Buy the G9. For a first machine, for a single car, for modern bodywork full of curves and short panels, the 9 mm tool is the better buy and it is not close: it runs slower when you need slow, it keeps the pad rotating in places the long-throw gives up, and it is the machine this site recommends to beginners for reasons that have nothing to do with price. Buy the G15 if you are correcting whole cars rather than panels, if those cars are trucks, SUVs or anything with large flat surfaces, and if you already know what a working pad looks like on paint.
Everything else about these two machines is the same. Same 6-speed dial, same 10 ft quick-connect cord, same BOSS hook-and-loop pad system, same Griot's guarantee. The whole decision is one published number - 9 mm against 15 mm - and the knock-on effects it has on speed range, backing plate and where the pad will and will not keep turning.
The published numbers
Everything in this table comes from Griot's own product pages for the two machines. We have not measured any of it, and neither tool was in our hands.
| G9 Random Orbital | G15 Long Throw Orbital |
|---|
| Throw | 9 mm | 15 mm |
| Motor | 1,000 W | 1,100 W |
| Speed range | 6 settings, 2,000-6,400 OPM | 6 settings, 3,000-5,300 OPM |
| Backing plate included | 6 in vented orbital | 5 in BOSS fanned orbital |
| Cord | 10 ft quick-connect | 10 ft quick-connect |
Two of those rows surprise people. The long-throw machine has a narrower speed range, and its slowest setting is 50% faster than the G9's. The next section is why, and it is the most useful thing on this page.
What throw length actually changes
On a dual-action polisher the pad does two things at once: it spins on its own axis, and the whole spindle orbits around a second center. The throw is the diameter of that orbit. A 9 mm throw drags the pad through a small circle; a 15 mm throw drags it through a circle nearly twice as wide.
That matters because correction is a function of how much pad travels across how much paint. Multiply the throw by the oscillations per minute and you get a rough measure of pad travel, and the arithmetic explains the speed ranges: a 15 mm orbit at 3,000 OPM moves the pad about as far per minute as a 9 mm orbit at 5,000 OPM. Griot's does not need to offer you 6,400 OPM on the G15, because the throw is already doing that work - and it cannot safely offer you 2,000, because 2,000 OPM on a 15 mm orbit is still a lot of pad movement in a place you may be trying to be gentle.
So the honest summary of a long throw is: more correction per pass, less granularity at the slow end. You buy speed over a hood and you give up control over a mirror cap.
Where the long throw gives up
A DA pad only cuts while it is rotating. Press too hard, run across a tight curve, catch an edge or a raised body line, and the pad stops spinning and just oscillates in place - which is exactly the built-in safety that makes these machines beginner-friendly, and also exactly what it feels like when nothing is happening.
A larger orbit reaches that point sooner, because it needs more flat contact area to keep the rotation going. On a flat hood or a van side, that is irrelevant. On an A-pillar, a bumper return, a wheel-arch curve or the dished area around a door handle, the G15 stalls where the G9 keeps cutting. This is the single most common complaint from people who bought a long throw as a first machine: not that it is unsafe, but that half the car suddenly needs a second, smaller tool.
That second tool is usually a mini. The mini polisher picks cover the class, and Griot's own answer is in the pick list above - a 3 in machine for the areas neither full-size tool handles well.
The backing plates are the tell
Notice that the faster machine ships with the smaller plate: 5 in on the G15 against 6 in on the G9. That pairing is deliberate on Griot's part and it is worth understanding before you order pads.
A long throw already moves a lot of pad. Put a big pad on top of that and you ask the motor to drive a large contact patch through a wide orbit, which is where DA machines bog down and stop rotating under pressure. Keeping the plate smaller preserves rotation and keeps the pad pressure concentrated, which is what actually removes a defect. The practical consequence: on the G15 you should be thinking in 5 in and 5.5 in pads, not the 6.5 in discs a lot of people have in a drawer already. Pads are the real consumable in this hobby, and the matched sets are in best polishing pads for a DA with the size argument made in full in 5 inch vs 6 inch polishing pads.
Which one, for your car
First machine, one car, mixed panels: G9. It is the machine behind our G9 review and the reason it keeps appearing in the best dual-action polisher picks. Slower floor speed means it doubles as a wax and sealant spreader, and the 6 in plate covers ground fast enough on flat areas that most people never feel limited.
Whole-car corrections, large flat panels, repeat work: G15. If you are correcting a pickup or a three-row SUV, or several cars a year, the throw difference compounds into real hours saved. The extra 100 W helps it hold speed when you lean on it, which is when a lesser machine bogs.
Tight modern bodywork, lots of curves: G9, and budget for a mini. Small hatchbacks, sports cars and anything with aggressive creases spend more time in places a 15 mm orbit dislikes than on surfaces where it shines.
Neither, yet, if the paint is not decontaminated. A machine is the third stage of a four-stage job, and the stage people skip is the one before it. If the car has never been clayed, start with the detailing kit picks and the clay options, then buy the machine.
What does not change between them
Both are dual-action machines with the forgiving stall behavior that makes the class safe to learn on, both run Griot's BOSS pads, and both are governed by the same technique: a test spot first, four to six slow passes per section, light pressure, let the pad and the liquid do the work. None of that changes with throw length, and it is covered step by step in how to use a dual-action polisher.
It is also worth saying plainly that the pad and the liquid matter more than the machine does. A G15 running a tired foam pad and a finishing polish will correct less than a G9 running a fresh microfiber cutting pad and a proper compound. If your budget forces a choice, buy the cheaper machine and the better consumables - the category-level version of this argument is in long throw vs short throw polishers, which compares the classes rather than these two specific tools.
Before you order either one
Count your flat panels
Walk around the car and ask how much of it is a surface you could rest a dinner plate on. If the answer is "most of it" - a truck, a van, an older sedan with slab sides - the long throw earns its money. If the answer is "the hood and the roof", the G9 will finish the whole car faster in practice, because it will not stall on the other two-thirds.
Buy the plate and pads together
The included plate sizes differ, so the pads you already own may not be the right size for the machine you are about to buy. Decide the pad diameter first, then order the plate that matches it, then stock three to four pads per stage - a correction pass eats pads faster than beginners expect, and a saturated pad stops cutting.
Do the test spot, whichever you buy
One hidden panel, your full pad-and-liquid combination, inspected under a light before you commit to the car. The machine does not change this and the longer throw makes it more important, not less, because it removes more per pass. A detailing light is what turns a test spot from a guess into a decision.
Do not buy throw length to fix technique
If a correction is not working, the cause is almost never the machine. It is a pad too soft for the defect, a polish that has dried out, too much pressure stalling the rotation, or paint harder than the abrasive. All four are cheaper to fix than a new polisher, and hard paint vs soft paint covers the one people most often miss.
Respect the slow end
If you intend to use one machine for everything, including spreading a sealant or a liquid wax, the G9's 2,000 OPM floor is a real advantage. Applying protection with a machine wants the lowest speed and the softest pad you own; a 3,000 OPM floor on a 15 mm orbit is more movement than that job needs, as waxing a car with a polisher explains.
Budget for the consumables, not just the tool
A polisher is the cheapest part of a correction once you count pads, compound, polish, panel wipe, tape and towels. Plan on the consumables costing a meaningful fraction of the machine on the first job - the full accounting is in DIY detailing cost vs a shop.
