So here I am with my shiny new Ryobi 18v ONE+ compressor (thanks, well-meaning relatives!), trying to top off my RV's dual rear tires like a responsible adult. I need to add about 110 PSI, and the front tires are no problem. The inner rear? Also fine. But that outer rear tire with the valve stem pointing toward the center of the rig? That's where my dignity goes to die.
I'm out there doing some kind of yoga pose, contorting myself to hold the regular chuck on the valve stem while simultaneously trying to keep my balance and not drop the hose. I watched another RVer breeze through this same task with some kind of extension that actually LOCKED onto the valve stem - no circus act required!
What is this magical device called, and can I somehow adapt it to work with my portable compressor? I'm tired of looking like I'm trying out for Cirque du Soleil every time I need to add 10 PSI!
You need a "locking chuck extension" or "clip-on chuck extension" that locks onto valve stems without holding. These 6-12 inch extensions can be adapted to most portable compressors with threaded adapters.
Find these on Amazon: Milton S-506 Lever Chuck Extension , Campbell Hausfeld 12-Inch Tire Chuck Extension , Air Hose Adapter Set
What you're looking for is called a "locking chuck" or "snap-on chuck" - specifically a dual-head chuck or straight-through chuck that locks onto the valve stem without needing to be held in place. Yes, you can absolutely adapt this to work with your Ryobi 18v ONE+ compressor. The most common types are the Milton S-506 single-head locking chuck or a Presta/Schrader locking chuck. These thread onto standard 1/4" NPT fittings, so you'll likely need a simple adapter hose or fitting to connect it to your Ryobi's existing chuck connection.
Your Ryobi 18v ONE+ comes with a basic trigger-style chuck that requires constant pressure to maintain the seal on the valve stem. This works fine for easily accessible tires, but creates a real problem for your outer rear dual tire where the valve stem points inward toward the RV frame. The awkward angle and tight space make it nearly impossible to hold that standard chuck firmly in place while the compressor runs.
The professional you observed likely used either a locking chuck (which clamps onto the valve stem and stays put) or a dual-head chuck that can approach the valve from different angles. These professional-grade chucks eliminate the need to manually hold pressure against the valve stem, which is exactly what you need for that difficult-to-reach rear tire position.
Your 160 PSI maximum pressure should handle most RV tires (which typically run 80-130+ PSI, though some large RVs may require 140+ PSI), so the Ryobi will handle the job fine, even if it takes longer than a shop compressor. The auto-shutoff feature will prevent over-pressurization while you're not actively monitoring.
First, examine your Ryobi's air hose connection. Most likely it has a quick-connect fitting or threaded connection where the current chuck attaches. If it's a quick-connect, you'll need a quick-connect to 1/4" NPT adapter. If it's already threaded, measure to confirm it's 1/4" NPT (most common).
Ensure the system is depressurized, then remove the existing chuck by either disconnecting the quick-connect or unscrewing the threaded connection. If threaded, turn counterclockwise while holding the hose steady. Clean any debris from the threads.
For your specific rear tire situation, approach the valve stem straight-on, press the chuck firmly onto the stem until it locks (you'll hear/feel a click), then start your compressor. The chuck will maintain its seal without manual pressure, allowing you to monitor from a comfortable position. When finished, turn off the compressor, wait for pressure to equalize, then release the locking mechanism (typically by pulling back a collar or lever) before removing the chuck.
This is definitely a DIY-friendly modification that most RV owners can handle in 10-15 minutes. However, consider professional help if you discover your Ryobi uses a proprietary connection that doesn't match standard air fittings, or if you're uncomfortable working with threaded air connections.
Also call a tire shop if you find that even with the new chuck, your outer rear tire consistently loses more than 5-10 PSI per month. This could indicate a slow leak in the valve stem, rim, or tire that needs professional diagnosis. Your Ryobi compressor is perfect for maintenance top-offs, but it's not the right tool for dealing with actual tire leaks or major pressure loss.
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