So we've had this 2000 400 4x4 in the family since its been new.
Its been beaten to hell and back and its still going strong.

It has a newer front axle in it (from a 2004 I believe? the original one got water in it and it basically exploded) making it 2/4 selectable.

I know on the internet there are 945,000 threads about tires sizing.

However I'm really wanting some more aggressive tires and I'm wondering a few things:


I have not ever had myself in a scenario where I've needed more ground clearance, but within reason I wouldn't mind going bigger.

• Whats the biggest recommended size on stock rims? stock suspension? stock axles?
  
• I know it affects top speed as well, how much will it affect hill climbing etc?
  
• Width wise, does it really matter if your stray from the stock 'wider in the back' design?

The stock tires have been fine for the most part (Carlisle 489s or Titan something or others, I don't remember). I ride in all sorts of terrain, from rocks to mud to just general trail riding. It gets its fair share of snow use as well.

• Whats a good middle of the ground all-terrain tire?
  
• How much will a really aggressive tire affect trail comfort?
  
  

Lastly, these seem like an amazing deal, but are almost certainly overkill for my wheeler.

With spacers would these be feasible to run?

27x10x12 TSL Vampires

 

With a 400 (376cc) do not get to heavy of a tire. I,d say at most 26" tires and even then get the lightest ones made like Maxxis Zilla.

Its about tire weight. Here is a good site with tire specs like weight and lug depths.
my larger wider Zillas with taller lugs weight as much as smaller 25" thinner Mudlite XLs. ATV Mud Tires : Best ATV Tires

 

i say go with the maxxis zillas in the 25" 24/32" tread depth or if you dont mind some loss in power the 26" 38/32" tread depth. But if you go with even 26s i would put some mod on like a slip on or something just to get the power back.