.12

@ peak torque in 1st low with 30's and 5.12 diff gears, speed = 12.17km/hr
Cruise revs with 30's, 4.88 diff gears, 100km/h, 5th= 4168rpm

I don't think diff gears are a good way of improving off road gearing, and that's why. To gain slightly improved off road gearing once tyres are taken into account, your cruise revs are murdered, and car becomes less useable.

Anyway, to compare with stock diffs and 4.1 transfer gears:

Speed @ peak torque in 1st low with 30's and 4.1 transfer gears = 9.08km/h
Cruise revs with 30's, 4.1 transfer gears, stock diff gears 100km/h, 5th= 3313rpm

You be the judge of where the money is better spent.

Steve.

Never mind though, I'm just dribbling shit.

i worked out that the 30'' tyres where going to take my high range up 12% and the thats the same as 4.16 t/ gears and i put the tyres on with no gear changes and it takes off the same just the speedo is out and the brakes dont work as good but there is more grip and the steering is lighter

[Gwagensteve]

What does that mean suzi-fan?

Steve.

[steak_knife]

Gwagensteve wrote:

What does that mean suzi-fan?

Steve.

he said soup's up..

[303zuke]

[quote="suzi-fan-22] i worked out that the 30'' tyres where going to take my high range up 12% and the thats the same as 4.16 t/ gears and i put the tyres on with no gear changes and it takes off the same just the speedo is out and the brakes dont work as good but there is more grip and the steering is lighter[/quote]

That's the other advantage of transfer gears over diff gears, your speedo will be corrected by the same amount in both Hi and Lo ratios, whereas diff gears won't correct your speedo.

[atari4x4]

i changed my diff ratio's from 4.6 to 5.1 & it fixed my speedo in both hi & low range?

[DMAC]

303zuke wrote:

[quote="suzi-fan-22] i worked out that the 30'' tyres where going to take my high range up 12% and the thats the same as 4.16 t/ gears and i put the tyres on with no gear changes and it takes off the same just the speedo is out and the brakes dont work as good but there is more grip and the steering is lighter

That's the other advantage of transfer gears over diff gears, your speedo will be corrected by the same amount in both Hi and Lo ratios, whereas diff gears won't correct your speedo.[/quote]



How?
Transfercase gears will not correct your speedo. The relationship between the tailshaft and axles is not altered with transfer case gears. It is only altered by changing diff ratios.

[DMAC]

atari4x4 wrote:

i changed my diff ratio's from 4.6 to 5.1 & it fixed my speedo in both hi & low range?

Ah ha. Proof. Wheel circumference must have been 11% larger.

[atari4x4]

DMAC wrote:

atari4x4 wrote:

i changed my diff ratio's from 4.6 to 5.1 & it fixed my speedo in both hi & low range?

Ah ha. Proof. Wheel circumference must have been 11% larger.

stock was a 215/65/r16 (27's) & i'm now on 31's & my speedo is spot on.

[DMAC]

atari4x4 wrote:

DMAC wrote:

atari4x4 wrote:

i changed my diff ratio's from 4.6 to 5.1 & it fixed my speedo in both hi & low range?

Ah ha. Proof. Wheel circumference must have been 11% larger.

stock was a 215/65/r16 (27's) & i'm now on 31's & my speedo is spot on.

Thats a 14.8% change in true wheel circumference so if you take into account the little flat bit at the bottom of the tyre sounds like it would be pretty close to fixing it up nicely.

[303zuke]

DMAC wrote:

303zuke wrote:

[quote="suzi-fan-22] i worked out that the 30'' tyres where going to take my high range up 12% and the thats the same as 4.16 t/ gears and i put the tyres on with no gear changes and it takes off the same just the speedo is out

That's the other advantage of transfer gears over diff gears, your speedo will be corrected by the same amount in both Hi and Lo ratios, whereas diff gears won't correct your speedo.

How?
Transfercase gears will not correct your speedo. [/quote]

D'oh! What was I thinking?? Brain fade there. You are of course right.

[DMAC]

At least we didn't get into how a diff works thats always funny.