“Wide Trail” is a marketing term that means almost nothing. No other tire company uses this term or something similar. Supposedly “Wide Trail” tires are designed for i30-35mm rims but that doesn’t mean they won’t work fine on other rim widths. Any 2.4 tire will reasonably work with i20-35 rims with the center of that range (i25-30 rims) being the best balance of weight vs performance. The Spur comes with “Wide Trail” Dissector and Rekon tires on i25 rims. Many bike companies put 2.4 Maxxis “Wide Trail” tires on i25 rims. I rode 2.4 Maxxis Ardents on i20 rims for many years.
I wouldn’t hesitate to put a 2.6 “Wide Trail” tire on an i25 rim. If I owned an Epic EVO, I would be using a 2.6 Rekon on the front because the 29×2.6 Rekon 60tpi/Dual/EXO/TR/860gm is my all time favorite Trail tire—the perfect balance of grip, weight, rolling resistance, and durability. If a 2.6 Rekon would fit on the back I would put one there also. But, given the rear frame clearance of the Epic EVO, I would probably go for the 2.4 Rekon on the back. However, the 2.4 Dissector on the front is also an excellent choice—slightly more grippy than the 2.6 Rekon and also just a bit slower rolling but similar in durability and weight.
If I bought a new Epic Evo, I would put the stock front tire on the back and just save the stock rear tire for an emergency spare. A 2.6 Rekon or 2.4 Dissector would go on the front. When the stock previously front now rear tire crapped out (which might not be long given how light it is), I would then install a 2.4 Rekon on the rear.
Sorry—maybe too much information—but I’m a tire junkie. I just can’t help myself. In my opinion, getting the perfect tire for where and how you ride is the most important improvement you can can make for your bike. Stock tires are seldom the best tires for where and how you ride. In my opinion, 29×2.4-2.6 tires that weight 825-950gms on i25-30 rims is the ideal setup for Trail riding. For the average Trail rider, this is the sweet spot where flotation, weight, durability, rolling resistance, and grip come together to provide the best riding experience.