If they aren't an option, it's because they physically won't fit. You can always switch spindles ingame from 8- or 6-lug to 5-lug which has the most amount of wheels available.
the only reason i was asking is because theres a gavril d truggy with huge like 44s on it lol and its still a gavril so i thought it might be possible
Are you talking about the offroad custom D15? Or a mod? If you're talking about the first one, then you most certainly can. Just use the appropriate spindle and select the same wheel. All the configurations of a vehicle are just different arrangements of the same parts, so any part on one D15 config can be used on another. Like this?
yeah the regular gavril d. hmmm. how about changing the tire to anything bigger than a 35? editing the file maybe?im just after big cralwer tires. i have the clearance for it. i never messed with the tire and wheel files. i did once and messed it up lol.