tyre sizes

When putting on larger tyres I would consider the extra pressure you would be putting on your wheel bearings----------not an issue if it's just 'around town' tho.Glenn.

Nick
Why don't you consult a tyre dealer?

Cheers
Ed

Depends what you mean by 'scrub'. If you mean uneven wear then that is a wheel alignment issue. According to VSB14 you are allowed to increase the width by 30% more than the manufacturers widest option on the tyre placard and you are allowed to increase the diameter up to 15mm provided:
The tyres are contained within the guards (or flares)
They don't contact any part of the vehicle t/out full suspension and steering travel.
If using different offset rims you don't increase the track by more than 25mm
Refer: http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/pdf/NCOP11_Section_LS_Tyres_Suspension_Steering_V2_1Jan_2011%20v3.pdf

Anything over 50mm bigger than stock is illegal, 33 fit into this category.
The bigger tyres if wider will cost you in fuel usage.
The tyres if biigger dia will cost you in fuel usage.
Makes the clutch work harder if a manual. Auto develops more heat in oil.
The give less braking force applied to the road surface. Cannot stop as quickly.
They reduce the climbing ability, as there is a lack of/less torque developed at the tyre/road surface. Less pull.
Lowers towing ability.

Give a bit more ground clearance.
Bigger tyres you will need exhaust and power mods. Shortens life of engine.

If greater offset rims are used they try to snap off the ball joints, particularly the top ones and make them work sideways instead of into the "cup" of the ball joint. Expect to be replacing top ball joints more often.
Flogs out tie rod ends and makes the rack and pinion get a belting because of the offset isn't even close to inline with the steering ball joint axis.
Makes the load on the wheel bearings more on the small outer bearing instead of being centrally positioned over the larger inner bearing.
Off road use means the larger tyre will grip more and if spinning will stop quickly when it touches after free spinning and the CV's break, unless you are careful with the No.10.

Everything in moderation.

Hi Nick,

If you're after some decent tyres (maybe M/T) then there are brands that make such tyres in sizes close to your stock ones (I presume 245/70R16).

I have to say I'm not a fan of large aftermarket tyres. I've seen what big rubber can do to CV's, diffs and drivetrains etc on vehicles with much heavier running gear than your Colorado. Also your Colorado has IFS - that means an extra set of CVs to worry about. Forget about the 33's mate. 245/75 or maybe 255's would the better option. Closer to your current tyre diameter, no scrubbing on the wheel arches. Go for LT construction.

Cheers,

Tim.

Geeze, a lot of doom and gloom above!

But I agree 33's are a bit big for a Colorado. They are a great size on a 70series or Patrol. I'll assume you're wanting to run 16" wheels that are 7" wide.

Alternatives:
235/85R16 - these are a great offroad tyre size because they have a 32" diameter but are less likely to hit the chassis and guards because they are not as wide. But they do alter the gearing a lot - you'll lose power on he highway because of the gearing. I have no knowledge of how they go on your Colorado.
245/75R16 - these are a 31" diameter tyre that are available in a huge range of brands with LT construction. This size suits the majority of colorado size utes fitted with 7" wide rims.

There are a lot of advantages of larger diameter tyres that are not stated in the above posts.
The extra clearance is worth heaps because it prevents you bottoming out in ruts
The extra diameter is worth heaps because you get a longer footprint that keeps you afloat in sand and mud and
When it comes to fuel consumption, you are often better off in the soft sand/ boggy situations - sure you'll use more fuel on the highway but offroad, when you want better consumption then the bigger tyres deliver.