WheelsCostco's wheels are another seemingly good deal, but there are some drawbacks built in there, too. If you want to buy wheels from Cotsco, you have to order them online. Then, you'll have them shipped to your home.Finally, you have to bring your wheels into Costco to have tires mounted (and bring the tires you want if you don't buy them at Costco). Installation is not free, either; it costs $18.99 per wheel. It's unclear whether you can bring wheels from somewhere else and have Costco tires installed on them, but Velox Wheel is currently Costco's only vendor for wheel orders.With Costco's selection of wheels, it seems like it would be far less work to shop elsewhere, specifically at stores that either have wheels in stock or get them shipped to their retail space. It's unlikely that the cost savings of DIY'ing part of the process is worth it, especially because Costco's wheels aren't the highest performance or flashiest. Ordering online also means you can't check out how the wheels look ahead of purchase.If all of that isn't enough to make you think twice about buying wheels from Costco, many customers complain about the installation service itself. From Costco's staff not reading directions to the finish chipping off during installation, not every buyer was happy after experiencing Costco's custom wheel service.Battery chargersAn automotive battery charger is a handy failsafe to have in your vehicle, but you might want to think twice about tossing Costco's battery charger into your cart during your next shopping trip. Reviews aren't great online for various battery products from Costco. Although the charger products aren't super expensive, there are better options out there.Costco's automotive battery chargers don't perform well or consistently, according to consumer reviews. For example, the UltraPro Elite Smart Battery Charger and Maintainer only costs $50, but offers little functionality and not much peace of mind, either. Consumer complaints say the unit falls apart easily (or arrives broken), the instructions are poor, and the cord is too short to be useful for charging a car battery without an extension cord.For something you might buy on a whim, this product is a bit of a gamble. For that reason, it's reasonable to be wary of other battery products at Costco, too.Battery jumpersBattery products are one of the least predictable things to buy at Costco, based on reviews. Some products receive decent reviews (such as Type S and Michelin products), while others are hit or miss. With a handful of jump starter/power bank products available, Costco doesn't seem to have all the functions dialed in.The portable CAT Cube jump starter, for example, was labeled a piece of junk by various reviewers who complained that it wasn't reliable (with some suspecting they received duds), overheated quickly, and in multiple cases couldn't start a dead battery at all. The complaints on the CAT Cube may reflect more on CAT than Costco, but with few options, it seems like Costco should put more effort into vetting its automotive products.Another less-than-stellar battery jumper comes from Imazing. While its overall rating isn't bad, many Costco shoppers reported various failures with this product, too. The moral of the story? Think twice about buying a battery jumper at Costco, and read reviews at other retailers first. Consider Michelin or UltraPro if the product is a must-have on your shopping list and Costco is your only option.Utility trailersCostco, like other big-box retailers, sells many things that the company doesn't necessarily know much about. Case in point? Costco sells utility trailers, something you wouldn't expect to see parked outside the garden center. Two models (apparently all the retailer has available currently) of Costco utility trailers have poor reviews, and it's not exactly shocking why.Both of Costco's utility trailers are from DK2, so there's no backup option to choose if you're in the market for a trailer and don't have many store options nearby. Despite costing $1,300 and up, the trailers don't have solid reviews and max out around four stars. That may not sound terrible, but for over $1,000, consumers will likely agree it's reasonable to expect a functional product.According to Costco shoppers' reviews, these utility trailers rust easily, the paint coating flakes off, assembly is a hassle (even when the manufacturer includes the right parts), and the hardware has a tendency to arrive damaged or incomplete (missing bearings). Some shoppers also reported issues getting their trailers licensed with their local department of motor vehicles for various reasons.With all of that in mind, even the heartiest DIY'er likely won't want to spend over a thousand dollars to try and piece together a trailer that's meant to be towed at highway speeds — especially one that may or may not include the right parts or withstand a 35 mph drive.Car wash systemsWashing your car can be a chore, but spending a ton of money on a wash system might not make it any easier — at least if you buy one from Costco. If a standard hose and bucket isn't the way you want to go while washing your car, an all-in-one system might sound like a treat. From a power-washing function to special bristle brushes that are gentle on your vehicle, a car washing kit sounds like it would be useful.However, reviewers say Costco's $550 wash system isn't worth the money at all. The system claims to deionize water to remove contaminants, ensuring your vehicle is shiny and not streaky or water-spotted afterward, but most consumers weren't able to reap those apparent benefits. Instead, reviews point out that the accessories do not attach securely, which means a useful life ranging from less than a minute to a few months before failure.The water-softening function seemed to work well, but with so many complaints about the fittings and accessories (leaks are a common theme), it doesn't seem worth the $550 gamble to try Costco's Unger wash system. Another Unger system — this one cheaper at $180 — had many more (and slightly higher-rated) reviews, but the complaints were similar. Consumers called the system "cheap," mentioned how the hoses were "too short," and filter media (which has to be replaced) was "too expensive."