Ryobi 18V high pressure inflator (P737D), tested

The P737D is the cheapest honest way onto a tool-battery inflator, and honest is the word that matters. It took 1:47 to move our reference 205/55R16 from 28 to 36 PSI — thirty-nine seconds behind the Milwaukee M12 and still more than twice as fast as any 12V plug-in unit — and its digital auto-stop landed within a PSI of our calibrated reference at all three checkpoints. What you give up for the bare-tool price is build quality and noise: 81 dB from a housing that flexes when you squeeze it. For a DIYer already on ONE+, that trade is close to a formality.

Three runs put the spread at about seven seconds, which is wider than the Milwaukee's four but tight enough that 1:47 is a number you can plan around. Practically, that is a full set of four tires topped up in about seven minutes of pump time, against roughly four and a half for the M12 and closer to twenty for a budget 12V unit. Our protocol — same mounted tire, same reference gauge, median of three — is documented on the how we test page.

The gauge is the pleasant surprise. We expected the usual budget behaviour of reading well at 32 PSI and wandering above it; instead the P737D stayed inside a PSI at 20, 32, and 50, with no directional bias we could pin down. It is not the half-PSI precision of the M12 or the M18, but it is better than the Craftsman V20 and better than several units costing twice as much. Full error table for all 22 models: how accurate are tire inflator gauges.

Five complete fills from a 4Ah pack is one more than the M12 manages on the same nominal capacity, which reflects Ryobi's larger 18V cells rather than any efficiency advantage — the tool is slower and takes longer per fill, but the pack is doing more work overall. For the monthly four-tire top-up, one battery covers several months of use.

At 81 dB it is one of the noisier tool-battery units, and the character is worse than the number suggests: a higher-pitched, buzzier note than Milwaukee's steady whirr, with an audible vibration through whatever surface it sits on. If noise is the deciding factor, our measured dB ranking is in best quiet tire inflators.

The P737D looks and feels like the ONE+ line it belongs to: green plastic, a big moulded handle, a broad flat base that keeps it upright on a driveway. There is a genuinely useful onboard nozzle store for the Presta adapter, needle, and cone, and the hose wraps into a channel that actually holds it.

Controls are a two-button pressure setter and a start trigger, with a small backlit LCD. The auto-stop works exactly as advertised — set 36, walk away, come back to 36 within a PSI. The screw-on chuck is plastic-bodied with a brass insert, which is where the cost-cutting first shows: it threads on fine but does not have the reassuring bite of Milwaukee's all-brass fitting, and cross-threading it in the cold is easier than it should be.

The housing is the other place the price lives. Squeeze the body and it gives; the battery interface has a little more play than a premium tool; the hose is a softer rubber that takes a set after being coiled for months. None of that has caused a failure on our unit, and Ryobi's ONE+ warranty is not stingy — but this is a consumer tool, and a jobsite drop that an M12 would shrug off is a real risk here. Basic care that extends its life is covered in tire inflator maintenance.

Buy it if you already own ONE+ batteries. That is the whole thesis, and it is a strong one: ONE+ is the most widely owned battery platform in American garages, the bare tool is regularly among the cheapest cordless inflators of any kind, and the performance gap to premium tools is smaller than the price gap. It is our value pick in best cordless inflators and it earns its place there on the bare-tool price alone. The 150 PSI ceiling also means it can handle a light-truck tire at 50–65 PSI, which the 120 PSI M12 does slowly.

Who should skip it: anyone with no Ryobi batteries — buying into ONE+ for an inflator alone makes no financial sense, and a good 12V or USB-C unit from the under-$50 ranking will serve you better. Skip it if you need half-PSI gauge precision for motorcycle or track work, skip it if noise matters, and skip it if the tool will live on a jobsite where it gets dropped weekly. Trailer and RV owners should also look higher up the range: 1:47 on a car tire scales badly to 80→100 PSI work, and RV inflators is the right department.

The comparison everyone actually makes is against the Milwaukee M12, and the shorthand is roughly half the price for about 80% of the performance. The 20% lives in three places: thirty-nine seconds of fill time, half a PSI of gauge certainty, and a housing that will still be tight in ten years. Milwaukee also wins on noise, weight, and chuck quality; Ryobi wins on max pressure (150 versus 120) and on tires per charge.

We put numbers on all of it in Ryobi vs Milwaukee. The short version: if you own batteries on one platform and not the other, buy that platform's inflator and ignore the comparison entirely — the battery you already own is worth more than the performance difference. If you own neither, the decision is about the rest of the tool line you intend to buy, not about the inflator. And if you are still deciding whether cordless is the right category at all, cordless vs 12V settles that first.