So I'm getting ready for a big RV trip and realized I've never actually looked at my spare tire since I bought this Class C RV. I mean, it's there in the compartment looking all tire-like, but I'm wondering if there's stuff I should be checking?
I keep hearing horror stories about people getting stranded because their spare was useless when they actually needed it. Turns out this happened to me - I discovered my spare was the wrong size (245 75R16 instead of 225 75R16), which could have been a major problem during a blowout.
What's the smart move here for spare tire maintenance? I learned to check not just the tire size, but also the air pressure. Mine was sitting at just 58psi, which thankfully I could fix with my air compressor.
I'd hate to be that person calling for help on the side of the highway! Anyone else have similar experiences?
Verify your RV spare tire is correct size and properly inflated before every trip. Tire shops sometimes install wrong sizes. Check pressure regularly as spares lose air.
Chris, you've learned an expensive lesson that many RV owners discover too late - tire shops can and do make mistakes with spare tire sizes, even when you're buying a complete set. Your experience with the 245/75R16 spare instead of the correct 225/75R16 for your Class C is unfortunately more common than it should be. The good news is you handled it perfectly by going back to the original shop and getting a free replacement. Your reminder is spot-on: every RV owner should verify their spare tire size and pressure immediately, regardless of how recently they bought their tires.
Tire shop errors with RV spares happen for several reasons. Many shops aren't familiar with RV-specific tire requirements and may grab the "closest" size from their inventory when mounting your spare. Class C RVs in particular can have confusing tire specifications because the front tires sometimes differ from the rear tires, and shops may accidentally match the spare to the wrong axle. Additionally, some shops use automated systems that might suggest a "compatible" size rather than the exact match.
The low pressure issue you experienced at 58 PSI is also typical - spare tires lose about 1-2 PSI per month just sitting there. Most Class C RVs require 75-80 PSI for their tires (though this varies by model and load rating - always verify against your specific RV's tire placard), so your spare was dangerously underinflated. Underinflated spares can fail catastrophically when you need them most, especially when they're suddenly loaded with the full weight of your RV.
To properly check your spare tire, you'll need a few essential tools. First, get a quality tire pressure gauge rated for at least 100 PSI - the cheap gauges from gas stations aren't accurate enough for RV tires. A digital gauge like the JACO ElitePro Digital Tire Pressure Gauge (around $25) is worth the investment. You'll also need a reliable 12V air compressor capable of reaching 80+ PSI, like the Viair 00088 88P Portable Air Compressor (about $60-80).
Keep a tire tread depth gauge handy to check spare tire condition, along with a flashlight or headlamp for inspecting the tire in your spare tire compartment. A tire crayon or permanent marker will help you mark the date when you last checked the pressure. Finally, have your RV's manual or a photo of the tire information placard that shows the correct tire size and pressure specifications.
Start by locating your spare tire - on Class C RVs, it's typically mounted underneath the rear or on the back of the vehicle. Before removing it, ensure you're parked on level ground, engage the parking brake, and use wheel chocks on the opposite end of the RV for safety. Then remove the spare completely from its mounting system so you can inspect it thoroughly. Check the sidewall markings against your other tires to confirm the size matches exactly. In your case, all tires should read 225/75R16, not 245/75R16.
Next, inspect the spare's overall condition. Look for cracks, bulges, or weathering in the sidewall rubber. Check the tread depth - even though it's a spare, it shouldn't be significantly more worn than your road tires if they were all purchased together. Examine the mounting hardware and spare tire carrier for rust, damage, or loose bolts that could cause problems when you need to deploy it quickly.
Check and adjust the tire pressure using your quality gauge. Class C RVs typically require 75-80 PSI for rear tires, but you must verify the exact pressure against your specific RV's tire placard as this varies by model and load rating. Inflate to the exact recommended pressure specified by the manufacturer. Write the date you checked it with a tire crayon so you'll remember to check again monthly (since tires lose 1-2 PSI per month as mentioned earlier).
Finally, practice removing and reinstalling your spare tire when you're not under pressure. Many RV owners discover their spare tire tools are missing, rusted, or inadequate only when they have a roadside emergency. Make sure your jack is rated for your RV's weight and that you have all the necessary tools easily accessible.
If you discover your spare is the wrong size like Chris did, take it back to the original tire shop immediately with your receipt and demand a free replacement - this is clearly their error. Most reputable shops will make it right, especially when you have proof of purchase. If they refuse, contact your credit card company if you paid by card, as many offer purchase protection for defective products.
Call a professional if your spare tire carrier mechanism is damaged, rusted, or won't release properly. These systems are safety-critical and need to work reliably in an emergency. Also seek professional help if your spare shows signs of sidewall damage or unusual wear patterns that suggest storage issues. Finally, if you're not comfortable with the physical demands of changing a tire on your Class C (they're heavy and the RV is tall), consider subscribing to a roadside assistance service that specializes in RVs, like Coach-Net or Good Sam Emergency Road Service.
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