This might help / I would like to chime in with my particular brand of pedantry:
A typical grey wolf requires something like 6-8 pounds of meat a day to live and reproduce and be generally happy. It weighs about 85 pounds. Let’s be generous and round that up to 8 pounds of meat a day for a 100 pound animal.
A wolf the size of a horse (a dire wolf) is going to weigh about 1,000 pounds (let’s be generous, because a Dire Wolf has more HD than a heavy warhorse, which weighs like 1,500-2,000 pounds). Let’s be generous and say that a Dire Wolf needs 80 pounds of meat and fat a day for an average animal of 800-1,000 pounds.
Meat is inherently more difficult to obtain, store, and transport than fodder for horses. An army on the march cannot graze its horses, so the 240gp/unit supply cost for cavalry includes the pounds of dry fodder for horses. An army on the march cannot allow its Dire Wolves to go foraging in the country - not that there would even be enough food for that many wolves of that size.
In ACKS, a pound of meat costs 1sp. That’s 8gp a day to feed a single dire wolf.
8gp a day. That’s 56gp a week per wolf. That’s 3,360gp a week to feed 60 wolves. You also have to feed the Goblins/Hobgoblins and supply them at the base cost of 240 for goblins, water, butchers, what have you. 3,600 a week.
All of this is to say that the base 240gp/week for a unit of cavalry just won’t cut it when it comes to wolves the size of horses.
Do they still seem like a bargain? Probably not.
But wait! We can redo these assuming you get your meat in head of cattle, which are cheaper per pound of meat. That averages to about 2cp per pound of meat. That still adds up to 672gp/week to feed 60 wolves. This is probably what I would do, and then I would add that 240gp base to that cost - have to feed all those cattle. Smooth it out and we get 912gp/week in supply costs for a unit of sixty wolf riders. You still need the base 240 added to that for shepherds and to I’d also rule that if you get defeated, your giant herd of cattle gets captured.
Run the numbers now, assuming a 4 week month:
Cost of a Unit of Heavy Cavalry per month: 3,600 + 240*4 = 4,560gp a month
Cost of a Unit of Wolf Riders per month, using cattle: 900 + 1,152*4 = 5,508gp a month.
Which is… remarkably similar. Fascinating. The wolf riders still make your army more susceptible to disruptions in your cash flow and changes in supply lines.
Of course, those prices assume you can enough head of cattle a month in your local city (Hint: You can’t. You can find 100 a month with a Class I Market as a supply base. That feeds about 625 dire wolves - ten units. A class II Market can support 3 units at that price. A Class III Market can only support a single unit of wolf riders at that price. Basically, Great Goblin Empire can support a limited supply of super-predator mounted cavalry.
If you also deplete your markets of sheep and goats - other animals you can drive, whose meat is more expensive at 3cp a pound, you get about 4 more units in a Class I market, 1 more unit in a class II market, and half a unit in a class III market.)
At a price where you have to source meat at slaughter prices (that’s 1sp a pound), you’re in big trouble.
A unit of wolf riders will cost a shocking: 900 + 3,600*4 = 15,300gp a month.
Let’s take the average of those two weekly costs, though, assuming you can get half your meat from herding cattle (A big assumption): 900 + 2,376*4 = 10,404gp a month. That’s more than twice what a unit of heavy cavalry costs to employ.
I’d like to extrapolate further and find some truly meaningful average that gives us a good supply price for carnivores, but I don’t have the time. Maybe in the future.
TL;DR: If your players insist on hiring legions of wolf riders, I suggest bringing up the increased supply cost that will entail. It probably cost about twice what heavy cavalry cost, once wages and supply are taken into account.
As an aside:
I’d like to point out Wolf Riders’ inferior morale score. Makes a huge difference in play. They’re also irregular cavalry, as Alex has noted.