By Mike Garrison
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Racing success in 17.5-turn spec classes requires a combination of skill and consistency on part of the driver, and equipment that is set up to squeeze every ounce of legal power out of your car. There are many ways to go about making a stock-class car faster, like aluminum drivetrain parts, ceramic bearings, lightweight chassis components, and direct-drive slipper eliminators. Since all cars must meet a minimum weight requirement, reducing rotating weight is of paramount concern - which is why 175RC.com introduced its new PolyPro hybrid pinion gears. The idea of replacing a heavy-duty steel or aluminum pinion gear with a thin piece of plastic seemed ludicrous and, in my mind, was just asking for trouble. I’ve been asked a lot about the PolyPro pinions, and despite my preconceived thoughts, I decided it was time to try one out and see what the hype was really all about.
175RC.com PolyPro Hybrid Pinion Gear
Available in 26T-33T, $4.49 each
The 175RC.com PolyPro Hybrid Pinion Gears are made of a machined aluminum hub and a non-slip, molded polymer gear. The pinion is considerably thinner than a standard metal spur gear, which is designed to not only eliminate weight, but reduce friction and allow you to simply reposition it to find a fresh spot on the spur gear if the teeth get damaged or worn - as opposed to having to replace the entire spur gear. The pinion gears are not labeled with the number of teeth, but rather color-coded with each distinct size being a different color gear. Each pinion gear also includes the necessary set screw to hold the pinion securely on the motor shaft.
For testing, I headed to Fastlane Raceway in Blue Springs, Missouri - which hosts a variety of events including the JConcepts Winter Indoor Shootout and Invitational, Offroad JAM, ROAR Regionals, and many more. The indoor track held their weekly club race, and I decided to test these pinion gears in a real-world racing environment. I chose to equip my Tekin GEN3 17.5 and RS Gen 2 ESC-powered TLR 22 3.0 buggy with the green 30-tooth pinion. For extra track time, I entered the 17.5 Buggy and 13.5 Buggy classes using the same 17.5-powered, PolyPro-equipped buggy in both. I broke out the digital scale when changing pinion gears and found that the steel 30-tooth pinion gear that came off my car weighs 7.7 grams, while the PolyPro pinion gear tips the scales at a mind-blowing .9 grams. The loss of nearly 7 grams by just changing pinions was quite impressive, but could it hold up to the rigors of racing? And would it make a difference?
Setting gear mesh with the PolyPro pinion installed requires the same process as with any other pinion gear, with backlash that's neither too tight nor too loose. On the track, the first noticeable difference using the PolyPro gear was the sound my car made. The gear is slightly quieter than metal pinion gears, but puts off a very powerful, higher-pitched “zinging” sound – similar to the sound that faster modified motors often make. Instantly the car sounded faster, but it was time to see if it was going to actually go faster.
175RC.com claims the gear provides quicker RPM. While I did not dyno test this theory, on the track I did notice a slightly quicker feel when accelerating out of the corners. I ran the PolyPro pinion back-to-back with my traditional pinion gear throughout qualifying and the mains. Track conditions remained the same for both classes throughout the night, and while I only slightly noticed a difference in how the car felt when driving my fastest lap times were .4-.6 seconds faster every run with the PolyPro pinion over the steel pinion gear. That doesn’t sound like much, but over the course of a five-minute race on a track with 14-second lap times that is nearly 9 seconds faster. Surprisingly, the lighter gear didn't seem to make any difference at all on the motor's running temperature.
Because I was very skeptical of the durability of a such a thin, plastic pinion gear, I tried to break it. I tried hard. I panic-revved every jump I could and landed with full throttle. I dialed my brakes up to 100% and locked them up repeatedly at the end of a full-length straightaway. I even punched the throttle while stuck in the pipe. I achieved a crunchy diff and broke the bead loose on one of my rear tires, but I failed to damage or break the PolyPro pinion gear in any way.
- Super lightweight – weighs less than 1 gram
- Color coded for easy identification
- Less expensive than most metal pinion gears
- Thin design allows you re-position on the spur gear to extend the spur gear’s lifespan
- Provides quicker acceleration
- There are truly no drawbacks.
I was wrong to assume anything negative about the 175RC.com PolyPro Hybrid pinion gears. For 17.5-class racing, these little items are a valuable piece of the puzzle for those looking to go as fast as possible. The PolyPro pinion gears shave as much as 7 grams of weight, significantly reducing the mass your motor has to rotate, which increases acceleration. They are less expensive than most metal pinion gears, and they produced an immediate and measurable improvement in my lap times. At some point, the polymer gear may wear and become weaker than a traditional metal pinion gear, but I have yet to find that point. There are a lot of products that claim to be a “must have for stock racing” but this is one of the few that I feel is worthy of that title.
Beacon Rating: 5 out of 5