Not for getting help — most road tractors don’t carry spares anymore, and mobile tire techs bring the tire with them. It mostly affects price and choice: with no spare, you’re buying whatever correct-size tire the responding tech stocks, at roadside pricing, rather than paying only for the service call to mount your own.
The economics are straightforward. With a usable spare, the job is labor: mount, torque, check the mate’s pressure. Without one, the job includes the tire itself, and roadside tire inventory skews toward solid mid-tier brands rather than a full menu — the tech’s truck is not a tire shop showroom. If you run premium rubber and care about matching, say so in the request; sometimes a nearby tech has it, and if not, you can choose a serviceable tire now and swap at your preferred shop later.
When RIG puts your tire call in front of the network, bids reflect exactly this: tire included or mount-only, brand on the truck, and the all-in number before anyone rolls. You see it and choose — there is no mystery invoice at the end.