(Click any picture to enlarge it)

Passenger side of the Micro RS4

Driver's side of the Micro RS4

Rear view of the Micro RS4

Close-up of the front, including the steering and suspension

The stock, removable four-AA battery holder

The Micro RS4, fully assembled, with electronics and Corvette body

Size comparison between the Micro RS4 and the Schumacher Mission

HPI Micro RS4
(reviewed by Darkseid)

URL for Product Info:
  HPI Micro RS4
1/18 Scale 4WD Electric R/C Kit
Street Price: $85-$105 (Varies)
HPI Racing


If you look up fun in the dictionary, there should be a picture of the Micro RS4! Small size, low cost and a nice list of features make this a worth while purchase for any R/C addict. That's before you even mention the long list of hop-ups for the car that seems to grow every day. Not since the Tamiya TAO2 and the more recent Traxxas T/E-Maxx, has a kit inspired so many companies to produce hop up items for it. But, even in stock form, this car is a blast to drive, especially indoors. Let's take a look...

  • Length: 7.9" (200mm)
  • Width: Front: 3.7" to 3.9" (94mm to 100mm), Rear: 3.8" to 4.3" (97mm to 109mm)
  • Wheelbase: 5.5" (140mm) to 5.9" (150mm) (adjustable)
  • Gear Ratio: 4.4:1 to 6.4:1 (adjustable)
  • Tires: Front: 1.1" x .57" (28mm x 14mm); Rear: 1.1" x .68" (28mm x 17mm)
  • Body: Varies by Kit (Corvette)

  • Woven Fibre Chassis (Fiberglass)
  • 4WD Drive Train
  • 180-sized Motor Included
  • Full Ball Bearings
  • Sealed Front Differential; Planetary Gear Rear Differential
  • Three Types of Wheels Included (Mesh, 5-Spoke, 6-Spoke)
  • Foam Front Bumper Included
  • Many Body Styles to Choose From
  • Independent Front Suspension
  • Solid Rear Axle
  • AA or AAA Battery Compatibility
  • High-Traction, Long-Wear Slicks


This was the most fun I have had building a kit, and I've built quite a few of them. It could be the fact that there are so few parts involved, or maybe because I knew this car was going to be just for fun. Either way it was a blast to build. There are only a couple of things that you must watch out for. First off is in Step 1. Tightening the locking nut on the diff side is not as simple as the manual makes it out to be. You must be sure that the diff can rotate freely, but not allowing too much play in the wheel itself. Tightening the nut down all the way, then backing it off one full turn is a good place to start.(that tip from HPI's web site) Take your time here, its an important step. Also be sure that you don't put the wheel guide (on the opposite side of the axle) on too tight, as this could cause the bearings to bind up, and thus the whole rear axle. (There's also a tip about how to avoid putting it on too tight on HPI's web site). Putting a drop of threadlock on the set screw in this step also isn't a bad idea. An ounce of prevention and all that, you know.

The next thing to pay attention to is how you mount your electronics. Using micro sized electronics makes this step easier of course. Even with micro sized electronics, if you're using one of the lower sitting bodies (Corvette or Viper) you still must take note of where you mount things. I was using the Corvette body and had issues with how high the servo and ESC plugs stuck up from my XXL receiver. Moving things around solved the problem though. Step 12 was probably the most difficult step -- and I use the term "difficult" very loosely. You must make sure that the two plastic gears go into the front diff case evenly. To accomplish this, push both gears in from the same side at the same time. Like I said, the term "difficult" is used loosely. Wiring up the Micro is pretty easy with the connectors they include with the kit. I got mine wired up in a few short minutes with a GM V12 speedo. If you have a speed control with Tamiya and bullet connectors, you'll be all set. There are also some speedo's made purposefully to be used in the Micro. If you have one of those, you've got it made. Take note of the warning on Page 17, and be sure your steering isn't hitting your servo. That's about it. There really aren't any "watch out or you'll screw up your whole kit" steps. Its an enjoyable and simple build, even for novice builders.


I tested my Micro at first by running through my living room. I ran it with the smallest pinion which gave some pretty good acceleration. It was a blast dodging table legs and the kids' toys. The car managed to get decent traction on low pile carpeting. It really performed well on industrial office-type carpeting. The ride gets really nice on prepared asphalt or hard floors. Simply put, the car handles just like a 1/10 sedan. The car isn't going to break any land speed records, but it's perfect for indoor racing. Plus there's plenty of speed to be added with optional motors and batteries.

I plan to add a pan chassis, mini servo, 2 or 3 AA cells and a faster motor to mine some time soon. For now though, I am having fun with it in stock form.

The Verdict

I would recommend the Micro to anybody. If you're on the fence about whether to get one or not, do it. You wont be disappointed! It's a fun kit to play around with, or if you're one of those "gotta race everything" people, it has plenty of "way too fast for your own good" potential. I highly, highly, highly suggest that as you build the kit, you have the assembly instructions from HPI's web site up on your computer. They show full color pics of every step and give tips on building the kit. It really helps to see what you're supposed to do, in those few steps that might give you problems. The link to their page is at the top of this review... use it!

  • Small Size
  • Choice of Wheels
  • Huge Selection of Bodies
  • Foam Bumper Included
  • Easy, Enjoyable Build
  • Great Instructions, Including Full Color Build Online
  • Great Handling
  • Amazing Hop up Potential
  • Small Size Inspires Grown Men to Use the Dreaded "c" Word: "cute"
  • Front Diff is a Little Rough
  • Belt Rubs Chassis Slightly
Darkseid's Rating











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