Scroll down to see available tire sizes
Here is a link to our favorite wheel/tire calculator;
This is a awesome web page, I have been building custom cars and 4x4s for many years, and have a large collection of different size wheels and tires that I've used to guestamate the perfect size wheel and tire combo, that I don't use anymore.

​Start with your stock wheel/tire on the left, add your clearances in the "specify your parameters" column. Then you can try different tire and wheel combos on the right. On vehicles with struts I use the Wheelwell Clearance to determine max tire diameter so that the tire will not rub on the
​coil spring perch. 

​www.wheel-size.com/calc/?wheel1=215-75-15X6.5ET5&wheel2=30X9.5-15X6.5ET5&fcl=50mm&wcl=30mm&scl=50mm&sr=0mm

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Astro / Safari Stock Wheel Sizes
1985-2002 Astro/Safari RWD & AWD
Tire 215/75R15, Rim 6.5 x 15 ET5, Bolt Pattern 5x127 (5x5"), Stud Thread 1/2-20 UNF, Center Bore 78.3

2003-2005 Astro/Safari RWD & AWD 
Tire 215/70R16, Rim 6.5 x 16 ET31, Bolt Pattern 6x139.7, Stud Thread 1/2-20 UNF, Center Bore 78.3
235/75R15 & 235/70R16 fits a 6" to 7" wide rim.

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2004-2020 Toyota Sienna FWD & AWD 
Tire 215/65R16, Rim 6.5 x 16 ET50, Bolt Pattern 5x114.3, Stud Thread M12x1.5, Center Bore 60.1
Tire 225/65R17, Rim 6.5 x 17 ET45, Bolt Pattern 5x114.3, Stud Thread M12x1.5, Center Bore 60.1
Tire 235/60R17, Rim 7 or 6.5 x 17 ET45, Bolt Pattern 5x114.3, Stud Thread M12x1.5, Center Bore 60.1
Tire 235/55R18, Rim 7 x 18 ET35, Bolt Pattern 5x114.3, Stud Thread M12x1.5, Center Bore 60.1
Tire 235/50R19, Rim 7 x 19 ET35, Bolt Pattern 5x114.3, Stud Thread M12x1.5, Center Bore 60.1
It's unknown if vans that came with larger diameter wheels had larger brakes and a smaller wheels will interfere.

toyo open country a/t ii available tire sizes

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bfgoodrich all-terrain ko2 - available tire sizes

general grabber at ii - available tire sizes