[Glavas]

I imagine this would have been covered about a thousand times, but searching I cannot for the love of me find it.

I understand my gearing with 30" muddies is going to be affected. How bad?

What options do I have to return it to factory or better?

Also

Where can I find the workshop manual? I swear I found it on AZ before, favourited it, but I've recently swapped to a new browser and can't find it

[atari4x4]

try here for the manual Aleks: http://www.suzukiinfo.com/

not 100% sure about the gearing with the sierra but there are heaps of people running transfer gears, you can do a diff ratio swap but transfer gears are easier.

[alien]

standard tyres are 26", so a 30" is 115.4% larger - this means:
40km/hr = 46.2
50km/hr = 57.7
60km/hr = 69.24
...etc - all the way to 100 = 115!

the same ratio goes for your rpm too... so if at 60 in 4th you're doing 2500rpm on 205/75's, on 30" youd be doing around 2100rpm.

for a 30" tyre, a 4.16 or 4.9 gearset would bring you nicely back to good gearing: http://www.lowrangeoffroad.com/index.ph ... -case.html

[whincup]

expect to use more right foot taking off, more left foot while offroad and slower on the highways... worth it for the improvement though right

[Glavas]

4.9 would be better creeping in low also wouldn't it?

Brilliant link. However, why does the 4.9:1 kit cost $525 and the 4.9:1 box only $160?

[atari4x4]

you missed the "from" $160 bit click on each product & see whats available.

http://www.lowrangeoffroad.com/index.ph ... cases.html

[Glavas]

Screw that I'll buy a second hand transfer, rebuild it with the gears and I'll chuck it in!

It occurred to me that the $160 is probably labour! lol.

Thanks for the help boys!

[atari4x4]

you will also want to look at some sort of upgraded mounting system.

[lump_a_charcoal]

I vote for the mighty kong - It is a skid plate too.

[shandy92]

alien wrote:

the same ratio goes for your rpm too... so if at 60 in 4th you're doing 2500rpm on 205/75's, on 30" youd be doing around 2100rpm.

i never thought this was right, as the RPM is run of the coil not something in the drivetrain. not saying ur wrong alien just thats what i was always told.

anyone confirm?

Mitch

[atari4x4]

shandy92 wrote:

alien wrote:

the same ratio goes for your rpm too... so if at 60 in 4th you're doing 2500rpm on 205/75's, on 30" youd be doing around 2100rpm.

i never thought this was right, as the RPM is run of the coil not something in the drivetrain. not saying ur wrong alien just thats what i was always told.

anyone confirm?

Mitch

bigger tyres affect gearing which in turn affects speed & rpm.

eg: a larger tyre require less revolutions per minute than smaller tyres to do the same speed.

[alien]

think of it this way mitch... take a CD, put a texta in the center of it - now rotate the texta until the cd has completed one full spin - notice how the distance the cd travels is quite a long way? Now take the texta out and roll that one full rotation - it doesn't go far at all...

the texta is your axle, the cd is your wheel - for the "axle sized wheel" to travel the distance of the cd at the same speed as the cd, the axle sized wheel is going to make many more rotations at a much higher speed (rpm) to keep up with the CD, which is doing a far lower rpm to achieve the same speed.

the difference however comes in the power delivery to that wheel... engines dont like operating below 1000rpm, and good power and economy comes after 2500rpm to around 3400rpm... gearing gets the given tyre size into that sweet spot. changing the size of the tyre throws this out of whack

[shandy92]

thanks for that alien and atari

i knew that tyres put out the gearing, i just didnt think the rpm changed.

cheers
Mitch

[JrZook]

shandy92 wrote:

thanks for that alien and atari

i knew that tyres put out the gearing, i just didnt think the rpm changed.

cheers
Mitch

RPM x Gearing X tire diameter = speed

Their all related, for the same speed at an increased tire diameter and no gearing alternations the RPM will have to decrease to satisfy the above formula.

Dan