I would say there are truly only 2 things that you must look for in a wheel/tire set for a Volcano SV - hex size and the distance from the inside edge of the rims to the place where the hex mounts on the wheels.

The stock hexes on the Volcano are 12mm. So you must buy wheels (rims) with a 12mm hex. Or there are hex adapters available to adapt other hex sizes to the 12mm needed for a Volcano. But one way or the other, you need 12mm to mount on the Volcano hexes. And of course, some wheels, like Jato front wheels, do not have hexes as they are for 2 wheel drive vehicles and are not normally driven (powered).

The other thing to watch for is the combination of the wheel width and the offset. If you buy wide wheels and tires, the inside edge of them can hit the hub, steering linkage or other parts of your truck. The stock wheels are 1.8 inches wide with tire width of about 2 5/8". If you buy another set that is the same width, you are pretty safe, but there are wheels that have an unusual offset where the mounting is not in the center of the wheel from inside to outside. If the wheel ends up being 1.8 wide with a tire similar to stock, but it sticks far towards the inside, you can run into the interference issue again. The safest ways to avoid this are (a) go to your LHS where you can test fit, or (b) read through the forums about tires that people have actually put on their Volcanos.

Finally, a couple thoughts about wheel diameter and tire diameter. The stock rims are 2.8 inch diameter. This gives a low profile look that some like. You can use that, or you can use something else. There are many more 2.2 diameter wheels and tires available, and as long as you get the same wheel outside diameter and tire bead diameter so they will go together, you can get whatever you want. My only caution is that the smaller bead diameter increases the chance of the hub or steering linkage running into the wheel. The outside tire diameter is also a matter of choice. The stock tires are about 5" diameter. If you get something smaller, you will accelerate faster and lose top end. If you get bigger something larger, you will lose acceleration and gain top end.

And for what it is worth, I have these rims.

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEW40&P=7]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEW40&P=7[/link]

And these tires.

[link=http://www.losipartshouse.com/servlet/the-26497/LOSA7682B-Fr-fdsh-R-Rock-Claws/Detail]http://www.losipartshouse.com/servlet/the-26497/LOSA7682B-Fr-fdsh-R-Rock-Claws/Detail[/link]

And I got them at the LHS test fitting to be sure. And I am glad I did, because they had an almost identical pair of rims, but they had a different offset and did not fit.

Good luck!

*edited to correct typos*